Zinc deficiency syndrome in a British youth with cystic fibrosis.

The patient was diagnosed as having cystic fibrosis at 5 years of age, and treated conventionally with antibiotics and pancreatic enzymes. The next year he had an episode of haematuria and proteinuria without oedema or hypertension. At 17 years he was referred to the cystic fibrosis clinic with depression, chronic cough, green sputum, recurrent abdominal pain, and steatorrhoea. He was prepubertal, with height and weight well below the 3rd centiles. He had considerable finger clubbing, dry skin, bilateral crackles at the lung bases, liver enlargement, and a normal blood pressure. His sweat electrolyte and urine protein, serum alkaline phosphatase, and plasma cholesterol concentrations were raised; the serum albumin concentration was decreased. Chest x-ray film showed moderately severe changes of cystic fibrosis; an intravenous pyelogram showed a normal renal tract and pancreatic calcification. Renal biopsy was refused. At 18 years 4 months he was further investigated for delayed puberty and short stature. His bone age was 11 years 8 months. Growth hormone response to levodopa was normal; the results of thyroid function tests were normal. Concentrations of testosterone were 72 5 mgl100 ml; of LH and FSH normal; of serum alkaline phosphatase over 120 IU/l; and of SHBD 645 IU 1. Rectal biopsy showed no evidence of amyloid disease. Five months later, his plasma zinc concentration was only 3-45-3 75 Hmol/l (23-25 tig'100 ml) on three occasions (normal 70-160). The urine zinc concentration was raised, 13 8 tmol 24 h (0-9 mg/24 h) (normal 076-7 6 [Lmol/l; 0-05-0 5 mg,'24h) and hair zinc concentration low, 110 ppm (mean adult value 180 +4, child 153 ±5). Intravenous injection of 10 MiCi 55Cr chromic chloride produced a faecal loss of 9-5 0° in 96 hours (normal less than 1 0,), indicating protein-losing enteropathy. Treatment with oral zinc sulphate 180 mg/day was then started, the patient himself increasing the dose on several occasions. After six months there was slight genital growth and a few pubic hairs appeared. He developed oedema, ascites, and increased diarrhoea. The serum albumin concentration was 16 g I. Diuresis was induced with frusemide and intravenous salt-free albumin, and control of oedema maintained with intermittent frusemide. His zinc balance remained poor, plasma values of 5 4 umol/l (35 Lg/100 ml) and hair zinc of 110 ppm being recorded. At 19 years 10 months renal biopsy showed features of focal proliferative glomerulonephritis. By then he was taking 1200 mg of zinc sulphate daily. His genitalia were enlarging and his bone age had advanced to 14 years. This progress has been maintained. At 20 years application of testosterone cream for two months increased the growth of pubic hair. His plasma zinc concentrate was then 15 9 Mmol/l (104 tsg/lOO ml); that of testosterone 33.9 ,umol/l (980 mg/100 ml). At 21 years he has crossed the 3rd centile for height and his genital development is 3 on the Tanner scale (see fig).