Event-related evoked potentials in chronic respiratory encephalopathy.

BACKGROUND: Cognitive event-related potential (P(300)) is an index of cognitive processing time. It was found to be prolonged in dementia, renal, and hepatic encephalopathies, but was not extensively assessed in respiratory failure. OBJECTIVE: To evaluate P(300) changes in patients with respiratory failure, and especially those with mild or subclinical hypoxic-hypercapnic encephalopathy. METHODS: Auditory event-related evoked potential P(300) latency was measured using an oddball paradigm in patients with respiratory failure due to any cause (partial pressure of oxygen in arterial blood (PO(2)) should be 75 mm/Hg or less). Apart from blood gases measurement, patients underwent the Mini-Mental State Examination (MMSE). Patient performances were compared with that of matched normal control. Patients were admitted into the study from outpatient clinics and wards at King Khalid University Hospital and Sahara Hospital. RESULTS: Thirty-four patients (12 women, 22 men) were admitted to the study. Ages ranged from 19-67 years with a mean of 46.1 years. Respiratory failure was severe or very severe in 11 patients (33%), and mild or moderate in the rest (66%). Mean value for PO(2) and partial pressure of carbon dioxide in arterial blood (PCO(2)) were 63.7 and 45.2 mm/Hg, respectively. pH mean was 7.4 and O(2) saturation was 90.7%. P(300) latency ranged from 218 to 393 milliseconds, with a mean of 338.4 milliseconds. In comparison with control (309.9 milliseconds), there was a significant difference (P = 0.007). P(300) amplitude differences were not significant. No significant difference in MMSE was noted between mild and severe respiratory failure. Results of detailed neuropsychological assessment were clearly abnormal but were limited by the small number of tested patients. P(300) latency changes correlated significantly with age as well as severity of respiratory failure. P(300) was also significantly delayed whether hypoxia occurred with or without hypercapnia. CONCLUSION: Results show a significant delay of P(300) latency in patients with severe and mild respiratory failure. This was associated with subclinical encephalopathy in most patients, evidenced by a near-normal MMSE score. Apart from confirming the importance of P(300) latency measurement as a marker of respiratory encephalopathy, this study asserts the causal relationship between hypoxemia and cognitive derangement. Furthermore, it promotes the early use of oxygen therapy in a selected group of patients with mild or moderate respiratory failure, who have responsibilities which involve taking rapid critical decisions.

Thrombosis complicating high dose intravenous immunoglobulin: report of three cases and review of the literature.

High dose intravenous immunoglobulin (IVG) is increasingly used in a broad range of immune mediated diseases. Thrombosis was exceptionally reported as a complication of this therapy. We describe three cases of thrombotic complications during or soon after IVIG treatment: myocardial infarction in a man and cerebral infarctions in an elderly man, associated with peripheral ischemia in a woman. In addition we review the published cases in the literature and discuss the possible etiologic factors.

Motor terminal latency index in carpal tunnel syndrome.

We determined the motor terminal latency index (MTLI) of the median nerve across the carpal tunnel in 41 upper extremities of 31 patients with carpal tunnel syndrome. Changes in motor nerve conduction velocity (MNCV), motor terminal latency (MTL), sensory action potential and the amplitude of the compound muscle action potential recorded from the abductor pollicis brevis muscle were all suggestive of proximal and distal segment involvement of the nerve across the carpal tunnel. There was no correlation between forearm MNCV and MTL (r = 0.40), although MTLI was correlated with MTL (r = 0.67) but not with MNCV, indicating a disproportionate conduction across the carpal tunnel.

Motor terminal latency index in carpal tunnel syndrome

We determined the motor terminal latency index [MTLI] of the median nerve across the carpal tunnel in 41 upper extremities of 31 patients with carpal tunnel syndrome. Changes in motor nerve conduction velocity [MNCV], motor terminal latency [MTL], sensory action potential and the amplitude of the compound muscle action potential recorded from the abductor pollicis brevis muscle were all suggestive of proximal and distal segment involvement of the nerve across the carpal tunnel. There was no correlation between forearm MNCV and MTL [r = 0.40], although MTLI was correlated with MTL [r = 0.67] but not with MNCV, indicating a disproportionate conduction across the carpal tunnel

Dementia in Saudi Arabia: experience from a university hospital.

OBJECTIVES: To describe the pattern of presentation, the types of dementia and the associated conditions in Saudi patients. MATERIALS AND METHODS: Hospital-based study using DSM-IV and ICD 10 criteria for consensus diagnosis of cases from clinical information and results of investigations. Dementia subtypes were made according to NINCDS-ADRDA, NINDS-AIREN and ICD 10 criteria while CDR was used for severity grading. RESULTS: A total of 77 demented patients (49 males, 28 females) were studied. The hospital frequency was 19.3/100,000 patients. The mean age at presentation was 74.6 years and age at onset was below 65 years in 17 patients. The types of dementia were: Alzheimer's disease (51.9%), vascular dementia (18.2%), mixed cases (15.6%), dementia with Parkinson's disease (7.8%) and treatable dementia (5.2%). Only 3 patients were in the severe clinical stage and infections were important causes of deterioration. CONCLUSION: The hospital frequency appears to be low probably because of the relatively young population. The pattern of dementia with preponderance of AD is similar to that in western countries and intervention directed at the risk factors for stroke could reduce the burden of vascular dementia.

Pattern of presentation of multiple sclerosis in Saudi Arabia: analysis based on clinical and paraclinical features.

We studied 89 MS patients comprising 38 males and 51 females seen over a 10-year period. The hospital frequency was 25/100,000 patients. The diagnosis was mainly clinical and was supported by neuroimaging, cerebrospinal fluid analysis and neurophysiological tests. Sixty-five patients (73%) were Saudis and the peak age of onset was in the third decade. Fifty-two patients (58.4%) had clinically definite MS, 17 (19.1%) had laboratory-supported definite MS, 15 (16.9%) were clinically probable MS cases and the remaining 5 (5.6%) had laboratory-supported probable MS. The mean age at onset of Saudi patients (25.9 years) was lower than that of the non-Saudis (29.4 years; p < 0.001). Involvement of the pyramidal system was the commonest mode of presentation. The clinical course was relapsing-remitting in 60.7%, progressive-relapsing in 20.2% and primary progressive in 19.1%. The number of systems involved was significantly associated with the duration of disease (p < 0.001). The demographic features and the variability of clinical presentation of Saudi MS patients is similar to the results from neighbouring countries. Combination of clinical features and paraclinical tests is essential for accurate determination of extent of dissemination and for unmasking clinically silent lesions.

Subacute sclerosing panencephalitis presenting as acute disseminated encephalomyelitis: a case report.

Subacute sclerosing panencephalitis is characterized by the insidious onset of diffuse cerebral dysfunction associated later with myoclonus and typical electroencephalographic changes. The disease progresses relentlessly to coma and death within 2 years. We report a case of acute onset and rapid course associated with atypical CSF, EEG and MRI features simulating acute disseminated encephalomyelitis. Brief review of relevant literature is presented.

Cerebral venous thrombosis in adults. A study of 40 cases from Saudi Arabia.

BACKGROUND AND PURPOSE: We undertook this study to determine the frequency, clinical patterns, and etiologies of cerebral venous thrombosis in a Middle Eastern country. METHODS: Records of all adults patients admitted with an angiographically documented diagnosis of cerebral venous thrombosis from 1985 through 1994 in two major hospitals of Riyadh, Saudi Arabia, were reviewed. RESULTS: Forty patients (20 men, 20 women) aged 16 to 40 years were identified. Hospital frequency was 7 per 100,000 patients, and the relative frequency against arterial strokes was 1:62.5. Nineteen cases (47%) had a clinical picture of pseudotumor cerebri. Behçet's disease was the cause in 10 cases (25%). Other causes included antiphospholipid antibodies in 4, protein S deficiency in 3, intracranial tumors in 3, systemic lupus erythematosus in 3, infections in 3, antithrombin III deficiency in 2, postpartum in 1, and oral contraceptives in 1. CONCLUSIONS: Cerebral venous thrombosis in adults is not uncommon in Saudi Arabia. Behçet's disease is the single most common etiology. Infection is no longer an important cause, whereas "new" coagulation disorders are common. Patients with a pseudotumor cerebri syndrome should undergo angiography or brain MRI before being labeled idiopathic.

Maximal thymectomy for myasthenia gravis.

Maximal thymectomy was carried out in 48 patients with myasthenia gravis (MG). There were 18 males and 30 females. Thymic hyperplasia was found in 38, and atrophic thymus in 8, patients. Two patients had thymoma. In the non-thymomatous myasthenia gravis complete remission was achieved in 16 patients (34.8%) and pharmacological remission in 20 patients (43.5%) thus giving a total remission in 36 (78.3%) patients. Six patients (13%) improved. There was no improvement in four patients. Thus, the overall benefit from thymectomy was 91.4% in this series. We found that sex, age at onset of disease and steroid therapy influenced the outcome of thymectomy. On the other hand, duration of disease, anti-acetylcholine receptor (AntiAchR) antibodies and thymic histology did not have any bearing on the complete remission rate.

Computed tomographic evidence of an extensive thrombosis and infarction of the deep venous system.

BACKGROUND: Massive bilateral infarcts due to deep venous system thrombosis are extremely rare and poorly documented. We present a case with computed tomographic evidence of both thrombosis and infarction of the whole deep venous system. CASE DESCRIPTION: A previously healthy 30-year-old woman who had taken oral contraceptives for 3 years complained of recurrent headaches and transient visual obscuration. Three months later, she suddenly became comatose and was found to have papilledema. She rapidly worsened, became decerebrate, and died within 48 hours. Noncontrast computed tomographic scan showed the spontaneous hyperdensity of the thrombosed deep veins and a massive bilateral centrobasilar hypodensity suggestive of a deep venous system infarction. CONCLUSIONS: This case shows that cerebral venous thrombosis can masquerade during 3 months as benign intracranial hypertension and then make a dramatic extension to the deep cerebral veins. It illustrates extensive thrombosis of the deep venous system as a possible cause of rapid coma and decerebration and stresses the importance of computed tomographic scan to show both the thrombosed veins and the venous infarct, which allows delineation of the deep venous system territory.

Computed tomographic changes of the brain in toxaemia of pregnancy.

Four cases of toxaemia of pregnancy examined with computed tomography scans of the brain are reported. A review of the literature reveals 19 other cases with previously reported CT brain scans. The review shows intracerebral oedema as the main finding. Haemorrhage, massive or punctate was noted in four cases. The pathogenesis of the CT changes and the clinico-radiological correlation of the visual disturbances are discussed.