Stiff person syndrome (SPS) complicated by respiratory failure: successful treatment with rituximab

Abstract

SPS is characterized by axial rigidity, progressive stiffness, and spontaneous reflexor action-induced painful spasms of the paraspinal, abdominal and occasionally proximal leg muscles associated with a lumbar hyperlordosis. Most patients have anti-glutamic acid decarboxylase (GAD) antibodies in both serum and cerebral spinal fluid (CSF) with additional evidence of autoimmune disease, including thyroid disorders, insulin-dependent diabetes mellitus (IDDM), adrenal insufficiency, vitiligo, pernicious anaemia and epilepsy [1–4]. According Solimena et al. [5, 6], IDDM is the most thoroughly documented condition, observed in 25% of patients presenting with SPS. A 56-year-old male presented with a 21-year history of type 1 diabetes mellitus and hyperthyroidism, hypertension for 10 years and a 6-year history of SPS (anti-GAD antibody positive). He had a 5-year history of progressive stiffness and painful spasms of his limbs and axial region. Prior to this presentation, he was treated symptomatically for SPS. At the time of admission he was taking Levetracetam 500 mg bd, Gabapentin 1,200 mg tds and Diazepam 10 mg tds. As he was already on these medications for muscle spasticity, its seems unlikely that another symptomatic treatment would have been effective, such as baclofen. In the weeks prior to this admission, there was a gradual worsening of axial muscular spasms along with anxiety attacks, generalized weakness, and anorexia and weight loss. On the day of admission, he was found face down in a field, cyanosed, with occasional jerking movement of his shoulders. He was brought into a regional hospital with a Glasgow Coma Scale score of 6/15 and intubated because of type II respiratory failure. He was transferred to our care for further investigation and management. A trial of extubation with bilevel positive airway pressure failed as he progressively became hypercapnic with episodes of agitation. He was intubated again and treated with Propofol and Lorazepam. He was vitally stable and afebrile. He appeared anxious during his physical examination. His cardiac and pulmonary examinations were unremarkable. The abdominal musculature was firm on palpation. He was confused and had slurred speech. He was initially hypertonic; reflexes were hard to elicit. The plantars were bilaterally flexor. There were no sensory deficits, and cranial nerve examination was normal. His routine laboratory blood tests (FBC, UE antiMUSK antibodies and anti-Ach receptor antibodies were negative. Paraneoplastic antibody screening (anti-Hu, antiYo, anti-Ri, VGKC, anti-Purkinje, VGCC, anti-Ma, amphiphycin, NMDAR) was negative. A number of trials of extubation failed, and a tracheostomy tube was inserted for long-term ventilation. It was difficult to wean him off of mechanical ventilation (taking approximately 6 weeks), and the course of his illness was complicated by infection (ventilatorassociated pneumonia). A. Qureshi (&) M. Hennessy Department of Neurology, University College Hospital Galway, Galway, Republic of Ireland e-mail: anasqureshi76@yahoo.com