CF patients exhibit a characteristic sputum microbiology (23). Haemophilus 
influenza and Staphylococcus aureus are often the first organisms recovered from 
samples of lung secretions in newly diagnosed CF patients. Pseudomonas aeruginosa 
is typically cultured from lower respiratory tract secretions thereafter. After 
repetitive antibiotic exposure, Pseudomonas aeruginosa , often in a mucoid form, is 
usually the predominant organism recovered from sputum and may be present as 
several strains with different antibiotic sensitivities. Pseudomonas cepacia has been 
recovered from CF sputum and is pathogenic. 
The first lung function abnormalities observed in CF children, increased 
RV/TLC ratios, suggest that small airways disease is the first functional lung 
abnormality in CF. As the disease progresses, both reversible and irreversible 
changes in FVC and FEV^ are noted. The reversible component reflects 
accumulation of intraluminal secretions and/or airway reactivity which occurs in 
40%-60% of CF patients. The irreversible component reflects chronic destruction 
of the airway wall and bronchiolitis. 
The earliest chest X-ray change in CF lungs is hyperinflation, reflecting small 
airway obstruction (24). Later, evidence of luminal mucus impaction, bronchial 
cuffing, and finally, evidence of bronchiectasis, e.g., ring shadows, are noted. For 
reasons that are still unknown, the right upper lobe displays the earliest and most 
severe changes. 
II.A.3.b. Gastrointestinal: 
The syndrome of meconium ileus in infants presents with abdominal 
distention, failure to pass stool, and emesis. The abdominal flat plate can be 
diagnostic with small intestinal air fluid levels, a granular appearance representing 
meconium, and a small colon. In children and young adults a syndrome termed 
meconium ileus equivalent or distal intestinal obstruction occurs. The syndrome 
presents with right lower quadrant pain, loss of appetite, emesis, and often a 
palpable mass. The syndrome can be confused with appendicitis, which occurs 
frequently in CF patients. The characteristic intestinal abnormalities are 
complicated by pancreatic insufficiency in more than 90% of CF patients. 
Insufficient pancreatic enzyme release yields the typical pattern of protein and fat 
malabsorption, with frequent bulky, foul-smelling stools. Signs and symptoms of 
malabsorption of fat soluble vitamins, including Vitamins A, D, E, and K, are also 
noted. Because pancreatic beta cells are typically spared, the appearance of 
hyperglycemia and a requirement for insulin is a late finding in CF and occurs in 
only a small percentage of patients. 
II.A.3.C. Genito-Urinary: 
Late-onset of puberty is common to both males and females with CF. The 
delayed maturational pattern is likely secondary to the effects of chronic lung 
disease and inadequate nutrition on reproductive endocrine function. More than 
95% of male patients with CF are azoospermic, reflecting obliteration of the vas 
deferens (25). 20% of CF women are infertile due to effects of chronic lung disease 
on the menstrual cycle and thick, tenacious cervical mucus that blocks sperm 
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Recombinant DNA Research, Volume 17 
