Parvez Ahmed, Asad Mahmood, Shahid Aziz.
A case of Sickle Cell Hemoglobin D disease - Two years follow-up.
J Coll Physicians Surg Pak Jan ;11(6):399-1.

Sickle cell Hb D disease is a rare disorder presenting clinically as a mild to severe sickle cell anemia. A case of a two-and-a-half-years old female child is reported here who presented with severe sickle cell disease. Patient`s father carried sickle cell trait (AS) and mother an Hb D trait (AD). She was diagnosed by Hb electrophoresis, sickling and solubility tests as well as family studies. The patient has been followed-up for two years.

A two-and-a-half-years old female child presented in November, 1998, with syndrome characterized by painful swelling of hands and feet. She also gave one year history of frequent attacks of severe bone pain in legs, feet and hands. Four weeks earlier she had been admitted in a tertiary care hospital with acute respiratory tract infection, swelling and painful extremities. She was treated with antibiotics and blood transfusion as well as investigated for juvenile rheumatoid arthritis. Rheumatoid factor and anti DNA antibodies were found negative. Her parents are second degree relatives. One younger male sibling is asymptomatic. Physical examination revealed tenderness of the extremities and mild hepatosplenomegaly. Her complete blood counts showed moderate anemia (Hb 8.4 g/dl), high leucocyte count (14.0 x 109/l) and reticulocytosis of 20%. The ESR was 4 mm fall after 1 hour. Peripheral smear showed marked anisopoikilocytosis, hypochromia, microcytosis, few macrocytes, microspherocytes, irregularly contracted cells, few target cells, occasional nucleated red cell and numerous sickle cells.

Hb electrophoresis showed a single band in the region of Hb S. Hb F was 4%. The sickling and Hb solubility test for hemoglobin S were positive. The differential diagnosis at this stage was between Hb SS and Hb SD as both Hb S and Hb D have similar mobility at alkaline pH and both are present in our population. Since facility for separation of Hb S from Hb D like citrate-agar gel electrophoresis at acid pH was not present, family studies were carried out to reach at a diagnosis.

Cellulose-acetate electrophoresis of both the parents showed heterogenous bands of Hb A and a band in the region of Hb S/D. Sickling test was positive in the father while it was negative in mother. The patient had inherited Hb S from father and Hb D from mother. So a final diagnosis of sickle cell Hb D disease was made.

Since her diagnosis the patient had been having similar attacks of bone pain and repeated respiratory tract infection. She had six hospital admissions over the past two years due to infections (thrice), vaso-occlusive crises in the form of severe bone pain (twice) and hemolytic crises (once). Her Hb ranged from 7-10 g/dl; blood transfusions were required thrice during this period. Renal functions were normal. Spleen had regressed and was no longer palpable; liver was palpable 5 cm below right costal margin. The body growth was normal. The patient was put on prophylactic antibiotics.

The younger sibling with sickle cell trait was asymptomatic. Genetic counseling was advised for any future pregnancy.

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