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The association between progressive myoclonic encephalopathy (Ramsay Hunt syndrome; progressive myoclonic ataxia) was recently the subject of a clinicopathological report in thisJournal 1 and of a review by Bhatia et al.2 A notable feature of these cases was the rapidly progressive nature of the encephalopathy. Most patients were unable to walk or died within two years of the onset of their neurological symptoms. The patient that we report is therefore remarkable in that her neurological illness began 13 years ago. Progressive myoclonic encephalopathy associated with coeliac disease may take a more benign course and we suggest that the condition should be considered in all patients with cerebellar ataxia, particularly if there is myoclonus.
The patient, now aged 64, presented at the age of 55 with a four year history of difficulty with fine finger movements in both hands, worse on the right such that she had difficulty picking up coins and doing up buttons. Her walking had also become slower. Examination at the age of 55 disclosed a jerky upper limb tremor with myoclonus but no gait ataxia. The tremor and myoclonus have slowly worsened and she has developed an ataxic gait. She now walks with a frame indoors, but has frequent falls. She uses a wheelchair outdoors. She has never had a seizure.
She has never had any specific bowel symptoms, but investigation of a macrocytic anaemia and folate deficiency associated with weight loss eventually led to the diagnosis of coeliac disease five years ago, confirmed by small bowel biopsy. However, coeliac disease was almost certainly present 10 years before this when she was investigated for anaemia at another hospital and an abdominal ultrasound disclosed hyposplenism. Reticulin antibodies were present. She was started on a gluten free diet and the haematological indices returned to normal. Vitamin E concentrations were normal. Her other medical history included pulmonary tuberculosis at the age of 22.
On examination she had spontaneous, and reflex and action myoclonus in the upper limbs and, to a lesser extent, in the leg. In addition, there was a postural upper limb tremor and finger-nose ataxia bilaterally. Her gait was ataxic and she walked with a frame. Tendon reflexes were normal and plantar responses flexor. Vibration sensation was absent below the knees, but proprioception in the big toes was normal. Neurophysiological studies confirmed multifocal spontaneous, reflex and action myoclonus particularly of the hands. Back averaging from the action jerks disclosed time locked cortical activity over the contralateral hemisphere, preceding each jerk by 27 ms. Somatosensory evoked potentials after finger stretch were pathologically enlarged.
The clinical and neurophysiological characteristics of her condition conform closely to those previously reported in patients with coeliac disease and the Ramsay Hunt syndrome, except that the rate of progression of her disease has been much slower. Of 11 cases reported in the literature,1-3 seven have been unable to walk or stand or have died within two years of the onset of their neurological illness. The longest reported survival after the onset of neurological symptoms has been six years (case 1 of Lu et al 3) at which time the patient was unable to walk. Our patient has now had neurological symptoms for more than 13 years and remains ambulant, albeit with a frame.
The present case shows that myoclonic encephalopathy associated with coeliac disease does not invariably have a rapidly progressive course. This case and the recent report of antigliadin antibodies in 17 out of 25 patients with ataxia of unknown cause (of whom four subsequently had abnormal small bowel biopsies consistent with coeliac disease4) suggests that coeliac disease should be considered in all patients with ataxia, particularly if there is myoclonus.