Spinal Epidural Haematoma After Neuraxial Anaesthesia

Spinal epidural haematoma after neuraxial anaesthesia is bleeding within the spinal canal that compresses the cord or cauda equina. It is a neurosurgical emergency, and delay beyond 8 to 12 hours reduces recovery.

Epidemiology. Estimated incidence is about 1 in 150,000 epidurals and 1 in 220,000 spinal anaesthetics, and higher (about 1 in 3,000 in some series) in women having knee replacement with anticoagulants.

Risk factors. Anticoagulants (low molecular weight heparin, direct oral anticoagulants, warfarin), antiplatelet drugs, thrombocytopenia, coagulopathy, liver disease, traumatic or repeated needle placement, catheter removal during anticoagulation, spinal abnormality, older age and female sex.

Pathophysiology.

Venous bleeding in the epidural space forms a clot that compresses neural structures and compromises spinal cord blood flow. Ischaemia causes irreversible damage after hours.

New or progressive back pain, leg numbness or weakness, a block that persists or returns after resolution, bladder or bowel dysfunction, and saddle sensory loss. Sensory and motor loss follow within hours.

Red flags.

• Motor block lasting over 4 to 6 hours after spinal, or reappearing after epidural.
• Bladder or bowel dysfunction.
• Severe back pain with leg symptoms.
• Recent anticoagulant dose.

Emergency MRI of the whole spine (CT myelography if MRI is not available). Do not wait for imaging if signs progress, and call neurosurgery at once. Send coagulation screen, platelets and anti-Xa level.

Differential diagnosis.

• Epidural abscess.
• Local anaesthetic effect.
• Cord ischaemia.
• Transverse myelitis.
• Disc herniation.
• Spinal tumour.

Immediate neurosurgical decompression by laminectomy within 8 hours of onset of deficits gives best outcome. Reverse anticoagulation to support surgery.

• Protamine sulphate (unfractionated heparin; also partial for low molecular weight heparin): 1 mg for each 100 units of heparin given in the previous 2 to 3 hours, by slow IV injection over 10 minutes; maximum 50 mg in a single dose; monitor blood pressure, activated clotting time and anaphylaxis; reduce in fish allergy and prior protamine exposure.
• Idarucizumab (dabigatran): 5 g IV (two 2.5 g doses within 15 minutes), single use; monitor thrombotic events.
• Andexanet alfa or prothrombin complex concentrate 25 to 50 units/kg IV (apixaban, rivaroxaban): maximum 5,000 units of prothrombin complex concentrate; monitor thrombotic events and clotting.
• Vitamin K 5 to 10 mg IV slowly with prothrombin complex concentrate 25 to 50 units/kg for warfarin; maximum vitamin K 10 mg in a single dose; monitor INR every 30 minutes.
• Tranexamic acid: 1 g IV over 10 minutes, repeated once after 8 hours; maximum 3 g daily; monitor for seizures and thrombosis; reduce in renal impairment.

Replace platelets for count under 50 x 10^9/L and fibrinogen for level under 1.5 g/L.

Prevention. Follow safe intervals between neuraxial procedures and anticoagulant doses: usually 12 hours after prophylactic low molecular weight heparin and 24 hours after treatment dose; 6 hours after prophylactic unfractionated heparin; 48 to 72 hours for most direct oral anticoagulants (longer in renal impairment); 5 days off warfarin with INR of 1.4 or under. Wait at least 4 hours after catheter removal before next anticoagulant dose. Avoid traumatic punctures.

Monitoring. Neurological checks of leg movement every 2 hours for 24 hours after neuraxial block and every 4 hours while an epidural catheter is in place with anticoagulation.

Referral and escalation. Neurosurgery at once. Document and disclose.