Prevalence of transcranial Doppler abnormalities in Nigerian children with sickle cell disease

Transcranial Doppler (TCD) ultrasonography helps to identify children with sickle cell disease (SCD) who are at an increased risk of stroke,making primary stroke prevention a reality. A cross-sectional study of145 Nigerian children aged ≥3 years with SCD was carried out to describe the pattern of cerebral blood flow (CBF) abnormalities. The mean time-averaged mean velocity (TAMV) was 152 ±27.0 cm/sec and122 ±22.0 cm/sec in Hb SS and Hb S1C group, respectively. Abnormal velocities were recorded in six (4.7%) of the Hb SS patients and none of the Hb S1C while conditional risk (CR) velocities were recorded in 19.7% of Hb SS (low conditional 11.0%, high conditional 8.7%) and low conditional in 5.6% of Hb S1C cases. Cerebral flow velocities showed a negative correlation with age and hematocrit. Compared with African-American children, Nigerian children with Hb SS disease have a considerably higher prevalence of CR velocities.

Dyserythropoiesis in homozygous haemoglobin C disease

Electron microscope studies of the bone marrow of three patients with homozygous haemoglobin C (HbC) disease have shown marked ultrastructural abnormalities in several of the polychromatic erythroblasts and marrow reticulocytes and the presence of phagocytosed erythroblasts within the macrophages. Such abnormalities were not found in the bone marrow of three patients with sickle cell anaemia indicating that the abnormalities represented a feature of HbC disease rather than a disturbance secondary to peripheral haemolysis. The characteristic ultrastructural finding in the polychromatic erythroblasts in HbC disease was the presence of grossly-disorganized nuclei showing multiple intranuclear clefts, the loss of parts of the nuclear membrane, oozing of nuclear material into the cytoplasm and an alteration of the structure and stainability of the nuclear chromatin. It is proposed that both the dyserythropoiesis and ineffective erythropoiesis in HbC disease may have resulted from the formation in vivo of very small aggregates of HbC within erythropoietic cells.

Hemoglobin C disease in infancy and childhood

We reviewed the clinical course, physical findings, and hematologic values in 16 pediatric patients with hemoglobin C disease, all but one identified by a newborn hemoglobinopathy screening program. The patients had a few symptoms or physical findings. Height and weight percentiles were normal. Patients typically had a mild hemolytic anemia characterized by microcytosis and target cells.

The hemoglobinopathies and pregnancy in Lagos

Thirty-four patients with abnormal hemoglobin were studied through 42 pregnancies under one obstetrician. There were 30 patients with sickle cell anemia (HbSS), two with sickle cell hemoglobin C disease (HbSC) and two with homozygous hemoglobin C disease (HbCC). There were 39 live births (including one pair of twins), and four perinatal deaths. The patients with HbSC and HbCC had five uncomplicated pregnancies and deliveries. Of the 36 pregnancies in patients with HbSS one aborted at 12 weeks. Intra-uterine growth retardation (14.3%) and pregnancy-induced hypertension (14.3%) were the most serious pregnancy complications. No patient had more than one crisis. Only one out of the 10 patients transfused needed more than two units of blood throughout pregnancy. The mean gestation at delivery was 37.5 +/- 3.2 (S.D.) weeks. The mean birth weight was 2.7 +/- 0.6 (S.D.) kg. The perinatal mortality was 114.3 per thousand live births and there was one maternal death.

Fetal health assessment in pregnancies complicated by sickle hemoglobinopathies

The contraction stress test (CST) and nonstress test (NST) are used as fetal health assessments. Severe sickle hemoglobinopathies in the parturient have been shown to place the fetus significantly at risk. This study correlates these fetal health assessment tests with outcome data in 58 pregnancies occurring in women with sickle cell disease. There were 30 patients with homozygous sickle cell anemia (HbS-S), 19 with hemoglobin S-C disease (HbS-C), and nine with hemoglobin S-thalassemia (HbS-Thal). All received prophylactic partial exchange transfusions as part of their antepartal care. At 34 weeks' gestation, NSTs followed by CSTs were begun in each patient. A total of 255 tests were performed. Of these, 19 NSTs and 24 CSTs were unsatisfactory or questionably abnormal and were repeated. There were no nonreactive NSTs, and no patient demonstrated a positive CST. The neonatal outcome revealed one infant who was small for gestational age and two infants who were of low birth weight but appropriate for gestational age. All infants survived and were normal. These data suggest that the fetal reactivity and placental reserve among these parturients with severe sickle hemoglobinopathies were uncompromised, as these tests have been shown to be relatively sensitive assessments of fetal well-being in other maternal disorders.

Interpretation of lung function tests in the sickle-cell haemoglobinopathies

Prediction equations have been evolved for the assessment of vital capacity, total lung capacity, and the single breath carbon monoxide transfer factor in haemoglobin SS and haemoglobin SC disease. These relationships take account of the growth disorder and anaemia in the sickle-cell states. The results suggest that, in the clinically stable state, any effects of alveolar capillary sickling and haemoconcentration and any altered reactivity of haemoglobins S and C with the test gas are of no significance for clinical respiratory physiology. Sex differences in lung function appear independent of haemoglobin type.