Lumbar puncture in infants and children — branching viva

Emergency department: a 4-month-old febrile infant with irritability and a full fontanelle needs a diagnostic lumbar puncture as part of a septic workup. The examiner asks how you would assess and prepare for the procedure, what positioning and needle you would choose, and how you would obtain a reliable opening pressure — then branches to the child who develops signs of raised intracranial pressure just as the LP is planned, to the CSF interpretation including a traumatic tap, and finally to the management of post-dural puncture headache.