[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anaesthesia and ICU](https://durgical.com/en/anaesthesia/) › [Regional anaesthesia](https://durgical.com/en/anaesthesia/areas/regional/) › Complications of neuraxial blocks: headache, hypotension, haematoma, infection

# Complications of neuraxial blocks: headache, hypotension, haematoma, infection

- Concept

Spinal and epidural blocks are usually safe, but they can cause headache, low blood pressure and, rarely, bleeding or infection that presses on the nerves.

Updated Nov 13, 2026

## Key points

- Hypotension is the commonest complication: sympathetic block; treat with vasopressor, fluid and, in pregnancy, left uterine displacement.
- Post-dural puncture headache is postural: worse upright, better lying, usually within days of the puncture.
- Risk of headache rises with large or cutting needles; pencil-point fine needles lower it.
- An epidural blood patch is the definitive treatment for a persistent, disabling headache.
- Back pain with a new, progressing motor or sensory deficit is a haematoma or abscess until imaging proves otherwise.

On this page

- The basics Key points
- What it is
- Key points
- How it works
- In practice
- Next step
- Memory aid
- Elsewhere in DurgiPedia

- Clinical Telling the serious complications apart

- Study Test yourself

- Connections Connections

## What it is

Neuraxial blocks share a set of complications that range from common and mild to rare and catastrophic. Hypotension is the most frequent: blocking sympathetic fibres dilates vessels and reduces venous return, and a high block can also slow the heart. Post-dural puncture headache follows leakage of cerebrospinal fluid through a hole in the dura; low pressure lets the brain sag and stretches pain-sensitive structures, and the veins dilate in compensation. It is typically frontal or occipital, much worse sitting or standing and eased lying flat, and may come with neck stiffness, nausea, tinnitus, hearing change or photophobia. Risk is highest in young women, in pregnancy, and with large or cutting needles and repeated punctures. Most settle with time and simple measures; an epidural blood patch seals the leak in persistent cases. Rare but serious are spinal epidural haematoma, linked mainly to coagulopathy and anticoagulants, and infection (epidural abscess or meningitis) from poor asepsis or bacteraemia. Both compress the cord or cauda equina and present with back pain and a progressive deficit; the outcome depends on rapid imaging and decompression. Others include high or total spinal block, nerve injury, urinary retention and local anaesthetic toxicity.

## Key points

- Hypotension and bradycardia: early and common, from sympathetic block; worse with hypovolaemia and aortocaval compression.
- Post-dural puncture headache: postural, from cerebrospinal fluid leak; may include neck pain, tinnitus and, rarely, a sixth nerve palsy.
- High or total spinal block: rising numbness, arm weakness, breathlessness, then apnoea, bradycardia and unconsciousness.
- Spinal epidural haematoma: rare; main risks are coagulopathy, anticoagulants and difficult or traumatic insertion.
- Infection: epidural abscess (fever, back pain, deficit) or meningitis (fever, headache, neck stiffness), rare with strict asepsis.
- Others: urinary retention, nerve or root injury, itching from intrathecal opioids, and systemic toxicity from intravascular injection.

## How it works

- Sympathetic fibres leave the cord from T1 to L2, so a high block removes vascular tone widely and the cardiac accelerator fibres (T1–T4).
- A hole in the dura leaks cerebrospinal fluid faster than it is made; low pressure pulls on meninges and vessels when upright.
- The blood patch places the patient's own blood in the epidural space, sealing the hole and raising pressure in the space.
- Blood or pus in the closed epidural space compresses the cord or cauda equina; ischaemia becomes permanent within hours.

## Telling the serious complications apart

| Complication | Typical picture | First action |
| --- | --- | --- |
| Post-dural puncture headache | Postural headache, afebrile, no deficit | Conservative care; blood patch if persistent |
| Spinal epidural haematoma | Back pain, rapidly progressing weakness or numbness, bladder change | Urgent MRI and neurosurgery |
| Epidural abscess | Fever, back pain, local tenderness, then deficit; days later | Urgent MRI, cultures, antibiotics, surgery |
| Meningitis | Fever, headache, neck stiffness, altered consciousness | Cultures, lumbar puncture if safe, antibiotics |
| High or total spinal | Rising block, arm weakness, breathlessness, apnoea | Airway, ventilation, vasopressors, support until it wears off |

## In practice

- Prevent hypotension by anticipating it: monitor closely, have vasopressor ready, and displace the uterus in pregnancy.
- Treat headache first with rest as wanted, fluids, simple analgesics and caffeine; offer a blood patch if it persists or disables.
- Look for red flags in a 'headache after a spinal': fever, focal signs, seizures or a non-postural pattern need other diagnoses ruled out.
- Follow the anticoagulant timing rules for insertion and for catheter removal; removal can cause a haematoma too.
- Check every patient after a block for regression; a block that returns or worsens is never assumed to be the drug.

## Next step

- Ask every patient on follow-up about headache, back pain, fever, weakness, numbness and passing urine.
- Request urgent MRI and a neurosurgical opinion for back pain with a new or progressing deficit; do not wait for the block to wear off.
- Call a senior for any headache that is severe, non-postural or febrile, or for a high block in progress.
- Discuss a blood patch with the anaesthetist when a postural headache persists and limits daily life or care of a newborn.
- Document the complication, explain it to the patient and arrange follow-up until it resolves.

## Memory aid

Upright worse, lying better: headache. Back pain plus deficit: scan now.

## Test yourself

Think of the answer, then tap the question to see it.

## What features distinguish a post-dural puncture headache?

It is postural: worse within minutes of sitting or standing and eased by lying flat; often frontal or occipital, with neck stiffness, nausea, tinnitus or photophobia, and no fever.

## Which factors increase the risk of post-dural puncture headache?

Young age, female sex and pregnancy, a large-bore or cutting needle (such as an accidental puncture with an epidural needle), and repeated dural punctures.

## What is the definitive treatment for a persistent post-dural puncture headache?

An epidural blood patch: the patient's own blood is injected into the epidural space near the puncture, sealing the leak and restoring pressure.

## A patient has back pain and progressive leg weakness the day after a spinal. What do you do?

Treat it as a spinal epidural haematoma or abscess: urgent MRI and immediate neurosurgical referral, because the neurological outcome depends on how quickly the cord is decompressed.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anaesthesia/complications-of-neuraxial-blocks-headache-hypotension-haematoma-infection/)

## Elsewhere in DurgiPedia

- [Headache physiology](https://durgical.com/en/physiology/headache-physiology/)
- [CSF and the blood–brain barrier](https://durgical.com/en/physiology/csf-and-the-blood-brain-barrier/)
- [Lumbar puncture](https://durgical.com/en/clinical-skills/lumbar-puncture/)
- [Spinal cord syndromes: complete, Brown-Séquard, central, anterior](https://durgical.com/en/clinical-exam/spinal-cord-syndromes-complete-brown-sequard-central-anterior/)
- [Coagulation tests: PT/INR, aPTT and platelets](https://durgical.com/en/physiology/coagulation-tests-pt-inr-aptt-and-platelets/)

## Connections

## Related 6

- [Spinal anaesthesia](https://durgical.com/en/anaesthesia/spinal-anaesthesia/)
- [Epidural anaesthesia and analgesia](https://durgical.com/en/anaesthesia/epidural-anaesthesia-and-analgesia/)
- [High or total spinal block](https://durgical.com/en/anaesthesia/high-or-total-spinal-block/)
- [Anticoagulants, antiplatelets and neuraxial blocks](https://durgical.com/en/anaesthesia/anticoagulants-antiplatelets-and-neuraxial-blocks/)
- [Intraoperative hypotension](https://durgical.com/en/anaesthesia/intraoperative-hypotension/)
- [Local anaesthetic systemic toxicity: the crisis](https://durgical.com/en/anaesthesia/local-anaesthetic-systemic-toxicity-the-crisis/)

## Related conditions 6

- [Spinal epidural abscess](https://durgical.com/en/conditions/spinal-epidural-abscess/)
- [Cauda equina syndrome](https://durgical.com/en/conditions/cauda-equina-syndrome/)
- [Bacterial meningitis](https://durgical.com/en/conditions/bacterial-meningitis/)
- [Acute urinary retention](https://durgical.com/en/conditions/acute-urinary-retention/)
- [Local anaesthetic systemic toxicity (LAST)](https://durgical.com/en/conditions/local-anaesthetic-systemic-toxicity/)
- [Migraine](https://durgical.com/en/conditions/migraine/)

## In Pharmacology 3

- [Local anesthetics](https://durgical.com/en/pharmacology/classes/local-anesthetics/)
- [Phenylephrine](https://durgical.com/en/pharmacology/phenylephrine/)
- [Ephedrine](https://durgical.com/en/pharmacology/ephedrine/)

[← All of anaesthesia](https://durgical.com/en/anaesthesia/)

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [Postdural Puncture Headache](https://www.ncbi.nlm.nih.gov/books/NBK430925/) (StatPearls (NCBI Bookshelf), 2025); [Spinal Anesthesia](https://www.ncbi.nlm.nih.gov/books/NBK537299/) (StatPearls (NCBI Bookshelf), 2022); [Epidural Anesthesia](https://www.ncbi.nlm.nih.gov/books/NBK542219/) (StatPearls (NCBI Bookshelf), 2025).

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Source: https://durgical.com/en/anaesthesia/complications-of-neuraxial-blocks-headache-hypotension-haematoma-infection/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/complications-of-neuraxial-blocks-headache-hypotension-haematoma-infection/