Intractable nausea and vomiting as presenting manifestation of neuromyelitis optica.

Neuromyelitis optica (NMO) is a rare severe, inflammatory, demyelinating disorder of central nervous system, characterized by recurrent optic neuritis and longitudinally extensive transverse myelitis (LETM), which may occur either simultaneously or in isolation. Intractable nausea and hiccough is a rare presentation of NMO, frequently leading to misdiagnosis and unnecessary investigations initially.[1]

A 29-year-old woman presented with a 6-week history of recurrent nausea and vomiting associated with giddiness. She did not have any headache, visual symptoms, weight loss, or true vertigo. She was evaluated initially by general physician with normal systemic examination and later by gastroenterologist with upper gastrointestinal tract endoscopy twice, which was normal. She received anti-emetics with symptomatic improvement. Again, she started having recurrent episodes of vomiting and giddiness followed by diplopia, swaying to both sides while walking, and weakness of lower limbs with painful paresthesias of right upper and lower limb for 10 days. Her neurological examination showed bilateral papillitis with early optic atrophy, bilateral horizontal gaze-evoked nystagmus, left lower motor neuron facial palsy, spasticity and asymmetric (the right side affected more than the left) pyramidal pattern of weakness of upper and lower limbs, exaggerated reflexes, bilateral extensor plantar response, and spinothalamic sensory loss over right side with a level at C7. There were no cerebellar signs. CSF analysis showed 35 cells/mm3, (all lymphocytes), protein (68 mg/dl), and normal glucose. Her MRI showed longitudinally extending transverse myelitis (more than 3 segments) with cervico-medullary hyperintensities without any periventricular or pericallosal lesions [Figure 1]. Serum NMO-IgG antibody was strongly positive. She received methyl prednisolone (1 gm/day for 5 days) initially and subsequently plasma exchange in view of poor response to the former. She had significant improvement in symptoms after plasma exchange.

Figure 1

(a) Axial FLAIR image at the level of posterior fossa, demonstrating hyperintensity in the dorsal medullary region at the area postrema (arrow). (b) Axial T1w contrast-enhanced image at the same level depicting contrast enhancement at dorsal medulla. (c) Sagittal T2 w cervical spine and brain stem, depicting patchy hyperintensities in dorsal pons, medulla, cervico-medullary junction, and segmental involvement of cervical spinal cord. (d) Sagittal T1 w image at the corresponding level, showing heterogenous moderate contrast enhancement at the corresponding areas

Nausea and vomiting are non-specific symptoms; their association with giddiness or headache should prompt consideration of a central cause.[2] Failure to correctly identify such an intracranial lesion may subject the patient to unnecessary investigations, delaying appropriate treatment. Vomiting is produced by both humoral and neuronal stimuli. The area postrema, a circumventricular organ, is situated in the floor of the fourth ventricle containing specialized ependymal cells, rich in aquaporin-4 receptors.[34] It is sensitive to blood-borne stimulants such as drugs, toxins, and various peptides. Any lesion that directly stimulates the area postrema or the nucleus tractus solitarius can present with vomiting. Inflammatory lesions in the dorsal component of the medulla have been implicated in presentations with sustained vomiting and hiccups in 14-20% of patients.[1]

A careful neurological history and examination is important in patients with isolated spontaneous vomiting, especially in the presence of negative gastrointestinal investigations. NMO is a potentially treatable disease, which can present with isolated nausea and vomiting to general physician and gastroenterologist more commonly, early recognition is important as early initiation of treatment may prevent subsequent optic neuritis or myelitis.[5]