Keith Brownlee. Jan, 2001.Making the diagnosis [online]. St James's University Hospital, UK. Available from http://www.cysticfibrosismedicine.com.

Cystic fibrosis presents in three main ways:

Meconium ileus: In 15% to 20% of newborn CF infants, the bowel is blocked by the sticky secretions. There are signs of intestinal obstruction soon after birth with bilious vomiting, abdominal distension and delay in passing meconium. The obstruction can often be relieved by gastrografin enemas but some infants require an operation. The outlook for these infants is now good as a result of the impressive improvements in neonatal surgery, anaesthesia and nutritional support (Caniano & Beaver, 1987).

Intestinal malabsorption: Over 90% of CF individuals have intestinal malabsorption (Morgan et al, 1999). In most this is evident in infancy. The main cause is a severe deficiency of pancreatic enzymes and bicarbonate although there is also evidence that the transport of some substances across the wall of the intestine is abnormal. Fortunately, modern acid-resistant pancreatic extracts control the malabsorption in most patients (Beverley et al, 1987; Lowdon et al, 1998).

Chest infections: Virtually all untreated CF patients have chest infections, usually from an early age. The viscid mucus in the airways is particularly prone to bacterial infections which, once established, are difficult to eradicate. The extent and severity of this damage to the bronchial tubes and lungs from these infections is the main factor in determining the physical state and survival of the patient. However, with early intensive antibiotic treatment, particularly by intravenous and nebulised routes, most CF individuals will remain free of significant chest problems throughout childhood.

Other clinical presentations: Cystic fibrosis may present in other ways including chronic or neonatal liver disease, nasal polyposis, asthma, rectal prolapse, heat exhaustion from salt depletion, male infertility, growth failure or pancreatitis (Shwachman et al, 1975; Masaryk & Achkar, 1983; Cohn et al, 1998).

Microbiology: Sputum, cough swab culture ie staphylococcus, heamophilus, pseudomonas

Radiology: Chest x-ray and CT scan for bronchiectasis, sinus CT scan

Pancreatic function: Fat soluble vitamin levels, faecal elastase (Cade et al, 1999), stool chymotrypsin, faecal fat assessment (Gilbert et al, 1988; Walters et al, 1990), quantitative faecal fat estimation.

Ultrasound examination: Male genitalia, semen analysis (when appropriate), clinical examination, ultrasound examination.

Exclusion of other diagnosis: Ciliary structure and function / immunological status / allergy / infection

References:

Beverley DW, Kelleher J, MacDonald A, Littlewood JM, Robinson T, Walters MP. Comparison of four pancreatic extracts in cystic fibrosis. Arch Dis Child 1987; 62: 564-568

Cade A, Littlewood JM, Walters M, Brownlee KG, Conway SP. Faecal pancreatic elastase: experience of present use in a regional paediatric cystic fibrosis centre. Pediatr Pulmonol. In press

Caniano DA, Beaver BL. Meconium ileus: fifteen year experience with forty two neonates. Surgery 1987; 102: 699-703

Cohn JA, Friedman KJ, Noone PG, Knowles MR, Silverman LM, Jowell PS. Relation between mutations of the cystic fibrosis gene and idiopathic pancreatitis. N Engl J Med 1998; 339: 653-658

Lowdon J, Goodchild MC, Ryley HC, Doull IJM. Maintenance of growth in cystic fibrosis despite reduction in pancreatic enzyme supplementation. Arch Dis Child 1998; 78: 377-378

Masaryk TJ, Achkar E. Pancreatitis as initial presentation of cystic fibrosis in young adults. Dig Dis Sci 1983; 28: 874-878

Morgan WJ, Butler SM, Johnson CA, Colin AA, FitzSimmons SC, Geller DE et al. Epidemiologic study of cystic fibrosis. Pediatr Pulmonol 1999; 28: 231-241

Shwachman H, Lebenthal E, Khaw KT. Recurrent acute pancreatitis in patients with cystic fibrosis with normal pancreatic enzymes. Pediatrics 1975; 55: 86-95

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