The place of computed tomography and lumbar puncture in suspected bacterial meningitis.

The place of computed tomography and lumbar puncture in suspected bacterial meningitis EDITOR,-We should like to respond to the recently published annotation on the place of computed tomography and lumbar puncture in suspected bacterial meningitis.' The table of contraindications to lumbar puncture in the child with suspected acute bacterial meningitis is welcome and we would agree that lumbar puncture should be avoided in these clinical situations. However, we would not accept that a contraindication to lumbar puncture amounts to a specific indication for computed tomography, which seems to be the inference. We would agree that computed tomography is indicated if the differential diagnosis ofbacterial meningitis is in any doubt but this applies irrespective of whether lumbar puncture is contraindicated. We think one should endeavour to separate the contraindica-tions to lumbar puncture from the indications for computed tomography. 1 Mellor DH. The place of computed tomography and lumbar puncture in suspected bacterial meningitis. I have to disagree with Drs Davidson and Carty as I believe that computed tomography is indicated in these children. With the exception of septic shock, all the contraindications to lumbar puncture given in my annotation are clinical features suggestive of raised intra-cranial pressure in a child with suspected bacterial meningitis. In this situation the diagnosis of bacterial meningitis cannot be confirmed because lumbar puncture is contra-indicated. Antibiotic treatment must be given promptly but some doubts have to be entertained about the diagnosis even by the experienced paediatrician. Some of the conditions that may mimic the presentation of bacterial meningitis with raised intracranial pressure (posterior fossa tumours, acute hydrocephalus, cerebral abscess, intracranial bleeding) require early diagnosis for appropriate management. This can be achieved safely by computed tomography. Rapid diagnosis of malignancy using flow cytometry EDITOR,-The paper by Williamson et al on flow cytometric diagnosis of malignancy illustrated some of the well known values of this aid to diagnosis.' However, although they did not state directly that their approach provided proof of malignancy, it is worth reminding clinicians that it is usually inappropriate to make the diagnosis of malignancy by immunophenotyping alone. Others have shown large numbers of CD1O, CD19, terminal transferase (Tdt), and HLA-DR positive lymphoid cells in the bone marrows of children with non-malignant disorders such as transient red cell aplasia and thrombocytopenic purpura as well as a range of non-haemopoietic tumours2 which could lead the unwary into making spurious diagnoses of leukaemia. Until large numbers of …