Wheezing - Case 1-6: 4-Month-Old Boy
Wheezing - Case 1-6: 4-Month-Old Boy: Excerpt from Pediatric Complaints and Diagnostic Dilemmas
I. History of Present Illness
A 4-month-old African-American boy was well until 9 days before admission, when
he developed fever to 38.9
°C and a cough. Seven days before admission, he was evaluated by his primary
physician and treated with ranitidine for suspected GER. Four days before
admission, he developed tachypnea and grunting and received nebulized
albuterol. On the day of admission he had continued fevers and worsening cough.
His oral intake was poor. He had taken only 2 to 3 ounces of breast milk every
4 hours over the past day. His urine output was also decreased. Several family
members had upper respiratory tract infections.
II. Past Medical History
He was born at 40 weeks' gestation after an uncomplicated pregnancy. He had received all of the
appropriate immunizations for age, including the second dose of
diphtheria-tetanus-alellular pertussis vaccine (DTaP). There was no family
history of asthma or sickle cell disease.
III. Physical Examination
T, 37.0°C; RR, 76/min; HR, 120 bpm; BP, 102/72 mm Hg; SpO2, 93% with 3 L O2/min by nasal cannula
Weight, 10th to 25th percentile; length, 10th percentile; head circumference,
10th percentile
He was awake and alert. The anterior fontanelle was open and flat. He had
flaring of the alae nasi. There were moderate intercostal, subcostal, and
supraclavicular retractions. Scattered rhonchi were present, with diminished
breath sounds at the bases bilaterally. There was no focal wheezing. The heart
sounds were normal. The spleen was palpable just below the left costal margin.
The remainder of the examination was normal.
IV. Diagnostic Studies
The WBC count was 10,200/mm3, with 15% band forms, 68% segmented neutrophils, and 12% lymphocytes. The
hemoglobin was 10.3 g/dL, and the platelet count was 277,000/mm
3. Arterial blood gas analysis revealed the following: pH, 7.42; PaCO2, 30 mm Hg; and PaO2, 90 mm Hg. Hepatic function panel revealed a total bilirubin of 0.3 mg/dL;
alanine aminotransferase, 55 U/L; aspartate aminotransferase, 82 U/L, and
lactate dehydrogenase, 3,280 U/L. No antigens to respiratory syncytial virus;
parainfluenza types 1, 2, and 3; influenza A and B; or adenovirus were detected
by immunofluorescence of nasopharyngeal aspirate. Serum immunoglobulin (Ig)
results were as follows: IgA, 24 mg/dL (normal range, 27 to 73 mg/dL); IgM, 528
mg/dL (normal range, 37 to 124); and IgG, 650 mg/dL (normal range, 292 to 816
mg/dL).
V. Course of Illness
The patient was treated with nebulized albuterol and a racemic mixture of
epinephrine without significant improvement in his respiratory status. An
echocardiogram showed normal cardiac anatomy. The patient required endotracheal
intubation for worsening respiratory distress. A chest radiograph suggested a
diagnosis (Fig. 1-9).
Discussion: Case 1-6
I. Differential Diagnosis
The most common cause of progressive respiratory distress during infancy is
bronchiolitis, which is most often caused by respiratory syncytial virus;
adenovirus; influenza viruses A and B; or parainfluenza viruses types 1, 2, and
3. The differential diagnosis of perihilar or diffuse infiltrates includes
B. pertussis, C. trachomatis, and M. pneumoniae. Herpes simplex virus and cytomegalovirus (CMV) can cause pneumonia in the
young infant. CMV pneumonia is frequently associated with hepatosplenomegaly,
thrombocytopenia, and lymphocytosis. PCP should be considered, particularly if
there are maternal risk factors for HIV infection. Other conditions
predisposing to PCP include primary B-cell defects, primary T-cell defects, and
combined defects. The immune disorders most likely to result in PCP are severe
combined immunodeficiency, DiGeorge anomaly, Wiskott-Aldrich syndrome, X-linked
agammaglobulinemia, and hyper-IgM syndrome.
Noninfectious causes of pneumonia include GER associated with pulmonary
aspiration. Occasionally, an anatomic defect such as TEF may predispose to
aspiration. Primary cardiac abnormalities (e.g., ventricular septal defect),
pulmonary vascular abnormalities, and impaired lymphatic flow (e.g., congenital
lymphangiectasia) can cause tachypnea and progressive respiratory distress in a
4-month-old child. Cystic fibrosis can masquerade as any of these conditions.
II. Diagnosis
The chest radiograph (Fig. 1-9) revealed hazy, ground-glass opacities
bilaterally. There was no pleural effusion.
The diagnosis of PCP was confirmed by Gomori methenamine silver staining of a
specimen obtained by bronchoalveolar lavage (BAL).
The patient was treated with intravenous trimethoprim-sulfamethoxazole (TMP-SMX;
20 mg/kg per day trimethoprim component) and prednisone. He required
ventilatory support for 5 days and made a gradual recovery. HIV DNA was
detected in the patient
's blood by polymerase chain reaction (PCR), confirming the underlying diagnosis
of HIV.
III. Incidence and Epidemiology
P. carinii is an opportunistic parasite with some features of protozoa but greater genetic
homology to fungi. Approximately 85% of immunocompetent children develop
asymptomatic primary infection by 3 years of age. Severe PCP after primary
infection occurs in immunocompromised infants and children.
The risk of PCP is related to the extent of immunosuppression and the use of
chemoprophylaxis. PCP occurs in children with the acquired immunodeficiency
syndrome (AIDS, 25% to 50%), severe combined immunodeficiency syndrome (25% to
50%), acute lymphocytic leukemia (10% to 20%), allogeneic bone marrow
transplantation (5%), and organ transplantation (2% to 10%) if no
chemoprophylaxis is given. Use of TMP-SMX prophylaxis reduces the PCP rate to
less than 5% in HIV-infected children. Children receiving agents that impair
cell-mediated immunity, including corticosteroids and cyclosporine, are at even
greater risk of developing PCP. Patients with a history of PCP are at high risk
for recurrence.
IV. Clinical Presentation
Infants with unrecognized HIV usually develop PCP between 2 and 6 months of age.
A bronchiolitis-like illness occurs, with gradually worsening tachypnea and
accessory muscle use. Physical examination reveals the absence of fever and a
paucity of findings on auscultation. Rales and cyanosis develop as the illness
progresses.
In older HIV-infected children, the spectrum of clinical manifestations varies.
The symptoms may initially be mild and slowly progressive, delaying the
diagnosis. High fevers are common. Findings on lung auscultation are often
unimpressive compared with the degree of dyspnea, tachypnea (80 to 100/minute)
and hypoxia. Scattered rales, rhonchi, or wheezes may be heard as the illness
resolves. In children with an underlying non-AIDS immunodeficiency disorder
such as leukemia or solid organ transplantation, the onset of symptoms occurs
more abruptly than in HIV-infected children, but the physical examination
findings are similar.
V. Diagnostic Approach
PCP should be considered in any immunocompromised patient with respiratory
symptoms, fever, and an abnormal chest radiograph. The diagnosis should also be
considered in any patient with risk factors for HIV infection. If the patient
does not have a known predisposing condition, testing to exclude HIV and
congenital immune deficiencies should be performed.
Chest roentgenogram. The chest radiograph typically shows bilateral alveolar disease, beginning in
the perihilar region and progressing to the periphery. The chest radiograph may
be normal in 10% of cases.
Examination of lower respiratory tract specimens. Definitive diagnosis requires demonstration of P. carinii in the pulmonary parenchyma or in lower respiratory tract secretions. Specimens
should be stained with either Gomori silver or fluorescein-labeled antibody
stains. The diagnostic yield of various procedures is as follows: induced
sputum (in children older than 5 years of age), 20% to 40%; BAL, 75% to 95%;
transbronchial biopsy, 75% to 95%; and open lung biopsy, 90% to 100%. The
optimal procedure to obtain a specimen depends on many factors, including the
age and clinical status of the patient. The traditional algorithm involves
examination of induced sputum in those patients older than 5 years of age,
followed by BAL if the sputum sample is negative. Open lung biopsy is reserved
for patients with a nondiagnostic BAL. Children younger than 5 years of age
should undergo BAL initially.
PCR, although still under investigation, may allow diagnosis with fewer invasive
procedures. PCR analysis of oral washes shows a sensitivity of 80% compared
with results of concomitant BAL.
Serum lactate dehydrogenase. Rising serum lactate dehydrogenase (LDH) reflects lung injury. Increased serum
LDH, although common in children with PCP, is a nonspecific finding.
Other studies. Additional studies should be performed to diagnose alternative or concomitant
respiratory conditions. Nasopharyngeal aspirates, sputum, or BAL specimens
should be sent for immunofluorescent viral antigen detection (respiratory
syncytial virus, influenza, parainfluenza, and adenovirus), viral culture, CMV
shell vial culture, and
Mycoplasma PCR.
Extrapulmonary involvement due to P. carinii is rare, but potential sites of dissemination include the lymph nodes, spleen,
retina, thyroid, gastrointestinal tract, and adrenal glands. Routine radiologic
imaging to exclude extrapulmonary manifestations of
P. carinii is not necessary.
VI. Treatment
TMP-SMX remains the treatment of choice for PCP in children. The oral route may
be used in mild cases, if the patient can reliably take and retain oral
medication. Most children require intravenous treatment. The course of
treatment is 14 to 21 days. If no improvement is demonstrated in 5 to 7 days,
treatment should be changed to pentamidine. Pentamidine, atovaquone, or
primaquine plus clindamycin may be used for children who are unable to tolerate
TMP-SMX. Adjunctive therapy with corticosteroids reduces the occurrence of
respiratory failure and improves oxygenation in moderately ill adults with PCP;
limited data in children suggest similar benefits.
Children with an episode of PCP require posttreatment prophylaxis with TMP-SMX
(5 mg/kg per day), either daily or three days per week for the duration of risk
(indefinitely for those with HIV). Because of the high risk of acquiring PCP
during the first year of life, all infants born to HIV-infected mothers require
PCP prophylaxis from 4 weeks to 12 months of age, regardless of their
CD4-positive T-lymphocyte count; prophylaxis may be discontinued sooner if HIV
infection is excluded. After 12 months of age, prophylaxis is required if the
percentage of CD4+ T cells is less than 15% or if the CD4+ count is less than
500 cells/
µL (less than 200 cells/µL in those older than 5 years of age). Patients in other high-risk groups,
including those with severe combined immune deficiency, lymphoproliferative
malignancy, and organ transplantation, also require PCP prophylaxis.
VII. References
1. Grubman S, Simonds RJ. Preventing Pneumocystis carinii pneumonia in human immunodeficiency virus-infected children: new guidelines for
prophylaxis.
Pediatr Infect Dis J 1996;15:165–168.
2. Hughes WT, Rivera GK, Schell MJ, et al. Successful intermittent
chemoprophylaxis for
Pneumocystis carinii pneumonia. N Engl J Med 1987;316:1627–1632.
3. Hughes WT. Pneumocystis carinii pneumonia. Semin Pediatr Infect Dis 2001;12:309–314.
4. Kovacs JA, Gill VJ, Meshnick S, et al. New insights into transmission,
diagnosis, and drug treatment of
Pneumocystis carinii pneumonia. JAMA 2001;386:2450–2460.
5. Opravil M, Marincek B, Fuchs WA, et al. Shortcomings of chest radiography in
detection
Pneumocystis carinii pneumonia. J Acquir Immune Defic Syndr Hum Retrovirol 1994;7:39–45.
6. Vargas SL, Hughes WT, Santolaya ME, et al. Search for primary infection by Pneumocystis carinii in a cohort of normal, healthy infants. Clin Infect Dis 2001;32:855–861.
7. Thea DM, Genevieve L, Weedon J, et al. Benefit of primary prophylaxis before
18 months of age in reducing the incidence of
Pneumocystis carinii pneumonia and early death in a cohort of 112 human immunodeficiency
virus-infected infants.
Pediatrics 1996;97:59–64.
Pictures
Book Source Details
- Book Title: Pediatric Complaints and Diagnostic Dilemmas
- Author(s): Samir S Shah MD; Stephen Ludwig MD
- Year of Publication: 2003
- Copyright Details: Pediatric Complaints and Diagnostic Dilemmas, Copyright © 2003 Lippincott Williams & Wilkins.
More About SCID
More Medical Textbooks Online about SCID
Review other book chapters online related to SCID:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: Immune Deficiency (The 5-Minute Pediatric Consult)
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
