Respiratory

Question 1

Cystic Fibrosis

Mode of inheritance?
Most common mutation?
What type of sweat?

Answer 1

Cystic Fibrosis

• -AR, delta F508 on chr 7
• -dysfunctional CFTR protein

Pathophysiology of Abnormal Secretions

1. Lungs
   - -increased Na absorption, decreased Cl secretion
   - -decreased Na, H2O content of mucous
2. Pancreas
   - -decreased Na, HCO3, and H20 secretion
   - -retention of pancreatic enzymes
3. Intestines
   - -decreased Cl, HCO3, and H20
   - -desiccation of intraluminal contents
4. Hepatobiliary
   - -decreased biliary secretions
5. Sweat Glands
   - -unable to reabsorb NaCl
   - -hypertonic sweat

Question 2

Cystic Fibrosis: respiratory manifestations
*productive cough, hyper-resonance, expiratory wheezing, clubbing

1. What type of lung dz by age 5?
2. Two most common causes of CF-related pneumonia in infants and young children?
   - -gram pos cocci in clusters
   - -gram neg coccobacilli
3. Most common cause of CF-related pneumonia in adolescents and adults?
   - -gram neg rod

Answer 2

Cystic Fibrosis

*obstructive lung dz by age 5; then progresses to restrictive (fibrosis)

CF-Related Pneumonia

• Infants and young children
  1. S. aureus
• -gram pos cocci in clusters
  2. H. influenzae
• -gram neg coccobacilli

*Adolescents and adults
1. Pseudomonas aeruginosa
–gram neg rod
2. Burkholderia cepacia
–gram neg rod
NB: Use of macrolides to tx gram neg can lead to sensorineural hearing loss

Question 3

Cystic Fibrosis: extra-respiratory manifestations

1. Pancreas
   - -deficiency of absorption of what vitamins?
2. Intestines
   - -what finding at birth?
3. Hepatobiliary
   - -decreased biliary secretions
   - -cholecystitis, cholelithiasis
4. Sweat Glands
   - -unable to reabsorb NaCl
   - -hypertonic sweat
   - -hypotonic dehydration
5. Genitourinary
   * Males
   - -azoospermia
   * Females
   - -endocervitis

Answer 3

Cystic Fibrosis: extra-respiratory manifestations

1. Pancreas
   - -retention of pancreatic enzymes
   - -destruction of alpha and beta cells
   - -malabsorption, DM, greasy and foul-smelling stools, fat-soluble vitamin deficiencies
2. Intestines
   - -dessication of intraluminal contents
   - -meconium ileus, intestinal obstruction
3. Hepatobiliary
   - -decreased biliary secretions
   - -cholecystitis, cholelithiasis
4. Sweat Glands
   - -unable to reabsorb NaCl
   - -hypertonic sweat (“salty baby”)
   - -hypotonic dehydration
5. Genitourinary
   * Males
   - -congenital absence of vas deferens –> azoospermia, infertility
   * Females
   - -abnormal menstrual cycle, thick cervical mucous –> decreased fertility
   * Both
   - -delayed puberty due to chronic lung dz and malnutrition

Question 4

Cystic Fibrosis: management

1. Clear airway secretions
   - -aerosol tx; albuterol/saline
   - -what mucolytic?
2. Most common aerosolized antibiotic?
3. What antibiotic regimen to cover pseudomonas?
4. What antibiotic to cover S. aureus?
5. Pancreatic enzyme replacement
6. Vitamin supplementation (ADEK)
7. Adequate fluids with exercise and hot weather

Answer 4

Cystic Fibrosis: management

1. Clear airway secretions
   - -aerosol tx; albuterol/saline
   - -human recombinant DNAse (mucolytic)
2. Tobramycin
   - -aerosolized antibiotic
3. Piperacillin, plus tobramycin or ceftazidime
   - -to cover pseudomonas (more common in adults)
4. Vancomycin
   - -to cover S. aureus (more common in young children)
5. Pancreatic enzyme replacement
6. Vitamin supplementation (ADEK)
7. Adequate fluids with exercise, hot weather

Question 5

Meconium Aspiration

CXR findings

• -patchy infiltrates
• -re: diaphragm?

Answer 5

Meconium Aspiration

Pathophysiology
hypoxia, fetal distress –> meconium passed –> aspirated in utero or in first postnatal breath –> airway obstruction, pneumonitis –> respiratory failure, pulmonary HTN

CXR: patchy infiltrates, flattened diaphragm

Question 6

tachypnea following birth of a term infant delivered by C-section; resolves within 48 hours

Dx?

Answer 6

Transient Tachypnea of the Newborn

Epidemiology
–term infant delivered by C-section; or rapid second stage of labor

Pathophys
–inadequate alveolar fluid clearance –> mild pulmonary edema

CXR
–perihilar streaking

Prognosis
–self-resolving

Question 7

DDx: stridor in infants and children

1. “barky cough” with fever, rhinorrhea, congestion; s/s improve with racemic epinephrine or bronchodilators; most common age 6m-6y
2. persistent stridor; worsens in supine position; improves in prone position
3. stridor that improves with neck extension; dysphagia; associated with cardiac abnormalities

Answer 7

DDx: stridor in infants and children

1. Laryngotracheobronchitis (Croup)
   - -“barky cough” with fever, rhinorrhea, congestion
   - -s/s improve with racemic epinephrine, bronchodilators
   - -most common age 6m-6y
2. Laryngomalacia
   - -persistent stridor
   - -worsens in supine position; improves in prone position
3. Vascular Ring
   - -stridor that improves with neck extension
   - -associated with cardiac abnormalities
   - -dysphagia
4. Foreign body aspiration
   - -Dx and Tx –> bronchoscopy

Question 8

Triad: recurrent sinusitis, bronchiectasis, and dextrocardia (situs inversus)

Dx?

Answer 8

Kartagener Syndrome
–AR

Path: aberrant production or attachment of dynein arms –> ciliary dyskinesia

Triad

• -recurrent sinusitis
• -bronchiectasis
• -sinus inversus