Symptoms of Chiari malformation

Many people with Chiari I have no symptoms at all, and the malformation is found on a scan done for another reason1. Symptomatic Chiari I is much less common than the symptom-free form2. When it does cause symptoms, they come from three sources: obstruction of cerebrospinal fluid (CSF) flow at the base of the skull, pressure on the brainstem, cerebellum and nerves, and a syrinx in the spinal cord.

The Chiari headache

The headache of Chiari malformation has a recognizable pattern. According to the International Classification of Headache Disorders, it is3:

• at the back of the head or the top of the neck (occipital or suboccipital)
• brought on by coughing or other straining, such as sneezing, laughing, lifting, bending or straining on the toilet
• brief, lasting less than five minutes

The trigger is the most distinctive feature. A headache that starts within seconds of a cough, in someone with tonsillar descent on MRI, is a strong combination. The usual explanation is that the tonsils plug the foramen magnum: straining briefly raises the pressure in the head, and the fluid can't move freely into the spine to even it out4.

Headaches that are present most days, build over hours, throb, or come with nausea and sensitivity to light usually have another cause, most often migraine or tension-type headache, even when the tonsils are low. Overlap with migraine is one reason the diagnosis is difficult5. A person can have both.

The pattern also predicts the response to surgery. Cough headaches respond better than headaches without a straining trigger, and headaches at the back of the head better than headaches elsewhere3. US guidelines say decompression may be performed to relieve strain-related headache, and that other symptoms respond less predictably6.

Symptoms from pressure on the brainstem and cerebellum

Crowding at the foramen magnum can affect the brainstem, the cerebellum, the lower cranial nerves and the upper spinal cord3. The resulting symptoms include:

• neck pain
• unsteadiness, poor coordination and clumsiness
• dizziness and vertigo
• difficulty swallowing, choking, or a hoarse voice
• ringing in the ears or a feeling of pressure in the ears
• sleep apnea, especially the central type, in which breathing pauses because the brain doesn't signal it
• abnormal eye movements (nystagmus), usually noticed by a doctor
• numbness or pain in the face, because the nerve centers for facial sensation extend down into the upper spinal cord

Symptoms rarely come alone: 95% of people with Chiari I report five or more distinct symptoms3. That makes it hard to tell which symptoms come from the malformation, and it is one reason patients and specialists can disagree about what an operation should be expected to fix.

Symptoms from a syrinx

A syrinx is a fluid-filled cavity inside the spinal cord. It usually forms in the neck and upper back and causes a different set of symptoms4:

• loss of pain and temperature sensation across the shoulders and arms, often in a cape-like pattern, with light touch preserved
• burns or cuts on the hands that weren't felt
• pain in the neck, shoulders and arms
• weakness and wasting of the small muscles of the hands
• stiffness and weakness in the legs (spasticity), later on

These symptoms reflect damage to the spinal cord and are taken more seriously than headache alone. The syringomyelia page explains why.

Chiari malformation in children

Young children can't describe a cough headache. They may show irritability, crying when straining, swallowing and feeding difficulty, noisy breathing or pauses in breathing during sleep, or delayed development.

In children, scoliosis can be the first sign of a syrinx caused by Chiari I. In a study of 43 children with Chiari I and a spinal curve, 49% had a syrinx, and children with a syrinx were much more likely to have a curve over 20° (86% against 41%)7. A curve in a young child, or one with unusual features, is a reason to scan the brain and whole spine.

Symptoms that are less likely to be caused by Chiari

Fatigue, brain fog, widespread pain, palpitations and anxiety are common in people with Chiari I, but they are also common in the general population and respond less predictably to surgery6. Some people have Chiari-like symptoms with minimal tonsillar descent, and others with large descent have none3. Whether symptoms began alongside a typical cough headache, and whether anything else explains them, helps decide whether they belong to the malformation.

There is no "Chiari face": the malformation doesn't change a person's appearance. Its effects on the face are neurological, such as numbness or pain.

When to get urgent help

Most Chiari symptoms develop slowly and need a planned appointment. Get medical help promptly for:

• new difficulty swallowing, choking on liquids, or a change in voice
• weakness or numbness in the arms or legs that is getting worse
• new problems controlling the bladder or bowels
• pauses in breathing during sleep, especially in a child
• a sudden, severe headache unlike the usual pattern, which needs emergency assessment like any sudden severe headache

References

1. National Institute of Neurological Disorders and Stroke. Chiari malformation. BrainFacts.org. Accessed October 3, 2026. Source ↩
2. Holste KG, Muraszko KM, Maher CO. Epidemiology of Chiari I malformation and syringomyelia. Neurosurg Clin N Am. 2023;34(1):9-15. doi:10.1016/j.nec.2022.08.001 PubMed ↩
3. Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders, 3rd edition: 7.7 Headache attributed to Chiari malformation type I (CM1). Cephalalgia. 2018;38(1):1-211. Accessed October 3, 2026. Source ↩
4. Rosenblum JS, Pomeraniec IJ, Heiss JD. Chiari malformation (update on diagnosis and treatment). Neurol Clin. 2022;40(2):297-307. doi:10.1016/j.ncl.2021.11.007 Source ↩
5. Bauer DF, Niazi T, Qaiser R, et al. Congress of Neurological Surgeons systematic review and evidence-based guidelines for patients with Chiari malformation: diagnosis. Neurosurgery. 2023;93(4):723-726. doi:10.1227/neu.0000000000002633 Source ↩
6. Jackson EM, Jernigan S, Raskin JS, et al. Congress of Neurological Surgeons systematic review and evidence-based guidelines for patients with Chiari malformation: symptoms. Neurosurgery. 2023;93(4):727-730. doi:10.1227/neu.0000000000002634 Source ↩
7. Chotai S, Nadel JL, Holste KG, et al. Longitudinal scoliosis behavior in Chiari malformation with and without syringomyelia. J Neurosurg Pediatr. 2021;28(5):585-591. doi:10.3171/2021.5.PEDS20915 PubMed ↩

Related pages

• MRI and diagnosis of Chiari malformationHow Chiari malformation is diagnosed: the MRI criteria, what the millimeters mean, whole-spine imaging, CSF flow studies and conditions that look the same.
• Syringomyelia in Chiari malformationSyringomyelia with Chiari malformation: what a syrinx is, why it forms, its symptoms, scoliosis in children, and what decompression surgery achieves.
• Chiari malformation surgeryChiari decompression surgery: who is offered it, the operation, the evidence on the dural patch and tonsil reduction, results, risks and recovery.
• Types of Chiari malformationThe types of Chiari malformation: Chiari 1 and 2, the rare types 3 and 4, borderline Chiari 0 and 1.5, and acquired tonsillar descent.