Oxygen consumption is increased relative to work rate in patients with McArdle's disease.

BACKGROUND: Patients with McArdle's disease suffer exercise incapacity as a result of myophosphorylase deficiency, and for a given work rate have excessive circulatory and ventilatory responses. We hypothesized that the rate of increase of oxygen consumption with work rate (DeltaVO2-DeltaWR slope) would also be elevated in such patients as a result of these excessive responses. PATIENTS AND METHODS: Five patients with McArdle's disease and five matched controls carried out a maximal incremental cardiopulmonary exercise test. Controls then carried out a second test matched to the maximal test of a paired patient. Venous blood was sampled at rest, peak exercise and recovery. RESULTS: During the matched test, the DeltaVO2-DeltaWR slope was higher in the patients than in the controls [19.9 (15.0-24.6) vs. 11.7 (9.2-13.5) mL min(-1) W(-1); mean (range); P = 0.022], and the peak-achieved VO2 was also greater in the patient group [1201 (890-1575) vs. 918 (599-1248) mL min(-1); P = 0.003]. A similar pattern was observed for heart rate [173 (165-182) vs. 108 (105-134) b.p.m.; P = 0.001] and plasma norepinephrine levels [12.6 (9.2-19.9) vs. 2.9 (2.2-4.9) nmol l(-1); P = 0.003]. CONCLUSION: There is an increased rate of rise in VO2 relative to work rate during exercise in patients with McArdle's disease. There is also a greater rise in catecholamines, which may be the result of a physiological response to substrate starvation, and is likely to contribute to the increase in VO2.

Superficial siderosis of the central nervous system many years after neurosurgical procedures.

Recurrent haemorrhage into the subarachnoid space causes superficial siderosis, which clinically manifests as cerebellar ataxia, sensorineural hearing loss, and myelopathy. Two patients developed clinical, radiological, and biochemical evidence of superficial siderosis many years after surgery. One had two posterior fossa operations, a left temporal craniectomy, and radiotherapy for a presumed brain tumour before developing clinical evidence of superficial sidersosis 37 years later. The other had small bilateral subdural collections from recurrent shunt revisions following posterior fossa surgery for a Chiari malformation, and then developed deafness and ataxia. The first patient currently has the longest recorded delay between presumed subarachnoid bleeding and clinical manifestations of superficial siderosis. Both patients provide further evidence that superficial siderosis of the central nervous system, a progressive neurodegenerative vascular condition, may be a delayed complication of neurosurgical procedures.

Human immunoglobulin for diabetic amyotrophy--a promising prospect?

Diabetic neuropathies are universally recognised and cause significant morbidity. At present improving glycaemic control is the only recognised treatment. A man with type 2 diabetes presented with disabling asymmetric lower limb proximal neuropathy. Rapid clinical, functional, and electrical improvement followed treatment with intravenous immunoglobulin. The aetiology of diabetic amyotrophy remains controversial but there is evidence for an immune mediated process and this case suggests a role for immunoglobulin in the management of this debilitating condition.

Effective diagnosis of spinal cord compression using telemedicine.

We report the case of a man with an acute cervical cord lesion which was diagnosed after a teleconsultation with a neurologist at a distant neurological centre. We show that the ability to assess patients clinically using real-time videolinks is also of use in detecting those patients who would benefit from specialist neurosurgical intervention, but who might otherwise be denied it because of their location.

Neurological examination is possible using telemedicine.

To compare the reliability of neurological examination performed by telemedicine and face to face, a junior doctor examined 23 patients face to face, these examinations being witnessed either by one or by two telemedicine observers using a telemedicine video-link at 384 kbit/s. The gold standard was a face-to-face examination from a panel of six consultant neurologists. Power, deep tendon reflexes, plantar responses, coordination, sensation, eye movements, facial strength, tongue movements, sitting balance and gait were studied. Seventeen patients satisfied the inclusion criteria, and a total of 1,084 matched pairs of observations were made. The reliability of the telemedicine examination ranged from fair to moderate for deep tendon reflexes, coordination and eye movement, to near perfect for plantar responses. Overall, examination by telemedicine compared favourably with face-to-face examination. Telemedicine examination was more sensitive in detecting abnormalities than face-to-face examination for all the neurological tests studied and more specific for all but one (plantar responses). The study showed that neurological examination using telemedicine is at least as good as face-to-face examination performed by a junior doctor.

Discordant repeat size and phenotype in Kennedy syndrome.

Previous reports in the literature have described correlation of increasing repeat length with severity of the phenotype, in Kennedy syndrome. We describe male siblings with different repeat lengths, with lack of expression of the phenotype in the sibling with the longer repeat length. The phenotype was identical to motor neurone disease. There is variability of expression in Kennedy syndrome and repeat length even in siblings cannot be taken as a conclusive indicator of severity. CAG repeat length cannot be used to predict the natural history of Kennedy disease. The diagnosis of Kennedy syndrome should be considered in male patients presenting with atypical motor neurone disease.

Scapulothoracic arthrodesis for patients with facioscapulohumeral muscular dystrophy.

Ten scapulothoracic arthrodesis procedures were performed in six patients with facioscapulohumeral muscular dystrophy in order to improve considerably restricted activities of daily living. Four of these procedures were bilateral. The duration of follow-up ranged from 28 to 120 months. All patients reported improved function in activities of daily living. Active shoulder abduction was improved by an average of 44 degrees, and active flexion increased by 56 degrees. There was no deterioration in improved upper limb function with time. Complications included pneumothorax, atelectasis, pleural effusion and re-exploration for a segment of retained drain.

Cerebral venous thrombosis occurring during an ectopic pregnancy and complicated by intracranial hypertension.

Thrombosis of the cerebral dural sinuses and veins has been described since the early 19th century. Clinically the process is characterised by diverse symptomatology and physical findings and in spite of advances in diagnostic radiological techniques it remains an under-recognised condition. It has been most commonly associated with sepsis, trauma, pregnancy, the puerperium and many other hypercoagulable states. We describe an apparently unique case of sagittal sinus thrombosis occurring during an ectopic pregnancy. This was subsequently complicated by intracranial hypertension in spite of clinical improvement and magnetic resonance imaging (MRI) evidence suggesting a return of venous patency. The clinical presentation, radiological features and management is discussed.

Headaches in the accident and emergency department.

Serious illness is not uncommon in patients attending accident and emergency departments with headache. Careful clinical assessment, focusing on characteristics of the headache, associated symptoms and certain examination findings, helps to identify those at risk, and permits the efficient management of everybody else.

Angina in McArdle's disease.

McArdle's disease (myophosphorylase deficiency) results in the inability to metabolise skeletal muscle glycogen to lactate. A patient with this condition developed angina and therefore offered a unique opportunity to explore the differential expression of the defective myophosphorylase gene in skeletal and cardiac muscle.

A double blind, placebo controlled, crossover trial of D-ribose in McArdle's disease.

To determine whether seven days oral D-ribose would improve exercise tolerance in a group of 5 patients with McArdle's disease, we performed a double blind placebo controlled crossover trial. Subjects performed weekly treadmill exercise tests with expired gas analysis until their times were reproducible. They then received 60 g D-ribose daily or placebo for seven days. Exercise testing was repeated on completion of this period. A seven day washout period then followed. Subjects then performed a new baseline exercise test prior to starting the other solution. Again after seven days the exercise test was repeated. There was no significant difference between pre-treatment exercise tests for peak oxygen consumption or level of leg fatigue. Patients did not like taking the ribose and D-Ribose does not appear to be of benefit to patients with McArdle's disease.

The prevalence of inherited neuromuscular disease in Northern Ireland.

A comprehensive study of inherited neuromuscular disease was carried out in Northern Ireland between 1 February 1993 and 30 June 1994. Cases were ascertained from eight different sources and investigations and diagnoses were reviewed. Five hundred and forty three individuals were identified giving an overall prevalence of inherited neuromuscular disease of 1 in 2900 of the population. The prevalence of myotonic dystrophy was higher than that in most previously reported studies and accounted for 25% of all cases. Congenital myopathies were also found more frequently than expected. The overall prevalence compares well with that estimated by Emery from the reported prevalence rates of individual diseases.

Respiratory gas exchange and metabolic responses during exercise in McArdle's disease.

During normal progressive exercise, the gas exchange anaerobic threshold occurs when CO2 production (VCO2) and ventilation (VE) increase so as to depart from a linear relationship to O2 consumption (VO2). This is thought to represent a gas exchange response to metabolic acidosis due to lactate accumulation. Patients with McArdle's disease have previously been reported to exhibit a steepened ventilatory response relative to VCO2, despite an inability to produce lactate. However, the VCO2 response has not been studied. We therefore investigated the VCO2-VO2 and VE-VO2 relationships in seven McArdle's disease patients and seven control subjects during symptom-limited maximal treadmill exercise. Analysis of gas exchange showed that whereas all control subjects had an easily identifiable anaerobic threshold, four of the patients had none and the other three displayed an attenuated threshold. The occurrence of the threshold in one patient was associated with a small rise in lactate and in another patient with an abrupt rise in leg discomfort, suggesting a pain response. Ammonia and the purine metabolite hypoxanthine were elevated during exercise in all patients, suggesting that ammonia may be a product of adenosine monophosphate degradation. Free fatty acid levels were also elevated, and a shift toward utilization of lipid may contribute to abnormal gas exchange responses. It is concluded that lactic acidosis contributes to the gas exchange anaerobic threshold but that other factors, such as discomfort, may be involved in the excess Ve seen during heavy exercise.

What people with epilepsy want from a hospital clinic.

A questionnaire was sent to 511 patients with epilepsy who were being reviewed at the clinics of two consultant neurologists. The questionnaire asked 19 questions about seizure type and how the diagnosis was given. It also asked how much information was given about the disease and advice about living with it. There were also questions about counselling and preference for hospital or community care. Over 96% returned the questionnaire. About one third said they were not told what epilepsy was, over 90% wanted more information about the disease, and about three quarters felt they had not been given enough information about the side-effects of antiepileptic drugs. Over 60% wanted to talk to someone other than a consultant about epilepsy, the most frequent person requested being a specialist nurse. Despite this, three quarters wanted to continue to attend the hospital clinic and 89% were generally satisfied with their hospital management. This survey has highlighted a number of shortcomings in the structure of our clinics. It should be possible to correct them by providing more structured information and having a nurse specialist available.