Abdulhakim Al-Rawas

Thiamine responsive megaloblastic anemia: The puzzling phenotype

Thiamine responsive megaloblastic anemia (TRMA) is characterized by a triad of megaloblastic anemia, non‐type 1 diabetes mellitus and sensorineural deafness. Other clinical findings have been described in few cases. The SLC19A2 gene on chromosome 1q 23.3 is implicated in all cases with TRMA. Our aim is to discuss the clinical manifestations of all Omani children diagnosed with TRMA and determine genotype–phenotype relationship.

Safety of stem cell mobilization in donors with sickle cell trait

High WBC plays a major role in the pathogenesis of many of the complications seen in patients with sickle cell disease (SCD).1 Individuals with Sickle cell trait may develop SCD-related complications in conditions of severe stress.2 G-CSF increases the WBC and may contribute to some of the complications in individuals with sickle cell trait when used in stem cell mobilization. To the best of our knowledge, only one small study3 assessed the safety of the mobilization of stem cells in individuals with sickle cell trait. Herein, we aimed to compare mobilization adverse events between donors with and without sickle cell trait.

Vincristine-induced neuropathy in pediatric patients with acute lymphoblastic leukemia in Oman: Frequent autonomic and more severe cranial nerve involvement

Vincristine (VCR) induced peripheral neuropathy is a common complication in children with acute lymphoblastic leukemia (ALL).

Efficacy and Safety of Dapsone Versus Trimethoprim/Sulfamethoxazol for Pneumocystis Jiroveci Prophylaxis in Children With Acute Lymphoblastic Leukemia With a Background of Ethnic Neutropenia

Study Objective: To study dapsone in comparison with trimethoprim/sulfamethoxazole (TMP/SMX) for Pneumocystis jiroveci (PJP) prophylaxis in children with acute lymphoblastic leukemia (ALL). Design: A retrospective study with a prospective follow-up. Patients: Pediatric ALL patients diagnosed between May 2009 and May 2014, who are still receiving or have completed their maintenance chemotherapy. Patients who completed chemotherapy were prospectively followed up for neutropenia. Methods: TMP/SMX was used as the initial PJP prophylaxis. An alternative drug was indicated if the patient remained cytopenic for >3 weeks. Average absolute neutrophilic count (ANC), average % of oral mercaptopurine (6-MP), and methotrexate doses were calculated over a period of 6 months before and after shifting to dapsone. Results: Sixty-two ALL patients were eligible for analysis. Twenty-four patients (38.7%) received TMP/SMX for PJP prophylaxis, whereas 34 patients received Dapsone (54.8%). Only 3 patients received IV pentamidine (4.8%), whereas 1 patient (1.6%) received atovaquone. The incidence of prophylaxis failure was 1/1041 months on TMP/SMX and 1/528 months on dapsone. After shifting to dapsone, patients maintained significantly higher ANC (1.46±0.46 vs. 1.17±0.40, P=0.0053), and received significantly higher doses of 6-MP (62.61%±11.45 vs. 57.45±10.14, P=0.0081) and methotrexate (64.9%±14.29 vs. 56.5%±9.9, P=0.0176), with a significantly shorter duration of chemotherapy interruption (1.94±1.2 vs. 3.25±1.29 wk, P=0.0002). Conclusions: Dapsone for PJP prophylaxis in ALL allowed patients to maintain higher ANC and to receive higher doses of chemotherapy, while maintaining a low incidence of PJP breakthrough infection.

Stem Cell Transplantation in Patients with Sickle Cell Disease

Hematopoietic stem cell transplantation (HSCT) is currently the only established cure for sickle cell disease (SCD). Replacement of the stem cell that has the defective beta globin allele with the normal gene decreases hemoglobin S and the risk of complications of SCD. The first case reported was a girl with acute myeloid leukemia and SCD who received HSCT and achieved long-term SCD and leukemia-free survival. Given the favorable outcomes of HSCT with thalassemia major using myeloablative preparative regimens, this approach became widely used in the initial studies of HSCT in SCD. The current standard of care is to use a myeloablative stem cell transplantation in patients with severe disease who have human leukocyte antigen–identical sibling. HSCT improves organ function, quality of life, and overall and disease-free survival. However, this is associated with high risk of gonadal dysfunction and graft versus host disease in addition to the mortality associated with the myeloablative HSCT. Reduced-intensity HSCT has also been reported with high rates of engraftment and favorable outcomes. This has been introduced to lower the gonadal dysfunction, mortality, and graft versus host disease associated with myeloablative approaches. Other approaches include HSCT using matched unrelated donors, cord blood units, and human leukocyte antigen haploidentical donors. Unfortunately, graft rejection is a common complication with these approaches. In this chapter, we review the indications of HSCT for SCD and outcomes of different transplant strategies including alternative donor transplant, graft rejection, and infertility after transplantation.

Hypertrophic Obstructive Cardiomyopathy in An Infant with Hemophagocytic Lymphohistiocytosis; Answer to a Riddle

Familial hemophagocytic lymphohistiocytosis (FHLH) is a hereditary hyperinflammatory condition with T-cell and macrophage activation. Treatment consists of immunosuppressive therapy plus bone marrow transplantation. Cardiac manifestations of FHLH were scarcely mentioned in the literature with conflicting pathophysiological explanations. We report a case of hypertrophic obstructive cardiomyopathy associated with FHLH. Guided by such a case, a clear vision regarding the real cause is thought to be obtained in the cloudy landscape of pathophysiology.

Single Dose Darbepoetin Alfa is Useful in Reducing Red Cell Transfusions in Leukemic Children Receiving Chemotherapy

The role of erythropoiesis-stimulating agents (ESAs) in the management of chemotherapy-induced anemia (CIA) is becoming increasingly recognized in the field of medical oncology, with paucity of data in pediatrics. We evaluated the efficacy and tolerability of a single-dose darbepoetin alfa, a long-acting ESA, given to 35 pediatric acute lymphoblastic leukemia (ALL) children during induction chemotherapy. Compared to a retrospective control group, the studied patients have required significantly less units of packed red blood cells (0.88 units/patient in the studied group versus 2.04 units in controls), with no major side effects. We recommend further prospective double-blinded studies with more tailored dosing regimens in pediatric ALL cases and solid tumors.