Letters to the Editor
Episodic Ataxia vs Somatization Disorder
Dear Editor:
The presentation of unexplained ataxia requires a broad differential including somatoform disorders. We report a case of episodic ataxia type 2 (EA-2) that was misconstrued as a possible somatoform disorder.
EA-2 is a rare disorder that results from a multitude of mutations in the CACNA1A gene. CACNA1A codes for calcium channel proteins and is heavily expressed in the cerebellum. Patients with EA-2 generally present before age 20 years with ataxic episodes associated with vertigo, weakness, and interictal nystagmus. Such episodes may last hours to days (1). A positive family history may aid in the diagnosis; however, de novo mutations are also known to occur (2), making genetic testing the only definitive diagnosis. Acetazolamide is considered the treatment of choice for EA-2, but not all patients respond to the drug (3).
Case Report
Ms C is a single Ghanaian woman, aged 24 years, currently attending fashion school. She was admitted to hospital after an abrupt onset of dizziness, limb ataxia, and disequilibrium that resulted in a fall. Ms C experienced these symptoms every 2 to 3 months. They persisted for 1 to 7 days before resolving spontaneously. She recalled suffering from these disabling episodes since age 11 years and attributed them to her sickle cell trait.
The psychiatry service was consulted to assess whether a somatoform disorder might be the cause of her ataxia. Although Ms C had several neurological complaints, she did not endorse any gastrointestinal, pain, or sexual symptoms necessary for the diagnosis of somatization disorder. While she had recently moved out of her family’s home following a deterioration of the relationship with her father and stepmother, there was no clear association between stressors in her life and the onset or exacerbation of her symptoms—a criterion required to diagnose conversion disorder. Her family did not identify any history of body dysmorphic disorder, hypochondriasis, or pain disorder. Ms C expressed concern about missing several classes in fashion school and was worried about falling behind. There was no indication of personality disorder or obvious secondary gain that would suggest a factitious disorder of malingering.
Ms C reported being raped twice in the past 2 years, but she did not meet the criteria for posttraumatic stress disorder or another anxiety disorder. She denied any depressive and psychotic symptoms or drug and alcohol use and had no other psychiatric history. At this point, we concluded that an Axis I disorder could not explain her symptoms, and the medical team continued to seek a medical cause to explain her presentation.
On physical examination, Ms C had limb ataxia, dizziness, gait unsteadiness, and diplopia on upward gaze. A noncontrast CT, EEG, electromyography, and ECG were all normal. Relevant laboratory tests were all within normal limits.
Subsequently, a diagnosis of EA-2 was entertained, and Ms C failed a trial of acetazolamide. She was discharged from the medical ward without a definitive cause for her symptoms and no psychiatric follow-up.
Discussion
The above case helps emphasize the need to rule out somatoform disorders in patients with neurologic complaints. Despite nonconfirmatory medical investigations, both the medical and psychiatric teams should continue to search for genetic causes of her ataxia, such as EA-2.
References
1. Jen J, Kim GW, Baloh RW. Clinical spectrum of episodic ataxia type 2. Neurology 2004;62(1):17–22.
2. Yue Q, Jen JC, Thew MM, Nelson SF, Baloh RW. De novo mutation in CACNA1A caused acetzolamide-responsive episodic ataxia. Am J Med Genet 1998;77:298–301.
3. Zasorin NL, Baloh RW, Myers LB. Acetazolamide-responsive episodic ataxia syndrome. Neurology 1983;33:1212–4.
4. American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th ed. Washington (DC): American Psychiatric Association; 1994.
Isaac I Bogoch, BScH
Craig Beach, MD
Sanjeev Sockalingam, MD
Keith Hansen, RN
Amy Cheng, BSc
Edward Kingstone, MD, FRCPC
Shree Bhalerao BSc, BA, PgD, MD, FRCPC
Toronto, Ontario
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