CORRELATION BETWEEN HAEMATOLOGICAL PARAMETERS AND ABNORMALITIES OF TRANSCRANIAL DOPPLER (TCD) ULTRASONOGRAPHY IN SICKLE CELL ANAEMIA PATIENTS AT THE AMINU KANO TEACHING HOSPITAL, KANO

Abstract

BACKGROUND: Abnormal TCD velocities in major arteries of Circle of Willis
can identify children with sickle cell anaemia at high risk of developing stroke
which is preventable by prophylactic blood transfusions. Lower prevalence of
abnormal TCD velocities have been reported in Nigerian children with sickle cell
anaemia compared to African-Americans. This has not been validated in children
with SCA from Northern part of the country.
OBJECTIVE: The aim of this study was to determine the pattern of TCD
abnormalities among children with SCA in Kano, North-western Nigeria, and to
correlate the findings with haematological parameters and haemolytic indices.
METHODS: One hundred children with SCA (HbSS) between the ages of 2 and
16 years were recruited into the study at steady-state. Basic sociodemographic
data, medical and transfusion history were collected using structured,
interviewer-administered questionnaire. A full blood count, reticulocyte
production index, HbF levels and some selected biochemical markers of
haemolysis were determined. The Time-averaged mean of maximal velocities in
four major intracranial blood vessels of the Circle of Willis namely, the MCA,
ACA, PCA and the tICA were measured using non-imaging TCD
ultrasonography. Flow velocities were classified into high, conditional and
standard risks based on the STOP-Trial protocol.
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RESULTS: The mean Hb concentration was 8.23 ± 1.42 g/dL, mean
Haematocrit was 23.71 ± 4.43% and mean TWBC count was 13.80 ± 4.59 x
109/L. The mean ANC was 7.51 ± 3.24 x 109/L and mean platelet count was
375.37 ± 153.45 x 109/L. The average reticulocyte count and the HbF levels were
7.26 ± 3.79% and 7.09 ± 4.72% respectively. Mean serum LDH was 1445.60 ±
1070.80 U/L with 47% of patients having values above 75th percentile of the
LDH distribution. 3% of the studied patients had abnormal TCD velocities
classified as high risk, 11% had intermediate (conditional) risk while 84% had
standard risk. Two percent (2%) were categorised as inadequate. Most
abnormalities were detected in the MCA. The TAMMV was positively correlated
with TWBC count, ANC, PLT count, reticulocyte count, LDH and total bilirubin,
while it was negatively correlated with haematocrit and HbF levels. There was no
statistically significant correlation between the TAMMV and age or sex of the
patients.
CONCLUSION: This study confirmed a lower prevalence of abnormal TCD
velocities in Nigerian children and showed a possible unique phenotype of SCA.
Keywords: Transcranial Doppler, Sickle Cell Anaemia, Kano, Haematological,
Nigerian.