Neurological Complications during Treatment of Middle East Respiratory Syndrome

Kim, Jee-Eun; Heo, Jae-Hyeok; Kim, Hye-ok; Song, Sook-hee; Park, Sang-Soon; Park, Tai-Hwan; Ahn, Jin-Young; Kim, Min-Ky; Choi, Jae-Phil

Patient 1 showed hypersomnolence, ophthalmoplegia, and weakness in all four limbs after a severe viral infection, and we therefore needed to differentiate between various conditions including GBS variant, Wernicke encephalopathy, prolonged neuromuscular blockade, and critical-illness polyneuropathy/myopathy. Because this patient had a preceding infection history, relative symmetric motor weakness, and a monophasic course with a clinical nadir within 4 weeks followed by a plateau, we considered GBS variant as a possible diagnosis. 14 BBE, one of the GBS variants, is considered a subtype of GQ1b antibody syndrome and is classically diagnosed based on its characteristic clinical features of progressive symmetric external ophthalmoplegia, ataxia, and impaired consciousness. 15 Because patient 1 had the classical triad of BBE accompanied by limb weakness, a diagnosis of BBE overlapping with GBS was suggested. 14 We excluded many BBEmimicking conditions in this patient based on his clinical history, brain MRI, and CSF findings. The presence of antiganglioside antibodies and albuminocytologic dissociation in the CSF supported the diagnosis of BBE as part of the GBS spectrum. Nevertheless, a diagnosis of BBE is largely dependent on its clinical presentation. The absence of laboratory findings does not rule out a BBE diagnosis. 16 Wernicke's encephalopathy was an important condition to eliminate in this patient because it also frequently manifests with varying degrees of encephalopathy, ophthalmoplegia, and ataxia. However, we considered it unlikely that Wernicke's encephalopathy was present in patient 1 for several reasons: 1) he showed none of the typical changes associated with Wernicke's encephalopathy in brain MRI, which has particularly high sensitivity (97-100%) in patients without alcohol abuse, 17 2) the ptosis and complete ophthalmoplegia that were observed in this patient are rare in Wernicke's encephalopathy, 18 and 3) thiamine deficiency was not confirmed in laboratory tests and the patient did not have dietary deficiencies or alcoholism. Critical-illness polyneuropathy/myopathy appears frequently in ICU patients but was not thought JCN to be present in patient 1 because ophthalmoparesis and ptosis are very rare in critical-illness polyneuropathy/myopathy. 19 Prolonged neuromuscular blockade was another possible consideration in this clinical setting, but a neuromuscular blocking agent was not administered in patient 1. The limb and ocular weakness had lasted for almost 2 months, and this duration would be an unusual response to the prolonged administration of a neuromuscular blocking agent. Neurological signs typically completely recover within 1-2 weeks in patients with prolonged neuromuscular blockade. 19 We hypothesized that patient 2 had ICU-acquired weakness or GBS. ICU-acquired weakness is diagnosed when a critically ill patient has limb weakness or ventilator dependency without heart or lung disease. 20 GBS was another possible diagnosis, since the patient experienced symmetric limb weakness following viral infection with a typical monophasic disease course. 14 These two diseases are differentiated by the presence of albuminocytologic dissociation in the CSF, positivity for antiganglioside antibodies, or demyelinating or axonal patterns in electrophysiology. 18, 19 Patient 2 was evaluated neurologically after discharge, when her neurological symptoms had substantially improved; a lumbar puncture was therefore not performed,