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RFS – Clinical Vignette

Chiari Malformation in the Concussion Clinic: Diagnosis and Management of Confounding and Overlapping Symptoms

A Clinical Vignette

Linsenmeyer, Mark MD; Combs, Josefine PsyD; Kegel, Nathan E. PhD; Franzese, Kevin DO

Author Information
American Journal of Physical Medicine & Rehabilitation: November 2020 - Volume 99 - Issue 11 - p 1074-1077
doi: 10.1097/PHM.0000000000001405

History and Physical Examination

A 20-yr-old woman with a history of anxiety presented to our outpatient concussion center with postconcussive symptoms. Her symptoms started 2.5 yrs before presentation when she was thrown into the air as a cheerleader and landed on the top of her head on a gymnasium floor. There was no loss of consciousness; however, acutely after the fall, she was disoriented and confused and she remains amnesic to the event. Immediate symptoms included dizziness, nausea and vomiting, neck pain, difficulty focusing her vision, emotional changes, and headache. She presented to urgent care the following day where no imaging was performed. Symptoms did not improve with rest, so she presented again to the emergency department 2 wks later where she was referred to a local concussion specialist. She started vestibular therapy and speech therapy. A magnetic resonance imaging (MRI) brain obtained 4 months after her injury was reported to the patient as normal and no further workup was pursued. Her symptoms gradually improved with activity modification and trigger avoidance; however, she remained symptomatic and was referred to our concussion center.

At her initial office visit, her primary complaint was a daily persistent headache described as frontal pressure as well as a posterior occipital headache with reported neck tightness. The headache worsened with computer use or concentration. She reported a “dent” at the top of her skull, which she had not noticed before her injury. Other complaints included phonophobia, photophobia particularly with fluorescent lighting, vestibular symptoms, memory and concentration difficulties, hypersomnia, anxiety, frustration, mydriasis, and visual disturbance especially with focus and contrast.

Regarding her history, she reported two additional concussions 4 and 6 yrs before presentation. These concussions’ symptoms resolved quickly and entirely without intervention. She reported a family history of anxiety and depression; otherwise, histories were unremarkable. Her only medication was duloxetine, which was prescribed for anxiety and headaches but was largely ineffective.

On physical examination, she appeared well, conversed easily, and was alert and oriented. Cranial nerves II–XII were intact with the exception of convergence at greater than 10 cm. All limbs had full strength, sensation was intact, and upper and lower limb muscle stretch reflexes were normal with negative Hoffman’s responses bilaterally. Cervical range of motion was full and no trigger points were palpable. Percussion/palpation along the nuchal ridge elicited tenderness bilaterally but no radiating symptoms along the occipital nerve distributions. She had a small palpable cranial depression at the superior aspect of the coronal suture.

What is in the differential diagnosis for the patient’s headaches? How might you treat her headaches and other symptoms?

Differential Diagnosis and Potential Approaches to Management

Given the patient’s late presentation, the differential diagnosis for her chronic daily headaches is quite different from that of an acute presentation. Many chronic primary and secondary headache syndromes can present after head trauma, including tension type headaches, migraines, hemicrania continua, cervicogenic headaches, temporomandibular joint injury, occipital neuralgia, trigeminal neuralgia, scalp dysesthesias, low cerebral spinal fluid pressure headaches, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks. Additional chronic secondary headache syndromes not related to trauma that should not be disregarded include neoplasm, arteriovenous malformations, cerebral venous thromboses, temporal arteritis, pseudotumor cerebri, spontaneous intracranial hypotension, and Chiari I malformations.1

Postconcussive migraines are the most likely diagnosis in this patient’s case, given the temporal association of the onset of her headaches immediately after her injury, her reportedly negative MRI, and her ongoing phonophobia and photophobia. Cervicogenic headaches are also high on the differential; however, the patient had normal cervical range of motion with no trigger points or muscle soreness on examination besides mild tenderness to palpation at the nuchal ridge.

Postconcussive migraines can persist for years after injury and are typically addressed using a combination of behavioral management strategies (listed in Table 1) and therapies. We counseled the patient to return to daily activities in an expose-recover fashion to allow for some symptom provocation, followed by a break to rehabituate to the activity.2 She was referred to vestibular therapy with the goal of reducing symptoms of disequilibrium and dizziness.3 She was referred to exertion therapy to assist with a guided return to exercise and to help alleviate anxiety.4 Finally, she was referred to neuro-ophthalmology for her visual symptoms. She continued to follow with concussion neuropsychology at our clinic. She was started on propranolol 20 mg 4 times a day for headache prophylaxis and rizatriptan 5 mg every 2 hours as needed for migraine abortion. Regarding imaging, our practice is to be conservative for patients with postconcussive syndrome especially in the absence of progressive neurologic signs or symptoms. However, we did obtain an x-ray of her skull and an MRI brain in this case for a constellation of reasons including her palpable skull defect, high-energy mechanism of injury, ongoing visual complaints, and lack of availability of outside imaging records.

TABLE 1 - Behavioral management strategies after concussion
• Regulated sleep
 ○ Maintain consistent bed time and wake time
 ○ Maintain a consistent schedule on weekends
 ○ Avoid napping for more than 20–30 mins
 ○ Avoid time in bed during the day
• Consistent meal schedule
 ○ Eat meals at same time each day
 ○ Do not skip meals, especially breakfast
 ○ Strive for a well-balanced diet
• Stay well hydrated
 ○ Consume 70–90 oz of water per day
 ○ Drink 16–20 oz of water within 1 hr of waking and 20 oz with every meal
 ○ Limit caffeine use to 8 oz/d
• Physical activity
 ○ 20–30 mins of exercise per day
 ○ Light cardio (walking) can be adequate depending on symptoms
 ○ Take breaks as needed when symptoms increase
 ○ Avoid activities with risk for brain injury
• Manage stress
 ○ Utilize vocational and/or academic accommodations
 ○ Increase mindfulness and utilize relaxation techniques when needed
 ○ Use an “exposure-recovery” model when returning to daily activities, making sure to take short breaks when symptoms are provoked and modify activities as needed

Diagnostic Results

She was evaluated by neuropsychology and underwent vestibular/ocular-motor screening, which evidenced vestibular and ocular dysfunction in the form of dizziness and nausea, especially on horizontal vestibular-ocular-reflex and visual-motion-sensitivity testing. Near point of convergence was measured outside of normal limits at 11 cm. She was administered the ImPACT neuropsychological screening test at her initial visit and at her 10-wk follow-up visit (Supplemental Table 1, Supplemental Digital Content 1, All scores fell in the impaired range at the initial visit. Given that the patient did not have a history of any learning disabilities (reported current grade point average was 3.9), these low scores were thought to reflect her subjective symptom severity rather than her actual cognitive abilities.

Magnetic resonance imaging of the brain revealed a Chiari malformation type 1 with the cerebellar tonsils extending 6.5 mm into the upper cervical canal. There were no intra- or extra-axial mass lesions, white matter abnormalities, or midline shift (Fig. 1A). Skull x-ray demonstrated flattening about the coronal suture; presence of previous fracture could not be determined given the time since injury (Fig. 1B). We also requested the MRI brain report from 4 months after her injury, which had been reported to the patient as normal; this did show mild cerebellar ectopia with the cerebellar tonsils lying approximately 5 mm below the foramen magnum.

A, A T1-weighted sagittal MRI scan demonstrating Chiari I malformation. B, A sagittal skull x-ray demonstrating no evidence of trauma, which is to be expected at 2.5 yrs since injury.

After reviewing the previously mentioned diagnostic results, what is your next step in management?

Diagnosis, Management, and Outcome

The patient was diagnosed with postconcussive migraines with vestibular dysfunction and underlying Chiari malformation type I (CMI). After initiation of therapies and pharmacologic management as described previously, at her 10-wk follow-up visit her ImPACT scores improved significantly across all domains (Supplemental Table 1, Supplemental Digital Content 1, Memory scores increased from the impaired range to average range. Speed scores remained below baseline expectations but significantly improved compared with her initial visit. Her vestibular/ocular-motor screening also significantly improved; she became dizzy only with visual-motion-sensitivity and her headache increased by only 1 point with vestibular-ocular-reflex horizontal. Her near point of convergence improved from 11 to 7 cm, albeit still outside of the 5 cm upper limit of normal. Subjectively, after 10 wks, her total symptom score improved from 83 to 55. She reported improvement in vestibular symptoms, nausea, frustration, anxiety, sleep, physical activity (able to run 1 mile/day), and anterior migraine-type headaches. She was referred to neurosurgery for evaluation, and an MRI spine was performed to assess for associated congenital abnormalities such as syringomyelia; none were found.

Notably, even with the previously mentioned interventions and improvement, she did not experience any improvement in her occipital headaches. She had no muscle tightness or soreness, restricted range of motion, or trigger points to suggest cervicogenic headaches. She reported ongoing dull, throbbing, posterior occipital headaches, each lasting about 3 mins, and worse with Valsalva. Given their quality and lack of improvement with management targeted toward migraines, whereas the remainder of her symptoms improved, these persistent headaches were attributed to her newly diagnosed CMI. She also reported continued visual difficulties which could be attributed to CMI. She continues follow-up with neurosurgery where she is currently being managed conservatively.


In this case, the patient’s postconcussive symptoms generally improved with individualized pharmacologic and therapeutic management; however, her persistent occipital headaches suggested a secondary etiology. It is unclear whether her concussion precipitated the CMI symptoms or whether these would have occurred even without a concussion. Regardless, her diagnosis of occipital headaches due to CMI was delayed by 2.5 yrs because of two separate conditions with overlapping symptoms. As first-line providers for those with concussions, physiatrists must be aware of CMI as a potential underlying cause of persistent symptoms unresponsive to typical management.

Chiari malformation type I represents a caudal displacement of the cerebellar tonsils through the foramen magnum. Less than 3-mm displacement is considered normal, 3- to 5-mm displacement is borderline, greater than 5-mm displacement is diagnostic in individuals older than 15 yrs, and greater than 6-mm displacement is diagnostic in individuals younger than 15 yrs.5 Chiari malformation type I is present in 0.5%–1.0% of the population.5 It can be associated with syringomyelia or syringohydromyelia in 60%–70% of cases.6 Chiari malformation type I can be asymptomatic or can present with nonspecific symptoms including headache, back/neck/shoulder pain, weakness, vestibular symptoms, diplopia, tinnitus, syncope, dysphagia, sleep disturbance, and incontinence. Signs of CMI may include cranial nerve dysfunction, evidence of brainstem compression, cerebellar signs, or even upper motor neuron syndrome. Posterior occipital or upper cervical headache is the most frequent symptom of CMI. This headache is often exacerbated by cough, postural changes, physical exertion, or Valsalva maneuvers, as was the case in this patient’s presentation.5

Symptoms of concussion may often overlap with those of CMI. Adding additional diagnostic challenge to these cases is the hypothesis that concussion may precipitate CMI symptoms.7 A 2008 retrospective review found that 11 (12.9%) of 85 patients who developed symptomatic CMI had a history of minor head or neck trauma preceding the onset of symptoms. For three of these patients, the onset of symptoms could be attributed directly to this trauma based on strict inclusion criteria.7 Concussion or neck trauma could precipitate symptoms in a patient with CMI through one of many mechanisms. The trauma itself could temporarily increase intracranial pressure that could worsen herniation of the cerebellar tonsils,8 which may have occurred in this patient’s case. Separately, neck trauma or whiplash injury could damage cerebellar tonsils which have already herniated and thus precipitate symptoms.9 There have been multiple reported cases of death after minor trauma in those with CMI. It is unlikely that the trauma itself causes CMI; CMI is typically congenital, and there have been no reported cases of CMI developing after minor trauma.7

Headaches associated with CMI are typically treated according to the presenting headache phenotype. This can include pharmacotherapy, physical therapy, and trigger point, steroid, or neurotoxin injections.5 Those who fail nonoperative medical management or who have concerning neurological symptoms should be referred to neurosurgery. The most common surgical intervention is a suboccipital craniectomy with cervical laminectomy.10


Chiari malformation type I is a rare cause of headache and other nonspecific neurologic symptoms. Although CMI is often asymptomatic, minor head trauma can precipitate symptoms.7 In this case, a young woman presented with chronic symptoms attributed to a concussion 2.5 yrs before presentation. Although many of her symptoms improved with therapies and pharmacologic management targeting postconcussive migraines, a posterior occipital headache persisted and was attributed to previously undiagnosed CMI. As first-line providers for concussion, physiatrists must be aware of CMI as a potential etiology of persistent headache and symptoms unresponsive to therapies and medications.

This case report conforms to all CARE guidelines and reports the required information accordingly (see Supplemental Checklist, Supplemental Digital Content 2,


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Postconcussion Syndrome; Arnold-Chiari Malformation; Brain; Headache

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