Undiagnosed CF patients, who are untreated, may present to the ED for a variety of complaints. Failure to thrive with a history of chronic GI and/or respiratory problems is a typical presentation.2 CF should be considered in any patient with chronic diarrhea, recurrent respiratory infections (especially with bronchiectasis or clubbing), or atypical asthma.2 Hypoproteinemia and edema may develop in those with prominent malabsorption.2 Malabsorption can lead to vitamin deficiencies, especially of fat-soluble vitamins.1,2 Hemorrhage due to vitamin K deficiency as well as neurologic abnormalities and hemolytic anemia from vitamin E deficiency have been described.1,2 Patients with clinical findings suggestive of CF should be referred for diagnostic evaluation.
Known CF patients can present to the ED with various acute complications, and the most common is a pulmonary exacerbation manifested by an increase of respiratory symptoms. Pulmonary exacerbations are thought to be due to more active airway infection. The youngest patients with CF have infections caused by Staphylococcus aureus or Haemophilus influenzae. Eventually, however, Pseudomonas aeruginosa becomes the most prevalent organism.4,5,8,9 In chronically infected CF patients, P. aeruginosa tends to mutate, becoming more mucoid, less motile, and very difficult to eradicate with antibiotics.4,8,9 Burkholderia (formerly Pseudomonas) cepacia is a particularly virulent organism in patients with CF patients.1,5 Nontuberculous mycobacterial infections can occur and are difficult to eradicate.1 Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging pathogen in the respiratory tracts of patients with CF. Because MRSA infections have been associated with a higher risk of mortality, they should be treated aggressively.10
Chronic airway infection and inflammation, along with repeated exacerbations, result in destruction of the airway.1,4,5,11 Bronchiolitis-like manifestations may develop initially, accompanied by bronchitis later.1 With prolonged disease, bronchiolar obliteration, bronchiolectasis, and bronchiectasis ensue.1,5 Mucus plugging and airway obstruction are prominent features of CF, leading to atelectasis, enlarged air spaces, and ventilation–perfusion mismatching.1,5
Pneumothorax (sometimes, a tension pneumothorax) may result from the rupture of an emphysematous bulla or bleb and must be excluded in any patient with CF who deteriorates suddenly.1,2 It is not unusual in older teenagers and adults, or in patients with significant impairment in lung function, and can often recur.2,12,13 Pneumothorax is a poor prognostic indicator and is associated with a subsequent increase in hospitalizations, hospital days, and 2-year mortality.13
Patients with CF may have hemoptysis, especially during exacerbations.1 Bleeding is usually minor and not dangerous. Massive hemoptysis—acute bleeding >240 mL/day or >100 mL/day over several days—is not rare and can cause life-threatening asphyxia or hypotension.12 It is thought to result from persistent airway inflammation and erosion into markedly enlarged bronchial arteries (which contain systemic pressures).12 Like pneumothorax, massive hemoptysis is more prevalent in older patients and in those with more severe pulmonary impairment.12 S. aureus in sputum cultures is also associated with an increased risk.12 Massive hemoptysis is a poor prognostic indicator, similar to pneumothorax.12
Hematemesis occurs less often but must be distinguished from hemoptysis.2 It is usually due to bleeding esophageal varices secondary to portal hypertension from advanced cirrhosis.2
Patients with progressively worsening lung disease may eventually develop pulmonary hypertension and right ventricular hypertrophy (cor pulmonale).2 A respiratory exacerbation may precipitate congestive heart failure.2 In time, most patients with CF die of respiratory failure complicated by cor pulmonale.
Acute GI complications of CF include meconium ileus, distal intestinal obstruction syndrome (DIOS), and rectal prolapse.1,2,14 Meconium ileus is obstruction of the terminal ileum by inspissated stool in the newborn period. These infants most commonly present with no passage of meconium within 24 hours of birth; this may progress to symptoms and signs of intestinal obstruction or even intestinal perforation (which sometimes occurs prenatally)15 (Fig. 38-2). DIOS occurs in older children with CF and is defined as acute obstruction in the ileocecal region. DIOS can be complete, presenting with bilious emesis, or incomplete, presenting with abdominal pain and distention alone.14 Intussusception, volvulus, and intestinal perforation are other potential related consequences of DIOS.1,2 Similarly, constipation and crampy abdominal pain are common in patients with CF. Rectal prolapse is associated with CF and is most commonly seen in children younger than 3 years old.1,2
Patients with CF usually have elevated sweat chloride and sodium concentrations, giving them their characteristically salty taste.1,2,4 Sweat salt and water losses, with associated renal compensation, can lead to acute or chronic electrolyte depletion and dehydration.2 These occur most commonly in infants with gastroenteritis and poor oral intake, or during the hot summer months, especially in arid climates.1,2
As patients approach adulthood, they may develop additional complications, such as CF-related diabetes, which occurs in up to 20% of adolescents and 40%–50% of adults.16 CF-related diabetes is primarily a result of insulin insufficiency, although fluctuating levels of insulin resistance also play a role, and is generally managed by insulin alone.16 Diabetic ketoacidosis is rare.16 Other complications include obstructive biliary tract disease (up to 30% of adults) and obstructive azospermia (95% of postpubertal males).1