Ms B, a 33-year-old white woman, presents with a complaint of severe daily headaches for the past 3 weeks. The patient has a 15-year history of hypertension and intermittent headache. She describes feeling the headaches in the back of her head (suboccipital region), and the pain radiates forward behind her eyes. She describes the headaches as continuous pressure that causes her to have a “fuzzy” feeling in her head. She also reports chronic neck and shoulder pain, upper and lower back pain, and fatigue.
Additional symptoms include dizziness, numbness and tingling in her hands, and difficulty with visual focusing, concentration, and memory. The headaches are intensified with coughing, laughing, and bending over, and they prevent her from participating in her yoga practice.
The patient reports that the headaches are unresponsive to triptans, nonsteroidal anti-inflammatory drugs, acetaminophen, tramadol, and steroids. Her blood pressure is controlled with oral losartan 50 mg/d. The patient reports taking daily supplements of magnesium, fish oil, and vitamin D.
Ms B’s vital signs are normal, and her blood pressure is well controlled at 120/72 mm Hg. Musculoskeletal examination reveals a slightly unsteady gait with dysmetria and reduced lateral range of motion of the neck to the left and right with muscle spasm of the cervical spine. Abnormal findings on neurologic examination include a diminished gag reflex with protruding tongue deviation to the right. Hoffman sign is positive bilaterally. Deep tendon reflexes are symmetrically increased 4+ with 2-beat clonus bilaterally. Physical examination is otherwise unremarkable.
Testing and Diagnosis
Considering Ms B’s headache symptoms and her neurologic examination showing signs of spinal cord compression, magnetic resonance imaging (MRI)of the brain and cervical spine are ordered. MRI reveals cerebellar tonsils extending 5 mm below the foramen magnum and a few small nerve root sleeve cysts bilaterally at C6-C7.
The patient was referred to a neurosurgeon who confirmed the diagnosis of Chiari malformation type I. Ms B subsequently underwent MRI of the thoracic and lumbar spine, which was negative for syrinx (syringomyelia) or tethered spinal cord. The neurosurgeon recommended that Ms B undergo decompression surgery.
Because of unrelenting symptoms and severely decreased quality of life, Ms B decided to move forward with surgery. Chiari decompression with microdissection was performed approximately 4 months after her initial symptoms began. The surgery included suboccipital craniectomy with duraplasty and C1 laminectomy. During surgery the cerebellar tonsils were found to be completely occluding the fourth ventricle. After resection, an arachnoid veil was discovered overlying the fourth ventricle, which was also resected allowing for normal flow of cerebrospinal fluid.
Chiari malformation is a medical condition characterized by cerebellar tonsillar herniation of ≥5 mm below the level of the foramen magnum and is a known rare cause of adult-onset headaches.1 Hans Chiari, an Austrian professor and pathologist, first identified hindbrain herniation while performing autopsies in the 1890s.2,3 He classified his findings into 4 categories based on severity of herniation (Table), with type IV being the most severe.4 While types II, III, and IV are typically diagnosed in utero or early childhood due to significant neurologic and physical deviations, Chiari malformation type I, the mildest type, is often not diagnosed until symptom development in early adulthood.4 Some patients go undiagnosed for many years and suffer from headaches and additional symptoms during this time.
Chiari I malformation may cause severe headaches that resemble Valsalva-induced headaches. Chiari I malformation has been increasingly detected, with a prevalence in some studies of 0.1% to 0.5% percent.5,6 Chiari malformations develop in utero when the tonsils of the hindbrain extend downward out of the skull into the spinal column, crowding the foramen magnum and impeding the flow of cerebrospinal fluid (CSF) between the head and the spine. This buildup of CSF causes pressure, resulting in sharp headaches and other neurologic symptoms. Other symptoms of Chiari malformation may include ataxic gait, nausea, dizziness, nystagmus, voice changes, dysphagia, facial pain, tinnitus, decreased hearing, neck and shoulder pain, paresthesia and/or weakness in the upper extremities, sleep apnea or insomnia, and heart palpitations.7
The degree of herniation does not reflect the severity of symptoms as some patients with Chiari malformation are asymptomatic.2,3,7 Primary care providers should be aware that Chiari malformation should be part of the differential diagnosis for the patient with frequent dull or sharp Valsalva-induced headaches. Herniation of the hindbrain as demonstrated on MRI of the brain confirms the diagnosis of Chiari malformation. Treatment is based on MRI findings and symptomatology. Suboccipital craniectomy with or without duraplasty is the treatment of choice with the goal of restoring normal flow of CSF to the foramen magnum.7,8
In addition to the Chiari I malformation, Ms B also had nerve root sleeve cysts and an arachnoid veil in the fourth ventricle, both of which contributed to her headaches. An arachnoid veil is webbing of the intradural membranes, which can further impede flow of the CSF.9 Surgical resection of this webbing restores CSF flow. Nerve root sleeve cysts, also known as Tarlov cysts, are usually considered a benign normal deviation and therefore may be underreported on MRI.10 Although they are usually found in the sacral region, these cysts can occur in the cervical spine and can additionally impede the flow of CSF, contributing to symptoms.10
At the patient’s 6-week postoperative follow-up visit, she presented without headache. She denied blurred vision or dizziness, and the numbness and tingling in her hands had resolved. She reported feeling lighter and clearer, and her blood pressure was noted to be lower, resulting in a tapering of her antihypertensive medication. The patient was advised to continue with range of motion exercises for her neck. She was informed that her recovery will be ongoing, and she was instructed to follow up with her neurosurgeon in 6 weeks.
Heather Jones, DNP, AGPCNP-C, is a certified adult gerontology primary care nurse practitioner and a clinical instructor in the Department of Health Behavior and Biological Sciences at the University of Michigan in Ann Arbor. She also works in clinical practice. Beth Ammerman, DNP, FNP-BC, is a certified family nurse practitioner and a clinical assistant professor in the Department of Health Behavior and Biological Sciences at the University of Michigan in Ann Arbor. She also works in clinical practice.
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4. Chiari malformation fact sheet. National Institutes of Health website. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet#4. Modified March 13, 2020. Accessed April 22, 2020.
5. Piper RJ, Pike M, Harrington R, Magdum SA. Chiari malformations: principles of diagnosis and management. BMJ. 2019;365:I1159.
6. Khoury C. Chiari malformations. UpToDate website. https://www.uptodate.com/contents/chiari-malformations?search=chiari%20malformation&source=search_result&selectedTitle=1~122&usage_type=default&display_rank=1. Updated June 21, 2019. Accessed May 7, 2020.
7. Gilmer HS. Chiari malformation program: education, treatment and support. Michigan Head & Spine Institute. https://www2.mhsi.us/images/education/MHSIchiariBooklet.pdf. Accessed April 23, 2020
8. Baisden J. Controversies in Chiari I malformations. Surg Neurol Int. 2012;3(Suppl3):S232-S237.
9. Jain M, Sahu NK, Naik S, Bag ND. Symptomatic Tarlov cyst in cervical spine. BMJ Case Reports. 2018;11(1):e228051.
10. Ciappetta P, Signorelli F, Visocchi M. The role of arachnoid veils in Chiari malformation associated with syringomyelia. Acta NeurochirSuppl. 2019;125:97-99.