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Biomedical subjects

A R Walker

Publications and source records attributed to A R Walker.

At least 37 records · Page 2Linked to original sources
PubMed2001

Acute hemorrhagic complication of diagnostic lumbar puncture.

OBJECTIVE: To present a case of an epidural hematoma after lumbar puncture in a pediatric patient without known risk factors for such a complication and to review the literature regarding this complication. DESIGN: Case report, review of the literature, and discussion. DATA SOURCES: A review of MEDLINE (1966-1998) for keywords "lumbar puncture" and "hemorrhage" or "hematoma" was conducted, and each bibliography was reviewed for other sources extending to 1911. Articles describing a case of spinal hematoma after a lumbar puncture for any procedure were included. RESULTS: A 5-year-old boy underwent a lumbar puncture for evaluation of lethargy and fever, and subsequently developed marked back pain and severe pain on flexion of his legs. Magnetic resonance imaging revealed an epidural blood collection. The patient's symptoms resolved over the next few days in association with steroid administration. Multiple reports of epidural and subdural hematomas were found on literature review, most occurring in the setting of coagulation abnormalities. These reports involve lumbar puncture in anesthetic, interventional, and diagnostic settings. CONCLUSION: Lumbar puncture is a frequently employed procedure. Known complications include epidural, subdural, and subarachnoid hemorrhage, usually in the setting of abnormal coagulation. The case presented is unusual in that the patient is a child and lacks any known risk factors for a hemorrhagic complication. Such a complication appears to be rare; only five of the 64 cases discovered in the literature review occurred following this diagnostic procedure in patients without known risk factors.

Acute Disease↗
PubMed2001

Changes in public health in South Africa from 1876.

The present population in South Africa, roughly 43 million inhabitants, is made up of Africans (77.2%), whites (10.5%), Coloureds (mixed race) (8.8%) and Indians (2.5%). In 1900 the infant mortality rate (IMR) among Africans was 330 per 1,000 live births; this has now fallen to 50-60. In Soweto, a primarily African city, IMR averages 20-25. Life expectancy in the past was only 25-30 years; by 1995, this reached 63 years. However, this could fall again due to the rapidly spreading HIV/AIDS epidemic. Life expectancy could fall to 40-45 years by 2010 with the AIDS epidemic being the cause of half of all deaths--a disastrous change from the previous relatively commendable public health situation. Formerly, the most common causes of deaths in young people were infections, diseases associated with malnutrition and gastroenteritis. Adults died almost solely from infections, including typhoid, dysentery, malaria and tuberculosis (TB). Even though diseases associated with malnutrition are less common today, many infections still remain a major problem, particularly TB, which is increasing. As late as 1970, Africans who reached 50 years had longer life expectancy than whites due to the low prevalences of the chronic diseases of lifestyle. This is no longer so, due to the recent rises in non-communicable disorders/diseases, principally obesity in women, hypertension, diabetes, stroke and the cancers of prosperity. In the not so distant future, the level of control of HIV/AIDS related diseases will be the major health/disease regulating factor among Africans. Among white, Coloured and Indian populations, there have been falls in the mortality rates of the young and, despite rises in lifestyle diseases, increases in life expectancy are continuing. For all populations other important public health regulatory factors include water supply, sanitation, clinic/hospital services and personal environmental factors, employment, dietary pattern and intake, smoking practices and alcohol consumption and physical activity, particularly in urban dwellers. Unfortunately, public health expenditure, also a highly regulating factor, has fallen from 8.2% of the gross domestic product in 1994 to 4.1% in 2000.

Health Status Indicators↗
PubMed2001

Age structure of a population of Ixodes ricinus (Acari: Ixodidae) in relation to its seasonal questing.

Three sites in south west Scotland, each having one deciduous and one coniferous woodland with populations of roe deer, were sampled over three years for Ixodes ricinus Linnaeus ticks using cloth drags. Nymphs and adult ticks were age graded by dissection of gut and Malpighian tubules and staining for lipid with Sudan red. Temperature and relative humidity were recorded in developmental and questing microclimates. Two annual cohorts of both nymphs and adults were found. For both instars one cohort became apparent in early spring and the other in autumn. The timing of the cohorts of nymphs corresponded to peaks of numbers questing, but neither females nor males had any clear seasonal pattern of questing. The maximum life of questing nymphs and adults was three to four months. Nymphs and adults were found questing at all months of the year and at temperatures ranging from 3.5 degrees C to 29.3 degrees C. Questing of larvae in summer peaks of numbers was positively correlated with temperature and negatively correlated with relative humidity. These results are explained by a descriptive model which invokes behavioural and morphogenetic diapause. Tests of the model are discussed and it is proposed that the main adaptive advantage of the complex life cycle is to permit moulting and oviposition to occur at favourable summer temperatures in ticks that have engorged at any time of the year.

Age Factors↗
PubMed2000

Risk of babesiosis and anaplasmosis in different ecological zones of Santa Cruz Department, Bolivia.

A cross-sectional study was done of seroprevalence of Babesia bigemina, B.bovis, and Anaplasma marginale in cattle from eastern Bolivia, to characterise the risk of tick-borne disease in three ecological zones. Nineteen farms were sampled in the subtropical humid zone, 13 in the dry subtropical zone and nine in the lower western valleys of the Andean massif. The enzyme-linked immunosorbent assay was used. All three pathogens were widespread. For B. bovis, seroprevalences were high (75-78%) in the two subtropical zones which thus had low risk of disease from this infection; but the western valleys were endemically unstable with higher risk. For B. bigemina, seroprevalences were lower (24-57%) in the two subtropical zones and thus these areas were endemically unstable for disease from this infection. However, the seroprevalence of B. bigemina in the western valleys was too low (13%) for risk of disease in susceptible cattle to be considered high. For A. marginale, the seroprevalences in the two subtropical zones were low (19-32%) and very low (6%) in the western valleys suggesting all these zones were endemically unstable for anaplasmosis. Data for individual farms were analysed for risk of both forms of babesiosis; this showed low risk of disease in the subtropical humid zone, higher risk in the dry subtropical zone and variable risk in the western valleys.

Agriculture↗
PubMed2000

Pathological effects and reduced survival in Rhipicephalus appendiculatus ticks infected with Theileria parva protozoa.

Pathological effects have been demonstrated in a number of arthropod species as a consequence of parasitic infection. This is usually manifest as reduced arthropod survival and/or fecundity. This paper describes the detrimental effects the protozoan parasite, Theileria parva has on Rhipicephalus appendiculatus ticks. R. appendiculatus ticks were dissected and sectioned at regular intervals during their nymph to adult moult after detaching from a T. parva infected calf, and assessed by light and electron microscopy. The reproductive capacity of the T. parva infected ticks was also compared with that of control, uninfected ticks. The number of T. parva forms seen during the ticks' moult were recorded and showed a substantial reduction as the moult progressed. A non-linear relationship between piroplasm ingestion by the engorged nymph and eventual adult salivary gland infection levels was shown. Tick gut and salivary gland pathology was noted at various stages throughout the moult and correlated with the parasite burdens in the affected organs at those timepoints. The reproductive performance of infected ticks was greatly impaired compared to controls. Infected female ticks had longer bloodmeal engorgement times, reduced bloodmeal volumes, smaller egg batch weights and greatly decreased egg hatching success. The pathological effects are discussed in relation to parasite population dynamics within the ticks and compared with similar examples of pathology evidenced with other parasite infected arthropod species.

Animals↗
PubMed2000

Field evidence that roe deer (Capreolus capreolus) are a natural host for Ehrlichia phagocytophila.

Samples of blood, spleen and legs from 112 culled roe deer (Capreolus capreolus) were collected from nine sites widespread in the United Kingdom. The prevalence of infection with Ehrlichia phagocytophila was determined by serology and polymerase chain reaction. Means of 58% of 102 plasma or serum samples were seroreactive by IFA, 38% of 84 blood samples and 29% of 82 spleen samples were positive by PCR. Ticks on legs of 71 roe deer were Ixodes ricinus larvae, nymphs and adults and 83% of legs were infested. Numbers of ticks corresponded positively to the percentage of samples positive for E. phagocytophila by serology and PCR for different sampling sites. Ixodes ricinus nymphs collected from the vegetation at one site with infected deer were analysed for infection with E. phagocytophila by examination of Feulgen stained salivary glands. Of 135 nymphs 5% were infected. These results confirm that roe deer are commonly parasitized by both E. phagocytophila and its vector tick in such a way that it is likely to be an important natural mammalian reservoir of E. phagocytophila.

Animals↗
PubMed2000

Breast-feeding in sub-Saharan Africa: outlook for 2000.

The World Health Organization (WHO) has stressed that 1.5 million infants die annually, unnecessarily, from deprival or from insufficiency of breast milk. Hence, the need for its maximal use, very particularly in impoverished populations, such as those in sub-Saharan Africa. In many developed populations, a generation ago the practice was very low, but now it has risen considerably. In contrast, in Africa and in most developing populations, despite the far greater need for breast-feeding, the practice is tending to decrease, especially among urban mothers. While the most common reasons given concern insufficiency of breast milk and employment of mothers, the latter, especially urban mothers, are under strong and increasing pressure to use proprietary replacement foods. These are often made up unsatisfactorily and are contaminated. Also influential are the often less than enthusiastic, and confusing, attitudes of staff at clinics and hospitals, albeit, due in part to their very heavy workloads. Additionally, there is society's relatively indifferent attitude to breast-feeding. Currently, a hugely adverse factor is the danger of human immunodeficiency virus (HIV) transference from seropositive mothers to their infants - in some African countries almost half of antenatal mothers are infected. Chances of early control of the infection are remote. However, apart from this danger, and from the pressure from replacement food companies, the outlook for breast-feeding practice in many African countries is unlikely to improve significantly until greater encouragement is given from State, local and other health authorities.

Africa South of the Sahara↗
PubMed2000

The frequency of blood pressure measurements in children in four EDs.

The study's objective was to assess the frequency of triage blood pressure measurements in pediatric patients and the recognition of an elevated blood pressure. The design was retrospective and included chart review. The setting consisted of four emergency departments associated with one medical school, including one level I academic center, two level II Community departments, and a regional children's hospital. A convenience sample of 437 patients, aged 1 month to 18 years, was selected. The frequency of triage blood pressure measurements was recorded. The number of patients whose blood pressure was higher than the 90th percentile for age and sex as established by the Second Task Force on Blood Pressure Control in Children was also recorded. The frequency of a second blood pressure measurement in patients with an elevated initial blood pressure was recorded. All frequency data were stratified by hospital and by age group. The results showed 294/437 (66%) of children had blood pressures measured at triage. Of these measurements, 153/294 (52%) reflected blood pressures greater than the 90th percentile for age and sex, but only 58/153 (38%) of patients with such blood pressures had a second blood pressure measured. Hospitals varied in their frequency of blood pressure measurement. Adolescents had their blood pressure measured more frequently, 981105 (93%) than two to 12-year-olds, 144/185 (78%) or 1-month to 2-year-olds, 52/147 (35%). Frequency of triage blood pressure measurements in children varied by institution and increased in frequency with age.

Adolescent↗
PubMed2000

Hyponatremic seizures in infancy: association with retinal hemorrhages and physical child abuse?

We present two cases of infants with hyponatremic seizures who had an unexpected finding of retinal hemorrhages. A review of the literature found no prior association between hyponatremic seizures and retinal hemorrhages. The retinal hemorrhages found in the first patient were a result of shaken baby syndrome (SBS) and associated with long bone fractures and a subdural hematoma. The second patient had retinal hemorrhages and cerebral edema, presumed to be a result of SBS. We suggest that children who become hyponatremic owing to neglect, lack of education, or intentional water poisoning may be at risk for other forms of child abuse. Additional research needs to be done to further elucidate the relationship between hyponatremic seizures and child abuse.

Child Abuse↗
PubMed2000

Breast cancer--can risks really be lessened?

Breast cancer, although uncommon in western populations in the past, continues to rise in incidence, and now affects up to one woman in nine. In some countries, such as the US and Australia, the mortality rate is decreasing, albeit slightly. In developing populations, while of low occurrence, the disease is rising in incidence. Risk factors, which include certain reproductive practices, diet and physical activity, while apparent in some contexts, appear much less so in others; moreover, the avoiding measures do not lend themselves to primary prevention. For early detection, although regular mammography is advocated, it is a subject of controversy. Basically, avoiding measures fall within the usual recommendations for a 'prudent' lifestyle - avoid obesity, increase physical activity, stop smoking and restrict alcohol consumption.

Africa↗
PubMed2000

Ischemic heart disease in black South African stroke patients.

BACKGROUND AND PURPOSE: Stroke patients in western countries frequently have coronary artery disease (CAD). In black Africans, CAD has been reported as being rare in both stroke patients and the general population. In this study, an attempt has been made to determine the prevalence of CAD in a black South African stroke population. METHODS: The prevalence of CAD was determined by indicators identified through a series of 5 observational studies in black patients diagnosed with stroke. CAD indicators included (1) bedside diagnosis in 741 patients; (2) resting ECG in 555 consecutively admitted patients; (3) a combination of clinical examination, cardiac ultrasound, radionuclide scintigraphy, and multigated blood pool studies in 102 consecutively admitted patients; (4) thallium scintigraphy in 60 patients; and (5) necropsy in 23 patients. RESULTS: On bedside questioning, only 0.7% complained of previous angina. There was no history given of myocardial infarction (MI), but documentation of this was found in the clinical notes of 0.7% of the patients. In the resting ECG study, evidence of myocardial ischemia was present in 14.6% and MI in 2.1%. In the combined study, cardiac ischemia was documented on ECG in 12.7% of patients and evidence of previous MI in 5.8%. Cardiac scintigraphic studies revealed changes of myocardial ischemia in 31.7% and MI in 13.3% of the 60 patients studied. Four (17.4%) of 23 patients in the necropsy study had histological evidence of previous MI, and 50% of all patients had evidence of >50% atherosclerotic stenosis in 1, 2, or 3 coronary arteries. CONCLUSIONS: The prevalence of CAD in black African stroke patients is significantly higher than has been documented in the general nonstroke black population as well as in stroke patients. Black stroke patients may have a risk for CAD similar to that of their white counterparts.

Adult↗
PubMed2000

In the rationing of healthcare in indigent African populations, which services should come first?

Governments, worldwide, have enormous difficulties in affording adequate funds for healthcare and its maintenance. In developing populations, almost all of whom are indigent, the diverse health problems being faced with limited funds are insufficiently appreciated. Information is given, for both developed and developing populations, principally those in sub-Saharan Africa, regarding various countries' gross national product (GNP) per capita, the percentage of GNP devoted to health services, and the allocation of health funds per capita. To illustrate the formidable health problems prevailing, some data are given on the magnitudes of morbidity/mortality situations, both for communicable and non-communicable diseases. Some examples are provided which exemplify opposing points of view regarding strongly contesting health claims for priorities in monetary support. Additionally, examples are given of some impoverished countries, which, despite highly adverse circumstances, have achieved enviable health statistics. In this respect it would be highly beneficial were the circumstances and means employed in these and similar contexts given wide publicity.

Adult↗
PubMed2000

Nutritional status and dental caries in a large sample of 4- and 5-year-old South African children.

BACKGROUND: Evidence from studies involving small samples of children in Africa, India and South America suggests a higher dental caries rate in malnourished children. A comparison was done to evaluate wasting and stunting and their association with dental caries in four samples of South African children. DESIGN: Cross-sectional study based on random sampling of birth records of two age bands. METHODS: A total of 2,728 4- and 5-year-old South African children from one rural community and three urban communities were examined for nutritional status and dental caries. RESULTS: In the total sample prevalences of wasting were mild (28%), moderate (4%) and severe (2%). For stunting the prevalences were mild (13%), moderate (3%) and severe (1%). For both conditions rural children showed higher proportions than the other groups. Statistical analysis showed statistically significant differences for wasting and stunting between the study groups. No significant association was found between the prevalence of caries and stunting or wasting, but an association was noted between wasting and decayed, missing and filled (dmf) surfaces (P = 0.003). CONCLUSIONS: In the series of children studied, nutritional status was not found to be clinically relevant to dental caries prevalence and experience.

Child Nutrition Disorders↗