Ross Hauser, MD

Patients with hypermobile Ehlers-Danlos syndrome (hEDS) and related connective tissue disorders often arrive at our office with a long list of diagnoses: pressure headaches, pulsatile tinnitus, dizziness, brain fog, POTS, cerebrospinal fluid (CSF) leaks, and craniocervical instability. These conditions should not automatically be assumed to have one cause. However, emerging research suggests that, in a subgroup of patients, they may be connected through abnormal regulation of intracranial pressure and impaired venous drainage from the brain.

This article explains what the research presently supports, where important uncertainties remain, and why the cervical spine and internal jugular veins may deserve careful evaluation in selected patients.

What is cerebral venous outflow?

Blood enters the brain through the arteries and must leave through the cerebral veins and dural venous sinuses. Much of that blood then passes through the internal jugular veins in the neck on its return to the heart. If a venous sinus or jugular vein is narrowed, compressed, or unable to accommodate changing flow demands, venous pressure upstream may rise.

This does not mean that every narrowed jugular vein is a disease. Extrinsic upper-jugular narrowing is common on routine CT angiography, frequently between the styloid process and the C1 transverse process, and many people with this anatomy have no symptoms. Imaging must therefore be interpreted together with symptoms, collateral veins, eye findings, pressure measurements when appropriate, and evidence of a physiologically important pressure gradient. (1)

When venous drainage is physiologically impaired, patients may develop symptoms associated with cerebral venous congestion or altered intracranial pressure. These can include:

• pressure-type headache;
• pulsatile tinnitus, often described as hearing the heartbeat in an ear;
• visual dimming, blurred vision, double vision, or papilledema;
• dizziness or imbalance;
• cognitive slowing or “brain fog”;
• symptoms affected by position, straining, coughing, or head rotation; and
• neck pain or a feeling of head pressure.

None of these symptoms is specific to venous outflow obstruction. Migraine, vestibular disorders, anemia, medication effects, sleep disorders, arterial disease, CSF-pressure disorders, and many other conditions can produce similar complaints.

In the video

• Cerebral venous outflow
• Internal jugular vein compression
• Intracranial pressure
• Pressure headaches, tinnitus, dizziness, and visual symptoms
• Diagnostic imaging and testing

Place it immediately after the section titled “What is cerebral venous outflow?”

A newly described connective tissue and venous-outflow phenotype

A 2024 retrospective study described 86 patients with connective tissue disorders and coexisting cerebral venous outflow disorders. Fifty-five percent had Ehlers-Danlos syndrome. The cohort was predominantly female (87%), White (90%), and notably non-obese—different from the classic demographic profile commonly associated with idiopathic intracranial hypertension (IIH). (2)

The most frequently reported presenting symptoms were pressure headache (98%), tinnitus (92%), dizziness (90%), and cognitive dysfunction (69%). Associated diagnoses included POTS in 55.8%, CSF leaks in 51.2%, dysautonomia in 45.3%, craniocervical instability in 37.2%, mast cell activation syndrome in 25.6%, and tethered cord syndrome in 23.3%. Medication allergies were reported by 87.2%, while 19.8% reported reactions to surgical tape. (2)

One of the most interesting findings was that these patients reported headache and quality-of-life impairment comparable to patients with classic IIH even though lumbar-puncture opening pressures were significantly lower. The authors proposed that patients with connective tissue disorders may be more sensitive to intracranial pressure or cerebral venous congestion.

That is an important hypothesis—not a settled conclusion. This was a retrospective cohort from a referral population without a healthy control group. Referral bias and coexisting diagnoses may influence the findings. It does not establish that hEDS causes venous obstruction, that a “normal” opening pressure is abnormal for a particular patient, or that venous intervention will help every symptomatic person.

Why connective tissue may matter

Connective tissue gives strength and elasticity to ligaments, fascia, blood-vessel walls, and the structures that stabilize the head and neck. In hEDS and hypermobility spectrum disorders, ligamentous laxity can permit greater-than-normal motion. Veins are also thin-walled, low-pressure structures and are more susceptible than arteries to deformation by adjacent anatomy.

Several pathways may overlap:

1. Reduced structural support

Lax ligaments may permit altered cervical alignment, excess upper-cervical motion, or settling of the head-neck relationship. In a susceptible patient, these changes could alter the space available for the internal jugular vein, particularly near C1 and the styloid process.

2. Dynamic rather than fixed compression

A conventional scan is a snapshot. A vein may appear acceptable in one position yet narrow with upright posture, rotation, extension, or another movement. Conversely, an apparent narrowing on a supine scan may be an incidental anatomical variant. Dynamic findings must be reproducible and correlated with physiology and symptoms before they are considered clinically meaningful.

3. Venous pressure and CSF pressure are linked

CSF is absorbed partly through structures that drain into the venous sinuses. If venous sinus pressure rises, the pressure gradient available for CSF absorption can fall. This relationship is one reason venous sinus stenosis is important in IIH. It can also be a feedback loop: increased intracranial pressure may narrow a compliant venous sinus, and the stenosis may then help maintain the pressure elevation.

4. Several pressure disorders may coexist over time

Connective tissue disorders are associated with spontaneous spinal CSF leaks, which classically cause low-pressure, upright headaches. Yet patients can have complex or changing pressure states, including rebound intracranial hypertension after a leak is sealed. A history of a CSF leak should therefore not be used by itself to conclude that current symptoms represent low pressure. (3)

Hypermobility, craniocervical obstruction, and signs of intracranial hypertension

A 2020 study evaluated 229 patients with myalgic encephalomyelitis/chronic fatigue syndrome. Hypermobility was identified in 50%. Among those who underwent brain MRI, 55% had increased optic nerve sheath diameter and 83% had one or more imaging signs interpreted by the investigators as possible intracranial hypertension. Cerebellar tonsils below the McRae line were seen in 56%. Among 125 patients who had cervical MRI, 80% were reported to have craniocervical obstructions. (4)

These results are provocative, but they require restraint. Imaging signs such as partially empty sella, optic nerve sheath enlargement, venous sinus narrowing, or low-lying cerebellar tonsils are not diagnostic of IIH on their own. The study involved a selected symptomatic population, and its definition of craniocervical obstruction is not universally used. The findings support further investigation; they do not show that all ME/CFS, hypermobility, or fatigue symptoms are caused by intracranial hypertension.

POTS and dysautonomia are common—but not proof of venous obstruction

POTS is characterized by excessive heart-rate increase on standing, accompanied by orthostatic symptoms, after other causes are excluded. Dysautonomia is an umbrella term for abnormal regulation by the autonomic nervous system. Both are frequently reported in hEDS, including in the 86-patient venous-outflow cohort.

A 2024 review found substantial adult literature describing cardiovascular and autonomic symptoms in hEDS, while emphasizing the limited pediatric evidence and the need for better studies of quality of life and management in children. (5)

The overlap matters clinically, but it should not be converted into a causal shortcut. POTS can involve low circulating volume, excessive sympathetic activation, neuropathy, deconditioning, immune factors, and other mechanisms. A diagnosis of POTS does not prove jugular compression, and jugular narrowing does not prove the cause of POTS.

Our Caring Medical cervical and venous-outflow hypothesis

At Caring Medical, we see a selected population with chronic neck symptoms, hypermobility, neurological complaints, and difficult-to-explain pressure or autonomic symptoms. Our clinical question is whether ligamentous cervical instability and abnormal cervical structure can, in some patients, contribute to impaired flow through the neck—venous outflow from the brain, arterial inflow, CSF movement, lymphatic drainage, or a combination of these systems.

In our 2024 narrative review, we proposed that forward-head posture and ligamentous cervical instability may alter the anatomical relationships through which blood and CSF move into and out of the brain. This paper develops a biomechanical hypothesis from anatomy and published observations; it is not a clinical trial and does not prove that correcting posture or treating ligaments normalizes intracranial pressure. (6)

Our 2026 retrospective study examined 84 consecutive patients with hEDS, aged 20 to 50, who were evaluated at an outpatient neck center. Nearly all had coexisting forward-head posture, reduced cervical curve depth, ligamentous cervical instability, and reduced internal jugular vein and vagus nerve cross-sectional area. Internal jugular vein area was significantly smaller at C1 than at C4-C5, a pattern consistent with possible upper-cervical carotid-sheath compression. (7)

This study directly adds cervical and neurovascular measurements to the phenotype described in the 2024 venous-outflow paper. It also has important limitations: it was retrospective, single-center, observational, and involved patients already seeking neck evaluation. It had no matched healthy control group and did not establish that the imaging findings caused symptoms. The data should be regarded as hypothesis-generating.

In a separate 2026 retrospective cross-sectional study of 227 young adults evaluated for chronic brain-based symptoms, we reported high frequencies of neck pain, brain fog, concentration difficulty, headache, anxiety, loss of cervical lordosis, C1-C2 instability, internal jugular vein narrowing, and increased optic nerve sheath diameter. Internal jugular vein cross-sectional area increased with cervical orthotic positioning compared with supine measurement. (8)

Again, a positional change in vein caliber is not proof that the vein caused the symptoms or that an orthotic is a treatment for IIH. It does, however, support the need to study cervical position and dynamic venous behavior rather than assuming that neck anatomy is fixed.

Readers seeking more detail may review our discussions of internal jugular vein stenosis, cervical instability, Ehlers-Danlos syndrome and cervical instability, and autonomic nervous system dysfunction and spinal instability.

How cerebral venous outflow disorders may be evaluated

There is no single screening test that establishes a symptomatic cerebral venous outflow disorder. Evaluation should begin with the clinical pattern and the exclusion of more common or dangerous causes.

Depending on the presentation, a coordinated evaluation may include:

• a detailed headache history, including whether pain is worse lying down, upright, with Valsalva maneuvers, or with head position;
• neurological and ophthalmological examination, including dilated optic-nerve assessment and visual-field testing when papilledema is suspected;
• MRI of the brain and orbits and MR or CT venography to assess venous sinuses, jugular pathways, collateral drainage, masses, thrombosis, and secondary signs of altered pressure;
• cervical imaging when trauma, hypermobility, neurological findings, or craniocervical pathology is suspected;
• Doppler ultrasound as a noninvasive assessment of venous caliber and flow, recognizing its operator and positional limitations;
• lumbar puncture when clinically indicated, performed and interpreted according to accepted technique; and
• catheter venography with manometry only when a specialist needs invasive confirmation of anatomy and pressure gradients for a treatment decision.

For established IIH, protecting vision is the first priority. A lower-than-expected lumbar-puncture opening pressure does not automatically exclude a complex pressure disorder, but symptoms alone should not be used to redefine diagnostic thresholds. The full neurological, ophthalmological, imaging, and pressure context matters.

What else must be considered?

Pressure headache, tinnitus, dizziness, and cognitive symptoms have many possible explanations. A responsible evaluation may need to consider migraine, vestibular migraine, Ménière’s disease, spontaneous intracranial hypotension, medication-overuse headache, sleep apnea, anemia, thyroid disease, arterial dissection, dural arteriovenous fistula, cerebral venous sinus thrombosis, Chiari malformation, mass lesion, infection, and primary eye disease.

Cerebral venous sinus thrombosis is different from non-thrombotic venous narrowing and requires urgent medical management. Vascular EDS is also distinct from hEDS: arterial and organ fragility can make invasive vascular procedures unusually hazardous. The subtype of connective tissue disorder must therefore be understood before an invasive procedure is considered.

Treatment

Treatment depends on the diagnosis—not merely the presence of a narrowed vein on a scan.

Conventional management of confirmed IIH may include weight management when applicable, medications that reduce CSF production, headache-directed care, and close monitoring of vision. Threatened vision may require urgent neurosurgical or neurointerventional treatment. Selected patients with a demonstrated venous sinus pressure gradient may be evaluated for venous sinus stenting, but stenting has risks and does not address every cause of intracranial hypertension.

External jugular compression presents a different problem from an intrinsic venous-sinus stenosis. A stent placed into a vein that remains trapped between external structures may not address the underlying mechanics and may introduce additional risk. Surgical decompression is appropriate only for carefully selected patients after specialist confirmation that the anatomy is clinically significant.

At Caring Medical, when cervical instability is objectively documented and matches the patient’s history and examination, we may discuss treatments intended to improve ligament and cervical stability. We do not present Prolotherapy as an established treatment for IIH or cerebral venous outflow obstruction. Controlled trials have not shown that cervical Prolotherapy normalizes intracranial pressure, reverses papilledema, or replaces neurological, ophthalmological, vascular, or neurosurgical care. Its proposed role is narrower: addressing a demonstrable painful or unstable cervical ligament problem in an appropriately selected patient.

Summary

The emerging research describes a clinically recognizable subgroup: often a non-obese woman with hEDS or another connective tissue disorder, severe pressure headache, tinnitus, dizziness, cognitive dysfunction, and overlapping POTS, dysautonomia, CSF leak, or craniocervical instability. The 2024 phenotype study gives this pattern a needed place in the literature. Our more recent studies add the possibility that upper-cervical structure and dynamic internal jugular narrowing may be relevant in a subset of these patients.

The next step is not to assume that every symptom originates in the neck. It is to ask better questions, use appropriately targeted and sometimes positional testing, protect vision, exclude dangerous alternatives, and determine whether an imaging abnormality is actually physiologically meaningful. Prospective controlled research is needed to define diagnostic criteria, identify which patients truly have pressure-sensitive venous congestion, and test whether treatment of cervical mechanics changes objective venous or intracranial-pressure outcomes.

Medical disclaimer: This article is for educational purposes and does not diagnose or treat any condition. Headache, visual symptoms, pulsatile tinnitus, and neurological changes may require urgent medical evaluation. Decisions about lumbar puncture, venography, stenting, surgery, or cervical injections should be made with qualified specialists after individualized assessment.

References

1 Jayaraman MV, Boxerman JL, Davis LM, Haas RA, Rogg JM. Incidence of extrinsic compression of the internal jugular vein in unselected patients undergoing CT angiography. AJNR American Journal of Neuroradiology. 2012;33(7):1247-1250. [Google Scholar]
2 Midtlien JP, Curry BP, Chang E, Kiritsis NR, Aldridge JB, Fargen KM. Characterizing a new clinical phenotype: the co-existence of cerebral venous outflow and connective tissue disorders. Frontiers in Neurology. 2023;14:1305972. Published online January 10, 2024. [Google Scholar]
3 Schievink WI. Spontaneous spinal cerebrospinal fluid leaks and intracranial hypotension. JAMA. 2006;295(19):2286-2296. [Google Scholar]
4 Bragée B, Michos A, Drum B, Fahlgren M, Szulkin R, Bertilson BC. Signs of intracranial hypertension, hypermobility, and craniocervical obstructions in patients with myalgic encephalomyelitis/chronic fatigue syndrome. Frontiers in Neurology. 2020;11:828. [Google Scholar]
5 Hertel A, Black WR, Walton LM, Martin JR, Jones JT. Cardiovascular symptoms, dysautonomia, and quality of life in adult and pediatric patients with hypermobile Ehlers-Danlos syndrome: a brief review. Current Cardiology Reviews. 2024;20(1). [Google Scholar]
6 Hauser RA, Matias D, Rawlings B. The ligamentous cervical instability etiology of human disease from the forward head-facedown lifestyle: emphasis on obstruction of fluid flow into and out of the brain. Frontiers in Neurology. 2024;15:1430390. [Google Scholar]
7 Hauser RA, Griffiths M, Watterson A, Matias D, Rawlings BR. Characterizing initial cervical spine and neurovascular findings in 84 consecutive patients with hypermobile Ehlers-Danlos syndrome: a retrospective study. Journal of Clinical Medicine. 2026;15(6):2212. [Google Scholar]
8 Hauser RA, Griffiths M, Watterson A, Matias D, Steilen C, Rawlings BR. Brain-based symptoms reported in young adults evaluated for cervical spine etiology: a retrospective, cross-sectional clinical study with preliminary data on over 200 patients. Frontiers in Neurology. 2026;17:1749266. [Google Scholar]