INTRACTABLE VOMITING DUE TO A BRAIN-STEM LESION IN THE ABSENCE OF NEUROLOGICAL SIGNS OR RAISED INTRACRANIAL-PRESSURE

The case of a 30 year old man who was believed to have a gastrointesti nal motility disorder causing his chronic vomiting is reported. He had been well until 21 months previously when he had developed recurrent vomiting which would occur up to 10 times in a 24 hour period. Vomitin g was not precipitated by eating and was not associated with any other symptoms. He had lost 25 kg in weight. A psychiatric assessment did n ot reveal a psychogenic cause for his vomiting. A brainstem magnetic r esonance imaging scan revealed an area of low signal in the low midbra in just above the pens to the left of the midline. After gadolinium co ntrast injection the area enhanced. There was Little or no mass effect , that is minimal displacement of normal structures, and minimal oedem a. The appearance was that of a low grade or early brainstem tumour. T here were no features of haemorrhage or infarct. The patient was manag ed with oral dexamethasone, resulting in prompt resolution of his symp toms. A search for a central neurological cause is recommended in a pa tient with unexplained persistent vomiting, even in the absence of oth er features to suggest a neurological problem. Autonomic function test ing may provide additional information.