A 17-year-old female student with known SCD (HbSS), on folic acid (FA) since early childhood and on hydroxyurea (HU) 500 mg/day for the past 5 years, was admitted to the medical ward with difficulty in breathing, persistent fever, chest pain, dry cough, and general body malaise for four days prior to admission. Her previous history included a stroke 5 years ago (from which she had made a good recovery) and avascular necrosis of the right hip joint. Prior to this admission, her last transfusion had been 5 years ago.
On physical examination, the patient was febrile (38 C), pale, mildly jaundiced, tachypnoeic, and dyspnoeic with no lower limb edema. Her respiratory rate was 50 breaths/min, pulse rate was 124 bpm, and blood pressure was 124/64 mmHg. Her oxygen saturation (SPO2) was 65% on room air and 100% on oxygen. On chest examination, there were reduced breath sounds in the right base. She had no palpable enlargement of the liver or spleen.
Hemoglobin was 84 g/L, leukocytosis of 19.8 x 109/L, with a predominance of neutrophils (12.4 x 109/L), and platelets of 535 x 109/L (Table 1). From previous records, her steady-state hemoglobin was about 70 g/L. Urine culture revealed no bacterial growth after 24 hours; renal function tests and serum electrolytes were within the normal range (Table 2). A chest X-ray showed right-sided consolidation, bilateral mid-zone changes, and cardiomegaly. A diagnosis of ACS was made, but pneumonia and septicemia could not be excluded. The patient was placed on oxygen supplementation and was started on IV cefoperazone/sulbactam 2 g bd, IV normal saline (NS) 3 L/24 hours, and oral ibuprofen; hydroxyurea and folic acid were continued. Pain was managed by syrup morphine 5 mg 4 hourly. Two units of packed red cells were cross-matched and transfused.
After 7 days, the difficulty in breathing worsened, and the patient was transferred to a High Dependency Unit (HDU). Pleurocentesis was performed, and a yellowish frothy fluid was aspirated and taken for culture, biochemistry, and cytology. Culture revealed no bacterial growth after 72 hours, and the biochemistry results were normal (glucose 0.5 mol/l and protein 35 g/L). Cytology showed presence of neutrophils, histiocytes, and lymphocytes. The results of these tests as well as serum adenosine deaminase (22.7 IU/L) and ESR (10 mm/hr) were regarded as not compatible with pulmonary tuberculosis. Viral serology for hepatitis B surface antigen, hepatitis C antibody, and ELISA for HIV I and II were all negative. Oral co-trimoxazole was added to her therapy as a cover for possible atypical pneumonia.
Despite improvement in the right basal consolidation on the repeat chest X-ray, the bilateral mid-zone changes were still present and there was no improvement in her clinical condition. On day 3 in the HDU, the patient's condition deteriorated: her RR was 72/min with PR of 124 b/min and SPO2 ranging between 60 and 66% on room air. The patient was prepared for manual RCE. Prior to exchange transfusion, the hemoglobin was 95 g/L (Table 1) and HbS quantified by HPLC was 66.4% (Figure 1), as a result of the recent blood transfusion.
RCE was performed in two steps 20 hours apart. In the first step, a total of 500 ml of the patient's blood was replaced by 250 ml of normal saline (NS) and 250 ml of packed red cells. The patient developed a febrile nonhemolytic transfusion reaction which was managed by IV paracetamol 1 g. After this initial step, the Hb was 98 g/L and HbS was 57.2% (Figure 1). 12 hours after the RCE, the patient was afebrile, and the SPO2 was 83-88% on room air. In the second step, 450 ml of the patient's blood was exchanged with 250 ml of NS and 200 ml of packed red cells. In total, 950 ml were replaced, corresponding to an estimated 30% of the total blood volume.
Twelve hours after the second RCE, the hemoglobin was 92 g/L and HbS was 48.9%. The patient was afebrile, with oxygen saturation of 97-100% on room air (Figure 1), RR of 28-30/min and pulse rate of 90 bpm. The patient was weaned off oxygen and 48 hours after exchange, the patient was moved back to the general ward, from where she was discharged three days later. A week later, she attended the outpatient hematology clinic, where she was found to be in good condition, with stable vital signs and a close to normal blood count. In her most recent follow-up (4 months after RCE), she is doing well and has no complaints. She is currently on folic acid 5 mg daily and hydroxyurea 500 mg daily.