# Clinical Cases: Respiratory Disorders

## Case 1: Croup (Laryngotracheobronchitis)

### Patient Demographics
- **Age:** 2-year-old male
- **Sex:** Male

### Chief Complaint
"He woke up with a barking cough and noisy breathing."

### History of Present Illness
A 2-year-old previously healthy male is brought to the emergency department at 2 AM by his parents. He had mild runny nose and low-grade fever (38.3C) for 2 days. Tonight, he woke up suddenly with a harsh, barking cough and noisy breathing. Parents describe the cough as sounding like a "seal barking." He is having difficulty breathing and appears scared. The symptoms seemed to worsen when he became upset and started crying. He has not had any similar episodes before. No choking episode or foreign body aspiration concerns. No recent travel or sick contacts beyond daycare.

### Growth Parameters
- **Weight:** 13 kg (50th percentile)
- **Height:** 87 cm (50th percentile)

### Physical Examination
- **General:** Anxious, mild distress, sitting upright in mother's lap, crying intermittently
- **Vital signs:** T 38.5C, HR 130, RR 32, SpO2 96% on room air
- **HEENT:**
  - Mild nasal congestion, clear rhinorrhea
  - Oropharynx mildly erythematous
  - No drooling
- **Neck:** No stridor at rest; inspiratory stridor when agitated/crying
- **Cardiovascular:** Tachycardia, otherwise normal
- **Respiratory:**
  - Inspiratory stridor when upset
  - Barking cough
  - Mild subcostal retractions
  - Good air entry bilaterally
  - No wheezing
- **Skin:** Warm, no mottling
- **Neurologic:** Alert, appropriate for age

### Westley Croup Score
- Stridor: 1 (with agitation only)
- Retractions: 1 (mild)
- Air entry: 0 (normal)
- Cyanosis: 0 (none)
- Consciousness: 0 (normal)
- **Total: 2 (mild croup)**

### Workup
- **Clinical diagnosis** - no imaging or labs required for typical presentation
- **If obtained:**
  - Neck X-ray (AP): "Steeple sign" - subglottic narrowing (not required for diagnosis)

### Diagnosis
**Viral croup (acute laryngotracheobronchitis) - moderate severity**

### Clinical Reasoning
The classic presentation of a toddler with prodromal URI symptoms followed by sudden onset of barky "seal-like" cough, inspiratory stridor, and hoarse voice in the fall/winter is pathognomonic for croup. The age (6 months to 3 years peak incidence), timing (worse at night), and clinical features make this a clinical diagnosis. Parainfluenza virus is the most common etiology. The Westley score of 2 indicates mild croup, though the stridor with agitation suggests moderate severity requiring treatment.

### Management
1. **Dexamethasone:** 0.6 mg/kg PO x 1 dose (max 10 mg) - single dose effective for all severity
2. **Keep child calm:** Minimize interventions that cause distress (crying worsens obstruction)
3. **Observation:** May discharge home after observation period (typically 2-4 hours) if:
   - No stridor at rest
   - Good oral intake
   - Normal oxygen saturation
   - Reliable follow-up
4. **Parent education:**
   - Cool night air may provide temporary relief
   - Return for worsening stridor at rest, increased work of breathing, drooling, or color change
5. **If moderate-severe (stridor at rest):**
   - Add nebulized racemic epinephrine 0.5 mL of 2.25% solution
   - Observe for 3-4 hours after epinephrine (rebound phenomenon)
6. **If no improvement with treatment:** Consider alternative diagnoses (bacterial tracheitis, epiglottitis, foreign body)

### Clinical Image
![Steeple sign on X-ray](case_01_image.jpg)

**Image Description:** Anteroposterior neck radiograph demonstrating the "steeple sign" - subglottic narrowing characteristic of croup, showing the tapered tracheal air column.

**Source:** Radiopaedia
**URL:** https://radiopaedia.org/cases/croup-steeple-sign-1
**License:** CC BY-NC-SA 3.0

---

## Case 2: Bronchiolitis

### Patient Demographics
- **Age:** 6-month-old male
- **Sex:** Male

### Chief Complaint
"He's been wheezing and having trouble breathing."

### History of Present Illness
A 6-month-old male born at 36 weeks gestation presents with 3 days of nasal congestion and cough, now with increased work of breathing and decreased feeding over the past 24 hours. He initially had clear rhinorrhea and sneezing, followed by worsening cough that sounds "wet." Parents noticed fast breathing and a "whistling" sound when he breathes. He is taking only half his usual bottle volumes and has had fewer wet diapers. No fever initially, but temperature was 38.0C this morning. His 4-year-old sister had a cold last week. He has no history of wheezing or respiratory problems.

### Growth Parameters
- **Weight:** 7.5 kg (40th percentile)
- **Length:** 66 cm (35th percentile)
- **Head circumference:** 43 cm (50th percentile)

### Physical Examination
- **General:** Tired-appearing infant, mild-moderate respiratory distress
- **Vital signs:** T 38.0C, HR 160, RR 56, SpO2 91% on room air
- **HEENT:** Copious clear nasal discharge, mild nasal flaring, pharynx clear
- **Cardiovascular:** Tachycardia, no murmur
- **Respiratory:**
  - Tachypnea with subcostal and intercostal retractions
  - Nasal flaring
  - Audible wheezing and crackles
  - Scattered expiratory wheezes and fine crackles bilaterally
  - Prolonged expiratory phase
  - No grunting
- **Abdomen:** Soft
- **Skin:** No cyanosis, mild perioral pallor
- **Neurologic:** Alert but less interactive than usual per parents

### Workup
- **SpO2:** 91% on room air (improves to 95% on 1 L NC)
- **Nasal swab RSV PCR:** Positive
- **Chest X-ray (if obtained):** Hyperinflation, peribronchial thickening, patchy atelectasis (not routinely recommended)
- **CBC, CMP:** Not indicated for typical bronchiolitis

### Diagnosis
**RSV bronchiolitis, moderate severity**

### Clinical Reasoning
This is a classic presentation of bronchiolitis: an infant <12 months with URI prodrome followed by lower respiratory symptoms (wheezing, crackles, tachypnea, retractions) during RSV season. The combination of prematurity (36 weeks), age <12 months, hypoxemia (SpO2 <92%), moderate respiratory distress, and decreased oral intake indicates moderate severity requiring hospitalization. RSV is confirmed by PCR, though testing is not required for clinical diagnosis.

### Management
1. **Hospitalization** indicated for:
   - Hypoxemia (SpO2 <92% on room air)
   - Moderate-severe respiratory distress
   - Decreased oral intake with dehydration risk
   - Age <6 months with RSV
2. **Supportive care (mainstay of treatment):**
   - Supplemental oxygen via nasal cannula to maintain SpO2 >90-92%
   - Nasal suctioning (gentle, before feeds and as needed)
   - IV or NG fluids if unable to maintain oral intake
   - Cardiorespiratory monitoring
3. **NOT recommended (per AAP guidelines):**
   - Bronchodilators (albuterol) - no proven benefit
   - Corticosteroids - no proven benefit
   - Antibiotics - unless secondary bacterial infection suspected
   - Routine chest X-ray
4. **Escalation criteria:**
   - High-flow nasal cannula if escalating oxygen needs
   - CPAP/BiPAP if progressive distress
   - ICU for impending respiratory failure, apnea
5. **Discharge criteria:**
   - SpO2 >90% on room air for 12-24 hours
   - Adequate oral intake
   - Decreased work of breathing
6. **Prevention:** Palivizumab for high-risk infants (preterm <29 weeks, CHD, CLD)

### Clinical Image
![Chest X-ray bronchiolitis](case_02_image.jpg)

**Image Description:** Chest radiograph demonstrating hyperinflation, peribronchial thickening, and patchy atelectasis characteristic of bronchiolitis.

**Source:** Radiopaedia
**URL:** https://radiopaedia.org/cases/bronchiolitis-3
**License:** CC BY-NC-SA 3.0

---

## Case 3: Acute Asthma Exacerbation

### Patient Demographics
- **Age:** 7-year-old female
- **Sex:** Female

### Chief Complaint
"She's having an asthma attack and her inhaler isn't working."

### History of Present Illness
A 7-year-old female with known asthma presents with progressive shortness of breath and wheezing for 2 days, worsening significantly today. She developed cold symptoms 4 days ago with runny nose and cough. She has been using her albuterol MDI every 2-3 hours with minimal relief. This morning she could not complete sentences without stopping to breathe. She has been coughing frequently, especially at night. She has a history of 2 prior ED visits for asthma in the past year, with one requiring a short course of oral steroids. She uses a daily inhaled corticosteroid (fluticasone) but admits to missing doses frequently. No recent fever. History of environmental allergies. Family history of asthma in mother.

### Growth Parameters
- **Weight:** 25 kg (50th percentile)
- **Height:** 122 cm (50th percentile)

### Physical Examination
- **General:** Anxious, sitting upright, speaking in short phrases (3-4 words), using accessory muscles
- **Vital signs:** T 37.4C, HR 128, RR 32, BP 108/70, SpO2 90% on room air
- **HEENT:** Nasal congestion, clear rhinorrhea
- **Neck:** Suprasternal retractions, no cervical lymphadenopathy
- **Cardiovascular:** Tachycardia, no murmur
- **Respiratory:**
  - Moderate respiratory distress
  - Accessory muscle use (sternocleidomastoid, intercostal)
  - Decreased air entry bilaterally
  - Diffuse expiratory wheezes bilaterally, scattered inspiratory wheezes
  - I:E ratio 1:3 (prolonged expiration)
  - No paradoxical breathing
- **Skin:** No cyanosis, mild diaphoresis
- **Neurologic:** Alert, anxious

### Workup
- **Peak flow:** 120 L/min (50% predicted - moderate obstruction)
- **SpO2:** 90% on room air (92% on 2 L NC)
- **Chest X-ray:** Hyperinflation, no infiltrates, no pneumothorax
- **Blood gas (if severe):** Not obtained for this severity

### Diagnosis
**Moderate-severe acute asthma exacerbation (viral-induced)**

### Clinical Reasoning
This child has a moderate-severe asthma exacerbation based on: speaking in phrases (not sentences), accessory muscle use, SpO2 90-95%, peak flow 50% predicted, and poor response to home bronchodilator therapy. Viral URI is the most common trigger. Risk factors for severe exacerbation include prior ED visits, prior oral steroid use, and poor adherence to controller medication. The prolonged expiratory phase and decreased air entry indicate significant airflow obstruction.

### Management
1. **Immediate treatment:**
   - Oxygen via nasal cannula to maintain SpO2 >94%
   - Continuous nebulized albuterol (0.5 mg/kg/hour, max 15 mg/hour) OR albuterol MDI 4-8 puffs every 20 min x 3
   - Ipratropium bromide 0.5 mg nebulized with first 3 albuterol treatments
   - Systemic corticosteroids: Prednisone 2 mg/kg PO (max 60 mg) or methylprednisolone IV if unable to tolerate PO

2. **Reassess after initial treatment:**
   - Peak flow, work of breathing, SpO2
   - If improving: Space bronchodilators to every 1-2 hours

3. **If severe/refractory:**
   - Magnesium sulfate 50 mg/kg IV (max 2 g) over 20 min
   - Consider terbutaline infusion
   - ICU for impending respiratory failure

4. **Disposition:**
   - Admit if requiring oxygen or frequent bronchodilators after 4-6 hours
   - Discharge criteria: Peak flow >70% predicted, SpO2 >94% on RA, symptoms controlled with q4h bronchodilator

5. **Discharge medications:**
   - Prednisone 1-2 mg/kg/day x 5 days (no taper needed)
   - Albuterol MDI with spacer every 4-6 hours as needed
   - Resume/optimize controller medication

6. **Asthma action plan review** and follow-up in 1-2 weeks

### Clinical Image
![Chest X-ray asthma](case_03_image.jpg)

**Image Description:** Chest radiograph demonstrating hyperinflation with flattened diaphragms characteristic of acute asthma exacerbation.

**Source:** Radiopaedia
**URL:** https://radiopaedia.org/cases/asthma-acute-exacerbation
**License:** CC BY-NC-SA 3.0