The acute influence of amateur boxing on dynamic cerebral autoregulation and cerebrovascular reactivity to carbon dioxide.

PURPOSE: The purpose of this study was to investigate the acute effect of head impacts, sustained over the course of three rounds of amateur boxing, on indices of cerebrovascular function. METHODS: Eighteen university amateur boxers (six female) completed three experimental trials in a randomised order; (1) three rounds of boxing (BOX), (2) an equivalent bout of pad boxing (where no blows to the head were sustained; PAD), and (3) a time-matched seated control trial (CON). Indices of cerebrovascular function were determined immediately before and 45 min after each trial. Specifically, dynamic cerebral autoregulation (dCA) was determined by considering the relationship between changes in cerebral blood velocity and mean arterial pressure during 5 min of squat-stand manoeuvres at 0.05 and 0.10 Hz. Cerebrovascular reactivity was determined using serial breath holding and hyperventilation attempts. RESULTS: Participants received an average of 40 ± 16 punches to the head during the BOX trial. Diastolic, mean and systolic dCA phase during squat stand manoeuvres at 0.05 Hz was lower after BOX compared to pre BOX (P ≤ 0.02, effect size (d) ≥ 0.74). No other alterations in dCA outcomes were observed at 0.05 or 0.10 Hz. The number of head impacts received during the BOX trial was associated with the change in systolic phase (r = 0.50, P = 0.03). No differences in cerebrovascular reactivity to breath holding or hyperventilation were observed. CONCLUSIONS: A typical bout of amateur boxing (i.e., three rounds) can subtly alter cerebral pressure-flow dynamics, and the magnitude of this change may be related to head impact exposure.

Myasthenia gravis with thymoma is more common in the Maori and Pacific Island populations in New Zealand.

BACKGROUND: The association of myasthenia gravis (MG) with thymoma is well recognized. Our clinical impression has been that MG associated with thymoma may be more common in patients of Polynesian descent than in other races. AIM: To determine the influence of ethnicity on the association of MG with thymoma in our population. METHOD: Review of all cases of thymectomy performed at Greenlane Hospital in Auckland for the 20-year period from June 1978 to June 1998. RESULTS: There were 103 thymectomies performed in the study period. Fifty-five thymomas were identified, 15 in subjects of Maori or Pacific Island ethnicity and 40 in subjects of other races, predominantly Caucasian. Ten of 15 Maori or Pacific Island subjects with thymoma had MG (67%), compared with 15 of 40 subjects of other races (37.5%, P = 0.05). The mean age of Maori or Pacific Island subjects with thymoma and MG was 42.5 years, compared with 56.3 years in subjects from other races (P = 0.06). All five Maori and Pacific Island subjects with invasive thymoma had MG, whereas only four of 15 subjects (27%) from other races with invasive tumours had MG (P < 0.01). The overall incidence of thymoma and the proportion of thymomas that were invasive did not differ between the ethnic groups. CONCLUSIONS: Myasthenia gravis with thymoma occurs more frequently among Maori or Pacific Island people than in other racial groups in our population. This is due to an increase in the proportion of cases with thymoma who have MG in this group, while the overall frequency of cases of thymoma is similar between groups. MG with thymoma in the Maori or Pacific Island populations also presents at a younger age and is more often associated with tumour invasion.

Bilateral hypoglossal nerve palsy due to vertical subluxation of the odontoid process in rheumatoid arthritis.

Two patients with rheumatoid arthritis involving the cervical spine developed a rapidly progressive dysarthria due to bilateral hypoglossal nerve palsies, in one patient as an isolated lesion, and in the other in conjunction with dysfunction of the vagus and glossopharyngeal nerves. Both patients showed upward movement of the axis, relative to the foramen magnum, which has been termed 'vertical subluxation of the odontoid' or 'cranial settling'. Mechanical injury to the nerves, secondary to this process, is the most likely mechanism.

A progress report on the New Zealand Multicentre Parkinson's disease trial. A comparison of low-dose treatment with bromocriptine or L-dopa.

A short-term and long-term prospective trial comparing 'low-dose' bromocriptine with L-dopa in the de novo treatment of Parkinson's disease began in 1983. One hundred and twenty-eight patients entered the trial by early 1987. One hundred and seven have remained on one drug. Statistical analysis indicates that a hundred patients in each treatment group will be necessary to avoid a type II statistical error in the comparison of these treatments.

Activation of epileptiform activity by mental arithmetic.

Activation of epileptic seizures or electroencephalographic epileptiform discharges by mental calculation is rare. We report the case of a 34-year-old right-handed accountant with a 20-year history of generalized tonoclonic seizures. Although clinical seizures were unrelated to performance of mental arithmetic, epileptiform activity appeared when she attempted difficult mental arithmetic. Apart from one occasion, epileptiform discharges did not impair her ability to provide accurate answers to mathematical problems.

Hypoglycemia masquerading as cerebrovascular disease (hypoglycemic hemiplegia).

Hypoglycemia produced hemiplegia with right-sided predilection in 16 patients initially suspected of having suffered a stroke. Fifteen patients had no demonstrable brain disease, and the hemiplegia cleared rapidly once the hypoglycemia was corrected. Invasive investigations such as carotid arteriography are not required in most patients. The features of hypoglycemia hemiplegia suggest that a selective neuronal vulnerability and not underlying focal brain disease is responsible in most cases.

The chronic and severe forms of eosinophilic meningitis.

Two cases of chronic eosinophilic meningitis (presumed to be due to Angiostrongylus cantonensis) and a third patient with a severe form of this disease are described. Such cases are rare in the published literature. All patients developed their illness in Western Samoa, an area previously thought to be free of the disease. The need to consider eosinophilic meningitis in patients with chronic and severe neurological disease who live in, or have recently come from, endemic areas is emphasised.

Head injury unmasking other brain diseases.

Sixteen patients previously free of neurological complaints sustained minor head injuries and subsequently presented acutely with a wide range of unexpected, serious brain diseases. These included brain tumours, berry aneurysms, arteriovenous malformations and brain abscess. The possible, responsible mechanisms include direct mechanical trauma to the asymptomatic brain lesion, hydrocephalus and brain oedema. This unusual complication of head injury should be suspected when a florid neurological syndrome follows a minor head injury. CAT scanning usually identifies the responsible disease. Because of its therapeutic implications, this complication deserves recognition in the differential diagnosis and management of head injuries.

Sodium valproate (Epilim) in epilepsy: a trial.

Of thirty-five patients with various types of epilepsy treated with sodium valproate, 15 achieved complete seizure control on that drug alone, 12 other patients benefited and eight failed to improve on the drug. Excellent results were more likely in those with petit mal epilepsy and in those whose epilepsy was controlled with other drugs at the expense of side effects. Three patients were unable to tolerate valproate, but in general few patients experienced side effects and several patients felt much better on valproate than on their previous drugs. A twice daily dosage regime was satisfactory. Plasma valproate levels at the final dose covered a wide range, 0.21 - 1.2mmol/l (34 to 190 microgram/ml) and did not correlate with response, lack of response or side effects.

Vertebral artery occlusion following manipulation of the neck.

A 23-year-old woman developed brainstem infarction following cervical manipulation. Vertebral angiography showed total occlusion of the left vertebral artery with a thrombus extending into the basilar artery. The literature dealing with this rare but serious complication of cervical manipulation is reviewed.

Coma in the Wernicke-Korsakoff syndrome.

Four comatose patients were found to have the Wernicke-Krosakoff syndrome. All had a history of alcoholism, previous alcoholic neurological disease, and poor nutrition. Intravenous or nasogastric tube feeding without vitamin supplements precipitated coma in three. Examination showed a diffuse encephalopathy with intact pupillary light reflexes, no focal neurological signs, and absent doll's eye and caloric responses. The tendon reflexes were uniformly absent. Two patients were hypothermic and one was hypotensive. Although the level of consciousness improved in all after parenteral thiamine, three died and one was left disabled. The Wernicke-Korsakoff syndrome merits wider recognition as a cause of coma and empirical treatment with thiamine in cases of coma of unknown cause is recommended.

Venepuncture nerve injuries.

6 patients seen in a blood-transfusion centre had painful peripheral-nerve injuries after venepuncture in the antecubital fossa. The nerves injured were the median nerve and the medial and lateral cutaneous nerves of the forearm in the antecubital fossa. The frequency of this injury was approximately 1/25 000 venepunctures. 3 patients were treated with carbamazepine, which relieved their pain. Although all patients recovered, early recognition of this complication of venepuncture is important, since successful treatment may obviate prolonged disabling symptoms and future litigation.