Hereditary fructose intolerance in early childhood: a major diagnostic challenge. Survey of 20 symptomatic cases.

Twenty infants and young children with hereditary fructose intolerance (HFI) were admitted to hospital. None was diagnosed at admission. Referals were for vomiting of unknown aetiology (16X), pyloric stenosis or hiatus hernia (5X), toxic condition (3X), and hepatomegaly of unknown origin (5X). Feeding difficulties (20X), vomiting (18X), and failure to thrive (16X) were leading symptoms. The most frequent clinical findings were hepatomegaly (18X), pallor (14X), haemorrhages (13X). Ascites, oliguria, tachypnoea, fever, splenomegaly and rickets were less frequent. Laboratory findings were indicative of disturbed hepatic and renal tubular function and also of disturbed intermediary metabolism (hypokaliaemia, hypophosphataemia). However, hypoglycaemia was found in only 4 out of 15 patients tested. Differential diagnosis after hospital admission centered on metabolic disorders such as glycogenoses, galactosaemia, tyrosinosis, or Wilson's disease. Hepatitis, toxic hepatosis, liver tumour, intrauterine infection and sepsis were also considered. Eleven children had first ingested fructose within the first 6 weeks of life. The diagnosis was usually established only many weeks or months after first fructose intake and appearance of symptoms. This documents how difficult the diagnosis of this disease can be both in practice and in hospital. The course was severe in 11 children and lethal in 4. In only 5 patients was the course mild. The 16 survivors are doing well under fructose-exclusion diet. Irreversible visual impairment after intraocular haemorrhage occurred once. In each case HFI could have been suspected immediately, had a detailed nutritional history been taken. Practising paediatricians should know the composition of commonly used infant formulae. They should never prescribe sugared condensed milk for intractable vomiting prior to excluding HFI. Solution for intravenous infusion containing fructose and sorbitol are life-threatening for undiagnosed HFI patients.