Dds for a child with fever and cough

Reading File

Finding Sources

Reading File

I now have solid textbook content. Here is a thorough differential diagnosis organized by category.

Differential Diagnosis: Fever + Cough in a Child

Age is the single most important factor for narrowing this list. The categories below apply broadly; distinguishing features help guide you further.

Infectious - Upper Respiratory

Diagnosis	Key Distinguishing Features
Viral URTI (rhinovirus, adenovirus, etc.)	Most common cause overall; runny nose, mild fever, no respiratory distress
Influenza	Abrupt onset, high fever, myalgia, headache, prominent dry cough
COVID-19	Variable presentation; loss of smell/taste in older children, may mimic influenza
Pharyngitis / Tonsillopharyngitis	Sore throat, exudate on tonsils, tender anterior cervical nodes
Sinusitis	Persistent cough (especially postnasal drip at night), facial pain, >10 days of URI symptoms

Infectious - Croup (Laryngotracheobronchitis)

Typical age: 6 months to 3 years (peak ~2 years)
Parainfluenza virus types 1-3 (most common cause); also RSV, influenza, adenovirus
Classic: barky/brassy cough, inspiratory stridor, low-grade to high fever (up to 39-40°C)
Preceded by 1-2 days of URI symptoms
Distinguishing clue: responds to nebulized racemic epinephrine and dexamethasone
Swanson's Family Medicine Review

Infectious - Lower Respiratory

Diagnosis	Key Distinguishing Features
Bronchiolitis (RSV most common)	Infants <2 years; wheezing, tachypnea, subcostal retractions, seasonal (winter); no prior atopy
Community-acquired pneumonia (bacterial)	Lobar consolidation on CXR, high fever, focal crackles/rhonchi, tachypnea, grunting; S. pneumoniae most common
Viral pneumonia	More diffuse infiltrates, less toxic appearance; atypicals can look similar
Atypical pneumonia (Mycoplasma, Chlamydophila)	School-age children; gradual onset, "walking pneumonia," dry persistent cough, low-grade fever
Pertussis (whooping cough)	Paroxysmal cough with whoop + post-tussive vomiting + apnea in infants; no/low fever; Bordetella pertussis
Tuberculosis	Prolonged fever, weight loss, diffuse adenopathy, exposure history; must not miss

Rosen's Emergency Medicine, Table 163.1

Infectious - Other

Diagnosis	Key Distinguishing Features
Epiglottitis	Ages 2-7 years (though now rare post-Hib vaccine); sudden high fever, drooling, muffled voice ("hot potato"), tripod position - airway emergency
Bacterial tracheitis	Rare but life-threatening; high fever, croupy cough, toxic appearance, does not respond to croup treatment
Measles	Cough + coryza + conjunctivitis + Koplik spots, then rash; fever can be high
Human Bocavirus (HBoV)	Causes URTI and LRTI including bronchiolitis and pneumonia; fever, cough, wheeze
RSV	Classically bronchiolitis in infants; fever, cough, wheezing, seasonal

Anatomic / Congenital (may present with recurrent or chronic cough + fever)

Diagnosis	Key Distinguishing Features
Cystic fibrosis	Chronic/recurrent cough, loose stools, failure to thrive, salty sweat, clubbing
Foreign body aspiration	Toddler; sudden onset choking episode, asymmetric breath sounds, unilateral hyperinflation on CXR
Tracheoesophageal fistula	Coughing/choking with feeds, recurrent aspiration pneumonia
Gastroesophageal reflux with aspiration	Recurrent pneumonia, emesis, weight loss
Congestive heart failure / Congenital heart disease	Murmur, hepatomegaly, cardiomegaly on CXR, rales
Vascular ring / tracheal anomaly	High-pitched brassy cough, stridor, dysphagia
Mediastinal mass	Chest pain, mediastinal widening on CXR

Rosen's Emergency Medicine, Table 163.1

Reactive Airway / Asthma

Recurrent cough + wheeze + fever (as a trigger); family/personal history of atopy
Look for reversibility with bronchodilators
Distinguish from bronchiolitis (infants, first episode, seasonal, no atopy)

Rare / Don't Miss

Diagnosis	Clue
Lung abscess	Prolonged fever, productive foul-smelling cough, CXR air-fluid level
Empyema	Pleuritic chest pain, decreased breath sounds, pleural effusion on CXR
Lymphoma / mediastinal malignancy	Progressive symptoms, B symptoms (night sweats, weight loss), superior mediastinal widening

Age-Based Quick Reference

Age Group	Top Diagnoses to Consider First
<2 months	RSV bronchiolitis, bacterial pneumonia (group B Strep, S. aureus), pertussis
2-24 months	Bronchiolitis (RSV), viral URTI, croup, pneumonia, pertussis
2-5 years	Croup, viral URTI/pneumonia, asthma exacerbation, foreign body aspiration
5-12 years	Mycoplasma ("atypical") pneumonia, influenza, asthma, pneumococcal pneumonia
Any age	TB if exposure history, CF if recurrent, epiglottitis if toxic + drooling

Red Flags Requiring Urgent Action

Stridor at rest + toxicity = epiglottitis or bacterial tracheitis (airway emergency)
Oxygen saturation <92% = urgent intervention
Altered mental status, apnea, or cyanosis = critical illness
Respiratory rate >60/min (infant), >40/min (child)

Sources: Rosen's Emergency Medicine (Table 163.1 - Differential Diagnosis of Asthma/Respiratory), Swanson's Family Medicine Review (Croup chapter), Scott-Brown's Otorhinolaryngology (Croup & Bacterial Tracheitis), Tietz Textbook of Laboratory Medicine (RSV/Bronchiolitis), Harrison's Principles (HBoV, respiratory pathogens)

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