Cough - Case 4-6: 4-Month-Old Boy
Cough - Case 4-6: 4-Month-Old Boy: Excerpt from Pediatric Complaints and Diagnostic Dilemmas
I. History of Present Illness
A 4-month-old boy, who was born prematurely at 28 weeks' gestation, presented with a 1-week history of a cough. Over the next 4 days,
his mother reported an increasing cough with no history of fever or rhinorrhea.
He had decreased oral intake and decreased urine output. He had some
posttussive emesis and no diarrhea. His uncle had been sick for the previous 3
weeks with rhinorrhea and a cough.
II. Past Medical History
He was born at 28 weeks' gestation and required endotracheal intubation for a short period after birth.
While in the newborn intensive care unit, he had course of necrotizing
enterocolitis that did not require surgery. He was ultimately discharged home
with an apnea monitor and oral caffeine. However, his mother had recently run
out of this medication, and he was no longer receiving it. He had two siblings
who were healthy.
III. Physical Examination
T, 37.2°C; RR, 27 to 40/min; HR, 138 bpm; BP, not obtained; SpO2, 96% in room air and decreasing to 93% with feeds
Weight, 25th percentile
On examination, he was alert with moderate respiratory distress and frequent
episodes of coughing. His chest examination was significant for grunting with
substernal, intercostal, and supraclavicular retractions. Rales were
appreciated on the right with good aeration throughout. No wheezes were heard.
The remainder of his physical examination was within normal limits.
IV. Diagnostic Studies
The complete blood count revealed 25,400 WBCs/mm3, with 51% lymphocytes, 17% atypical lymphocytes, 25% segmented neutrophils, and
6% monocytes. The hemoglobin was 12.3 gm/dL, and the platelet count was
494,000/mm
3.
VI. Course of Illness
The patient received an albuterol nebulizer treatment, with no significant
relief. While in the emergency department, he had frequent episodes of
coughing, with two episodes complicated by bradycardia to 60 bpm and
desaturations to 80%. A chest radiograph was obtained (Fig. 4-5). A presumptive
diagnosis was made, and the appropriate test was sent for confirmation of the
diagnosis.
Discussion: Case 4-6
I. Differential Diagnosis
A cough in infancy is most likely related to an infectious process, with viral
processes the leading causes. Respiratory syncytial virus is a common cause of
cough. However, other infectious etiologies should always be considered. Even
with good adherence to vaccine regimens, bacterial infections such as
B. pertussis are possible in infants. M. pneumoniae infections also occur rarely in infants.
Reactive airways disease, most often secondary to viral infection, is also a
common cause of cough in infancy. GER should be considered as well, even if
gastrointestinal symptoms are few.
Less common causes for cough in infancy include congenital malformations such as
tracheoesophageal fistula, tracheobronchomalacia, vascular rings, lobar
emphysema, bronchogenic cysts, pulmonary sequestration, laryngeal cleft, and
cystic adenomatoid malformation. Furthermore, one should attempt to elicit a
history for any possible swallowing disorder that might lead to recurrent
aspiration.
Other, less common causes of cough in infancy include CF, congestive heart
failure, interstitial pneumonitis, and congenital immunodeficiencies.
This patient's history is suggestive of an infectious etiology, because he was in good health
until approximately 1 one week before presentation. However, his history of
prematurity should add one more disease to the differential diagnosis:
bronchopulmonary dysplasia. Such patients are also more likely to develop
reactive airways disease in response to a viral infection.
II. Diagnosis
Chest radiography revealed bilateral perihilar infiltrates (see Fig. 4-5). Given
the combination of the radiographic findings, worsening cough, dramatic
leukocytosis, lymphocytosis with a substantial number of atypical lymphocytes,
and contact with an adult with prolonged cough, a presumptive diagnosis of
B. pertussis infection was made. A nasopharyngeal specimen was sent for B. pertussis polymerase chain reaction (PCR) analysis and was positive. Therefore, the diagnosis is infection with B. pertussis.
III. Incidence and Epidemiology
B. pertussis, a gram-negative bacillus, is the causative organism for what is commonly
referred to as whooping cough. A whooping cough syndrome can also be seen with
Bordetella parapertussis, M. pneumoniae, C. trachomatis, Chlamydia pneumoniae, and some adenoviruses.
Pertussis is considered one of the most highly communicable diseases, with
transmission occurring via contact with respiratory tract secretions of an
infected patient. With waning immunity from childhood vaccination, adults and
adolescents are commonly the source of infection in infants and young children.
The true incidence of pertussis is unknown, because many cases in adolescents
and adults are unrecognized. However, it is known to be a worldwide threat,
with an estimated 40,000,000 cases and 360,000
deaths per year. In general, the disease is endemic, but there are 3- to 5-year
cycles of epidemics that occur in addition to the endemic levels. For unknown
reasons, girls are affected at much higher rates and with higher morbidity than
boys.
IV. Clinical Presentation
The incubation period is 1 to 3 weeks. Infection is divided into three stages.
The catarrhal stage begins with symptoms of a mild upper respiratory tract
infection and lasts a few days to 1 week. The paroxysmal stage follows, with
the characteristic inspiratory whoop. Posttussive emesis is common, and fever
is infrequent. The whoop is typically absent in infants, because they are
unable to generate the force needed for this maneuver.
Increased intrathoracic and intraabdominal pressures during coughing may lead to
conjunctival and scleral hemorrhages, petechiae on the upper body, epistaxis,
and retinal hemorrhages. In infancy, apnea is a common complication of
B. pertussis infections. Even young adults can have episodes of laryngospasm. Seizures result
from either hypoxia or hyponatremia due to inappropriate secretion of
antidiuretic hormone.
In most cases, a pertussis infection lasts 6 to 10 weeks, but it is not uncommon
for infants and children to have persistent coughs for 3 to 4 months.
Respiratory distress between paroxysms of coughing suggests superinfection with
various viruses (adenovirus, respiratory syncytial virus, cytomegalovirus) or
bacteria (
S. pneumoniae, S. aureus). Other complications include pneumothorax, encephalopathy, and feeding
difficulties in infancy. The disease is most severe in infants younger than 1
year of age, especially premature infants.
V. Diagnostic Approach
Blood counts. Leukocytosis (WBC count greater than 15,000/mm3), usually due to an absolute lymphocytosis, is present in more than 75% of
unvaccinated children during the late catarrhal and paroxysmal stages. The
degree of lymphocytosis typically parallels the severity of illness.
Lymphocytosis is less common and less extreme in previously vaccinated children
who develop pertussis. Eosinophilia is uncommon.
Chest roentgenogram. Pulmonary infiltrates are often seen and are most commonly perihilar.
Classically, a
“shaggy” right heart border is seen, but the finding is nonspecific. Chest radiography
should be performed to exclude other causes of cough or respiratory distress,
such as pneumonia or congestive heart failure.
Bordetella pertussis culture. Growing the organism in culture is certainly the gold standard for diagnosis.
However, during the paroxysmal phase, the ability to grow the organism
decreases significantly.
Direct immunofluorescent assay. This is performed on nasopharyngeal secretions and has a variable sensitivity
and low specificity. Furthermore, it requires a significant level of skill and
is therefore not very reliable or reproducible.
Polymerase chain reaction. PCR has been used to document B. pertussis infections even after the organism will no longer grow in culture. Therefore, it
is able to detect disease even in the late paroxysmal stage. This is the
preferred method to confirm the diagnosis of pertussis.
VI. Treatment
Because young infants with pertussis have a high risk for complications, there
should be a low threshold for admitting these patients. Many of these infants
require admission to the intensive care unit to monitor for apneic episodes and
neurologic sequelae.
Infants should be treated with a macrolide antibiotic, and erythromycin is the
most common choice. The length of therapy is generally recommended to be 14
days. Azithromycin and clarithromycin appear to be effective as well. There is
some controversy as to whether antibiotics given during the catarrhal stage
decrease disease severity. However, antibiotics should still be given, even in
the paroxysmal stage, because they limit the spread of the disease to others.
Studies are underway to assess the efficacy of pertussis immune globulin as an
adjunctive therapy in extremely ill infants.
Antibiotic prophylaxis is recommended for all household members and close
contacts and usually consists of 10 to 14 days of erythromycin. Prevention is
essential to limit the morbidity and mortality from pertussis, and the
acellular pertussis vaccine is currently the recommended form. It is given in
combination with diphtheria and tetanus toxoids (DTaP). It is recommended that
children receive five doses before school entry.
VII. References
1. American Academy of Pediatrics. Pertussis. In: Pickering LK, Peter, G, Baker
CJ, et al., eds.
2000 Red Book: report on infectious diseases, 25th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2000:448.
2. Hewlett EL. Bordetella species. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's principles and practice of infectious diseases, 5th ed. Philadelphia: Churchill Livingstone, 2000:2414–2419.
3. Hoppe JE. Neonatal pertussis. Pediatr Infect Dis J 2000;19:244–247.
4. Long SS, Edwards KM. Bordetella pertussis (pertussis) and other species. In: Long SS, Pickering LK, Prober CG, eds. Principles and practice of pediatric infectious diseases, 2nd ed. New York: Churchill Livingstone, 2003:880–888.
5. Senzilet LD, Halperin SA, Spika JS, et al. Pertussis is a frequent cause of
prolonged cough illness in adults and adolescents.
Clin Infect Dis 2001;32:1691–1697.
6. Sprauer MA, Cochi SL, Zell ER, et al. Prevention of secondary transmission
of pertussis in households with early use of erythromycin.
Am J Dis Child 1992;146:177–181.
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.
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