Lumbar Puncture: Background, Indications, Contraindications

Absolute contraindications for lumbar puncture are the presence of infected skin over the needle entry site and the presence of unequal pressures between the supratentorial and infratentorial compartments. The latter is usually inferred from the following characteristic findings on computed tomography (CT) of the brain:

• Midline shift

• Loss of suprachiasmatic and basilar cisterns

• Posterior fossa mass

• Loss of the superior cerebellar cistern

• Loss of the quadrigeminal plate cistern

Relative contraindications for lumbar puncture include the following:

• Increased intracranial pressure (ICP)

• Coagulopathy

• Brain abscess

Indications for performing brain CT scanning before lumbar puncture in patients with suspected meningitis include the following [9] :

• Patients who are older than 60 years

• Patients who are immunocompromised

• Patients with known CNS lesions

• Patients who have had a seizure within 1 week of presentation

• Patients with an abnormal level of consciousness

• Patients with focal findings on neurologic examination

• Patients with papilledema seen on physical examination, with clinical suspicion of an elevated ICP

Cranial CT scanning should be obtained before lumbar puncture in all patients with suspected SAH in order to diagnose obvious intracranial bleeding or any significant intracranial mass effect that might be present in awake and alert SAH patients with a normal neurologic examination. [10, 11]