CONFIRMING DIAGNOSIS Although signs of respiratory distress in a premature neonate during the first few hours of life strongly suggest IRDS, a chest X-ray and arterial blood gas (ABG) analysis are necessary to confirm the diagnosis.
❑ Chest X-ray may be normal for the first 6 to 12 hours (in 50% of neonates with IRDS), but 24 hours after birth it will show the characteristic ground-glass appearance and air bronchograms.
❑ ABG analysis shows decreased partial pressure of arterial oxygen; normal, decreased, or increased partial pressure of arterial carbon dioxide; and decreased pH (from respiratory or metabolic acidosis or both).
❑ Chest auscultation reveals normal or diminished air entry and crackles (rare in early stages).
When a cesarean delivery is necessary before 36 weeks’ gestation, amniocentesis enables the determination of the lecithin/sphingomyelin (L/S) ratio and the presence of phosphatidylglycerol. An L/S ratio of more than 2:1 and the presence of phosphatidylglycerol decrease the likelihood of IRDS.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Respiratory syncytial virus infection:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Diagnosis is usually based on clinical findings and epidemiologic information.
❑Many facilities can perform rapid tests for the virus using fluid obtained from the nose.
❑Cultures of nasal and pharyngeal secretions may show RSV; however, the virus is labile, so cultures aren't always reliable.
❑Chest X-rays help detect pneumonia.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Introduction: Respiratory Disorders:
Diagnostic tests
(Professional Guide to Diseases (Eighth Edition))
Diagnostic tests evaluate physiologic characteristics and pathologic states within the respiratory tract.
Noninvasive tests include:
❑ Chest X-ray shows such conditions as atelectasis, pleural effusion, infiltrates, pneumothorax, lesions, mediastinal shifts, pulmonary edema, and chronic obstructive pulmonary disease (COPD).
❑ Computed tomography scan provides a three-dimensional picture that’s 100 times more sensitive than a chest X-ray.
❑ Magnetic resonance imaging identifies obstructed arteries and tissue perfusion, but movement of the heart and lungs reduces the image’s clarity.
❑ Sputum specimen analysis assesses sputum quantity, color, viscosity, and odor; microbiological stains and culture of sputum can identify infectious organisms; and cytologic preparations can detect respiratory tract neoplasms. Sensitivity tests determine antibiotic sensitivity and resistance.
❑ Pulmonary function tests measure lung volume, flow rates, and compliance. Normal values, individualized by body stature and age, are reported in percentage of the normal predicted value. Static measurements are volume measurements that include tidal volume, volume of air contained in a normal breath; functional residual capacity, volume of air remaining in the lungs after normal expiration; vital capacity, volume of air that can be exhaled after maximal inspiration; residual volume, air remaining in the lungs after maximal expiration; and total lung capacity (TLC), volume of air in the lungs after maximal inspiration. Dynamic measurements characterize the movement of air into and out of the lungs and show changes in lung mechanics. They include measurement of forced expiratory volume in 1 second, maximum volume of air that can be expired in 1 second from total lung capacity; maximal voluntary ventilation, volume of air that can be expired in 1 minute with the patient’s maximum voluntary effort; and forced vital capacity, maximal volume of air that the patient can exhale from TLC. (Peak flow rate, which can be obtained at the bedside, is also a dynamic measurement of pulmonary function.)
❑ Exercise stress test evaluates the ability to transport O2 and remove CO2 with increasing metabolic demands.
❑ Polysomnography can diagnose sleep disorders.
❑ Lung scan (ventilation-perfusion or scintiphotography scan) demonstrates ventilation and perfusion patterns. It’s used primarily to evaluate pulmonary embolus.
❑ Arterial blood gas (ABG) analysis assesses gas exchange. Decreased PaO2 may indicate hypoventilation, ventilation-perfusion mismatch, or shunting of blood away from gas exchange sites. Increased partial pressure of arterial carbon dioxide (PaCO2) reflects marked ventilation-perfusion mismatch or hypoventilation; decreased PaCO2 reflects increased alveolar ventilation. Changes in pH may reflect metabolic or respiratory dysfunction.
❑ Pulse oximetry is a noninvasive assessment of arterial oxygen saturation.
❑ Capnography may be used either transcutaneously or in ventilator circuit to determine PaCO2 trends.
Invasive tests include:
❑ Bronchoscopy permits direct visualization of the trachea and mainstem, lobar, segmental, and subsegmental bronchi. It may be used to localize the site of lung hemorrhage, visualize masses in these airways, and collect respiratory tract secretions. Brush biopsy may be used to obtain specimens from the lungs for microbiological stains, culture, and cytology. Lesion biopsies may be performed by using small forceps under direct visualization (when present in the proximal airways) or with the aid of fluoroscopy (when present distal to regions of direct visualization). Bronchoscopy can also be used to clear secretions and remove foreign bodies.
❑ Thoracentesis permits removal of pleural fluid for analysis.
❑ Pleural biopsy obtains pleural tissue for histologic examination and culture.
❑ Pulmonary artery angiography, the injection of dye into the pulmonary artery, can locate pulmonary embolism. This is considered the gold standard for diagnosing pulmonary emboli.
❑ Positron emission tomography scan uses a short-life radionuclide. Increased uptake of the substance is seen in malignant cells.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Lung cancer:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Typical clinical findings may strongly suggest lung cancer, but firm diagnosis requires further evidence.
❑Chest X-ray usually shows an advanced lesion, but it can detect a lesion up to 2 years before symptoms appear. It also indicates tumor size and location.
❑ Sputum cytology, which is 75% reliable, requires a specimen coughed up from the lungs and tracheobronchial tree, not postnasal secretions or saliva.
❑ Computed tomography (CT) scan of the chest may help to delineate the tumor's size and its relationship to surrounding structures.
❑ Bronchoscopy can locate the tumor site. Bronchoscopic washings provide material for cytologic and histologic examination. The flexible fiber-optic bronchoscope increases the test's effectiveness.
❑ Needle biopsy of the lungs uses biplane fluoroscopic visual control to detect peripherally located tumors. This allows firm diagnosis in 80% of patients.
❑ Tissue biopsy of accessible metastatic sites includes supraclavicular and mediastinal node and pleural biopsy. Directed needle biopsy may be performed in conjunction with CT scan.
❑Thoracentesis allows chemical and cytologic examination of pleural fluid.
Additional studies include preoperative mediastinoscopy or mediastinotomy to rule out involvement of mediastinal lymph nodes (which would preclude curative pulmonary resection).
Other tests to detect metastasis include bone scan, bone marrow biopsy (recommended in small cell carcinoma), CT scan of the brain or abdomen, and positron emission tomography.
After histologic confirmation, staging determines the extent of the disease and helps in planning the treatment and predicting the prognosis. (See Staging lung cancer.)
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Severe acute respiratory syndrome:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Diagnosis of severe respiratory illness is made when the patient has a fever greater than 100.4° F (38° C) or upon clinical findings of lower respiratory illness and a chest X-ray demonstrating pneumonia or acute respiratory distress syndrome.
Laboratory validation for the virus includes cell culture of SARS-CoV, detection of SARS-CoV ribonucleic acid by the reverse transcription polymerase chain reaction (PCR) test, or detection of serum antibodies to SARS-CoV. Detectable levels of antibodies may not be present until 21 days after the onset of illness, but some individuals develop antibodies within 14 days. A negative PCR, antibody test, or cell culture doesn’t rule out the diagnosis.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Colorado tick fever:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
CONFIRMING DIAGNOSIS A history of recent exposure to ticks along with moderate to severe leukopenia, complement fixation tests, or virus isolation confirm the diagnosis.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Lassa fever:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
CONFIRMING DIAGNOSIS Isolation of the Lassa virus from throat washings, pleural fluid, or blood confirms the diagnosis.
Recent travel to an endemic area and specific antibody titer support the diagnosis.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Relapsing fever:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
CONFIRMING DIAGNOSIS Diagnosis requires demonstration of the spirochetes in peripheral blood smears during febrile periods, using Wright's or Giemsa stain.
Borrelia spirochetes may be more difficult to detect in later relapses because their number declines in the blood. In such cases, injecting the patient's blood or tissue into a young rat and incubating the organism in the rat’s blood for 1 to 10 days commonly allows spirochete identification.
In severe infection, spirochetes are found in the urine and cerebrospinal fluid. Other abnormal laboratory results usually include a white blood cell (WBC) count as high as 25,000/µl, with increases in lymphocytes and erythrocyte sedimentation rate; however, the WBC count may be normal. Because the Borrelia organism is a spirochete, relapsing fever may cause a false-positive test for syphilis in 5% to 10% of cases.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Rheumatic fever and rheumatic heart disease:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Diagnosis depends on recognition of one or more of the classic symptoms (carditis, rheumatic fever without carditis, polyarthritis, chorea, erythema marginatum, or subcutaneous nodules) and a detailed patient history. Laboratory data support the diagnosis:
❑ White blood cell count and erythrocyte sedimentation rate may be elevated (during the acute phase); blood studies show slight anemia due to suppressed erythropoiesis during inflammation.
❑ C-reactive protein is positive (especially during acute phase).
❑ Cardiac enzyme levels may be increased in severe carditis.
❑ Antistreptolysin-O titer is elevated in 95% of patients within 2 months of onset.
❑ Electrocardiogram changes aren’t diagnostic; but PR interval is prolonged in 20% of patients.
❑ Chest X-rays show normal heart size (except with myocarditis, heart failure, or pericardial effusion).
❑ Echocardiography helps evaluate valvular damage, chamber size, and ventricular function.
❑ Cardiac catheterization evaluates valvular damage and left ventricular function in severe cardiac dysfunction.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Cough, barking:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
Ask the child’s parents when the barking cough began and what other signs and symptoms accompanied it. When did the child first appear to be ill? Has he had previous episodes of croup syndrome? Did his condition improve upon exposure to cold air?
Spasmodic croup and epiglottiditis typically occur in the middle of the night. The child with spasmodic croup has no fever, but the child with epiglottiditis has a high fever of sudden onset. An upper respiratory tract infection typically is followed by laryngotracheobronchitis.
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Cough, productive:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
When the patient’s condition permits, ask when the cough began and how much sputum he’s coughing up each day. (The normal tracheobronchial tree can produce up to 3 oz [89 ml] of sputum per day.) At what time of day does he cough up the most sputum? Is his sputum production affected by what or when he eats, his activities, or his environment? Ask him if he has noticed an increase in sputum production since his coughing began. This may result from external stimuli or from such internal causes as chronic bronchial infection or a lung abscess. Also ask about the color, odor, and consistency of the sputum. Blood-tinged or rust-colored sputum may result from trauma due to coughing or from an underlying condition, such as a pulmonary infection or a tumor. Foul-smelling sputum may result from an anaerobic infection, such as bronchitis or a lung abscess.
How does the cough sound? A hacking cough results from laryngeal involvement, whereas a “brassy” cough indicates major airway involvement. Does the patient feel any pain associated with his productive cough? If so, ask about its location and severity and whether it radiates to other areas. Does coughing, changing body position, or inspiration increase or help relieve his pain?
Next, ask the patient about his cigarette, drug, and alcohol use and whether his weight or appetite has changed. Find out if he has a history of asthma, allergies, or respiratory disorders, and ask about recent illnesses, surgery, or trauma. What medications is he taking? Does he work around chemicals or respiratory irritants such as silicone?
Examine the patient’s mouth and nose for congestion, drainage, or inflammation. Note his breath odor: Halitosis can be a sign of pulmonary infection. Inspect his neck for distended veins, and palpate it for tenderness, masses, and enlarged lymph nodes. Observe his chest for accessory muscle use, retractions, and uneven chest expansion, and percuss it for dullness, tympany, or flatness. Finally, auscultate for pleural friction rub and abnormal breath sounds, including rhonchi, crackles, or wheezing. (See Productive cough: Causes and associated findings, pages 206 and 207.)
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Cough, nonproductive:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
Ask the patient when his cough began and whether any body position, time of day, or specific activity affects it. How does the cough sound—harsh, brassy, dry, or hacking? Try to determine if the cough is related to smoking or a chemical irritant. If the patient smokes or has smoked, note the number of packs smoked daily multiplied by years (“pack-years”). Next, ask about the frequency and intensity of the coughing. If he has any pain associated with coughing, breathing, or activity, when did it begin and where is it located?
Ask the patient about recent illness (especially a cardiovascular or pulmonary disorder), surgery, or trauma. Also ask about hypersensitivity to drugs, foods, pets, dust, or pollen. Find out which medications the patient takes, if any, and ask about recent changes in schedule or dosages. Also ask about recent changes in his appetite, weight, exercise tolerance, or energy level; recent exposure to irritating fumes, chemicals, or smoke; and recent travel to foreign countries.
As you’re taking his history, observe the patient’s general appearance and manner: Is he agitated, restless, or lethargic; pale, diaphoretic, or flushed; anxious, confused, or nervous? Also, note whether he’s cyanotic or has clubbed fingers or peripheral edema.
Cultural Cue: Because of the fear of being known as someone with tuberculosis (TB), the patient may be reluctant to provide information about his signs and symptoms such as cough. Ask the patient at risk for TB—those born in another country, those in contact with acute TB, and those with high-risk behaviors—about potential TB exposure.
Next, perform a physical examination. Start by taking the patient’s vital signs. Check the depth and rhythm of his respirations, and note wheezing or “crowing” noises that occur with breathing. Feel the patient’s skin: Is it cold or warm; clammy or dry? Check his nose and mouth for congestion, inflammation, drainage, or signs of infection. Inspect his neck for distended veins and tracheal deviation, and palpate for masses or enlarged lymph nodes.
Examine his chest, observing its configuration and looking for abnormal chest wall motion. Do you note any retractions or use of accessory muscles? Percuss for dullness, tympany, or flatness. Auscultate for wheezing, crackles, rhonchi, pleural friction rub, and decreased or absent breath sounds. Finally, examine his abdomen for distention, tenderness, or masses, and auscultate it for abnormal bowel sounds.
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Fever [Pyrexia]:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
If the patient’s fever is only mild to moderate, ask him when it began and how high his temperature reached. Did the fever disappear, only to reappear later? Did he experience any other symptoms, such as chills, fatigue, or pain?
Obtain a complete medical history, noting especially immunosuppressive treatments or disorders, infection, trauma, surgery, diagnostic testing, and use of anesthesia or other medications. Ask about recent travel because certain diseases are endemic.
Let the history findings direct your physical examination. (See Differential diagnosis: Fever, pages 338 and 339.) Because fever can accompany diverse disorders, the examination may range from a brief evaluation of one body system to a comprehensive review of all systems. (See How fever develops, page 340.)
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Cough:
History
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
A. Characteristics of the cough. What is the type of cough (barking, brassy, wheezy, nocturnal, paroxysmal)? What are the duration, timing, and triggers? Are there associated symptoms of fever, sputum production, dypsnea, hemoptysis, and weight loss? Are there clear relieving factors? Ask specifically about postnasal drip as patients often do not volunteer this information. A good history is the key to diagnosis.
1. Upper respiratory causes most commonly relate to postnasal drip. In adults, sinusitis, pharyngitis, and allergic rhinitis should be considered. In children, concomitant otitis media should be excluded.
2. Lower respiratory causes include lung (bronchitis, asthma, pneumonia, bronchiectasis, and in children, foreign body aspiration) and cardiac [congestive heart failure (CHF) and mitral stenosis].
3. Nonrespiratory causes include GERD, drug effects [e.g., angiotensin converting enzyme (ACE)-inhibitors], and psychogenic.
B. Smoking patients should be identified early as bronchitis and lung cancer are possibilities. Passive smoking is also a risk factor, especially in children. Office visits for cough represent teachable moments for smoking cessation education. Smoking cessation has been shown to reduce respiratory symptoms by 50%.
C. Psychosocial impact of the cough reflects severity and the need for further workup. Has the patient missed school or work? Is the sleeping partner disturbed? Is there avoidance of exercise because it triggers cough? In chronic, episodic cough, a correct diagnosis of asthma can considerably improve quality of life. A psychogenic cause for cough and behavioral problems in children may be unmasked here.
D. Other information. Associated chest pain should direct the history toward pleurisy or rib fracture secondary to chronic cough. Occupational exposures (toxic fumes, chemicals, birds and animals), systemic diseases [rheumatoid arthritis, breast and prostate cancer metastases, human immunodeficiency virus disease (HIV)] and drug exposure (ACE-inhibitors, cyclophosphamide, and methotrexate) are important factors to consider in the cause. Cough with significant weight loss should trigger a workup for TB, HIV, or lung cancer in the smoker.
Physical examination
A. Focused physical examination (PE) should include vital signs (temperature, pulse, respiratory rate, and blood pressure), ear, nose, sinuses, throat (ENST), and a full lung examination with the chest uncovered. Normal lung examination often excludes pneumonia but not asthma, bronchitis, COPD, GERD, or lung cancer. It is more effective to examine the lung before the ENST in young children because the ENST examination is more traumatic and can induce crying. In the older patient, especially the postmenopausal woman, rib palpation may be included to isolate fracture secondary to osteoporosis.
B. Additional PE. The cardiovascular examination is directed at a diagnosis of CHF. Associated lymphadenopathy suggests infection or neoplasm. Wasting can be ominous (cancer or HIV). Abdominal examination may reveal a tender enlarged liver in CHF, or epigastric tenderness in GERD (Chapters 7.5 and 9.6).
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Fever:
History
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
A. Taking a detailed patient history is critical; include questions relating to travel, animal exposure, occupation, injuries or operations, household members or contacts who are ill, medications, past illnesses, and a complete review of systems.
B. Chills, malaise, myalgia, headache, and fever are common with infectious diseases.
C. The febrile pattern may be helpful in making a diagnosis. Antipyretics, antibiotics, and glucocorticoids affect the fever pattern. Specific patterns of fever are shown in Table 2.4.
Physical examination
A. The examination should include the skin, lymph nodes, eyes, nail beds, heart, lungs, abdomen, joints, nervous system, and genitourinary system, including rectal and bimanual pelvic examinations.
B. Infections will increase the pulse rate approximately 10 beats per minute for each 0.5°C (1.0°F) temperature increase.
C. When fever is present, the respiratory rate will frequently increase above the usual 12 to 14 breaths per minute.
D. Infections with Mycoplasma pneumonia, psittacosis, and typhoid fever are often associated with a relative bradycardia.
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Rash Accompanied by Fever:
History
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
History is quite important and should include standard items, such as onset, duration, aggravating factors, relieving factors, and associated symptoms. Additionally, other factors to consider, include:
A. Exposure history. Are any other family members or close contacts ill? Is there a history of exposure to brackish water, mosquitoes, foreign travel, and so forth?
B. Are there any underlying illnesses or a significant possibility of immunologic compromise (e.g., undiagnosed HIV infection)?
Physical examination
A. Examine the lesions and their distribution carefully. Classify the rash as petechial, maculopapular, vesiculobullous, erythematous, or urticarial. Note the distribution of the rash. For instance, rubella and rubeola generally begin on the face and spread to the trunk, whereas RMSF petechiae tend to occur on the ankles and wrists first.
B. Conduct a general physical examination. Areas of particular concern are:
1. Head, eyes, ears, nose, and throat. The presence of Koplik’s spots is pathognomic for rubeola. The discovery of a tick lends support to the diagnosis of RMSF. Sinusitis may represent a source for meningococcemia. Pharyngitis in a young adult with diffuse erythema may be caused by C. haemolyticum. Mucous membrane swelling may indicate early anaphylaxis.
2. Lung examination. Expiratory wheezing, especially in a patient who has recently received medications or contrast dye, can indicate anaphylaxis. Evidence of pneumonia is consistent with psittacosis and mycoplasma.
3. Cardiac examination. Cardiovascular collapse is associated with meningococcemia and other sepsis. A new murmur (Chapters 7.6 and 7.7) may indicate subacute bacterial endocarditis in a patient with subungual or scleral petechiae.
4. Genital examination. Purulent urethral drainage or evidence of pelvic inflammatory disease supports consideration of gonorrhea. A chancre would support a diagnosis of syphilis, although palmar lesions often occur well after healing of the initial chancre.
5. Joint examination and extremities. A petechial rash near the ankles and wrists is suggestive of RMSF. Evidence of joint swelling supports a diagnosis of meningococcemia or gonococcemia. A maculopapular rash may be seen in juvenile rheumatoid arthritis and other rheumatologic conditions as well.
6. Neurologic examination. Evidence of meningitis supports a diagnosis of meningococcemia. Patients with RMSF may also have meningeal signs.
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Sore Throat:
Differential Overview
(Field Guide to Bedside Diagnosis)
❑ Rhinovirus
❑ Group A streptococci
❑ Ebstein-Barr virus
❑ Adenovirus
❑ Influenza
❑ Candida/thrush
❑ Herpes simplex virus
❑ Peritonsillar abscess
❑ Mycoplasma pneumoniae
❑ Coxsackievirus
❑ Primary HIV
❑ Neisseria gonorrhea
❑ Epiglottitis
❑ Corynebacterium diphtheriae
❑ Leukemia
Diagnostic Approach
The most important consideration is whether the patient has a group A strep infection because prompt treatment prevents rheumatic fever. The findings of fever, tender anterior cervical adenopathy, and tonsillar exudate can be combined to make the diagnosis more or less likely. Rapid antigen tests have a sensitivity of 80% to 90% and specificity of 95% to 100%, so give a reasonably accurate diagnosis. Because of limitations in sensitivity however, patients with a high suspicion on clinical grounds should have a backup culture taken.
Prior probability in an adult population with sore throat is 5% to 10%, and in a pediatric population 20% to 25%. A prominent sore throat out of proportion to the degree of pharyngeal inflammation should raise the possibility of acute epiglottitis and acutely impending airway compromise. Persistent unilateral tonsillar enlargement in a young adult without sore throat should raise the suspicion of lymphoma.
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Source: Field Guide to Bedside Diagnosis, 2007
Fever of Unknown Origin:
Differential Overview
(Field Guide to Bedside Diagnosis)
Infection
❑ HIV
❑ Tuberculosis
❑ Endocarditis
❑ Osteomyelitis
❑ Malaria
❑ Syphilis
❑ Zoonosis
❑ Typhoid fever
❑ Chronic meningococcemia
Neoplasm
❑ Lymphoma
❑ Liver metastases
❑ Renal cell carcinoma
❑ Atrial myxoma
Collagen-Vascular Disease
❑ Giant cell arteritis
❑ Systemic lupus erythematosus
❑ Vasculitis
❑ Rheumatic fever
❑ Still disease
Other
❑ Drugs
❑ Heat stroke
❑ Factitious
❑ Malignant hyperthermia
❑ Multiple pulmonary emboli
Diagnostic Approach
Fever of unknown origin (FUO), when a fever over 101°F (38.5°C) remains unexplained for longer than 3 weeks, is usually a result of infection (40%), neoplasm (20%), or collagen-vascular disease (20%). It is most commonly caused by an atypical presentation of a common disease. Always document the fever before pursuing the evaluation.
Consider relatively hidden (deep) sites: retroperitoneum (hematoma or infection), bone, dental, sinus, ovary, prostate, subphrenic (following abdominal surgery), renal, spleen, or prostheses. With FUO in a hospitalized patient, consider sequestered sites (e.g., sinuses in intubated patients or implanted hardware), indwelling lines, C. difficile, or drug reactions. With FUO in a neutropenic patient, consider catheters, perianal infections, Candida, and Aspergillus. Cardinal signs may be absent, e.g., meningitis with opportunistic pathogens without meningismus in 63%, and pneumonia without purulent sputum in 92%. Neutropenic fevers are usually due to bacteremia, with fungal organisms becoming predominant after 7 days of unremitting fever. Fever may also be due to the underlying neoplasm, drugs such as antibiotics, or blood products.
Examine for subtle clues:
• Petechial eruptions in meningococcemia and Rocky Mountain Spotted Fever
• Pustular lesions in gonococcemia or staphylococcal sepsis
• Ecthyma gangrenosum in Pseudomonas sepsis
• Splinter hemorrhages, conjunctival hemorrhages, Roth spots, Osler nodes, and Janeway lesions in endocarditis
• Choroidal tubercles in miliary tuberculosis and candidemia
• Splenomegaly in endocarditis, lymphoma, and cirrhosis
• Hepatic bruit or friction rub in subphrenic abscess
• Temporal artery or scalp tenderness or jaw claudication in giant cell arteritis
• Epitrochlear lymphadenopathy in syphilis
Extreme elevations of fever (.40°C) are found in heat stroke, hypothalamic dysfunction, meningitis, midbrain hemorrhage, falciparum malaria, Rocky Mountain Spotted Fever, typhus, sepsis, malignant hyperthermia, and hypernephroma.
Relative bradycardia occurs in salmonellosis (typhoid fever), meningitis with increased intracranial pressure, mycoplasma and legionella pneumonia, factitious fever, tularemia, brucellosis, mumps, hepatitis, and with concomitant beta blockers. Bradycardia in fever may also signal cardiac conduction abnormalities in acute rheumatic fever, Lyme disease, viral myocarditis, or endocarditis with valve ring abscess.
Relapsing fevers (days of fever alternating with days without) occur in brucellosis (fever with physical activity), Hodgkin disease, extrapulmonary tuberculosis, malaria, and Lyme disease. Hectic fever (difference between peak and trough .1.5°C) suggests abscess, pyelonephritis, ascending cholangitis, tuberculosis, lymphoma, and drug reactions. Absence of diurnal variation suggests a central source. Reversal of the diurnal pattern (“typhus inversus”) occurs with disseminated tuberculosis, typhoid fever, polyarteritis nodosa, and salicylate toxicity.
FUO in patients from the developing world include tuberculosis, typhoid, amebic liver abscesses, AIDS, and geographically restricted infections such as malaria, schistosomiasis, brucellosis, kala azar, filariasis, or Lassa fever. They may present after long incubation or latency periods.
When FUO lasts longer than 6 months, consider factitious fever, granulomatous hepatitis, neoplasm, Still disease, infection, collagen-vascular disease, or exaggerated circadian rhythm.
Patients who remain undiagnosed have a good prognosis (83% resolution in 1 year, 4% mortality).
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Source: Field Guide to Bedside Diagnosis, 2007
Acute Cough:
Differential Overview
(Field Guide to Bedside Diagnosis)
❑ Viral upper respiratory infection
❑ Asthma
❑ Sinusitis
❑ Mycoplasma bronchitis
❑ Pneumonia
❑ Gastroesophageal reflux
❑ Congestive heart failure
❑ ACE inhibitor
❑ Aspiration
❑ Cough in HIV
❑ Thermal
❑ Fume inhalation
❑ Pertussis
❑ Lung abscess
Diagnostic Approach
The main issue in diagnosis is differentiating respiratory viruses, which cause most cases, from bacterial infection such as pneumonia, which would benefit from treatment with antibiotics, and from influenza, for which antivirals are effective. The classic presentation of bacterial pneumonia is acute onset with a progressive course marked by cough productive of yellow or green sputum, fever to 100˚ to 104˚F with chills or rigors, and pleuritic chest pain. The patient often appears “toxic.” The affected lung will often have coarse rales and bronchial breath sounds, and there may be localized percussive dullness. Viral pneumonia is associated with upper respiratory signs such as nasal congestion and sore throat, and by a nonproductive cough. Use of the Pneumonia diagnosis rule is helpful: Temperature .37.8˚C (100˚F); pulse .100; rales; decreased breath sounds; and no asthma each score 1.
Detection of induced bronchial hyperreactivity (reactive airways disease), which benefits from bronchodilator or corticosteroid treatment, is also important. Wheezing, shortness of breath, and a predisposition (atopy or smoker) are helpful clinical clues.
A cough appearing mostly at night suggests congestive heart failure or reflux. Confusion and absence of fever are common presenting findings in older adults.
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Source: Field Guide to Bedside Diagnosis, 2007
Chronic Cough:
Differential Overview
(Field Guide to Bedside Diagnosis)
❑ Upper respiratory infection
❑ Allergy
❑ Asthma
❑ Chronic bronchitis
❑ Chronic sinusitis
❑ Gastroesophageal reflux
❑ ACE inhibitor
❑ Pollutants
❑ Psychogenic
❑ Foreign body
❑ Congestive heart failure
❑ Lung cancer
❑ Tuberculosis
❑ Mediastinal mass
❑ Bronchiectasis
❑ Pulmonary fibrosis
❑ Cystic fibrosis
❑ Aspergillosis
Diagnostic Approach
Chronic cough persists 3 weeks or longer. During vigorous coughing intrathoracic pressure of 300 mm Hg and expiratory velocity of 500 miles per hour develop, which over time are responsible for the secondary effects of exhaustion, insomnia, chest wall pain, dizziness, syncope, and urinary incontinence. Postnasal drip, asthma, and gastroesophageal reflux are responsible for 99.4% of cases in patients with the characteristics: nonsmoker, no use of ACE inhibitor, and normal or stable chest x-ray.
Green color in the sputum may be caused by either polymorphonuclear leukocytes or eosinophils. Hoarseness suggests tumor with involvement of the vocal cords or recurrent laryngeal nerve, or it may suggest chronic esophageal reflux.
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Source: Field Guide to Bedside Diagnosis, 2007
Acute respiratory failure in COPD:
Diagnosis
(Handbook of Diseases)
Progressive deterioration in ABG levels and pH, when compared with the patient’s baseline values, strongly suggests ARF in COPD patients. (In patients with essentially normal lung tissue, a pH less than 7.35 usually indicates ARF, but COPD patients display an even greater deviation from this normal value, as they do with blood Paco2 and Pao2.) The following findings further support the diagnosis:
Bicarbonate levels are increased, indicating metabolic alkalosis or metabolic compensation for chronic respiratory acidosis.
Hb levels and hematocrit are abnormally low, which may be due to blood loss, indicating decreased oxygen-carrying capacity.
Serum electrolyte levels may indicate hypokalemia, which may result from compensatory hyperventilation — an attempt to correct alkalosis; hypochloremia is common with metabolic alkalosis.
White blood cell count is elevated if ARF is due to bacterial infection; in certain cases of profound septicemia, the leukocyte count may be decreased. Gram stain and sputum culture can identify pathogens.
Chest X-rays reveal pulmonary pathology, such as emphysema, atelectasis, lesions, pneumothorax, infiltrates, or effusions.
Electrocardiogram reveals arrhythmias, which commonly suggest cor pulmonale and myocardial hypoxia. Large P waves (“p pulmonale”) may indicate a history of right-sided heart failure.
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Source: Handbook of Diseases, 2003
Respiratory acidosis:
Diagnosis
(Handbook of Diseases)
❑ The following arterial blood gas (ABG) levels confirm respiratory acidosis: a Paco2 exceeding the normal level of 45 mm Hg, pH usually below the normal range of 7.35 to 7.45, and a bicarbonate level that’s normal in the acute stage but elevated in the chronic stage.
❑ Chest X-ray, computed tomography scan, or pulmonary function test may help diagnose lung disease.
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Source: Handbook of Diseases, 2003
Respiratory alkalosis:
Diagnosis
(Handbook of Diseases)
Arterial blood gas (ABG) analysis confirms respiratory alkalosis and rules out respiratory compensation for metabolic acidosis. Findings include a Paco2 below 35 mm Hg, a pH that’s elevated in proportion to the fall in Paco2 in the acute stage but that drops toward normal in the chronic stage, and a bicarbonate level that’s normal in the acute stage but below normal in the chronic stage.
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Source: Handbook of Diseases, 2003
Respiratory distress syndrome:
Diagnosis
(Handbook of Diseases)
Although signs of respiratory distress in a premature neonate during the first few hours of life strongly suggest respiratory distress syndrome, the following tests are necessary to confirm the diagnosis:
❑ Chest X-ray may be normal for the first 6 to 12 hours (in 50% of neonates with respiratory distress syndrome) but later shows a fine reticulonodular pattern.
❑ Arterial blood gas (ABG) analysis shows decreased partial pressure of arterial oxygen (Pao2); normal, decreased, or increased partial pressure of arterial carbon dioxide; and decreased pH (from respiratory or metabolic acidosis or both).
❑ Pulmonary function studies may be necessary.
When a cesarean section is necessary before the 36th week of gestation, amniocentesis allows determination of the lecithin-sphingomyelin ratio, which helps to assess prenatal lung development and the risk of respiratory distress syndrome.
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Source: Handbook of Diseases, 2003
Respiratory syncytial virus infection:
Diagnosis
(Handbook of Diseases)
The following clinical findings and epidemiologic information aid in the diagnosis:
❑ Cultures of nasal and pharyngeal secretions may show RSV.
❑ Serum antibody titers may be elevated, but before age 6 months, maternal antibodies may impair test results.
❑ Serology for RSV is positive.
❑ Chest X-rays help detect pneumonia or bronchiolitis.
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Source: Handbook of Diseases, 2003
Lung abscess:
Diagnosis
(Handbook of Diseases)
The following tests are used to diagnose a lung abscess:
❑ Auscultation of the chest may reveal crackles and decreased breath sounds.
❑ Chest X-ray shows a localized infiltrate with one or more clear spaces, usually containing air-fluid levels.
❑ Chest computed tomography scan confirms the presence of localized infiltrate or nodular density, occasionally with air-fluid level. Chest imaging may also identify airway masses or foreign bodies that have led to abscess formation.
❑ Percutaneous aspiration of an abscess or bronchoscopy may be used to obtain cultures to identify the causative organism. Bronchoscopy is only used if abscess resolution is eventful and the patient’s condition permits it.
❑ Blood cultures, Gram stain, and sputum culture are also used to detect the causative organism.
❑ White blood cell count commonly exceeds 10,000/µl.
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Source: Handbook of Diseases, 2003
Lung cancer:
Diagnosis
(Handbook of Diseases)
Typical signs and symptoms may strongly suggest lung cancer, but a firm diagnosis requires further evidence, including the following:
❑ Chest X-ray usually shows an advanced lesion, but it can detect a lesion up to 2 years before symptoms appear. It also indicates tumor size and location.
❑ Sputum cytology is marginally helpful in obtaining a diagnosis. It requires a specimen coughed up from the lungs and tracheobronchial tree, not postnasal secretions or saliva.
❑ Computed tomography (CT) scan of the chest may help to delineate the tumor’s size and its relationship to surrounding structures.
❑ Bronchoscopy can locate the tumor site. Bronchoscopic washings provide material for cytologic and histologic examination. The flexible fiber-optic bronchoscope increases the test’s effectiveness.
❑ A needle biopsy of the lungs uses biplane fluoroscopic visual control or CT guidance to detect peripherally located tumors. This allows a firm diagnosis in 80% of patients.
❑ Tissue biopsy of accessible metastatic sites includes supraclavicular and mediastinal node and pleural biopsies.
❑ Thoracentesis allows chemical and cytologic examination of pleural fluid.
Additional studies include preoperative mediastinoscopy or mediastinotomy to rule out involvement of mediastinal lymph nodes (which would preclude curative pulmonary resection).
Other tests to detect metastasis include a bone scan, positron emission tomography scan, bone marrow biopsy (recommended in small cell carcinoma), and a CT scan of the brain or abdomen.
After histologic confirmation, staging determines the extent of the disease and helps in planning treatment and predicting the prognosis. (See Staging lung cancer.)
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Source: Handbook of Diseases, 2003
Rheumatic fever and rheumatic heart disease:
Diagnosis
(Handbook of Diseases)
Recognition of one or more classic signs or symptoms (carditis, polyarthritis, chorea, erythema marginatum, or subcutaneous nodules) and a detailed patient history allow diagnosis. The following laboratory data support the diagnosis:
❑ White blood cell count and erythrocyte sedimentation rate may be elevated (during the acute phase); blood studies show slight anemia from suppressed erythropoiesis during inflammation.
❑ C-reactive protein is positive (especially during the acute phase).
❑ Cardiac enzyme levels may be increased in those with severe carditis.
❑ Antistreptolysin O titer is elevated in 95% of patients within 2 months of onset. (Rising antiDNase B test results can also detect recurrent streptococcal infection.)
❑ Electrocardiography changes aren’t diagnostic, but the PR interval is prolonged in 20% of patients.
❑ Chest X-rays show normal heart size (except with myocarditis, heart failure, or pericardial effusion).
❑ Echocardiography helps evaluate valvular damage, chamber size, and ventricular function.
❑ Cardiac catheterization evaluates valvular damage and left ventricular function in those with severe cardiac dysfunction.
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Source: Handbook of Diseases, 2003
Cough, barking:
History
(Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series)
Determine when the barking cough began and other associated signs and symptoms. Determine when the child first appeared to be ill and ask if there have been previous episodes of croup syndrome.
Spasmodic croup and epiglottiditis typically occur in the middle of the night. The child with spasmodic croup has no fever, but the child with epiglottiditis has a high fever of sudden onset. An upper respiratory tract infection typically is followed by laryngotracheobronchitis.
Physical examination
Assess the respiratory system, noting rate and pattern of respirations. Assess the patient for signs of hypoxia. Stay alert for signs of airway obstruction (nasal flaring, sternal retraction, stridor).
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Source: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, 2007
Cough, productive:
History
(Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series)
Determine the onset of the cough and amount of daily sputum production. (The normal tracheobronchial tree can produce up to 3 oz [89 ml] of sputum per day.) Determine the time of day that the most sputum is produced and relationship of food to sputum production. Also ask about the color, odor, and consistency of the sputum. Blood-tinged or rust-colored sputum may result from trauma due to coughing or from an underlying condition, such as a pulmonary infection or tumor. Foul-smelling sputum may result from an anaerobic infection, such as bronchitis or lung abscess.
Determine cough characteristics. A hacking cough results from laryngeal involvement, whereas a “brassy” cough indicates major airway involvement. Ask the patient about cigarette, drug, and alcohol use and if there has been weight or appetite changes. Find out if he has a history of asthma, allergies, or respiratory disorders, and ask about recent illnesses, surgery, or trauma. Determine a medication history, including over-the-counter medications. Ask the patient if his work involves chemicals or respiratory irritants.
Physical examination
Examine the patient’s mouth and nose for congestion, drainage, or inflammation. Note breath odor: Halitosis can be a sign of pulmonary infection. Inspect his neck for jugular vein distention, and palpate for tenderness and masses or enlarged lymph nodes. Observe his chest for accessory muscle use, retractions, and uneven chest expansion, and percuss for dullness, tympany, or flatness. Finally, auscultate for pleural friction rub and abnormal breath sounds — rhonchi, crackles, or wheezes.
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Source: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, 2007
Fever:
History
(Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series)
If the patient’s fever is mild to moderate, ask him when it began and how high his temperature reached. Did the fever disappear, only to reappear later? Did he experience any other symptoms, such as chills, fatigue, or pain?
Obtain a complete medical history, noting immunosuppressive treatments or disorders, infection, trauma, surgery, diagnostic testing, and use of anesthesia or other medications. Ask about recent travel because certain diseases are endemic.
Physical examination
Let the history findings direct your physical examination. Because fever can accompany diverse disorders, the examination may range from a brief evaluation of one body system to a comprehensive review of all systems. (See How fever develops, pages 148.) Assess vital signs and evaluate the patient for complications related to the fever such as dehydration, body aches, fatigue, anorexia, and seizure activity.
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Source: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, 2007
Cough, barking:
History
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Ask the child’s parents when the barking cough began and what other signs and symptoms accompanied it. When did the child first appear to be ill? Has he had previous episodes of croup syndrome? Did his condition improve upon exposure to cold air?
Spasmodic croup and epiglottiditis typically occur in the middle of the night. The child with spasmodic croup has no fever, but the child with epiglottiditis has a high fever of sudden onset. An upper respiratory tract infection typically is followed by laryngotracheobronchitis.
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Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Cough, productive:
History
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
When the patient’s condition permits, ask when the cough began, and find out how much sputum he’s coughing up each day. (The normal tracheobronchial tree can produce up to 3 oz [88.7 ml] of sputum per day.) At what time of day does he cough up the most sputum? Does his sputum production have any relationship to what or when he eats, or to his activities or environment? Ask him if he has noticed an increase in sputum production since his coughing began. This may result from external stimuli or from such internal causes as chronic bronchial infection or a lung abscess. Also ask about the color, odor, and consistency of the sputum. Blood-tinged or rust-colored sputum may result from trauma due to coughing or from an underlying condition, such as a pulmonary infection or a tumor. Foul-smelling sputum may result from an anaerobic infection, such as bronchitis or lung abscess.
How does the cough sound? A hacking cough results from laryngeal involvement, whereas a “brassy” cough indicates major airway involvement. Does the patient feel pain associated with his productive cough? If so, ask about its location and severity and whether it radiates to other areas. Does coughing, changing body position, or inspiration increase or help relieve his pain?
Next, ask the patient about his cigarette, drug, and alcohol use and whether his weight or appetite has changed. Find out if he has a history of asthma, allergies, or respiratory disorders, and ask about recent illnesses, surgery, or trauma. What medications is he taking? Does he work around chemicals or respiratory irritants, such as silicone?
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Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Fever:
History
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
If the patient’s fever is only mild to moderate, ask him when it began and how high his temperature reached. Did the fever disappear, only to reappear later? Did he experience other symptoms, such as chills, fatigue, or pain?
Obtain a complete medical history, noting especially immunosuppressive treatments or disorders, infection, trauma, surgery, diagnostic testing, and use of anesthesia or other medications. Ask about recent travel because certain diseases are endemic.
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Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Cough, nonproductive:
History
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Ask the patient when his cough began and whether body position, time of day, or specific activity affects it. How does the cough sound — harsh, brassy, dry, or hacking? Try to determine if the cough is related to smoking or a chemical irritant. If the patient smokes or has smoked, note the number of packs smoked daily multiplied by years (“pack years”). Next, ask about the frequency and intensity of the coughing. If he has pain associated with coughing, breathing, or activity, when did it begin? Where is it located?
Ask the patient about recent illness (especially a cardiovascular or pulmonary disorder), surgery, or trauma. Also ask about hypersensitivity to drugs, foods, pets, dust, or pollen. Find out which medications the patient takes, if any, and ask about recent changes in schedule or dosages. Also, ask about recent changes in his appetite, weight, exercise tolerance, or energy level and recent exposure to irritating fumes, chemicals, or smoke.
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Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Cough:
Clinical Features and Diagnosis
(The Diagnostic Approach to Symptoms and Signs in Pediatrics)
Infection/Inflammation
Upper Respiratory Tract Infection
URI (commoncold) is acute viral infection.Common pathogens include rhinoviruses,parainfluenza viruses, respiratory syncytial virus (RSV), and coronaviruses.Other viruses that occasionally cause common cold are adenoviruses,enteroviruses, influenza viruses, and reoviruses.Usual clinical findings are watery,mucoid, or purulent discharge; dry, hacking cough; and inflamednasal mucosa.Diagnosis is clinical. Sinusitis
Usuallypresents with history of purulent nasal discharge and persistentcough of >10 days' duration. Less common presentationis combination of fever, headache, and facial pain or sinus tenderness.Usually clinical diagnosis.CT should be performed when orbitalabscess or intracranial complication is suspected. Laryngitis
Most frequentcause is viral URI.Hoarseness and dry, hacking cough,which may last up to 1 wk, are usual clinical findings.Usually clinical diagnosis. Croup
Characterizedby a barking cough and stridor ħ fever.See Chap.63, Stertor, Stridor, and Airway Obstruction. Tracheitis
Often crouplikeillness with cough and stridor precedes sudden onset of respiratory distressand high fever.Clinical picture suggests bacterialtracheitis.See Chap.63, Stertor, Stridor, and Airway Obstruction. Bronchitis
Inflammatoryprocess affecting trachea and bronchi. Most episodes are causedby viruses (e.g., RSV, parainfluenza viruses, influenza viruses,rhinoviruses, and adenoviruses).Hacking cough appears several daysafter onset of typical URI. Rhonchi may be heard, but crackles areinfrequent. Presence of wheezing usually indicates presence of reactiveairways disease.Usually clinical diagnosis. Pertussis
B. pertussisinfection begins with nasal discharge, which is followed by paroxysmal coughthat often has staccato quality. Whoop may follow paroxysm.Fever may or may not occur.There is usually leukocytosis withpredominance of lymphocytes.Apnea is serious complication, especiallyin young infants.Duration of illness may be as longas 6–10 wks.Chest radiograph may be normal or showperihilar infiltrates.Positive direct immunofluorescent assayof nasopharyngeal secretions suggests diagnosis, but false-positiveand false-negative results occur.Positive nasopharyngeal culture confirmsdiagnosis. Bronchiolitis
Usuallycaused by RSV and occasionally by parainfluenza viruses, influenzaviruses, and adenoviruses.Occurs during winter months, oftenin epidemics.Rhinorrhea usually precedes cough,which may be persistent and harsh. Expiratory wheezing is prominentfinding.See Chap.75, Wheezing. Pneumonia
Definedas inflammation of lung parenchyma that may be caused by infection.Frequently presents with fever, cough,and respiratory distress. Crackles and wheezes may be heard on exam.Decreased breath sounds and dullness to percussion indicate areaof lung consolidation.Presence of pneumonia usually can beconfirmed by chest radiography, although early in illness radiographcan appear normal.Specific cause requires further investigation. Viral
Accountsfor most cases of pneumonia in infancy and childhood.Most common viruses causing pneumoniainclude RSV, parainfluenza viruses, adenoviruses, and influenzaviruses. Less common causes are rhinoviruses and coronaviruses.Cytomegalovirus and herpes simplexvirus may cause pneumonia in newborn or in immunocompromised individuals.May also be caused by measles, varicella,and Hantavirus infection.Chest radiograph frequently shows involvementof both lungs, with peribronchial thickening, perihilar linear densities,and patchy infiltrates. Segmental or lobar consolidation, hilaradenopathy, and pleural effusions are unusual.Nasal wash cultures or polymerase chainreaction (PCR) of nasal secretions may sometimes diagnose specificviral infection.RSV antigen may be detected by enzymeimmunoassay or immunofluorescent techniques. Bacterial
Pathogenscausing bacterial pneumonia vary with age of child.Most common causes of bacterial pneumoniain neonates are group B Streptococcus and gram-negative entericbacteria (E. coli, K. pneumoniae, P. aeruginosa).In infancy, childhood, and adolescence,S. pneumoniae is most common, whereas S. aureus and group A Streptococcusare much less common.H. influenzae type b has become unusualcause of pneumonia, since advent of H. influenzae vaccine.M. tuberculosis can cause infectionat any age.Clinical findings with bacterial pneumoniausually include fever, cough that may be productive of sputum inolder child, and some degree of respiratory distress.Leukocytosis with predominance of polymorphonuclearleukocytes is common finding.Pleural effusions and pneumatocelesare more frequent with bacterial pneumonia than with viral pneumonia.Chest radiograph usually shows segmentalor lobar infiltrate.Diagnosis of bacterial pneumonia canbe confirmed by positive blood, pleural fluid, or lung biopsy cultures.McCarthy et al. (1999) demonstrated that PCR may be used to diagnosepneumonia caused by S. pneumoniae using sample of pleural fluid.Pharyngeal or sputum culture that haslarge numbers of single organism is suggestive but not diagnostic.Counterimmune electrophoresis and latexagglutination tests have successfully detected bacterial antigensof S. pneumoniae, group B Streptococcus, and H. influenzae typeb in urine, so these tests may be diagnostic. Tuberculosis
Usual modeof transmission of M. tuberculosis infection is by inhalation.Positive skin test with PPD may beobserved 2–12 wks after exposure.Children with disease usually haveprimary pulmonary TB with cough and fever.In most cases of TB infection, individualis asymptomatic, primary complex of infection is not seen on chestradiograph, and disease does not progress.In TB disease, individual has clinicalor radiographic findings and disease may be pulmonary or nonpulmonary.Chest radiograph shows involvementof segment or lobe, usually with enlarged regional lymph nodes.With progression, cavitary lesions or miliary disease can occur.Acid-fast bacilli smears and culturesshould be performed in anyone with suspected TB. In young child,especially if cough is nonproductive, best culture material is fromearly morning gastric aspirate. Otherwise, isolation of tuberclebacilli by culture of sputum, urine, pleural fluid, cerebrospinalfluid, other body fluids, or biopsy material confirms diagnosis.Negative PPD never excludes infectionor disease with TB. Anergy may be due to young age, viral infections,immunosuppression, and severe disseminated TB. Chlamydia
Pneumoniadue to C. trachomatis usually occurs in infants 1–3 mosof age.Clinical findings include conjunctivitisor history of conjunctivitis, staccato cough, tachypnea, crackles,and mild peripheral eosinophilia. Fever is variable finding.Chest radiograph usually shows hyperinflationand bilateral interstitial infiltrates.Positive nasopharyngeal or eye cultureconfirms diagnosis. Legionella
Legionnaire'sdisease is transmitted by inhalation of aerosolized water contaminated withLegionella species.Most common cause of Legionella infectionin U.S. is L. pneumophila serogroup 1.Frequent findings include fever, nonproductivecough, headache, and myalgia.Chest radiograph usually shows infiltrate.Pulmonary nodules ħ cavitation also may occur.Diagnosis can be confirmed in a numberof ways:positiveculture of sputum or lung tissuedetection of organisms on smears ofrespiratory tract secretions by direct immunofluorescent assay usingmonoclonal or polyclonal antibodiesDNA probesserologic testing using indirect immunofluorescenceantibody assay