Cerebral artery conditional blood velocity in sickle cell disease: a multicentre study and evidence for active treatment

OBJECTIVE

To obtain multicentre data on the prevalence of normal, high or conditional (intermediate) blood velocity in the cerebral arteries among children with sickle cell disease (SCD) in Nigeria.

DESIGN

A prospective observational study in five tertiary healthcare institutions. By transcranial Doppler (TCD) ultrasonography, cerebral artery peak systolic blood velocity (PSV) was determined in 193 children with SCD and time averaged mean of the maximum blood velocity (TAMMV) in a different cohort of 115 children. This design was to make the findings relevant to hospitals with TCD equipment that measure either PSV or TAMMV.

SETTING

Nigeria.

PARTICIPANTS

308 children (126 girls, 182 boys; age 2-16 years).

MAIN OUTCOME MEASURES

Percentage of children with SCD who have normal, high or intermediate (often termed conditional) PSV or TAMMV.

RESULTS

In the cohort of 193 children, PSV was normal in 150 (77.7%), high in 7 (3.6%) and conditional in 36 (18.7%). In the cohort of 115 children, TAMMV was normal in 96 (84%), high in 7 (6%) and conditional in 12 (10%). There were no significant differences in gender or age distribution between the PSV and TAMMV cohorts. Altogether, cerebral artery blood velocity was normal in 246/308 children (80%), high in 14 (4.5%) and conditional in 48 (15.5%).

CONCLUSION

Since conditional blood velocity in cerebral arteries can progress to high values and predispose to stroke, the proportion of children with SCD who are affected (15.5%) raises the question of whether regular monitoring and proactive intervention ought to be the standard of care.

Important clinical and laboratory correlates of glomerular filtration rate in sickle cell anemia

BACKGROUND

Renal impairment is routinely assessed using the estimated glomerular filtration rate (eGFR) and it may be helpful to obtain certain clinical or laboratory markers, which show relationship with glomerular filtration rate (GFR) in sickle cell disease (SCD).

AIM

To assess the relationship between important clinical and laboratory parameters in SCD, and the eGFR.

PATIENTS AND METHODS

Steady state clinical and laboratory data were obtained from 228 homozygous SCD patients seen over a 7-year period. The GFR was estimated using (isotope dilution mass spectrometry) traceable modification of diet in renal disease (MDRD) and Cockroft-Gault methods. The correlation coefficient and independent t-test were done to assess the level of significance between the eGFR_MDRD and the known indicators of disease severity.

RESULTS

The serum alkaline phosphatase (ALP) and serum direct bilirubin levels both showed significant inverse relationship with eGFR_MDRD P = 0.012 and P = 0.24, respectively. The patients' age, Hb, leukocyte count, platelet count, serum direct bilirubin and aspartate transaminase did not show a significant correlation. The eGFR_MDRD was more discriminatory revealing that 20.3% of the patients had suboptimal GFR. Proteinuria in steady state was observed in 20.3% of the patients.

CONCLUSION

High serum direct bilirubin and ALP are associated with a deteriorating eGFR_MDRD. Other clinical and laboratory indicators of disease severity in SCD do not show the relationship with the GFR. MDRD_GFR estimation seemed to be a more appropriate method of estimating GFR in SCD.

Is renal medullary carcinoma the seventh nephropathy in sickle cell disease? A multi-center Nigerian survey

INTRODUCTION

Previous studies had enlisted renal medullary carcinoma (RMC) as the seventh nephropathy in sickle cell disease (SCD). Clinical experience has contradicted this claim and this study is targeted at refuting or supporting this assumption.

OBJECTIVE

To estimate the prevalence of RMC and describe other renal complications in SCD.

MATERIALS AND METHODS

14 physicians (haematologists and urologists) in 11 tertiary institutions across the country were collated from patients' case notes and hospital SCD registers.

RESULTS

Of the 3,596 registered sickle patients, 2 (0.056%) had been diagnosed with RMC over a ten year period, thereby giving an estimated prevalence rate of 5.6 per 100,000. The most common renal complication reported by the attending physicians was chronic kidney disease (CKD). The frequency of routine renal screening for SCD patients varied widely between centres - most were done at diagnosis, annually or bi-annually.

CONCLUSION

The ten year prevalence of RMC in Nigerian SCD patients was determined to be 5.6 (estimated incidence of 0.56). RMC is not more common in SCD patients and therefore cannot be regarded as a "Seventh Sickle nephropathy". Most of the managing physicians reported that the commonest nephropathy observed in their SCD patients was chronic kidney disease.

Stroke prevalence amongst sickle cell disease patients in Nigeria: a multi-centre study

BACKGROUND

Stroke is a life-changing, debilitating complication of sickle cell disease (SCD). Previous studies had recorded high stroke prevalence amongst this group of patients. Nigeria has a large population of people affected by this condition and this study aims to assess the stroke prevalence in this large population.

METHODOLOGY

Stroke prevalence data from 14 physicians working in 11 tertiary health centres across the country was collated by doctors using the sickle cell registers and patient case notes. This data was then collated and used to obtain the overall stroke prevalence in adult and children.

RESULTS

The stroke prevalence in sickle cell disease patients in Nigeria was observed to be 12.4 per 1000 patients. Prevalence in the adult patients was 17.7 per 1000 patients and 7.4 per 1000 patients in children. Twenty three percent of the affected patients had more than stroke episode.

CONCLUSION

The stroke prevalence in Nigeria is lower than previously recorded rates and further studies will be required to investigate other factors which may play a role.

Priapism in homozygous sickle cell patients: important clinical and laboratory associations

OBJECTIVE

To evaluate the relationship between the occurrence of priapism and important steady-state clinical and laboratory parameters in homozygous sickle cell disease (SCD).

SUBJECTS AND METHODS

Steady-state clinical and laboratory data were obtained from the medical records of 126 male patients seen in the clinic over a 7-year period. Estimated prevalence rates, correlation coefficients and independent t tests were calculated to assess the relationship between priapism and several important clinical and laboratory indices. Patient data on age, haemoglobin concentrations, the frequency of crises per annum, leucocyte counts, platelet counts, serum bilirubin and aspartate transaminase were evaluated.

RESULTS

The prevalence of priapism was determined to be 21.4%, and 22.2% of those affected had erectile dysfunction. There was a significant positive correlation between priapism and older age (p = 0.049) and lower leucocyte counts (p = 0.008). There was no significant relationship with other clinical or laboratory indices.

CONCLUSION

About 1 in 4 of all homozygous older SCD patients had priapism, and an approximately similar ratio developed erectile dysfunction; they also had lower steady-state leucocyte counts. Other clinical and laboratory indicators of disease severity in SCD did not positively correlate with the occurrence of priapism, and this may imply an alternative pathogenetic mechanism.