Rosen & Barkin's 5-Minute Emergency Medicine Consult (187 page)

• Most affected patients should be admitted to the hospital.
  
• ICU admission is required for any instability or cyanosis.
  

Reversible causes of hypoxia:

• Reactive airway disease responsive to β-agonists
  
• Pulmonary edema in patient with known CHF but no suspicion of myocardial injury and diuresis
  

• First assume hypoxemia and immediately assess airway and breathing
  
• Chocolate-colored blood or unchanging oxygen saturation despite aggressive administration of oxygen: Think methemoglobinemia.
  

• BheemReddy S, Messineo F, Roychoudhury D. Methemoglobinemia following transesophageal echocardiograph: A case report and review.
  Echocardiography
  . 2006;23(4):319–321.
  
• Kurklinsky AK, Miller VM, Rooke TW. Acrocyanosis: The flying Dutchman.
  Vasc Med.
  2011;16(4):288–301.
  
• McMullen SM, Patrick W.
  Cyanosis. Am J Med.
  2013;126(3):210–212.
  
• LeBlond R, Brown D, DeGowin R.
  DeGowin’s Diagnostic Examination
  . 9th ed. McGraw Hill Companies; 2009.
  
• Stack A. Cyanosis.
  Synopsis of Pediatric Emergency Medicine.
  4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:64–67.
  

CODES

• 770.83 Cyanotic attacks of newborn
  
• 782.5 Cyanosis
  

BASICS

• Defect of the cystic fibrosis transmembrane conductance regulator (CFTR)
  
• CFTR functions as an ATP-regulated chloride channel that regulates the activity of chloride and sodium channels on the cell surface:
  
  • Abnormal electrolyte transport in exocrine glands and secretory epithelia
    
  • Decreased exocrine pancreatic function with malabsorption
    
  • Thickened mucus, recurrent pulmonary infections, and progressive obstructive damage to the lungs
    
  • Recurrent sinus disease
    
• Occurs in 1:3,600 live births in White population, 1:29,000 in African American population; 1:6,500 in Hispanic population
  
• 30% of cases diagnosed by newborn screening
  
• 75% cases diagnosed in the 1st 2 yr of life
  
• ∼30,000 children and young adults in US have CF.
  
• Median life expectancy in US about 40 yr.
  
• 40% of CF patients are older than 18 yr.
  
• 10 million Americans are unknown, asymptomatic carriers of the defective gene.
  
• 16% of lung transplants in US due to CF
  

Recessively inherited genetic disease, involving the CFTR gene on the long arm of chromosome 7:

• Different mutations; variable phenotypes.
  
• Classic disease: Homozygous DF508 mutation.
  
• Most common lethal genetic disease in US
  

Common organisms in patients with pneumonia; often multiple drug resistance:

• Staphylococcus aureus:
  
  • MSSA/MRSA
    
• Pseudomonas aeruginosa:
  
  • Prevalence increases with age; >70% of adults are chronically infected.
    
• Haemophilus influenzae
  
• Stenotrophomonas maltophilia
  
• Burkholderia cepacia:
  
  • Prevalence 3%
    
  • Associated with rapid clinical deterioration
    
• Achromobacter xylosoxidans
  
• Mycobacteria (nontuberculous):
  
  • Mycobacterium avium
    complex,
    Mycobacterium abscessus
    
• Aspergillus
  

DIAGNOSIS

• General:
  
  • Failure to thrive
    
  • Recurrent respiratory tract infections
    
  • Anasarca in infancy
    
  • Salty taste of skin
    
• Head, ears, eyes, nose, and throat (HEENT):
  
  • Nasal polyps; severe headaches due to sinusitis; otitis media
    
• Pulmonary:
  
  • Persistent cough. Initially dry, then productive
    
  • Recurrent pneumonitis or bronchiolitis in 1st yr of life
    
  • Wheezing
    
  • Hemoptysis
    
  • Pneumonia
    
  • Chronic bronchitis
    
  • Bronchiectasis
    
  • Respiratory distress
    
  • Pneumothorax
    
  • Pneumomediastinum
    
  • Most common cause of CF hospitalization
    
• Cardiac:
  
  • CHF
    
  • Cor pulmonale; pulmonary hypertension
    
• GI:
  
  • Abdominal pain
    
  • Meconium ileus
    
  • Distal intestinal obstructive syndrome (DIOS) or “meconium ileus equivalent”
    
  • Gastroesophageal reflux
    
  • Cholelithiasis
    
  • Pancreatitis/pancreatic insufficiency
    
  • Ileocecal intussusception
    
  • Foul smelling, fatty stools
    
  • Jaundice/cirrhosis
    
  • Rectal prolapse
    
  • Hematemesis
    
  • Small intestine bacterial overgrowth
    
• Extremities:
  
  • Bone pain
    
  • Edema/joint effusions
    
  • Decreased thickness of cortical bone
    
• Recurrent venous thrombosis
  
• Cardiorespiratory failure is most common cause of death.
  

• Sweat chloride test
  
• DNA analysis if sweat test equivocal
  
• Nasal potential difference if DNA inconclusive
  

• Sweat chloride test:
  
  • Chloride concentration >60 mEq/L
    
  • With classic signs and symptoms, a positive test result confirms the diagnosis.
    
• Stool sample:
  
  • Decreased elastase, trypsin, or chymotrypsin
    
  • Increased fat in 72-hr fecal fat excretion
    
• Immunoreactive trypsin (IRT):
  
  • Defines increased risk and/or diagnosis
    
  • May be falsely positive or negative
    
• DNA analysis:
  
  • Indicated if symptoms are highly suggestive, but sweat test result is negative
    
  • 90% of CF chromosomes identified
    
  • Positive if 2 abnormal genes present
    
  • Genotyping cannot establish the diagnosis.
    
  • 1,300 CTFR mutations listed
    
  • Ameliorating or neutralizing 2nd mutation may be present.
    
• CBC:
  
  • Thrombocytopenia
    
• Serum electrolytes:
  
  • Hyponatremic, hypochloremic alkalosis
    
• Serum glucose:
  
  • Hyperglycemia and new-onset diabetes in adolescents and adults; ketoacidosis is rare.
    
• Liver function tests and PT:
  
  • Obtain if hematemesis or hemoptysis or signs of liver failure
    
• ABG:
  
  • Hypoxemia. Metabolic alkalosis
    
• Sputum culture:
  
  • May have pseudomonal colonization.
    
• Studies indicated in high-risk patients with unclear diagnosis:
  
  • Nasal potential-difference measurements:
    
    • Complex and time-consuming study
      
  • Semen analysis:
    
    • Azoospermia
      

• Chest radiograph:
  
  • Hyperaeration
    
  • Peribronchial thickening
    
  • Atelectasis
    
  • Hilar lymphadenopathy
    
  • Pneumothorax/pneumomediastinum
    
  • Bronchiectasis
    
  • Blebs
    
  • Chest CT identifies blebs/bronchiectasis
    
• Abdominal radiographs and/or CT:
  
  • Indicated if abdominal pain, vomiting, or abdominal distention
    
  • Distal intestinal obstruction syndrome
    
  • Intussusception
    
• Barium enema:
  
  • Indicated if suspicion of intussusception
    
• Sinus films:
  
  • Limited use because routine sinus films are always cloudy
    
  • CT scan is needed to assess sinuses for pre-operative planning.
    

Bronchoalveolar lavage:

• High percentage of neutrophils and absolute neutrophil count
  
• Unnecessary if obvious pulmonary symptoms
  

• Respiratory:
  
  • Asthma
    
  • Recurrent pneumonia
    
  • Bronchiectasis
    
  • Pertussis
    
  • Immunodeficiency
    
  • Foreign body aspiration
    
  • α
    ₁
    -Antitrypsin deficiency
    
  • Ciliary agenesis
    
• GI:
  
  • Chronic diarrhea
    
  • Gastroenteritis
    
  • Milk allergy
    
• Elevated electrolyte levels in sweat:
  
  • Fucosidosis
    
  • Glycogen storage disease type I
    
  • Mucopolysaccharidosis
    
  • Hypothyroidism
    
  • Vasopressin-resistant diabetes insipidus
    
  • Adrenal insufficiency
    
  • Familial cholestasis
    
  • Familial hypoparathyroidism
    
  • Malnutrition
    
  • Ectodermal dysplasia
    
  • Atopic dermatitis
    
  • Infusion of prostaglandin E
    ₁
    

TREATMENT