Normal variations in rate of albumin excretion and albumin to creatinine ratios in non-diabetic children

SIR,-Dr J R Harper's article (7 September, p 65 1) raises an important issue and rightly questions a long accepted clinical practice. Unfortunately the discussion fails to address certain key points and leaves the reader confused whether or not practice should be revised. I would like to present a somewhat different argument. I suggest that lumbar puncture should not be performed in any patient with depressed consciousness in whom raised intracranial pressure, from any cause, may be implicated unless the operator is prepared to measure the pressure of the cerebrospinal fluid and, if necessary, reduce it pharmacologically before the fluid is allowed to escape or the needle is removed (allowing it to leak into the epidural space). In the case described the child showed signs suggestive of transtentorial and transforaminal herniation two hours after diagnostic lumbar puncture in the context of clinically probable bacterial meningitis with depressed consciousness. The phrase "apparently normal pressure" presumably indicates that this was not measured, although the child's clinical state and subsequent events indicate that intracranial pressure was raised. It would certainly be wrong to conclude that the lumbar puncture caused this child's deterioration but equally incorrect to conclude that there was no suspicion of this. Dr Eykyn supports her argument by stating that patients with meningococcal meningitis do occasionally die suddenly within a few hours of admission, but presumably these patients have all had a lumbar puncture. This clinical course is by no means unique. ' I haV recently seen a very similar course in a 2 year old child, but in this case a ventricular catheter was inserted2 3 and intracranial pressure lowered as soon as deterioration occurred, about an hour after lumbar puncture (subsequent computed tomography confirmed downward displacement of the fourth ventricle). Ventilatory support was required but she recovered fully. Cerebral herniations do occur in meningitis and the close temporal association with lumbar puncture suggests that it may contribute to this complication. ' All the contributors agree that antibiotic policy is unlikely to be altered on the basis of cerebrospinal fluid. Surprisingly, none mention immunological methods of diagnosis' and no guidance is given for managing pyogenic meningitis in which the organism fails to grow, usually because of prior antibiotic therapy. I suggest the following approach to investigation and treatment for three distinct clinical situations. (1) In the patient who is fully conscious but not particularly ill and in whom meningitis is considered possible or probable lumbar puncture is indicated. (2) In the patient with probable meningitis but whose conscious level is depressed or who has another acquired neurological abnormality lumbar puncture should not be performed. After blood cultures and, if appropriate, skin scrapings have been obtained treatment should be started with chloramphenicol with or without penicillin. Other antibiotics may be more appropriate-for example, in the newborn or where chloramphenicol resistance is prevalent. Subsequent deterioration is an indication for intracranial pressure monitoring (at the bedside2 3) or administration of mannitol 0-25 g/kg "blind. " (3) In the patient who is desperately ill and unconscious and who may have meningitis priority should be given to general supportive measures. These should include broad spectrum antibiotic cover with good brain penetration. Lumbar puncture should not be performed, but once the general condition is stable intracranial pressure should be monitored.4 If a ventricular catheter is used cerebrospinal fluid can be obtained via this route. ROBERT MCWILLIAM