Pseudoagoraphobia, a Diagnostic Clue in Stiff-Limb Syndrome

Abstract

Background: Stiff-limb syndrome is part of stiff person spectrum, presenting with fluctuating gait disorders attributed to leg stiffness, spasms, and posturing. It could also manifest with anxiety and specific phobias such as pseudoagoraphobia. We aimed to describe the importance of specific gait phobia as a diagnostic clue to anti-glutamic acid decarboxylase stiff-limb syndrome.

Cases: We reported on 2 cases of stiff-limb syndrome sharing a similar diagnostic path and phenomenology. Both were featured by pseudoagoraphobia, which has documented to typically cover organic conditions, and a remarkable diagnostic delay attributed to misdiagnoses. Presence of pseudoagoraphobia should not point to the diagnosis of a functional disorder-although a negative instrumental workup is documented.

Conclusions: Both cases are emblematic of the high misdiagnosis rate affecting stiff person syndrome patients. A proper diagnostic process, including the identification of a pseudoagoraphobia, should help in reaching a diagnosis and providing an early and effective treatment.

Keywords: anti‐GAD antibodies; functional movement disorders; gait; spasticity; stiff man syndrome.

Figure 1

(A) The Hamilton Depression/Anxiety (HAM‐D/HAM‐A) scales. (B) The Symptom‐Checklist‐90 (SCL‐90) scale: somatization, obsessions‐compulsions, interpersonal‐sensitivity, depression, anxiety, hostility, phobic‐anxiety, paranoid‐ideation, psychoticism, sleep‐problems (SOM/O‐C/INT/DEP/ANX/HOS/PHOB/PAR/PSY/SLEEP).

Figure 2

Patient 1 (A) and 2 (B) clinical course on timelines. *Later discontinued drugs. The diagnosis of type 2 diabetes of patient 1 was then revised as LADA (latent autoimmune diabetes in adults) attributed to anti‐GAD presence. anti‐GAD ab, anti–glutamic acid decarboxylase antibodies; CBT, cognitive‐behavioral therapy; DRD, dopa‐responsive dystonia.