Adalimumab-induced sensory vasculitic neuropathy.

Vasculitis and other autoimmune conditions are known complications of tumour necrosis factor alpha (TNF-α) inhibitor use. By definition, TNF-α inhibitor induced vasculitis is a secondary systemic vasculitis. However, its phenotype is varied and can present as an isolated vasculitic neuropathy. This presents a diagnostic challenge as the gold standard for diagnosis of a vasculitic neuropathy is a peripheral nerve biopsy that meets predefined histopathological criteria. Given the poor sensitivity of the peripheral nerve biopsy, it is important that clinicians take a good history and maintain a high index of suspicion, as this is a treatable iatrogenic condition. Here we present a case of adalimumab-induced sensory vasculitic neuropathy, treated according to the Peripheral Nerve Society guideline for non-systemic vasculitic neuropathy, given her disease phenotype.

Sensory Ganglionopathy and the Blink Reflex: Electrophysiological Features.

BACKGROUND: Sensory ganglionopathy (SG) is characterised by asymmetrical sensory fibre degeneration, with the primary pathology occurring at the level of the dorsal root ganglion. It is seen in the context of autoimmune, paraneoplastic, and degenerative disorders. There is limited literature examining the electrophysiological correlate of the trigeminal ganglion and associated pathways, the blink reflex (BR), in cases of SG. Previous work has suggested that the BR is preserved in cases of SG associated with paraneoplasia. METHODS: The local clinical neurophysiology database was searched for patients diagnosed with SG from peripheral nerve conduction studies in whom the BR was performed. Twenty-six patients were included in the final analysis. RESULTS: Sjögren's syndrome constituted the most common SG aetiology (8/26), followed by idiopathic cases (7/26) and paraneoplasia (5/26). BR abnormalities were seen in 9 of the 26 patients (34.6%) across all aetiologies. No patients reported sensory disturbance in the distribution of the trigeminal nerve, indicating that the changes noted are subclinical. Three patients showed abnormality of the R1 response; in the remaining six patients, only R2 responses were affected. CONCLUSIONS: Subclinical abnormalities of both R1 and R2 can be seen in the context of SG of varying aetiologies, including paraneoplasia. Performing the BR in patients with suspected of having SG may be helpful in providing additional evidence of patchy sensory fibre involvement that is characteristic of the disease.

Diabetes insipidus secondary to sarcoidosis presenting with caseating granuloma.

Diabetes insipidus is a rare complication of sarcoid infiltration of the hypothalamic-pituitary region. Non-caseating granuloma formation is typical of sarcoidosis. Anterior and posterior pituitary function may be affected. MRI coupled with endocrinology assessment is the usual method of investigation. A 25-year-old Caucasian male with no significant medical history presented with polyuria and polydipsia. Water deprivation test confirmed diabetes insipidus. CT scanning of the chest confirmed lymphadenopathy. Lymph node biopsy revealed caseating granuloma. Extensive investigation for tuberculosis was negative. The patient was started on intranasal desmopressin and steroids with marked improvement in symptoms. This is the first reported case of neurosarcoidosis with diabetes insipidus and caseation on histology that we are aware of. Differentiating between caseation due to sarcoidosis and tuberculosis on histology is possible by the use of special stains. Return of normal endocrine function is unusual and the patient is likely to require desmopressin therapy for life.