076 A rare case of anti-glutamate decarboxylase antibody syndrome presenting with recurrent vomiting

Abstract

IntroductionAnti-glutamte decarboxylase antibody (anti-GAD) has been linked with various neurological syndromes including stiff-person syndrome, limbic encephalopathy, cerebellar ataxia, eye movement disorders and epilepsy (collectively known as ‘anti-GAD positive neurological syndromes’).1 We describe a very atypical phenotypic presentation of anti-GAD syndrome with unexplained vomiting and weight loss.CaseA 46 years old lady with no past medical or family history of note, presented with 6 months history of severe headaches and recurrent attacks of episodic vomiting (4–6 episodes of multiple vomiting daily) with no identified precipitant and complete normality in between the episodes with no other associated symptoms. She reported 15 kg of unintentional weight loss. Neurological examination and investigations including MRI brain, CT angiogram and liver enzymes, immunoglobulins, thyroid function, vasculitic screen were normal. Upper GI endoscopy, gastric emptying studies, CT imaging of chest, abdomen and pelvis and whole body PET scan were unremarkable. Serum autoimmune antibody screen was positive with high titre of anti-GAD antibody (1200 kU/liter). The cerebrospinal fluid anti-GAD antibody titre was raised at 103.7 kU/liter with otherwise normal parameters including negative oligoclonal bands. The nerve conduction studies did not show continuous motor activity or spasmodic reflex myoclonus (seen in stiff-person syndrome).2 A therapeutic trial of immunosuppression was introduced with moderate improvement in symptoms.ConclusionAnti-GAD neurological syndromes are rare and this is a unique presentation of the same. It is not completely understood why the presence of one antibody causes varied syndromes. The hypothesis is that the recurrent vomiting is possibly due to diaphragmatic spasms.ReferencesSaiz A, Blanco Y, Sabater L, et al. Spectrum of neurological syndromes associated with glutamic acid decarboxylase antibodies: diagnostic clues for this association. Brain 2008;131:2553–2563.Buechner S, Florio I, Capone L. Stiff person syndrome: A rare neurological disorder, heterogeneous in clinical presentation and not easy to treat. Case Rep Neurol Med2015; 2015:278065.