Diagnosis of Cystic Fibrosis in South Africa

1. Diagnosis of Cystic Fibrosis in South Africa Robin J Green With aknowledgement to Prof A Westwood (UCT)

2. Respiratory patterns: Gastrointestinal patterns Other patterns Recurrent or persistent lower respiratory symptoms Steatorrhoea ± poor growth Neonatal conjugated hyperbilirubinaemia Pneumonia with slow response to treatment Chronic diarrhoea (not watery) Hypochloraemic hypokalaemic metabolic alkalosis (from salt loss in sweat) Early onset bronchiectasis or COPD Rectal prolapse (especially recurrent) Heat prostration with hyponatraemia Difficult asthma Unexplained failure to thrive Oedema/rash/anaemia looking like kwashiorkor but social circumstances or feeding history do not fit Severe ‘bronchiolitis’ Meconium ileus Male infertility/azoospermia Nasal polyposis Meconium plug Recurrent pancreatitis Adult onset bronchiectasis Meconium peritonitis Salty skin Chest infection caused by Pseudomonas aeruginosa Thickened bowel wall on antenatal ultrasound; antenatal features of intestinal obstruction Intussusception after infancy / recurrent intussusception Presentation patterns of CF

3. TYPICAL CYSTIC FIBROSIS PROBABLE • Poor growth from an early age, and/or • Persistent diarrhoea or smelly stools, and/or • Persistent or recurrent chest problems, and/or • Other typical features in bold type in the Table • NOTE: in some children, it will be important first to exclude HIV infection

4. TYPICAL CYSTIC FIBROSIS POSSIBLE • Most patterns in regular type in the Table • Any combination of these patterns with a pattern in italics

5. ATYPICAL CYSTIC FIBROSISPOSSIBLE • Mild versions of any respiratory pattern in regular type in the Table • Combinations of the above • Any item in italicsin the Table

8. FAECAL PANCREATIC ELASTASE-1 TEST • Sample required: Random stool. Room temperature is OK. Turn-around time about 2 weeks. • Availability: National Health Laboratory Service and Private Laboratories • Cost: approx R250 • Interpreting the result: <160μg/g pancreatic insufficiency (PI) likely (NB false positive possible if watery stool sent). Villous disease can also cause low levels.160-200μg/g uncertain, CF-type PI unlikely; >200μg/g not PI.

9. SWEAT CONDUCTIVITY & SWEAT ELECTROLYTE TESTING • Sample required: Measured amount of sweat. Must be booked with lab. Result available either same day or next day • Availability: Patient must go to a laboratory that does the test. • Cost: *** • Interpreting the result: See Diagnostic algorithms

10. CYSTIC FIBROSIS MUTATION ANALYSIS • Sample required: Blood sample in EDTA tube. • Availability: A laboratory that can do a full South African panel test is required - National Health Laboratory Service, Johannesburg; • Cost: R300 - R 2000depending whether testing for all South African mutations becomes necessary • Interpreting the result: See diagnostic algorithms

11. Conclusion • Remember CF as a differential in children with respiratory and GIT disease • CF occurs in black patients • When CF diagnosis is probable do a sweat test or genetic study • When CF diagnosis is possible do a faecal elastase