-IBIS-1.5.0-
tx
respiratory system
cystic fibrosis
diagnoses

definition and etiology

definition:
An inherited disease of the ecrine perspiration glands and the exocrine glands, causing problems mainly in the digestive and respiratory tracts. CF usually begins in infancy presenting as chronic respiratory infections, abnormally thick mucus secretions, pancreatic insufficiency, and susceptibility to extremes of heat.

etiology:
CF is an inherited autosomal recessive gene, although the underlying metabolic defect is unknown. It is more common in white people (1:1600-2000), than black people (1:17,000), and is rare in Orientals. It is most common in descendants of European origin. In 90% of patients, diagnosis is made in infancy or childhood: 10% of patients with milder symptoms escape detection until adolescence or young adulthood.

Glandular involvement occurs in one of three ways:
• Glands becoming clogged by viscid or solid eosinophilic material in the lumen (intestinal glands, pancreas, gallbladder, submaxillary glands and intrahepatic glands).
• Glands that produce an marked increase in their normal histological secretions (tracheal, bronchial, Brunner's glands).
• Glands that produce normal histological secretions, but exude excessive amounts of sodium and chloride (sweat, small salivary, and parotid glands).

signs and symptoms

signs and symptoms:

respiratory/cardiovascular
• Bronchitis; bronchopneumonia; bronchiectasis; lung abscesses; aspergillosis (allergic): most common bacteria colonizing CF lungs: Pseudomonas aeruginosa, Pseudomonas cepacia.
• Atelectasis.
• Sinusitis, nasal polyps.
• Pulmonary hypertension.
• Cor pulmonale and congestive heart failure.
• Hemoptysis.
• Pneumothorax.
• Respiratory failure.

gastrointestinal
• Intestinal
» Meconium ileus.
» Volvulus.
» Ileal atresia.
» Rectal prolapse.
» Intussusception.
» Fecal impaction.
» Pneumatosis intestinalis.
• Pancreatic
» Nutritional deficit and failure to
thrive due to pancreatic
insufficiency.
» Steatorrhea.
» Diabetes mellitus.
» Recurrent pancreatitis.
• Hepatobiliary
» Atropic gallbladder, cholelithiasis.
» Loss of bile salts.
» Focal biliary cirrhosis.
» Portal hypertension: esophageal varices, hypersplenism, hemorrhoids.

reproductive system
• Males: sterility, absent or defective vas deferens/epididymis/ seminal vesicles.
• Females: decreased fertility, increased viscosity of vaginal secretions (although many women have been able to carry pregnancies to term).

skeletal
• Retarded bone age.
• Demineralization.
• Hypertrophic osteoarthropathy.

other
• Clubbing of nails.
• Salt depletion.
• Heatstroke.
• Retinal hemorrhage.
• Salivary gland hypertrophy.
•Apocrine gland hypertrophy.

lab findings:
• Meconium in neonates contains significant amounts of serum proteins, particularly albumin. Meconium ileus may present as initial finding.
• Pilocarpine iontophoresis sweat test: CF patients have increased levels of sodium and chloride.
• Pancreatic secretions show no or just slight amounts of digestive enzymes and bicarbonate.
• Stool trypsin is not present or present only in greatly decreased amounts.
• Hair analysis (+) for increased sodium.
• Serum ELP shows increased gamma globulin.

diagnosis:
• Respiratory changes evident on x-ray.
• Pancreatic insufficiency with associated symptoms.
• Increased sodium and chloride levels with pilocarpine test.

course and prognosis

Today, the average survival for CF patients is approximately 20 years; many patients survive into their 20s and 30s. Prognosis is better with the earlier diagnosis so that complications (esp. pulmonary) are better identified and properly treated. Sickness and death are related mostly to the severity of pulmonary involvement.

differential diagnosis

• Asthma.
• Bronchitis.
• Proper diagnosis is needed to prevent treating the sequelae of CF as the primary problem(s).


footnotes