Eventually, Ms. M’s upbeat nystagmus, persistent abnormal movements, rapidly progressive dementia, and elevated CSF protein 14-3-3 made the CJD diagnosis. Protein 14-3-3 is 94% sensitive and 84% specific for diagnosing CJD.11 Ms. M’s EEG findings did not suggest CJD, but these findings are less sensitive and occur later than the CSF findings.11
Finally, conversion disorder is almost always acute, not slowly progressive as with Ms. M.
Table
Conversion disorder, sporadic Creutzfeldt-Jakob disease share many symptoms
| Complaint | Conversion disorder | Sporadic CJD |
|---|---|---|
| Paralysis | May not follow motor pathways | No |
| Myoclonus | Yes | Cardinal manifestation |
| Ataxia | May be bizarre in character | Present in 25% to 30% of patients, reflecting multiple disease subtypes |
| Hyperreflexia | No | Yes (40% to 80% of patients) |
| Dysphagia | Yes | No |
| Vomiting | Yes | No |
| Aphonia | Yes | No |
| Diplopia | Yes | Rare |
| Nystagmus | Rare | Yes |
| Blindness | Hysterical blindness detectable by ophthalmologic examination | Rare |
| Deafness | Yes | Rare |
| Anesthesia | Yes | No |
| Paresthesia | Yes | No |
| Depression | Yes | Yes |
| Other psychiatry diagnoses | Yes | More common in variant CJD |
| Progressive dementia | No | Cardinal manifestation |
| Temporal relationship with stress | Yes | No |
| Left-side symptoms more common | Yes | No |
Getting the diagnosis right
DSM-IV-TR criteria state that conversion disorder symptoms cannot be otherwise explained “after appropriate investigation,” but what constitutes “appropriate” is unclear. Extensive inpatient evaluation eventually produced the correct diagnosis for Ms. M, but such a detailed evaluation may be too expensive and expansive for every patient with conversion disorder symptoms.
In the conversion disorder study,4 the 10 misdiagnosed patients received one to eight supplemental diagnostic techniques before being correctly diagnosed. In five of the patients, however, the general neurologic examination was identified as the diagnostic technique responsible for final diagnosis.
These findings suggest that a neurologic examination is key to evaluating complaints that suggest conversion disorder and to identify neurologic conditions. The results can also suggest somatic disorders, as exam findings will reflect patients’ perceptions of neurologic processes. For example:
- patients with conversion motor symptoms may have tonic contractures of antagonistic muscles to “paralyze” certain joints
- those with conversion sensory symptoms rarely have sensory impairments that follow known innervation patterns.
Motor complaints, such as localized paralysis or abnormal movements, should be evaluated with a brain MRI to look for lesions along the motor or cerebellar tracts. Sensory pathways can be further investigated with brain MRI and the relevant evoked potential(s) (visual, brainstem, or somatosensory).
Order EEG for patients with convulsions, particularly prolonged EEG monitoring with a video component, and measure serum prolactin immediately after an episode. In some cases, the neurologic exam alone or in conjunction with these initial studies can make the diagnosis. If the clinical situation warrants, more-detailed evaluations may be necessary.
Related resources
- Wise MG, Rundell JR. Clinical manual of psychosomatic medicine: a guide to consultation-liaison psychiatry. Arlington, VA: American Psychiatric Publishing; 2005.
- National Institute of Neurological Disorders and Stroke. Creutzfeldt-Jakob disease fact sheet. www.ninds.nih.gov/disorders/cjd/detail_cjd.htm.
- Duloxetine • Cymbalta
- Mirtazapine • Remeron
The authors report no financial relationship with any company whose products are mentioned in this article, or with manufacturers of competing products.