Serotonin syndrome and stiff-person syndrome: diagnostic challenges in psychosomatic medicine

Management of severe arterial hypertension associated with serotonin syndrome: a case report analysis based on systematic review techniques

Serotonin syndrome is thought to arise from serotonin excess. In many cases, symptoms are mild and self-limiting. But serotonin syndrome can become life threatening, when neuromuscular hyperexcitability spins out of control. Uncontainable neuromuscular hyperexcitability may lead to cardiovascular complications, linked to extreme changes in blood pressure. Currently, there is little guidance on how to control blood pressure in hyperserotonergic states. We report a case with treatment-resistant arterial hypertension, followed by a clinical review (using systematic review principles and techniques) of the available evidence from case reports published between 2004 and 2016 to identify measures to control arterial hypertension associated with serotonin syndrome. We conclude that classic antihypertensives may not be effective for the treatment of severe hypertension associated with serotonin syndrome. Benzodiazepines may lower blood pressure. Patients with severe hypertension not responding to benzodiazepines may benefit from cyproheptadine, propofol or both. In severe cases, higher cyproheptadine doses than currently recommended may be necessary.

Clinical Spectrum of Stiff Person Syndrome: A Review of Recent Reports

Background

“Classic” stiff person syndrome (SPS) features stiffness, anti-glutamic acid decarboxylase (anti-GAD) antibodies, and other findings. Anti-GAD antibodies are also detected in some neurological syndromes (such as ataxia) in which stiffness is inconsistently present. Patients with otherwise “classic” SPS may either lack anti-GAD antibodies or be seropositive for others. Hence, SPS cases appear to fall within a clinical spectrum that includes conditions such as progressive encephalomyelitis with rigidity and myoclonus (PERM), which exhibits brainstem and autonomic features. We have compiled herein SPS-spectrum cases reported since 2010, and have segregated them on the basis of likely disease mechanism (autoimmune, paraneoplastic, or cryptogenic) for analysis.

Methods

The phrases “stiff person syndrome”, “PERM”, “anti-GAD antibody syndrome”, and “glycine receptor antibody neurological disorders” were searched for in PubMed in January 2015. The results were narrowed to 72 citations after excluding non-English and duplicate reports. Clinical descriptions, laboratory data, management, and outcomes were categorized, tabulated, and analyzed.

Results

Sixty-nine autoimmune, 19 paraneoplastic, and 13 cryptogenic SPS-spectrum cases were identified. SPS was the predominant diagnosis among the groups. Roughly two-thirds of autoimmune and paraneoplastic cases were female. Anti-GAD antibodies were most frequently identified, followed by anti-amphiphysin among paraneoplastic cases and by anti-glycine receptor antibodies among autoimmune cases. Benzodiazepines were the most commonly used medications. Prognosis seemed best for cryptogenic cases; malignancy worsened that of paraneoplastic cases.

Discussion

Grouping SPS-spectrum cases by pathophysiology provided insights into work-up, treatment, and prognosis. Ample phenotypic and serologic variations are present within the categories. Ruling out malignancy and autoimmunity is appropriate for suspected SPS-spectrum cases.