Spontaneous intracranial hypotension, low fluid pressure around the brain from a spinal CSF leak, can cause tinnitus: guideline figures put it at more than one patient in four, alongside a headache that builds upright and eases lying flat.
It is uncommon, easy to miss and treatable. When ear symptoms lead, it can pass for Ménière's disease.
What is spontaneous intracranial hypotension?
Cerebrospinal fluid (CSF) cushions the brain and spinal cord inside a tough membrane, the dura. In spontaneous intracranial hypotension, fluid escapes from the spine with no procedure or injury to explain it. A 2023 British multidisciplinary consensus guideline names three routes: a tear in the dura, a leaking pouch in the spinal lining, or a CSF-venous fistula, a connection that drains fluid straight into a vein.
A population study in Beverly Hills, California, found 3.7 new cases per 100,000 people a year between 2006 and 2020. A study in Olmsted County, Minnesota, found 3.8 per 100,000 adults, and half of its 14 cases were CSF-venous fistulas.
The International Headache Society's classification, ICHD-3, defines a low-pressure headache by CSF pressure below 60 mm of CSF, or evidence of a leak on imaging. Its description names what usually comes with it: neck pain, tinnitus, changes in hearing, sensitivity to light and nausea.
What does the headache feel like?
The hallmark is an orthostatic headache, one driven by posture. The 2023 guideline's working definition:
- absent or only mild on waking, or after lying flat for a long time;
- starting within 2 hours of becoming upright;
- improving by more than half within 2 hours of lying flat again;
- consistent in when it starts and stops.
It is not universal. In a 2021 meta-analysis of 144 studies, 92% of patients with a headache described it as orthostatic, and 3% had no headache at all. In a Swiss questionnaire study of 79 treated patients, 12 (15.2%) did not report an orthostatic headache at the start. ICHD-3 notes that the postural pattern is clearest at onset and can become much less obvious over time, so how the headache began matters.
How often does it cause tinnitus and hearing changes?
Often, though the figures vary widely between studies.
- The guideline's symptom table, adapted from a 2021 review by Wouter Schievink: muffled hearing or ear fullness in 37.1%, tinnitus in 27.7%, reduced hearing in 26.2%.
- The 2021 meta-analysis: tinnitus in a pooled 20% (95% CI 14% to 26%) and hearing disturbances in 28%, across 32 studies and 1,531 patients.
- 442 patients in Taiwan: tinnitus in 39.7% of women and 26.7% of men.
- 348 inpatients in China: any ear symptom in 29.9%, tinnitus in 14.7%. Of the 34 who had hearing tests, 32 had sensorineural (inner-ear or nerve) loss, mostly mild to moderate.
- 100 people with CSF-venous fistulas at the Mayo Clinic: tinnitus in 55, second only to headache, after symptoms lasting a mean of 40.9 months.
- 79 patients answering a Swiss questionnaire: auditory disturbances, a broader category than tinnitus, in 59.5%.
In this list, the lowest tinnitus figure comes from inpatient records and the highest from a specialist centre's long-standing cases; how symptoms were collected may explain some of the spread. A 2020 case report in Practical Neurology estimates that ear and balance symptoms affect up to 70% of patients and are probably under-reported.
None of these series says what the tinnitus sounds like: a steady tone, a hum, or a pulse.
Why would a spinal leak affect the ear?
The inner ear's fluid is connected to the CSF by two narrow channels, the cochlear and vestibular aqueducts. The explanation these reports favour is that falling CSF pressure passes along them into the inner ear.
- Hydrops. A 2020 series of three patients in Otology & Neurotology supported the theory that low pressure travelling through the cochlear aqueduct produces endolymphatic hydrops, the inner-ear fluid build-up linked with Ménière's disease. In a 2026 French series of 12 patients with ear or balance problems, 66.7% had tinnitus and specialised MRI showed hydrops in four (33.3%), all low-grade.
- Posture. The 2020 Practical Neurology case describes a 36-year-old woman whose hearing returned to normal when she lay flat, confirmed on hearing tests, and recovered fully after blood patches.
- More loss than reported. In a 2015 Korean series of 16 patients with intracranial hypotension, only 5 reported ear or balance symptoms, but hearing tests found sensorineural loss in 7 of the 13 tested.
The guideline adds a longer-term reason to take hearing seriously: a persistent leak may lead to superficial siderosis, and clinicians should be more suspicious of it when someone with a leak develops unsteadiness or hearing loss. A 2023 Australian series describes siderosis as a progressive disease that often impairs hearing and balance in both ears. In its five patients, whose spinal defects mostly followed injury or surgery, all were diagnosed late, and repair in four did not restore hearing or balance.
These are small series, and the mechanism is a hypothesis. No study found for this article has measured whether the ringing itself eases lying down, as hearing can.
How is it the mirror image of intracranial hypertension?
Idiopathic intracranial hypertension is the opposite problem: pressure around the brain that is too high. A 2022 review lists its primary symptoms as headache, vision loss and pulsatile tinnitus. In spontaneous intracranial hypotension the pressure or volume is too low, and the headache eases lying down.
A 2026 review in Headache argues the two share one physiology, and describes movement in both directions:
- Rebound intracranial hypertension. After a leak is sealed, some people develop high-pressure symptoms: a frontal headache worse lying down and in the morning, with nausea, vomiting or blurred vision. A 2024 review reports an incidence of 27.4% in one large single-centre analysis, with onset usually within 48 to 72 hours and 94% resolving within 3 months.
- "Popping the balloon". People with idiopathic intracranial hypertension can develop a spinal leak and drop from high pressure to low, with orthostatic headache and ear symptoms replacing the old ones.
The review notes that the true incidence of these transitions has not been systematically quantified; the 2021 meta-analysis cites rebound rates from 7% to 27.4%. That meta-analysis also found lumbar puncture pressure normal in 32% of patients and high in 3%. Its authors wondered whether some of the high-pressure group had intracranial hypertension, though the only mildly raised pressures argue against it; alternatively, raised pressure might predispose to a leak.
Why is it so often missed?
In a 2003 series of 18 consecutive patients, 17 (94%) had first been given another diagnosis, most often migraine, meningitis or a psychological disorder. The delay ran from 4 days to 13 years, with a median of 5 weeks.
A 2022 UK survey of 64 patients found people had seen their GP an average of three times before being referred, and in just under half the first specialist did not make the diagnosis.
A 2026 case report describes a 39-year-old woman treated for Ménière's disease with a low-salt diet and betahistine, without improvement, whose fluctuating hearing was worse during the day and better lying down. A second look at her brain scans showed signs of a leak, and treating it brought near-complete resolution. The guideline offers one pointer against migraine: migraine favours aura and vertigo, a leak favours hearing impairment and tinnitus.
How is it diagnosed?
The guideline's first tests are MRI of the brain with contrast and MRI of the whole spine, and it advises against routinely doing a lumbar puncture just to confirm the diagnosis. Scans for tinnitus covers imaging more generally, and the diagnosis guide the wider workup.
A 2006 JAMA review summarised the brain signs as SEEPS: subdural fluid collections, enhancement of the brain's outer lining (the pachymeninges), engorged veins, pituitary hyperaemia and sagging of the brain. In the 2021 meta-analysis, lining enhancement appeared in 73%, engorged veins in 57% and sagging in 43%. But brain MRI was normal in 19%, and lumbar puncture pressure was low in only 67%.
Researchers in Bern built a 9-point score from six brain MRI signs, three of them measures of brain sagging; 5 points or more places a patient in the group most likely to have a spinal leak.
Finding the leak itself takes myelography: contrast placed in the spinal fluid and imaged by CT or digital subtraction as it escapes. The guideline mainly reserves it for people who have not improved, or improved only briefly, after blood patching, because its purpose is to plan targeted treatment.
What is the treatment, and how good is the evidence?
- Conservative care, briefly. The guideline advises bed rest and 2.0 to 2.5 litres of fluid a day for up to 2 weeks from onset. In the meta-analysis this alone worked for 28%.
- Epidural blood patch. Some of the patient's own blood is injected just outside the dura, where it can seal the leak. The guideline makes a non-targeted patch, placed without knowing the leak's site, the first-line treatment, given as early as possible with up to 40 mL of blood, ideally at least 20 mL. A single patch succeeded in 64% in the meta-analysis; larger patches did better than smaller ones, 77% against 66%, and targeted and non-targeted patches performed similarly, as a 2025 meta-analysis of seven comparative studies also found.
- Targeted treatment. When patches fail and myelography finds the leak, options include a patch or fibrin sealant at the site, surgery, or, for a CSF-venous fistula, blocking the vein from inside. In the Mayo series of 100 patients treated this way, 58 people reported resolution and 37 improvement; 19 developed rebound high pressure needing acetazolamide.
A 2023 evidence map found 139 studies of blood patching or surgery, with a median of 14 participants; none reached the top level of evidence, and 92.1% were retrospective cohorts or case series. The 2021 meta-analysis found no controlled interventional studies, and warns its 64% may be an overestimate because an older diagnostic definition counted improvement after a patch as part of the diagnosis.
For the ears, the evidence is thinner still. In a 2016 Italian series of 28 people given a blood patch, 16 had hearing changes; their rating fell from a median of 4 to 1 within two days, and at two months 4 of the 16 still had mild changes. A 2026 self-report survey after surgical repair, of people with spontaneous or post-procedure leaks recruited through patient groups, found tinnitus improved only moderately, less than the headache. No study found for this article measured tinnitus as its main outcome.
When should you get checked?
The guideline says the condition should be considered in anyone with an orthostatic headache. It asks for referral to a neurologist within 2 to 4 weeks for someone who can look after themselves, within 48 hours for someone who cannot but has help, and emergency admission for someone who has neither.
Some changes need urgent care. The condition can cause bleeding over the brain (a subdural haematoma) and clotting in the brain's veins; in the Taiwanese cohort, subdural haematoma occurred in 29.7% of men and 10.8% of women. The guideline calls for urgent specialist referral for rapid deterioration or a serious complication, and for venous imaging to be considered after any sudden change in the headache. After treatment, a new headache that is worse lying down should be assessed for rebound high pressure, and after a blood patch the guideline advises urgent attention for symptoms including new severe back or leg pain, leg weakness or numbness, bladder or bowel problems, and fever.
When you are seen, it helps to say:
- how long after getting up the headache starts, and how quickly lying down eases it;
- whether your hearing, ear fullness or ringing changes with position;
- whether it began after a spinal anaesthetic, an epidural or a lumbar puncture, a different condition covered in tinnitus after surgery or anaesthesia.
Tinnitus when lying down covers the other conditions that change with posture, and the when to seek care tool sorts which ear symptoms need prompt attention.