Stiff-person syndrome in a patient with comorbid bipolar and panic disorders: A case report and literature review

Abstract

Stiff-person syndrome (SPS) is a neurologic disorder characterized by muscle stiffness, rigidity, and muscle spasms, and it can increase a patient's risk for falls. It is recognized as a rare disease with limited clinical guidelines to manage the condition and its symptoms. Currently, there is even less clinical guidance for the management of common comorbid conditions in these patients. This patient case report aims to evaluate the efficacy of various medications for symptom management in a patient with SPS and comorbid psychiatric disorders, specifically bipolar I and panic disorder. Throughout the patient's course of treatment, various medications were trialed, including fluoxetine, hydroxyzine, valproic acid, propranolol, and clonazepam. Ultimately, fluoxetine, hydroxyzine, and propranolol were discontinued due to adverse drug reactions and incomplete symptom resolution. The patient's bipolar I disorder was adequately managed with valproic acid. Once the clonazepam was changed from as-needed to scheduled dosing, the patient's panic disorder and anxiety-triggered spasms were well controlled. The efficacy of benzodiazepines, specifically high doses of diazepam, in alleviating muscle spasms and anxiety in SPS has been demonstrated in the literature. Case reports including patients with SPS that are prescribed selective serotonin reuptake inhibitors provide controversial evidence as some studies report exacerbation of SPS symptoms with prolonged use. As this case report and literature review suggest, patients with SPS and comorbid panic disorder and anxiety-triggered spasms may benefit from the use of benzodiazepines. The use of other medication classes for the treatment of other comorbid psychiatric disorders in a patient with SPS is lacking evidence.

Keywords: SPS; SSRIs; benzodiazepines; bipolar disorder; clonazepam; fluoxetine; panic disorder; selective serotonin reuptake inhibitors; stiff-man syndrome; stiff-person syndrome.