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19-Year-Old Diagnosed With Conversion Disorder Actually Had Rare Autoimmune Encephalitis

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A 19-year-old university student in China was diagnosed with dissociative-conversion disorder after developing anxiety, trembling legs, excessive sweating and unexplained weight loss. She had recently failed an examination, providing an apparently convenient psychological explanation for her symptoms. But the diagnosis was wrong. Further investigation revealed a rare autoimmune neurological disease called anti-metabotropic glutamate receptor 5 (mGluR5) encephalitis. After receiving immunotherapy, she recovered completely, with no recurrence reported at 18 months.

The case was published in Frontiers in Neurology in December 2023. The researchers explicitly described the original conversion-disorder diagnosis as a misdiagnosis. This was not simply a patient questioning a diagnosis or a speculative alternative explanation. The medical team identified antibodies associated with autoimmune encephalitis in both her blood and cerebrospinal fluid, documented additional immune abnormalities and treated her accordingly.


How a neurological disease became a psychiatric diagnosis

The patient was a 19-year-old university student who had undergone surgery to remove her left ovary because of a teratoma eight years earlier. Before her hospital admission, she had experienced a stressful event involving a failed examination. Over approximately two months, she developed anxiety, orthostatic leg tremors (shaking of the legs while standing), sweating and a weight loss of 4 kg.

An outpatient doctor diagnosed her with dissociative-conversion disorder and prescribed escitalopram, an antidepressant commonly used to treat anxiety. Hospitalisation was also recommended. Her symptoms persisted, and by the time she was admitted to hospital, approximately 11 weeks into her illness, she was unable to complete standard balance and walking assessments, including the Romberg test and straight-line walking test.

The combination of anxiety, a recent stressful experience and unusual movement symptoms had apparently been enough to support the initial psychiatric diagnosis. The published report does not document which positive clinical signs, if any, were used to establish conversion disorder. It does, however, explicitly identify that diagnosis as incorrect.

That distinction matters. A stressful event is not evidence that neurological symptoms are psychologically caused. Anxiety can accompany neurological disease, and an unfamiliar movement disorder does not become a psychiatric disorder merely because the examining clinician cannot immediately explain it.


The investigations that changed everything

Further neurological investigations uncovered evidence that the original diagnosis had missed. Repeat brain MRI examinations were described in the case presentation as showing no lesions. Routine cancer biomarkers, serum immune indices, electroencephalography (EEG) and electromyography (EMG) were also reported as negative. Those findings had not identified the cause of her symptoms, but they had not established conversion disorder either.

The decisive findings came from cerebrospinal fluid analysis and specialised autoimmune antibody testing:

  • Serum mGluR5 antibodies: Positive at a titre of 1:1,000.
  • Cerebrospinal fluid mGluR5 antibodies: Positive at a titre of 1:32.
  • Cerebrospinal fluid IgG: Elevated at 0.0749 g/L, above the reported reference range of 0.005–0.041 g/L.
  • Oligoclonal bands: Positive only in cerebrospinal fluid, supporting immune activity within the central nervous system.
  • Cerebrospinal fluid cell count: Normal.

The diagnosis was anti-mGluR5 encephalitis, an exceptionally rare form of autoimmune encephalitis involving antibodies directed against a receptor involved in glutamate signalling in the nervous system. Unlike many previously described patients with this disease, she did not present with the prominent cognitive dysfunction, psychosis or altered consciousness that clinicians might ordinarily associate with autoimmune encephalitis.

Instead, her dominant neurological manifestation was an orthostatic leg tremor. The researchers considered this an unusual presentation of the disease, one that could easily complicate early recognition.

There is also an inconsistency in the published paper worth noting. Although the case presentation states that repeat brain MRI scans showed no lesions, the caption accompanying Figure 1 describes lesions throughout the brain. The report does not reconcile these statements. Its MRI findings therefore cannot be presented without acknowledging that contradiction.


Treatment and recovery

Once the autoimmune diagnosis was established, the patient received treatment directed at the immune system rather than relying solely on psychiatric medication. She was given high-dose intravenous methylprednisolone at 1,000 mg daily for five days, together with intravenous immunoglobulin (IVIG) at 0.4 g/kg/day. This was followed by oral prednisone and continued escitalopram.

Two weeks after discharge, her anxiety and leg tremors had improved mildly. At the six-week follow-up, the researchers reported complete recovery, and her serum mGluR5 antibody titre had fallen from 1:1,000 to 1:32. At the 18-month follow-up, she remained recovered without reported recurrence.

Because she received both immunotherapy and anti-anxiety medication, the case cannot isolate the precise contribution of every treatment. Nevertheless, the antibody findings, other cerebrospinal fluid abnormalities and clinical response supported the authors' diagnosis of autoimmune encephalitis. The report provides no evidence that conversion disorder was the correct explanation for her neurological symptoms.


Why the original diagnosis was a problem

The authors reviewed the existing literature and noted that anti-mGluR5 encephalitis had usually been associated with psychiatric disturbances, cognitive impairment, sleep problems, seizures and altered consciousness. In a previously reported group of 14 patients, 13 had mental or psychiatric disturbances, 11 had cognitive disorders, nine had sleep dysfunction, eight had seizures and six had disturbances of consciousness. Only four had motor disorders.

This patient's presentation was therefore unusual, but unusual does not mean unexplained by neurological disease. Her orthostatic tremor was precisely the kind of manifestation that could be missed when clinicians expect a rare condition to follow a familiar pattern.

The researchers concluded that clinicians, particularly psychiatrists, should consider autoimmune encephalitis during differential diagnosis, including when psychiatric symptoms appear early. Their report demonstrates that the absence of a typical presentation does not exclude a serious neurological condition.

There is an obvious problem with diagnosing conversion disorder before adequately investigating a patient whose symptoms remain unexplained. In this case, the initial diagnosis was made despite persistent leg tremors, sweating, weight loss and subsequent documented balance impairment. The paper does not establish exactly how extensively the patient was investigated before the original diagnosis, so it would be inaccurate to claim that no neurological assessment occurred. What it establishes is that the original diagnosis was wrong and that further investigation identified a treatable autoimmune disease.

A 19-year-old with anxiety and trembling legs was diagnosed with conversion disorder. Further testing found autoimmune encephalitis. Six weeks after treatment, she had recovered completely. The original diagnosis did not explain her illness. It delayed the identification of what was actually wrong.

The broader lesson is not that every unusual movement disorder is autoimmune encephalitis. It is that clinicians cannot use psychiatric symptoms, recent stress or an unfamiliar neurological presentation as substitutes for diagnostic evidence. Normal routine investigations do not prove a functional disorder, and rare neurological diseases do not cease to exist because they are absent from a clinician's usual diagnostic experience.

For this patient, specialised testing made the difference between remaining under an incorrect psychiatric diagnosis and receiving treatment for the disease she actually had. Fortunately, she recovered. The report does not quantify how much the initial misdiagnosis delayed treatment or whether that delay caused additional harm, but the diagnostic error itself is clearly documented.

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