Diagnostic Tests for Hantavirus
Hantavirus Tests: Book Excerpts
Hantavirus Diagnosis: Book Excerpts
Diagnostic Tests for Hantavirus: Online Medical Books
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Solitary Pulmonary Nodule:
Physical examination
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
should include a search for evidence of weight loss, chronic obstructive pulmonary disease, and primary or metastatic disease of other organs.
Testing
The key question is to determine which one of the SPNs is malignant and warrants invasive and immediate action. The following factors can help determine a course of management:
A. Location. Generally, most malignant lesions are found in the upper lobes.
B. Appearance. The smooth margins seen on computerized tomography (CT) scan characterize benign lesions, whereas spiculated, irregular borders are associated with malignant growths.
C. Size. Small size (<2 cm) is most frequently a sign of benignity, although it can be caused by an early, isolated pulmonary metastasis from a primary cancer at another site.
D. Calcifications. Peripheral, concentric patterns (“bull’s eyes” in granulomas, “popcorn ball” in hematomas) (3) have been associated with benign lesions, but the presence of calcifications has not been found to be a reliable indicator in predicting malignancy, because 14% of cancerous lesions can be calcified.
E. Aging. The CT scan of the chest is widely available and noninvasive. It accurately measures the nodule and defines its location and morphology.
F. Preliminary results with high resolution computerized tomography with contrast indicate good accuracy in the determination of the nodule malignancy. The MRI is not a preferred imaging tool to analyze a pulmonary nodule but its superior capacity to enhance vascular structures can be useful in the differential diagnosis.
Diagnostic assessment
Controversy exists as to the best way to manage SPN. The decision to observe or to intervene is guided by the following parameters: patient’s age, smoking history, location of the nodule, availability of previous
x-ray studies, and presence and type of calcifications.
A. Observation. A stable (no growth in 2 years) calcified lesion in a nonsmoker, aged less than 35 years, is almost certainly benign, and can safely be managed by repeat chest x-ray study every 3 months in the first year, then every year for 2 years. The patient’s cooperation and the family physician’s meticulous follow-up are essential to the success of this plan.
B. Intervention. An irregular, noncalcified lesion, particularly in a smoker or older patient, warrants invasive intervention to obtain a tissue diagnosis.
1. Fiberoptic bronchoscopy is the procedure of choice for centrally located SPNs.
2. For peripheral lesions, percutaneous needle biopsy is a quick, relatively easy procedure when done by an experienced operator. Its low rate of specificity and potential risks of pneumothorax and bleeding make it a poor choice because the goal is to reach a diagnosis with the least discomfort to the patient.
3. Thoracoscopic fine-needle aspiration is becoming an alternative to percutaneous needle biopsy. In a small surgical series, it provided an accurate diagnosis in all cases and helped to define the next surgical step (4).
4. A new surgical technique, video-assisted thoracic surgery (VATS), is fast becoming the diagnostic tool of choice for suspected SPN (5). Its yield is excellent and its capacity allows resectability of benign lesions without thoracotomy; its very low rate of morbidity and mortality are welcome additions to the approach to this difficult problem.
References
1. Turpin S, Maroves H, Costa P, Medeiros F, Ramos M, de Olivera JP. The solitary pulmonary nodule: a retrospective study of 119 cases. Acta Med Port 1998;11(6):
533–538.
2. Swensen SJ, Silverstein MD, Ilstrup DM, Schleck CD, Edell ES. The probability of malignancy in solitary pulmonary nodules. Application to small radiologically indeterminate nodules. Arch Intern Med 1997;157:849–855.
3. Caskey CI, Templeton PA, Zerhouni EA. Current evaluation of the solitary pulmonary nodule. Surg Clin North Am 1990;28(3):511–520.
4. Bousahra M 2nd, Clowry L Jr. Thoracoscopic fine needle aspiration of solitary pulmonary nodules. Ann Thorac Surg 1997;64:1191–1193.
5. Hazelrigg SR, Magee MJ, Cetindag LB. Video assisted thoracic surgery. Chest Surg Clin North Am 1998;8:763–774, vii. >>
» READ BOOK EXCERPT ONLINE »
Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Epigastric Distress:
Physical examination
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
A. General assessment. Obtain vital signs. Is the patient febrile—indicating an infectious cause? Tachycardia and hypotension can indicate dehydration or GI bleed. Is the patient in acute distress? Jaundiced?
B. Cardiopulmonary assessment. Evaluate the heart and lungs to rule out any cardiac or pulmonic process that could present with epigastric distress. Is there evidence of an arrhythmia, myocardial infarction, or congestive heart failure? Are there crackles or rales suggesting a pneumonia?
C. Abdominal examination. Are bowel sounds present? Decreased or absent bowel sounds can indicate a small bowel obstruction, acute surgical abdomen (appendicitis, perforated ulcer), or pancreatitis. Rebound tenderness should prompt consideration of an acute surgical abdomen. The right upper quadrant (RUQ) should be palpated. A palpable liver warrants evaluation for other signs of liver disease—jaundice, ascites, skin changes. Murphy’s sign—sudden cessation of the patient’s inspiratory effort during deep palpation of the RUQ—is suggestive of acute cholecystitis (3). Tenderness to palpation of the left upper quadrant can indicate splenic infarct such as seen with sickle cell disease. Tenderness of the midepigastric area can represent peptic ulcer disease, dyspepsia, “nonclassical” presentation of acute appendicitis, or any other of the above-mentioned conditions. A rectal examination with testing for occult blood should be a part of the examination, particularly with any concern about GI bleeding (Chapter 9.7).
Testing
A. Clinical laboratory tests. Laboratory tests should be directed by the history and physical examination. A complete blood count is indicated if signs are seen of infection or bleeding. An elevated white blood cell count is consistent with appendicitis or pneumonia. A decreased hemoglobin or hematocrit warrants further evaluation for GI bleed. Other laboratory tests that might be indicated by the history and physical examination include liver function tests (hepatitis, gallbladder disease), amylase and lipase (pancreatitis—although no single laboratory test is diagnostic for pancreatitis), creatine kinase-MB (CK-MB), and/or troponin (cardiac pathology). Laboratory testing for Helicobacter pylori is controversial except for those with documented PUD. Keep in mind that of patients who have PUD, 90% are infected with H. pylori and only 10% to 20% of patients infected with H. pylori develop PUD (4).
B. Diagnostic imaging. Plain film x-ray studies are helpful only if bowel obstruction or perforation is suspected. RUQ ultrasound is warranted if gallbladder disease or pancreatitis is suspected. Computed tomography scan of the abdomen could be considered in cases of difficulty in differentiating acute abdominal pain or when needed to evaluate for possible complications. Barium studies are not indicated in the acute setting, but can be helpful in the diagnostic workup for gastric ulcer, GERD, and esophagitis.
C. Endoscopy. Esophagogastrodoudenoscopy in the setting of an upper GI bleed may help to identify the source of the bleeding, assuming the patient is sufficiently stable to tolerate the procedure (Chapter 9.7). The diagnoses of PUD, gastritis, and esophagitis are best made using endoscopy, which also allows evaluation for the presence of H. pylori (5).
D. Other tests. Other tests useful in the evaluation of epigastric distress include an electrocardiogram to assess for possible cardiac disease and chest radiographs and a pulmonary function test to evaluate for possible pulmonary disease.
Diagnostic assessment
The key to the successful approach to a patient presenting with epigastric distress begins with a careful history. If the distress is of acute onset, a more urgent and directed evaluation is needed. Vital signs and physical examination should be directed to evaluate for fever (infection), hypotension (GI bleed), and non-GI causes (MI, ruptured aneurysm). Epigastric distress of a chronic nature can be evaluated using history, directed laboratory testing, and diagnostic imaging.
References
1. Scott M, Gelhot AR. Gastroesophageal reflux disease: diagnosis and management. Am Fam Physician 1999;59(5):1161–1169.
2. Isselbacher KJ, Podolsky DK. Approach to the patient with gastrointestinal disease. In: Fauci AS, ed. Harrison’s principles of internal medicine. New York: McGraw-Hill, 1998:1579–1583.
3. Swartz MH. Textbook of physical diagnosis, history and examination. Philadelphia: WB Saunders, 1994:324.
4. NIH Consensus Conference. Helicobacter pylori in peptic ulcer disease. JAMA 1994;
272(1):65–69.
5. Rank JM, Vennes JA. Gastrointestinal endoscopy. In: Bennet JC, Plum F, eds. Cecil textbook of medicine. Philadelphia: WB Saunders, 1996:636–642.
» READ BOOK EXCERPT ONLINE »
Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Respiratory Distress and Apnea:
Diagnostic Approach: Respiratory Distress
(The Diagnostic Approach to Symptoms and Signs in Pediatrics)
In preterminfants, most common cause of respiratory distress is respiratorydistress syndrome. In term infants, transient tachypnea, meconiumaspiration, pneumonia, and pneumothorax are most common lower respiratorytract disorders causing respiratory distress. Other nonpulmonarycauses of respiratory distress in neonates are congenital heartdisease, persistent fetal circulation, and septicemia. In infancyand childhood, most common causes of respiratory distress are bronchiolitis,croup, asthma, pneumonia, foreign body aspiration, and congenitalor acquired heart disease with cardiac failure.History and physical exam suggest mostlikely cause for respiratory distress. Oxygen saturation in roomair indicates degree of hypoxemia. Certain tests should be considereddepending on clinical circumstances:Airway radiography or endoscopy for upperairway obstructionChest radiography for lower respiratorydisorders or cardiac diseaseCBC for anemiaSerum electrolytes and creatinine;blood urea nitrogen; and venous/capillary pH for metabolicacidosisECG and 2-D echocardiography for cardiacfailureChest CT for any airway, lung, or mediastinal mass
» READ BOOK EXCERPT ONLINE »
Source: The Diagnostic Approach to Symptoms and Signs in Pediatrics, 2006
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