Julius A Ogeng'o

Evaluation of Risk Factors for Alzheimer’s Disease in Elderly East Africans

A number of biological risk factors have been implicated for Alzheimers disease (AD). The investigation of prevalence rates of AD in crosscultural populations has much potential in validating these factors. We previously assessed brain amyloid beta (A beta) protein deposition and other lesions associated with AD as possible markers for preclinical AD in elderly nondemented East Africans. In further analysis, we demonstrate that 17-19% of elderly East African subjects without clinical neurological disease exhibited neocortical A beta deposits and minimal neurofibrillary changes at necropsy that was qualitatively and quantitatively similar to that in an age-matched elderly control sample from Cleveland, OH. A beta deposits varied from numerous diffuse to highly localized neuritic plaques and were predominantly reactive for the longer A beta 42 species. In parallel studies, we evaluated another recently implicated factor in AD, the apolipoprotein E genotype. We found relatively high frequencies of the apolipoprotein E-epsilon 4 allele in elderly nondemented East Africans. The frequencies were comparable to those in other African populations but higher than in subjects from developed countries. Our limited study suggests that elderly East Africans acquire cerebral lesions found in AD subjects but the apolipoprotein E-epsilon 4 allele may not be a highly specific factor for the disease among East Africans.

Anatomy and prevalence of atlas vertebrae bridges in a Kenyan population: An osteological study

Atlas bridges are bony outgrowths over the third segment of the vertebral artery. They may exist as incipient, incomplete, or complete bridges, converting the groove into a deep sulcus, incomplete, or complete foramen respectively. These bridges and their associated foramina display bilateral and sex differences in their prevalence and type. Occurrence of these bridges may predispose to vertebrobasilar insufficiency and Barre–Lieou syndrome. The coexistence of lateral and posterior bridges as well as side predilection is not clear in either sex. Their relative occurrence may also point to some evolutionary patterns. We studied the prevalence, side predilection, coexistence, and anatomical features of atlas bridges using 102 dry atlases (49 males and 53 females) obtained from the osteology department of the National Museums of Kenya. Complete posterior bridges occurred in 14.7% and 13.7% on the right and left sides, respectively. A lateral bridge was found in 3.9% of cases on the right side only. There was positive correlation in the coexistence of the bridges. A retrotransverse foramen was found in 13% of cases. This study has found that posterior and lateral atlas bridges occur in association especially on the right side. Complete bridges were more prevalent in females and were more often present on the right side. This pattern seems to mirror the sexual predilection of vertebral artery compression syndromes. Gender roles may have an influence on the occurrence of these bridges and therefore the syndromes as well. Clin. Anat. 23:649–653, 2010.

Cerebral amyloid beta protein deposits and other Alzheimer lesions in non-demented elderly east Africans.

There is little knowledge of the existence of Alzheimer disease (AD) or Alzheimer type of dementia in indigenous populations of developing countries. In an effort to evaluate this, we assessed the deposition of amyloid β (Aβ) protein and other lesions associated with AD in brains of elderly East Africans. Brain tissues were examined from 32 subjects, aged 45 to 83 years with no apparent neurological disease, who came to autopsy at two medical Institutions in Nairobi and Dar es Salaam. An age‐matched sample from subjects who had died from similar causes in Cleveland was assessed in parallel. Of the 20 samples from Nairobi, 3 (15%) brains exhibited neocortical Aβ deposits that varied from numerous diffuse to highly localized compact or neuritic plaques, many of which were also thioflavin S positive. Two of the cases had profound AS deposition in the prefrontal and temporal cortices and one of these also exhibited moderate to severe cerebral amyloid angiopathy. Similarly, 2 of the 12 samples from Dar es Salaam exhibited diffuse and compact Aβ deposits that were also predominantly reactive for the longer Aβ42 species compared to Aβ40. We also noted that Aβ plaques were variably immunoreactive for amyloid associated proteins, apolipoprotein E, serum amyloid P and complement C3. Tau protein reactive neurofibrillary tangles (NFT) were also evident in the hippocampus of 4 subjects. By comparison, 4 (20%) of the 20 samples from randomly selected autopsies performed in Cleveland showed Aβ deposits within diffuse and compact parenchymal plaques and the vasculature. These observations suggest Aβ deposition and some NFT in brains of non‐demented East Africans are qualitatively and quantitatively similar to that in age‐matched elderly controls from Cleveland. While our small scale study does not document similar prevalence rates of preclinical AD, it suggests that elderly East Africans are unlikely to escape AD as it is known in developed countries.

Spinal cord termination in adult Africans: relationship with intercristal line and the transumbilical plane.

The level of cord termination and level of vertebral intersection of intercristal line and transumbilical plane (TUP), frequently used landmarks, show ethnic variation. The relationship of the spinal cord termination to these lines is vital in spinal surgery and anesthesia, but data on these parameters are scarce in the African population. The purpose of this work is to determine the level of cord termination and establish its relationship with intercristal line and TUP. One hundred and twelve specimens obtained from the department of Human Anatomy at the University of Nairobi were used in this study. The conus medullaris was exposed by laminectomy and its vertebral level together with those of intercristal line and TUP recorded. The distance of conus medullaris from intercristal plane was measured in millimeters. Data obtained were coded and analyzed using Statistical Package for Social Sciences (SPSS) for windows version 16.0 Chicago, Illinois, 2002. Students t‐test was used in the statistical assessment of gender differences. A P value of less than 0.05 was considered significant. The median level of termination of the cord was the upper third of L2, 51.9% of cases terminating below this. There was no statistically significant gender difference in the level of termination of the cord. The intercristal plane passed through L4/L5 disc (70.9%) and below (29.1%). The TUP corresponded with intercristal line in 78.2% of subjects. The mean distance of the spinal cord termination from intercristal line was 99 ± 24 mm. The spinal cord terminates at or below the upper third of L2. Care should be exercised during lumbar punctures and spinal epidural anesthesia among Africans. Intecristal line and TUP are safe landmarks to use in location of conus medullaris. Clin. Anat. 23:563–565, 2010.

Pattern of limb amputation in a Kenyan rural hospital.

Causes of limb amputations vary between and within countries. In Kenya, reports on prevalence of diabetic vascular amputations are conflicting. Kikuyu Hospital has a high incidence of diabetic foot complications whose relationship with amputation is unknown. This study aimed to describe causes of limb amputations in Kikuyu Hospital, Kenya. Records of all patients who underwent limb amputation between October 1998 and September 2008 were examined for cause, age and gender. Data were analysed using the statistical package for Social Sciences (SPSS) for Windows Version 11.50. One hundred and forty patients underwent amputation. Diabetic vasculopathy accounted for 11.4% of the amputations and 69.6% of the dysvascular cases. More prevalent causes were trauma (35.7%), congenital defects (20%), infection (14.3%) and tumours (12.8%). Diabetic vasculopathy, congenital defects and infection are major causes of amputation. Control of blood sugar, foot care education, vigilant infection control and audit of congenital defects are recommended.

Pattern of congestive heart failure in a Kenyan paediatric population

Background Heart failure in children is a common cause of morbidity and mortality, with high socio-economic burden. Its pattern varies between countries but reports from Africa are few. The data are important to inform management and prevention strategies. Objective To describe the pattern of congestive heart failure in a Kenyan paediatric population. Methods This was a retrospective study done at Kenyatta National Hospital, Nairobi Kenya. Records of patients aged 12 years and younger admitted with a diagnosis of heart failure between January 2006 and December 2010 were examined for mode of diagnosis, age, gender, cause, treatment and outcome. Data were analysed using the Statistical Programme for Social Scientists version 16.0 for windows, and presented in tables, bar and pie charts. Results One hundred and fifty-eight cases (91 male, 67 female) patients’ records were analysed. The mean age was 4.7 years, with a peak at 1–3 years. The male:female ratio was 1.4:1. All the cases were in New York Heart Association (NYHA) class II–IV. Evaluation of infants was based on the classification proposed by Ross et al. (1992). Diagnosis was made based on symptoms and signs combined with echocardiography (echo) and electrocardiography (ECG) (38%); echo alone (12.7%); ECG, echo and chest X-ray (CXR) (11.4%); and ECG alone (10.8%). The underlying cause was established on the basis of symptoms, signs, blood tests, CXR, echo and ECG results. Common causes were infection (22.8%), anaemia (17.1%), rheumatic heart disease (14.6%), congenital heart disease (13.3%), cardiomyopathy (7.6%), tuberculosis and human immunodeficiency virus (6.9% each); 77.9% of patients recovered, 13.9% after successful surgery, and 7.6% died. Conclusion Congestive heart failure is not uncommon in the Kenyan paediatric population. It occurs mainly before five years of age, and affects boys more than girls. The majority are due to infection, anaemia, and rheumatic and congenital heart diseases. This differs from those in developed countries, where congenital heart disease and cardiomyopathy predominate. The majority of children usually recover. Prudent control of infection and correction of anaemia are recommended.

Variant origin of the superior thyroid artery in a Kenyan population.

Variant anatomy of the superior thyroid artery is important during surgical procedures, interpretation of angiograms, and interventional radiography in the neck. Pattern of the variations shows population differences but there is no data from the Kenyan population. This study therefore investigated the variations in origin of the superior thyroid artery in a Kenyan population. Forty six necks (36 males and 10 females) from 46 cadavers of black Kenyans in Department of Human Anatomy University of Nairobi, Kenya were bilaterally dissected to expose the origin of the superior thyroid artery. Pattern of origin of the vessel was determined on both sides in males and females. It originated from the external carotid artery common carotid artery and linguo‐facial trunk in 80%, 13%, and 6.5% of the cadavers respectively on the right side. All but one of the superior thyroid arteries were ventral branches. There was asymmetric origin in 6.5% of cases. Origin from the common carotid artery was associated with high carotid bifurcation. Nearly 20% of superior thyroid arteries showed variant origin. Of these, 6.5% arose from the linguo‐facial trunk, much higher than in the Caucasian and Oriental populations. Origin from common carotid artery is substantially lower than prevailing figures from other populations. These findings support ethnic variations. Preoperative angiographic evaluation is recommended. Clin. Anat. 25:198–202, 2012.

Pediatric stroke in an African country

Background: The pattern of pediatric stroke displays ethnic and geographical variations. There are few reports from black Sub-Saharan Africa, although relevant data are important in prevention, clinical diagnosis, treatment and prognostication. Aim: To describe subtypes, risk factors, localization, age and gender distribution of pediatric stroke in the black Kenyan population. Study Design and Setting: Retrospective cross-sectional study in a single regional referral and teaching hospital. Statistical Analysis: Data were analyzed by SPSS version 13.0 for Windows and presented in tables and bar and pie charts. Materials and Methods: The study was performed at the Kenyatta National Hospital, a level-6 regional referral health facility with an annual pediatric in-patient turnover of about 40,000 patients. Files of patients aged 1 month to 18 years over a period of 5 years were analyzed for stroke subtypes, localization, risk factors, age and sex distribution. Only those files with complete information were included. Results: Thirty-two of the 712 stroke patients (4.5%) were pediatric. The male:female ratio was 1.7:1. Ischemic stroke comprised 56.3% (n = 18). Mean age was 7.7 years (range, 1.5–18 years). The most common sites were cortical (51%), lacunar (41%) and brain stem (8%). The most common risk factors were connective tissue disorders (28.1%), heart disease (25%), human immunodeficiency virus (9.4%) and infection (9.4%). Conclusion: Pediatric stroke is not uncommon in the Kenyan population. The risk factor profile comprising connective tissue disorders and infection differs from that reported in other populations, inviting large community-based studies.

Pattern of acute myocardial infarction in an African country

OBJECTIVE The objective of this study was to describe the pattern of acute myocardial infarction in an African country. These data are important for prevention strategies but are scarce from sub-Saharan African countries and altogether absent from Kenya. METHODS AND RESULTS This was a retrospective study done at Kenyatta National Hospital, Kenya. Cases of acute myocardial infarction admitted to the hospital between January 2000 and December 2009 were examined for mode of diagnosis, age, gender, risk factors, and outcome. Only those with confirmed diagnosis were included. Results were analysed by SPSS version 13.0 for Windows, and are presented in tables and bar charts. One hundred twenty cases (80 men; 40 women) were analysed. Clinical diagnosis had been confirmed by electrocardiography and cardiac enzymes (87.5%), angiography (8.3%) and echocardiography (4.2%). Mean age was 56.8 years and male:female ratio 2:1. Common risk factors were hypertension (35%), diabetes mellitus (20.8%), smoking and infection 12.5% each and alcohol (10.8%). The majority (50.8%) of the patients recovered, 44.2% developed congestive cardiac failure and only 5% died. CONCLUSION Acute myocardial infarction is not uncommon in Kenya. Over 30% of the patients are 50 years and younger and it carries a high morbidity from heart failure. Risk factors comprise a combination of non-communicable diseases, namely hypertension and diabetes mellitus, coexisting with infections. Control measures targeting both categories are recommended.

Pattern of odontogenic and nonodontogenic cysts

AbstractThe jaws are host to a variety of cysts due in large part to the tissues involved in tooth formation. Odontogenic cysts (OCs) are unique in that they affect only the oral and maxillofacial region. There are few studies from sub-Saharan Africa. This study was aimed at describing the pattern of various types of cysts in the oral and maxillofacial region in a Kenyan population. This was done at the Departments of Oral and Maxillofacial Surgery and Oral Medicine and Pathology, University of Nairobi Dental Hospital. This was a retrospective audit. All histopathologic records were retrieved from 1991 to 2010 (19 years) and were counted. The following information was extracted and recorded in a data sheet: age, sex, and the type of cystic lesions. There were 194 cysts (4.56%) diagnosed of 4257 oral and maxillofacial lesions. Of these, 64.4% were from male and 35.6% were from female patients with an age range of 1 to 70 years (mean, 23.76 [SD, 14.05] years; peak and median of 20 years). The most common OCs (57.2%) were dentigerous and radicular, whereas the most common nonodontogenic cyst (42.8%) was nasopalatine duct cyst. Other soft tissue cysts reported were epidermoid, branchial, thyroglossal, dermoid, and cystic hygroma. Oral and maxillofacial cysts are not uncommon in this population, the majority being the OC, dentigerous cyst, followed by the nonodontogenic cyst, nasopalatine cyst. The cysts are male predominant and occur 10 to 15 years earlier compared with those in the white population.