Low-pressure headache

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Intracranial hypotension is better understood as inadequate cerebrospinal-fluid volume and buoyancy than as a numerical pressure disorder. Loss of buoyancy permits pain-sensitive meninges and bridging veins to stretch while intracranial veins enlarge to preserve total intracranial volume. A dural tear, leaking meningeal diverticulum or direct fistula into a paraspinal vein may be responsible. A leak following a lumbar puncture or neuraxial anaesthetic has an identifiable precipitant; spontaneous intracranial hypotension often begins without major trauma and may be delayed in reaching diagnosis.

Orthostatic headache is diagnostically useful but not uniform. Some people deteriorate within seconds of standing, others after hours, and improvement after recumbency may be slow. Migraine, postural tachycardia, cervicogenic pain and Chiari malformation can also vary with posture. Conversely, a long-standing cerebrospinal-fluid leak may become non-postural. The whole phenotype, procedural history, neurological examination and imaging must therefore be integrated rather than applying a single timing rule.

Management aims to restore function and seal the leak while detecting complications. A limited conservative period is reasonable for stable, recent symptoms, particularly after dural puncture, but incapacitating or persistent symptoms justify early procedural discussion. Spontaneous disease should enter a multidisciplinary pathway able to interpret brain and whole-spine MRI, choose dynamic myelography for the suspected leak type and offer targeted treatment. Exact techniques and thresholds are specialist decisions and depend on local expertise.

Key points

Low-pressure headache usually reflects loss of cerebrospinal-fluid volume through a dural leak or a cerebrospinal-fluid venous fistula; measured lumbar opening pressure is often normal.
The classic symptom is headache that develops or worsens after becoming upright and improves after lying flat, but the delay and recovery time vary and chronic cases can lose obvious orthostatic behaviour.
Ask about recent lumbar puncture, spinal or epidural anaesthesia, spinal surgery, vigorous stretching or minor trauma, and features suggesting an underlying connective-tissue disorder.
Neck pain, nausea, tinnitus, muffled hearing, photophobia, diplopia and a sense of imbalance are common accompaniments; cranial-nerve palsy or cognitive change indicates more severe traction.
Brain MRI with gadolinium may show diffuse smooth pachymeningeal enhancement, venous engorgement, pituitary enlargement, subdural collections and downward brain sag, yet a normal scan does not exclude a leak.
Do not perform lumbar puncture simply to demonstrate low pressure when the history and imaging suggest spontaneous intracranial hypotension, because another dural puncture may worsen the syndrome.
Post-dural-puncture headache is a clinical diagnosis after a known procedure; inspect for infection or neurological complication and involve the relevant anaesthetic service early when symptoms are disabling.
Short initial measures include recumbency for comfort, oral fluids to avoid dehydration and simple analgesia, but prolonged bed rest does not close a persistent spontaneous leak.
An epidural blood patch is both a therapeutic seal and a specialist procedure; spontaneous disease may need repeated non-targeted patching, leak localisation and targeted patch, embolisation or surgery.
Current pathways differ between post-procedural and spontaneous disease, so discuss timing, imaging technique, anticoagulation and procedural preparation with anaesthesia or a specialist neuroradiology service.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Dural puncture

Lumbar puncture, spinal or epidural procedures and spinal surgery can create a dural hole through which cerebrospinal fluid continues to escape.

Spontaneous spinal leak

A ventral dural tear, ruptured meningeal diverticulum or less obvious defect may arise spontaneously or after minor mechanical strain.

CSF–venous fistula

An abnormal connection can drain cerebrospinal fluid directly into a paraspinal vein without a conventional extradural fluid collection.

Connective-tissue susceptibility

Underlying meningeal fragility and spinal structural abnormalities increase leak risk in some people, although no systemic disorder is identified in many cases.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Cerebrospinal-fluid volume loss
Persistent spinal leakage or venous drainage reduces the intracranial cerebrospinal-fluid cushion even when a lumbar opening-pressure measurement remains normal.
2
Brain sag and traction
Reduced buoyancy permits downward displacement when upright, stretching meninges, bridging veins and cranial nerves and producing orthostatic pain.
3
Compensatory venous expansion
Intracranial veins enlarge to preserve total cranial volume, contributing to diffuse pachymeningeal enhancement, pituitary enlargement and headache.
4
Secondary collections
Traction can tear bridging veins or split dural layers, allowing subdural fluid or blood to accumulate.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Orthostatic phenotype

Head pain is absent or mild on waking, increases after sitting or standing and improves when supine; record the delay to onset and recovery rather than merely writing postural headache.

Post-procedural syndrome

Headache within days of lumbar puncture, epidural placement or spinal intervention, often with neck stiffness, auditory symptoms or nausea, supports a procedure-related dural leak.

Associated traction symptoms

Horizontal diplopia, tinnitus, altered hearing, facial sensory symptoms or imbalance can result from cranial-nerve and posterior-fossa traction and strengthen the syndrome.

Spontaneous leak context

Abrupt onset after trivial twisting, coughing or exercise, meningeal diverticula, hypermobility or other connective-tissue features should prompt a specialist spontaneous intracranial-hypotension pathway.

Complicated low pressureRed flag

New focal deficit, seizure, somnolence or a changing non-postural headache may reflect subdural haematoma, venous thrombosis or marked brain sag and needs urgent neuroimaging.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Focused history and neurological examinationFirst step
Why
Define the postural timing, precipitant and possible complication.
Interpretation and limitations
Document cranial nerves, gait, cognition, meningism and fundi where feasible; fever, papilloedema, focal signs or reduced consciousness require an alternative emergency pathway.
02
Contrast-enhanced MRI brain
Why
Seek intracranial consequences of low cerebrospinal-fluid volume and competing pathology.
Interpretation and limitations
Smooth pachymeningeal enhancement, venous sinus distension, pituitary engorgement, subdural fluid and brain sag support the diagnosis; absence of these findings does not rule it out.
03
MRI whole spine
Why
Look for an extradural collection and guide subsequent leak localisation.
Interpretation and limitations
A longitudinal collection suggests a fast dural leak and influences patient positioning for myelography; a cerebrospinal-fluid venous fistula may leave no extradural collection.
04
CT or digital-subtraction myelography
Why
Localise a persistent leak or cerebrospinal-fluid venous fistula before targeted intervention.
Interpretation and limitations
Technique and positioning must match the suspected mechanism; specialist neuroradiologists may use dynamic acquisition because contrast can disperse rapidly.
05
Lumbar opening pressure
Why
Provide physiological information only when lumbar puncture is independently justified.
Interpretation and limitations
A low value supports intracranial hypotension, but many confirmed cases have normal pressure; avoid a diagnostic puncture that adds another dural defect without changing management.
06
Urgent CT or venous imaging
Why
Investigate sudden deterioration, seizure or a major change in phenotype.
Interpretation and limitations
Select imaging for subdural haemorrhage, cerebral venous thrombosis or another acute cause rather than assuming uncomplicated leak-related pain.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Migraine

Nausea, photophobia and movement sensitivity overlap, but a reproducible posture–symptom relationship and brain-sag imaging favour low-volume headache.

Cerebral venous sinus thrombosis

Progressive headache, papilloedema, seizure or prothrombotic risk requires venous imaging because venous thrombosis may mimic or complicate pressure disorders.

Chiari malformation

Tonsillar descent can resemble brain sag, but congenital posterior-fossa anatomy and absence of diffuse low-pressure features support primary Chiari disease.

Orthostatic or cervicogenic symptoms

Postural tachycardia, hypotension and upper-cervical pain can worsen upright without cerebrospinal-fluid loss; measured physiology and targeted imaging distinguish them.

Additional chapter-specific clues

Diagnostic mimic

Prominent tachycardia without leak features, migrainous episodicity independent of posture, fever or a thunderclap onset should broaden assessment before attributing everything to cerebrospinal-fluid loss.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Immediate triageSeparate a stable leak from an emergencyFirst stepA new headache has a convincing upright-worse pattern or follows dural puncture.

1Record onset, postural latency, procedure and medicines, then assess observations, mental state, focal neurology, meningism and features of raised intracranial pressure or infection.
2Send thunderclap headache, seizure, reduced consciousness, new deficit, fever or severe progressive symptoms through urgent same-day imaging and specialty assessment.
3For a neurologically stable patient, give safety-net advice, avoid dehydration, provide suitable simple analgesia and arrange review rather than promising spontaneous resolution.

02Known punctureManage post-dural-puncture headacheTypical orthostatic symptoms follow lumbar puncture or neuraxial anaesthesia.

1Notify the procedural or obstetric anaesthetic team, confirm there is no infective or neurological complication and review antithrombotic treatment before any intervention.
2Offer short-term supportive care when symptoms are mild, while explaining that caffeine may transiently reduce pain but does not reliably seal the dural defect.
3Discuss epidural blood patch when daily activity or infant care is substantially impaired, symptoms persist or conservative treatment fails; follow local consent and anticoagulation rules.

03Spontaneous diseaseImage and treat a suspected spontaneous leakOrthostatic symptoms arise without recent intentional dural puncture or remain unexplained.

1Arrange contrast brain MRI and whole-spine MRI through neurology, documenting why a normal opening pressure or non-postural late phenotype would not exclude the diagnosis.
2Refer promptly to a service with neuroradiology and spinal expertise if symptoms are disabling, scans are supportive or a brief conservative period has not restored function.
3Use specialist-selected non-targeted blood patching first in many pathways, then localise persistent leakage with tailored myelography before targeted patch, fistula embolisation or surgery.

04After treatmentRecognise recurrence and rebound pressureSymptoms change after an epidural patch or leak-directed procedure.

1Reassess the direction and timing of headache rather than assuming persistent low pressure; a new supine-worse or morning headache can represent rebound intracranial hypertension.
2Check vision and fundi when raised-pressure symptoms emerge and obtain specialist advice before repeating a blood patch or starting pressure-lowering medicine.
3Plan graded return to activity, recurrence advice and follow-up imaging only where clinically indicated, with earlier review for neurological decline.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

Provides short-term symptom relief while diagnosis and leak-directed management are arranged.

Paracetamol

Use the usual adult oral dose according to the BNF, reducing or avoiding it where low body weight, liver disease or excess alcohol changes the safe maximum.

Check combination products and total daily exposure; analgesia must not delay assessment of neurological deterioration or replace definitive treatment of a persistent leak.

May produce temporary vasoconstriction in post-dural-puncture headache but does not repair the dural defect.

Caffeine

Oral caffeine is sometimes used for brief symptomatic relief at a locally agreed dose; intravenous regimens require anaesthetic or specialist prescribing and monitoring.

Benefit is short lived and evidence is limited; consider pregnancy or breastfeeding, arrhythmia, anxiety, insomnia and toxicity from repeated or concentrated preparations.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Subdural haematoma

Stretched bridging veins can rupture, producing blood collections, mass effect, seizure or altered consciousness during ongoing cerebrospinal-fluid loss.

Cranial-nerve dysfunction

Traction commonly affects ocular-motor or auditory pathways, causing diplopia, tinnitus, hearing change and disabling disequilibrium during persistent low pressure.

Cognitive or consciousness decline

Severe brain sag can distort diencephalic and brainstem structures, causing cognitive change, movement disorder or rarely profound reduced consciousness.

Chronic disability and procedural burden

Persistent leakage can prevent upright activity and work, while repeated patches, imaging and surgery carry infection, bleeding and further-puncture risks.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Track upright tolerance, time to headache onset, time to recovery when supine and ability to perform ordinary activities rather than using pain score alone.
Repeat neurological assessment promptly if pain changes character, loses its usual postural relationship or is accompanied by confusion, seizure, diplopia or weakness.
After a blood patch, monitor the procedural site, neurological status and symptoms of infection, recurrent leakage or new raised intracranial pressure.
Review antiplatelet and anticoagulant medicines with the procedural team before neuraxial treatment; never improvise interruption outside the relevant protocol.
Ensure a persistent spontaneous case has an accountable specialist team and a plan for advanced leak localisation rather than serial non-specific emergency attendances.
Assess work, driving, falls and caring responsibilities, providing practical restrictions and return advice tailored to diplopia, dizziness and cognition.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Pressure can be normal

The disorder's historical name is misleading: only a minority of imaging-confirmed spontaneous cases have a markedly low lumbar opening pressure.

Chronic posture fades

As disease persists, the headache may take longer to appear or become continuous, so earlier history is often more discriminating than today's pattern.

Spine MRI guides technique

An extradural cerebrospinal-fluid collection points toward a dural tear, whereas its absence raises the possibility of a venous fistula and different myelography positioning.

Subdurals may be secondary

Draining a collection without treating the driving leak can permit recurrence; neurosurgical and leak specialists should coordinate sequencing unless mass effect demands emergency action.

Rebound reverses posture

A new frontal, morning or recumbent-worse headache after successful sealing may reflect raised pressure rather than treatment failure, changing the appropriate response.

11Common pitfallsFrequent interpretation and management errors.

01
Excluding the diagnosis because one opening pressure is normal.
02
Ordering lumbar puncture solely to prove low pressure despite supportive imaging.
03
Assuming every postural headache is a cerebrospinal-fluid leak without checking mimics.
04
Using prolonged bed rest as definitive treatment for disabling spontaneous disease.
05
Repeating blind procedures indefinitely without specialist leak-localisation review.
06
Missing a subdural haematoma or cerebral venous thrombosis when symptoms change.
07
Calling rebound intracranial hypertension recurrent low pressure after a successful patch.