Gareth was born in 1982 as a normal delivery at term, birth weight 2.92 kg, and had normal Apgar scores following an uneventful pregnancy. Five hours after delivery he was hypothermic and was found to have a blood glucose of 1.0 mmol/l. The hypoglycaemia resolved with continuous nasogastric feeds followed by three-hourly bottle feeds. He was discharged from hospital three days later.

At 5 weeks of age he presented to his general practitioner (GP) with an eight-hour history of episodes of floppiness associated with a dusky complexion. There had been a one-week preceding history of coryzal illness and a cough with intermittent episodes of cyanosis. In the preceding weeks there had been poor weight gain, he had been slow to feed and had occasional non-projectile vomiting. The GP suggested that the most likely diagnosis was a viral upper respiratory tract infection but, given the history, he arranged for the baby to be admitted for further evaluation at the local hospital.

On arrival the baby was apyrexial, hypotonic and poorly perfused. Further examination revealed normal heart sounds with palpable upper limb pulses but impalpable femoral pulses, a shallow and irregular respiratory effort, and hepatomegaly of 3–4 cm with normal genitalia. There were normal spontaneous movements and no abnormal posturing. A full septic screen was performed and he was commenced on intravenous antibiotics. The microscopy and culture of the blood, urine and cerebrospinal fluid was not suggestive of infection. His initial biochemical investigations are shown in table 1.

COMMENT

• In an ill 5-week-old baby, it is important to ascertain the perinatal history. Specifically, there should be enquiry as to whether or not there was a history of pyrexia during labour, prolonged rupture of membranes, maternal group B streptococcus carriage and whether or not the mother or baby was given antibiotics …