Post-Dural Puncture Headache

Post-dural puncture headache (PDPH) is a positional headache that begins within 5 days of dural puncture, worse upright and relieved by lying flat, caused by cerebrospinal fluid leak.

Epidemiology. Incidence depends on needle type and size: 0.1% to 2% after 25 to 27 gauge pencil point spinal needles, 5% to 10% after 22 gauge cutting needles, and 50% to 80% after accidental dural puncture with 16 to 18 gauge epidural needle. Peak age is 18 to 40 years, with female predominance.

Risk factors. Young age, female sex, pregnancy, low body mass index, previous PDPH, history of chronic headache, large cutting needle, bevel orientation perpendicular to dural fibres and multiple punctures.

Pathophysiology.

Cerebrospinal fluid leak lowers intracranial pressure. Traction on pain sensitive structures when upright and compensatory cerebral vasodilation (adenosine mediated) cause headache. Traction on cranial nerves explains tinnitus, diplopia and hearing loss.

Frontal or occipital headache within 5 days (often 24 to 48 hours), worse within 15 minutes of sitting or standing and eased within 15 to 30 minutes of lying flat, with neck stiffness, nausea, photophobia, tinnitus, hearing change, diplopia and, rarely, cranial nerve palsy.

Red flags.

• Fever or meningism.
• Focal neurological deficit.
• Seizure.
• Non-positional headache.
• Headache that persists beyond 6 weeks.

Clinical. Exclude other causes in atypical presentation or lack of response: meningitis, subdural haematoma, cerebral venous thrombosis, pre-eclampsia, pneumocephalus, intracranial haemorrhage and migraine. MRI with contrast (diffuse pachymeningeal enhancement, brain sag) or CT in selected cases.

Differential diagnosis.

• Migraine or tension headache.
• Meningitis.
• Cerebral venous thrombosis.
• Subdural haematoma.
• Pre-eclampsia.
• Pneumocephalus.
• Posterior reversible encephalopathy syndrome.

Reassure, give fluids and analgesia, and allow supine rest as comfort requires (bed rest does not prevent but helps symptoms).

• Paracetamol: 1 g orally every 6 hours for 3 to 5 days; maximum 4 g daily; reduce to 2 to 3 g daily if under 50 kg, malnourished or in hepatic impairment.
• Ibuprofen: 400 mg orally every 8 hours with food for up to 5 days; maximum 1.2 g daily; monitor renal function and blood pressure; avoid in peptic ulcer, renal impairment and pre-eclampsia with low platelets.
• Caffeine: 300 mg orally once daily to twice daily (or 500 mg IV in 1 L saline over 1 hour) for up to 3 days; maximum 900 mg daily; monitor palpitations, tremor and insomnia; avoid in uncontrolled hypertension, arrhythmia and breastfeeding in high doses.
• Neostigmine and atropine, aminophylline 250 mg IV and gabapentin 300 mg orally three times daily have limited evidence and are optional (gabapentin maximum 1.8 g daily; reduce in creatinine clearance under 60 mL/min).

Epidural blood patch for moderate to severe headache failing 24 to 48 hours of conservative treatment: 15 to 20 mL (stop at pressure or pain in the back or legs) of fresh autologous blood injected into the epidural space at or one level under the puncture, with sterile technique.

Success is about 70% to 90% after first patch (permanent in about 60%), and a repeat patch is possible after 24 to 48 hours.

Contraindications are fever, bacteraemia, local infection, coagulopathy and refusal. Lie flat for 1 to 2 hours afterwards and avoid straining for 24 hours.

Sphenopalatine ganglion block or greater occipital nerve block offers non-invasive alternatives.

Monitoring. Headache severity, neurological examination and temperature daily until resolved.

Referral and escalation. Neurology and imaging for atypical features or persisting headache beyond 1 week after patch. Anaesthetic review for patch.

Special groups. Breastfeeding mothers can use paracetamol, ibuprofen and caffeine in usual doses.