Julius Ogeng’o

Variations in branching of the posterior cord of brachial plexus in a Kenyan population

Background Variations in the branching of posterior cord are important during surgical approaches to the axilla and upper arm, administration of anesthetic blocks, interpreting effects of nervous compressions and in repair of plexus injuries. The patterns of branching show population differences. Data from the African population is scarce. Objective To describe the branching pattern of the posterior cord in a Kenyan population. Materials and methods Seventy-five brachial plexuses from 68 formalin fixed cadavers were explored by gross dissection. Origin and order of branching of the posterior cord was recorded. Representative photographs were then taken using a digital camera (Sony Cybershot R, W200, 7.2 Megapixels). Results Only 8 out of 75 (10.7%) posterior cords showed the classical branching pattern. Forty three (57.3%) lower subscapular, 8(10.3%) thoracodorsal and 8(10.3%) upper subscapular nerves came from the axillary nerve instead of directly from posterior cord. A new finding was that in 4(5.3%) and in 3(4%) the medial cutaneous nerves of the arm and forearm respectively originated from the posterior cord in contrast to their usual origin from the medial cord. Conclusions Majority of posterior cords in studied population display a wide range of variations. Anesthesiologists administering local anesthetic blocks, clinicians interpreting effects of nerve injuries of the upper limb and surgeons operating in the axilla should be aware of these patterns to avoid inadvertent injury. A wider study of the branching pattern of infraclavicular brachial plexus is recommended.

Pattern of hypertensive kidney disease in a black Kenyan population.

Background: Hypertensive kidney disease is a major cause of morbidity and mortality. Its pattern displays geographical and ethnic variations. Data on these patterns are important for informing management and prevention strategies, but on Kenyans such data are scarce. Objective: By means of a retrospective study at Kenyatta National Hospital, Nairobi, we aimed to describe the pattern of hypertensive kidney disease in a black Kenyan population. Methods: Records of hypertensive patients who had impaired kidney function between January 2000 and December 2010 were examined for mode of diagnosis, age, gender, comorbid factors, treatment and outcome. Data were analyzed using the Statistical Package for Social Sciences, version 16.0 for Windows, and are presented using tables and bar charts. Results: A total of 114 cases (72 males, 42 females) were analyzed. The mean age was 42.7 years (range 12–83), peaking at 51–70 years. The male to female ratio was 1.7:1. Comorbid factors included left ventricular hypertrophy (21.1%), congestive heart failure (15.8%), alcohol (11.4%), cerebrovascular accidents, smoking and retinopathy (10.5% each). Multiple comorbid factors were present in 8.8% of the cases. The majority (52.6%) of the patients survived on hemodialysis, 8.8% underwent successful renal transplant and 22.8% died. Conclusion: Hypertensive kidney disease affects all age groups, males more than females. It is commonly associated with other cardiovascular conditions and carries a high morbidity. Vigilant control of blood pressure is recommended.

Pattern of congenital neck masses in a Kenyan paediatric population

BACKGROUND The distribution of congenital neck masses varies between countries and is important in diagnosis and treatment modalities. Data from Africa is scarce, and altogether absent from Kenya. OBJECTIVE To describe the pattern of congenital masses in a Kenyan paediatric population. SET UP: Kenyatta National Hospital, Nairobi Kenya. STUDY DESIGN Prospective descriptive cross-sectional. METHODOLOGY Children aged 15 years and below with neck masses who presented to various surgical clinics and wards at the Kenyatta National Hospital between December 2006 and April 2007 were included in the study. They were examined for age, gender, type and location of the neck mass. Mode of investigation and final diagnosis were recorded. Data was analyzed by using statistical package for social sciences. Descriptive statistics were applied to determine means, frequencies and modes. Ninety-five percent confidence interval was used and p value of 0.05 taken as significant. Data are presented in form of tables. RESULTS Two hundred and thirty-five children (129 male) with neck masses were examined. Fifty-one (22%) of these masses were congenital. Thyroglossal duct cysts were the most common (29%) followed by cystic hygromas (21%) and branchial cleft cysts (20%). Fifty-one percent of the masses were present at birth. The midline was the most common location (31.4%) followed by anterior border of sternocleidomastoid (27.5%) and submandibular region (19.6%). Ultrasound was the commonest diagnostic investigation. CONCLUSION Congenital defects constitute an important differential diagnosis for paediatric neck masses in Kenya. Thyroglossal duct cysts, cystic hygromas and branchial cleft cysts are the most prevalent occurring most commonly in the midline and anterior border of sternocleidomastoid muscle. An understanding of the distribution of these masses improves diagnosis, preoperative decision making and their overall management.

Ischemic Cortical Stroke in a Kenyan Referral Hospital

Background: The pattern of stroke displays ethnic and geographical variations. In Sub-Saharan Africa there is scarcity of data from Eastern and Central Africa. Objective: To describe the characteristics of patients with ischemic cortical stroke in a Kenyan referral hospital. Study design and set up: Retrospective study at Kenyatta National Hospital, Nairobi Kenya. Patients and methods: Records of adult black Kenyan patients seen with ischemic cortical stroke at Kenyatta National Hospital, Nairobi, Kenya between January 2007 and December 2011 were examined for age, sex, site, comorbidities and outcome. Only files with complete data were included. Data were analyzed by SPSS version 17.0 for Windows and presented in tables and bar charts. Results: Three hundred and seven cases of ischemic cortical stroke were analyzed. Mean age was 54.7 years, with 20.6% of cases occurring below 40 years. The male: female ratio was 1:1.2 with female predominance in all age groups. Brain regions most commonly affected were fronto-parietal (32.8%) and parietal (31.6%), while 11.6% involved extensive regions of the cerebral cortex. Predominant single comorbidities were hypertension (64.1%), smoking (19.2%), alcohol (13.4%), HIV infection (6.8%) and bacterial infections (6.8%). Multiple risk factors were implicated in 42.4% cases. Two hundred (65.1%) suffered paralysis; 70 (22.8%) clinically recovered and 37 (12.1%) died within 90 days. Conclusion: Ischemic cortical stroke occurs in young individuals in over 20% of the study population and is female predominant. Hypertension, cigarette smoking and infections including HIV are the leading comorbidities, and it causes high morbidity. Control measures comprising regulation of blood pressure, reduction of smoking and prudent management of infections should be instituted from early in life.

Vertebral Artery Hypoplasia in a Black Kenyan Population

This study examined the characteristics of vertebral artery hypoplasia in 346 arteries of adult black Kenyans. The circumference was measured on haematoxylin/eosin stained microscopic sections of the distal one-third of the intracranial vertebral arteries using scion image analyser. Internal diameter was calculated in millimetre. Data were analysed using SPSS version 16.0. Vertebral artery hypoplasia (diameter < 2.0 mm) occurred in 100 (28.9%) arteries. Sixty of these (17.3%) were on the left and 40 (11.6%) on the right. Sixty (17.3%) were in females while 40 (11.6%) were in males. The side and gender differences were statistically significant at confidence interval of 95%. Frequency of vertebral artery hypoplasia was higher than in most other populations studied. The condition differs from that in other populations because it is more common on the left side and in females. We recommend ultrasound, angio-CT, or angio-MRI evaluation of vertebral arterial system before diagnostic or interventional procedures on posterior circulation.

Pattern of origin of anterior inferior cerebellar artery in a black Kenyan Population

Background: Pattern of origin of anterior inferior artery is important in interpretation of posterior circulatory stroke and during posterior cranial fossa surgery for aneurysms, arteriovenous malformations, tumors, posterior cerebral revascularization, and in diagnostic as well as interventional neuroradiology. The pattern displays ethnic variation but data from African populations are scanty. This study therefore aimed to describe the pattern of origin of anterior cerebellar artery in a black Kenyan population. Materials and Methods: One hundred and seventy three [99 male: 74 female] basilar arteries from adult formalin fixed brains were studied at Department of Human Anatomy, University of Nairobi, Kenya. Site and pattern of origin of anterior inferior cerebellar arteries were recorded. Data were analyzed by SPSS version 17.0 for Windows, and presented in a table and macrographs. Results: Anterior inferior cerebellar artery arose directly from basilar artery in 138 (79.8%), as common trunk with labyrinthine artery in 24 (13.9%), from verterbral and labyrinthine arteries in 3% cases each. Conclusion: In about 14% cases, anterior inferior cerebellar and labyrinthine arteries arise as common trunks from basilar artery. These proportions differ with those in prevailing literature from Caucasian and oriental populations. Extra care should therefore be exercised during surgery and neuroradiology in the posterior cranial fossa, and in interpretation of signs of posterior circulation stroke. Pre-operative ultrasound evaluation of the vascular bed is recommended.

Stroke, cerebrovascular diseases and vascular cognitive impairment in Africa

With increased numbers of older people a higher burden of neurological disorders worldwide is predicted. Stroke and other cerebrovascular diseases do not necessarily present with different phenotypes in Africa but their incidence is rising in tandem with the demographic change in the population. Age remains the strongest irreversible risk factor for stroke and cognitive impairment. Modifiable factors relating to vascular disease risk, diet, lifestyle, physical activity and psychosocial status play a key role in shaping the current spate of stroke related diseases in Africa. Hypertension is the strongest modifiable risk factor for stroke but is also likely associated with co-inheritance of genetic traits among Africans. Somewhat different from high-income countries, strokes attributed to cerebral small vessel disease (SVD) are higher >30% among sub-Saharan Africans. Raised blood pressure may explain most of the incidence of SVD-related strokes but there are likely other contributing factors including dyslipidaemia and diabetes in some sectors of Africa. However, atherosclerotic and cardioembolic diseases combined also appear to be common subtypes as causes of strokes. Significant proportions of cerebrovascular diseases are ascribed to various forms of infectious disease including complications of human immunodeficiency virus. Cerebral SVD leads to several clinical manifestations including gait disturbance, autonomic dysfunction and depression. Pathological processes are characterized by arteriolosclerosis, lacunar infarcts, perivascular spaces, microinfarcts and diffuse white matter changes, which can now all be detected on neuroimaging. Except for isolated cases of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy or CADASIL, hereditary arteriopathies have so far not been reported in Africa. Prevalence estimates of vascular dementia (2-3%), delayed dementia after stroke (10-20%) and vascular cognitive impairment (30-40%) do not appear to be vastly different from those in other parts of the world. However, given the current demographic transition in both urban and rural settings these figures will likely rise. Wider application of neuroimaging modalities and implementation of stroke care in Africa will enable better estimates of SVD and other subtypes of stroke. Stroke survivors with SVD type pathology are likely to have low mortality and therefore portend increased incidence of dementia.