Effect of acute uncomplicated malaria on platelet counts.

OBJECTIVE: To determine the effect of uncomplicated malaria on platelet count. PATIENTS AND METHODS: Adult Nigerians (residing in the Lagos metropolis) who were diagnosed as having uncomplicated malaria were treated with a standard regime of chloroquine. Platelet counts were obtained before treatment, Day 0, and again on day 14 when parasitaemia had been cleared in the patients. There were 40 (21 males, 19 females) patients enrolled for the study. Their ages ranged from 15 years to 56 years with a mean +/- SEM of 27. 4 +/- 1.8 years. 28 (14 males, 14 females) patients had both day 0 and 14 platelet counts. RESULTS: The malaria parasite counts ranged from 1020 /mm(3) to 72,000 /mm(3) at day 0 with a mean +/-SEM of 15,638.0 +/- 3,727.0/mm(3) and zero on day 14. The mean platelet count on day 0 was 137.0 +/- 58.4x 10(9)/L while the day 14 mean platelet count was 234.0 +/- 96.9 x 10(9)/L. Comparison of mean platelet counts on day 0 with those on day 14 showed a highly statistically significant difference (p < 0.001). The degree of malaria parasitaemia was not significantly related to the level of platelet count. Transient thrombocytopenia is very common in uncomplicated malaria in semi -immune adults. The mechanism, aetiology, and clinical relevance of the phenomenon deserve further studies.

Comparison of Siriraj Stroke Score and the WHO criteria in the clinical classification of stroke subtypes.

Clinical distinction between cerebral haemorrhage (CH) and cerebral infarction (CI) is important in the management of stroke patients in areas where CT scan facility is lacking or access limited by cost and distance. This distinction is necessary in our environment where an increasing proportion of patients are suspected to have haemorrhagic stroke. This study compares Siriraj stroke score (SSS) and the WHO criteria for the acute stroke syndrome as simple tools for this purpose. The computerised tomography (CT) brain scans of all patients referred with clinical diagnosis of stroke at the University College Hospital (UCH), Ibadan, and RADMED diagnostic centre. Lagos were retrieved and reviewed as well as the case notes of these patients at the referral hospitals. Relevant clinical data were extracted from the case records. The patients were classified into either CI or CH using the WHO criteria for acute stroke syndrome and the SSS. This classification was compared with the CT scan diagnosis using the latter as the gold standard. Data analysis was performed with Epi-info software, and Kappa statistics (k value) for comparability test with 95% confidence interval was used to compare the two clinical criteria with the gold standard. Ninety-six patients had complete clinical records and CT scan features consistent with the diagnosis of stroke, of which 52 were diagnosed as CI and 44 as CH. SSS had sensitivity of 50% for haemorrhage and 58% for infarction with an overall accuracy of 54.2%. The WHO criteria for the acute stroke syndrome had sensitivity of 73% for haemorrhage and 69% for infarction with an overall accuracy of 71%. The kappa coefficient was 0.18 for the SSS and 0.41 for the WHO criteria. The diagnostic accuracy of the WHO criteria for the acute stroke syndrome is higher than that of the Siriraj stroke score. The WHO criteria showed moderate agreement (k=0.41) with the CT scan, while the SSS showed no agreement (k=0.18). When CT scan is not affordable or its use is limited by distance, the WHO criteria for acute stroke syndrome could be more useful. A prospective study with a larger sample size is suggested for definitive conclusion.

Effectiveness of high dose dexamethasone in the treatment of acute stroke.

A prospective double-blind placebo-controlled, randomised clinical trial was carried out to determine the effectiveness of short-course of high dose dexamethasone therapy on mortality and neurological recovery in stroke patients. During a sixteen month period of study, 230 patients with clinical diagnosis of stroke were seen. Of these, 40 were eligible for the study (27 were presumed to have had haemorrhagic stroke; and 13 were presumed to have had cerebral infarction). The commonest cause of exclusion was presentation after 24 hours of the ictus. Patients were sequentially paired and randomised into high dose dexamethasone and placebo groups in a double-blind fashion. There were twenty patients in either group. Of the 27 patients with haemorrhagic stroke, 15 were in the dexamethasone group and 12 in the placebo group. Of the 13 patients with cerebral infarction, 5 were in the dexamethasone group and 8 in the placebo group. Each patient received 100 mg of dexamethasone stat, and 16 mg every 6 hours for a period of 48 hours or equivalent volumes of placebo. Assessment of each patient was done using a neurological score. Sequential analysis by Armitage was employed, using survival at 1 month as the primary criterion of effectiveness. Survivors were followed-up for 6 months. At the end of one month, 16 patients (80%) had died in the dexamethasone group and 17 (85%) in the placebo group. The average day of death was six days in the dexamethasone group and 15 days in the placebo group, but this was not statistically significant. Of the seven survivors at one month, four were in the dexamethasone group and 3 in the placebo group. Five of them had cerebral infarction and two had haemorrhagic stroke. The two in the haemorrhagic subgroup who survived the first month died at the 2nd and 4th month respectively. At the end of six months, only the five patients with cerebral infarction were alive. Of these, 2 in the dexamethasone group were back at work while the third was chair-bound. The 2 survivors in the placebo group were chair and bed bound respectively. In conclusion, this study failed to demonstrate any benefit of a short-course of high dose steroid in improving the mortality of stroke patients and its use should be discouraged. However, possible benefit in the morbidity of survivors in the patients with cerebral infarction requires further studies.

Misdiagnosis of stroke--a computerised tomography scan study.

Misdiagnosis of stroke has significant implication for definitive therapy. This study assessed the frequency of misdiagnosis of stroke using computerised tomography (CT) scan of the brain. One hundred and fifty-six patients admitted over a five year period (1991-1996) with clinical features suggestive of stroke had their CT brain scan reviewed. Only 89 (57%) had neuroradiological features consistent with stroke, of which 59 (66%) had cerebral infarction while 30 (34%) had cerebral haemorrhage. In 67 (43%) of the cases, there were no features of cerebro-vascular accident (CVA) on the CT scan. In this group, cerebral atrophy was the commonest radiological abnormality (21/67), followed by brain tumor (10/67) and subdural haematoma (9/67). The CT scan was normal in 25 patients. The misdiagnosis of surgically treatable conditions in as many as 21 (13.5%) of the 156 patients calls for better neurological evaluation of patients admitted for stroke in tertiary and non-tertiary hospitals. Where available, patients with clinical diagnosis of stroke should have CT scan evaluation to ensure that patients who can be helped surgically are identified early and appropriately treated.

Human resources development for the prevention of blindness in Anglophone West Africa.

As recent as 1986, acute shortage of qualified manpower was one of the major difficulties in the prevention of blindness in Africa. Following the WHO sub-regional workshop on Manpower development for Prevention of Blindness, the West African Health Community in collaboration with the National Prevention of Blindness programmes in Anglophone West Africa made concerted efforts at developing appropriate manpower at all levels of eye care. Eight categories of eye care workers were identified and personnel to population ratios adopted for each. Curriculum was developed and training begun for two new cadres-Primary Eye care Trainers and Diplomate Ophthalmologist. These are expected to boost the training of Integrated Eye Care workers for primary eye care and increase surgical services, especially cataract surgery rates, at secondary eye care level respectively. There are constraints and difficulties but the support provided by two non-government organisations (Sight Savers International and Christoffel Blindenmission) had been helpful in overcoming some of these. Significant progress has been made in the last decade in developing the required manpower but large deficits still remain. The political will, commitment and co-operation of all stakeholders would be required to achieve the desired targets for the next decade.

Central somatosensory conduction in normal Nigerians and patients with spinal cord disorders

Spinal and scalp somatosensory evoked potentials obtained by tibial nerve stimulation were recorded in 24 normal adult Nigerians and 11 patients with non-traumatic spinal cord disorders. The morphology and means of latencies of the major somatosensory evoked potential (SEP) components in the normal subjects (N21: 22.6 + 1.4 msec; P40: 39.1 + 2.5 msec; N50: 48.3 + 2.3 msec and P60: 62.4 + 3.9 msec) were similar to those reported in other populations. Seven of the 11 patients had abnormal central somatosensory conduction (CSC) as judged by a weighted scoring scheme. This was abnormal in all four patients with impaired proprioception and in three of seven patients with normal proprioception. This preliminary report shows that SEP studies are useful in detecting sub-clinical posterior column dysfunction in Nigerian patients with spinal cord disorders and the severity of this could be graded with the CSC scoring scheme

Comparison of magnetic resonance imaging with somatosensory testing in MS suspects.

Two hundred patients suspected of having multiple sclerosis (MS), including 42 with progressive myelopathy and 11 with optic neuritis, were investigated with somatosensory evoked potentials (SEPs) and magnetic resonance imaging (MRI). Most had minimal neurological deficit, the mean Kurtzke scale being 2.65. There were 117 patients had two or more MRI lesions suggestive of MS, with a total of 527 lesions identified; 290 (55%) involved the somatosensory pathways, most commonly lying in the mid-periventricular region (thalamo-cortical radiations). There was good correlation between positive and negative MRIs and SEPs. The MRI was abnormal more frequently than the SEP, except in progressive myelopathy when both were abnormal with equal frequency. It is proposed that some cases of myelopathy in MS may be due to periventricular rather than spinal pathology. The morphology of the MRI lesion would favor conduction block not slowing of the SEP as being the prime abnormality. This appeared to be true of leg SEPs.

Far-field potentials from peripheral nerve: generated at sites of muscle mass change.

Using a forearm-sternal referential recording montage, three peripheral nerve far-field potentials, P4, P7, and P9, were elicited by median nerve stimulation. The latencies correlated with the distances between the stimulating cathode at the wrist and the proximal forearm, mid-upper arm, and the shoulder, respectively. At these sites, the electrophysical characteristics of the surrounding volume conductor suddenly changes. Altered girth of muscle mass seemed to be a factor.

Electrophysiologic quantification of distal polyneuropathy in diabetes.

Electrophysiologic studies of the lower limb (reflex, motor, and sensory) were done in 50 diabetics, 30 of whom were age- and sex-matched with controls. The results were analyzed by a 0 to 9 rating--electrophysiologic polyneuropathy (EPN) score. The median EPN scores were 0.5 in controls and 3.5 in diabetics (p less than 0.001). Diabetics with mild or no distal polyneuropathy (DPN) had a median EPN score of 2.4 compared with 4.7 in those with overt DPN (p less than 0.0001). The EPN score correlated positively with known duration of diabetes and showed differences with age and therapy. It provides a single electrophysiologic parameter for evaluating DPN in diabetics.

The effects of induced hypoxia on the cardiovascular system in dogs poisoned with tetanus toxin.

Tetanus toxicity was induced in dogs by injecting the toxin subcutaneously in the groin. On developing generalised toxic symptoms, these dogs were characterised by signs of increased sympathetic discharge to the cardiovascular system as evidenced by high basal values of blood pressure, heart rate and LV dP/dt max. Mild to moderate hypoxia induced by ventilation with 10% O2 in N2 had no appreciable effect on the cardiovascular variables. However, moderate to severe hypoxia induced by ventilation with 7% O2 in N2 further increased the sympathetic discharge to the heart and blood vessels resulting in increases in heart rate, LV dP/dt max and blood pressure. These responses were abolished by adrenergic blockers. The responses in the tetanus dogs were identical to those seen in dogs without tetanus toxicity. Atropine or moderate lactic acidaemia did not alter the responses to hypoxia. Beta-adrenergic blockers appear to be useful drugs in the control of tetanus patients who show evidence of increased sympathetic activity or who develop hypoxaemia.

Social problems of adolescent and adult epileptics in a developing country, as seen in Lagos, Nigeria.

Adolescent and adult epileptics attending the Neurology Clinic were interviewed about their social problems. Forty-nine percent were attending normal school; a third of these believed that seizure disorder affected their school performance. Of 40% who had attended school but left, about half withdrew from school prematurely because of the frequency of their seizures. Ninety percent of those who could be employed had jobs. About a third of these had lost income because of the illness. Self-employed patients were most affected. Very few patients lost their jobs despite most employers' knowledge of their employees' epilepsy. About one-sixth had lost friends or spouses because of epilepsy and a few had withdrawn from social activities for fear of having a seizure in public. Others had no problems interacting with other members of the society. Most of the patients claimed they took antiepileptic drugs regularly. One third had difficulty paying for these drugs. One quarter denied being epileptics. In conclusion, the social difficulties of adolescent and adult epileptics in Nigeria are similar to those of epileptics elsewhere. Educational problems are most common and these are related to poor seizure control. This is partly due to financial difficulties in obtaining drugs regularly.

An experimental morphometric study of neutral lipid accumulation in skeletal muscles.

The neutral lipid content of skeletal muscle fibers was determined by computing the lipid accumulation index (LAI) on transverse cryostat sections stained with Oil Red O. The LAI was defined as: (total area of neutral lipid droplets in a fiber) x 100/(total cross-sectional area of a fiber). The biceps, diaphragm, and soleus muscles were studied in 3 groups of guinea pigs: normal animals, animals fasted for 48 hours, and animals subjected to muscle denervation and then fasted for 48 hours. In normal animals, the highest mean LAI was found in the diaphragm (4.93) in comparison with lower values in the biceps (2.25) and soleus (2.09). After fasting, these values were markedly increased; there was also a concomitant increase in plasma free fatty acid (FFA) concentration. Prior denervation further increased the LAI in biceps and soleus but reduced it in the diaphragm. Type 2A fibers tended to show high lipid accumulation when the plasma FFA concentration was high. Type 2B fibers never accumulated much lipid under any circumstances. Type 1 fibers varied in their response in the different muscles.

A simple, direct extraction method for gas-liquid chromatographic determination of valproic acid in plasma.

A single high-recovery extraction process is described for rapid gas-liquid chromatographic (GLC) determination of valproic acid (VPA). The drug is extracted from acidified plasma into an equal volume (0.2 ml) of chloroform. Evaporation is avoided by extraction into a chloroform bed, from which an aliquot is analysed by isothermal GLC employing a column packed with 10% DEGS. The reproducibility and accuracy of the method was good. In 100 plasma samples from patients, there was an excellent correlation (r = 0.98) between VPA levels determined concomitantly by this method and the technique for Kupferberg. Single plasma samples can be analysed in 20 min, and 40 samples can easily be analysed daily by a single technician. Ethosuximide concentrations can also be determined simultaneously. The method is suitable for emergency and routine use in drug monitoring laboratories.

Seizures following intracranial surgery: incidence in the first post-operative week.

Consecutive craniotomies (118) drawn from major hospitals, and performed for disorders other than epilepsy or acute trauma were reviewed. The final diagnosis included tumor (70), subdural hematoma (13), aneurysm (10), arteriovenous malformation (7), and miscellaneous lesions (18). Eighty-seven (73.7%) patients had not experienced seizures prior to neurosurgery, 11 of these (12.6%) had a seizure within the first week, in six the attack occurred within 24 hours, and of these three had further attacks. In contrast, of the 31 patients (26.3%) that had one or more seizures prior to operation, 11 patients (35.5%) had seizures within the first week. In ten patients seizures occurred within the first 24 hours and of these seven had one or more recurrences later in the week. Anticonvulsant drugs were administered to 72 patients before operation, including all those with a history of seizures, but loading doses were not utilized to ensure therapeutic levels. In patients with predisposing factors to postoperative seizures, anticonvulsant drugs should be administered before or immediately following craniotomy in adequate dosage to rapidly achieve and maintain effective plasma levels. Phenytoin, owing to its minimal sedative effects is the drug of choice. A loading dose of 18 milligrams per kilogram can be safely administered as an admixture to an intravenous infusion of 0.9% saline with careful monitoring of cardiopulmonary function.

Central and peripheral conduction times in multiple sclerosis.

Somatosensory evoked potentials (SEPs) were recorded simultaneously from the cervical spine and scalp in 25 normal subjects and 105 patients with established or suspected multiple sclerosis (MS) using median nerve stimulation. The normal latency of the main peak of the cervical SEP (N14) following median nerve stimulation at the wrist was 13.7 +/- 0.8 msec. The peak latency of the first cortical event of the scalp SEP (N20) was 19.1 +/- 0.9 msec. The difference in these latencies (N20 -- N14) reflects a conduction time between the dorsal column nuclei and cortex. It measured 5.45 +/- 0.7 msec. The conduction times between the wrist and Erb's point and Erb's point and N14 measured 8.6 +/- 0.7 msec and 5.1 +/- 0.6 msec respectively. There was a 68.6% overall incidence of abnormalities of N14, N20 or (N20 -- N14) in the patients. This incidence was over 80% in definite and early probable or latent MS, 68.2% in progressive spinal MS and 40.0% in suspects. SEPs were also simultaneously recorded from the lower thoracic spine (T12) and scalp in a different group of 25 normal subjects using tibial nerve stimulation. The latency of the thoracic SEP (N21) was 21.4 +/- 1.5 msec and that of the first cortical event of the scalp SEP (P40) was 38.6 +/- 2.2 msec. The difference in these latencies (P40 -- N21) which reflects conduction between T12 and the cortex measured 17.2 +/- 1.7 msec. Conduction between the ankle and popliteal fossa was 7.0 +/- 0.65 msec and between the popliteal fossa and N21, it was 14.5 +/- 1.1 msec. All of a small group of MS suspects showed abnormality of P40 or (P40 -- N21).

An electrophysiological quantitation of the cubital tunnel syndrome.

Four hundred and ninety-two ulnar nerves were studied in 237 patients with cubital tunnel syndrome and 233 subjects without clinically apparent ulnar neuropathy. Terminal motor and sensory latencies, motor and sensory conduction velocities, sensory action potential amplitudes and dispersons, and needle electromyography were analysed by a 0 to 10 rating--the EMG score. The patients were clinically graded from 1 (least severe) to 4 (most severe). The median EMG scores of these were 0.9/10 (N = 70); 1.6/10 (N = 81); 4.7/10 (N = 46); and 7.1/10 (N = 56), respectively. The median EMG score for the controls was 0.6/10 (N = 239) and 14.7% had asymptomatic ulnar entrapments. This incidence reached 30% in controls who were 60 years or older. In 25 other controls, the above sulcus sensory action potential was analysed. Its mean dispersion was 4.9 +/- 1.0 s-3. This measurement was significantly prolonged in 84.6% of 13 studies in which the EMG score was 0/10. These patients had either sensory symptoms only or an additional mild sensory deficit. Comparison of the EMG score obtained with sequential studies would allow one to objectively evaluate improvement or deterioration of the clinical state, giving a rational means of determining the need for surgery.

Amplitude of the F wave: a potential means of documenting spasticity.

The amplitude of 32 averaged F responses (F32) recorded with surface electrodes was 1 percent of the amplitude of the M wave. The largest F response (Fmax) was 4.5 percent of the M wave. In spasticity, Fmax did not increase in amplitude but became more persistent, resulting in a significant increase of F32. There was a positive correlation between the amplitude of F32 and the M wave, and this relationship was abnormal in 60 percent of the studies of patients with spasticity.