DIAGNOSIS, GUIDELINES FOR COMPREHENSIVE CARE, AND CARE PATHS AND PROTOCOLS FOR MANAGEMENT OF ACUTE AND CHRONIC COMPLICATIONS  the Sickle Cell Disease Care Consortium (Arizona, Colorado, Georgia, Missouri, New Mexico, Tennessee, Texas, and Utah)

Overview: Some severe manifestations of sickle cell disease warrant maintenance therapy with chronic blood transfusions. The goal is to suppress erythropoiesis sufficiently and to provide enough normal red blood cells to maintain the percentage of the patient's cells (i.e. hemoglobin S) at less than 30%. Experience has shown that this approach significantly reduces the risk of recurrent stroke. Such transfusions also reduce markedly the incidence of many other sickle-related complications such as vaso-occlusive pain and acute chest syndrome. In addition to preventing acute complications, chronic transfusions may prevent the progression of chronic organ damage and even reverse some pre-existing organ dysfunction. This has been shown most clearly in patients with Hb SS and functional asplenia, some of whom show improved splenic reticuloendothelial function after receiving chronic transfusions. Many children with sickle cell disease treated with chronic transfusions also experience an increased sense of wellbeing, with improved energy levels, exercise tolerance, growth velocity and sexual development. Thus, transfusions to chronically replace sickle cells with normal erythrocytes can be considered a specific therapy that markedly ameliorates the disease.

Indications:

• Stroke

• Transient ischemic attack

• Abnormal TCD

• Severe or recurrent acute chest syndrome

• Severe debilitating pain

• Following splenic sequestration (as alternative to observation or early surgical splenectomy)

• Recurrent priapism

• Chronic organ failure

• Intractable leg ulcers

• Severe chronic anemia with high output cardiac failure

• Selected pregnancies

Outpatient Transfusions:

• PRBC 10-15 ml/kg (minor-antigen-matched, sickle-negative, leukocyte-depleted) given over 3-4 hr with standard monitoring. Minor -antigen matching for Rh (C,D,E,) and Kell should be provided for all patients. More extensive matching should be provided if available, especially for patients with previous alloimmunization. Frequency of transfusions (usually q 3-4 weeks) is adjusted to maintain Hb S £ 30% (typically with nadir Hb >9-10 gm/dl). For patients receiving chronic transfusions for stroke who have had no recurrent neurologic events for 3 years, consider decreasing frequency of transfusions to maintain Hb S £ 50%. Record volume of RBC transfused. Serial erythrocytapheresis is an alternative approach to chronic simple transfusions that is associated with substantially less iron loading and should be seriously considered for patients with adequate venous access.

• Patients should be immunized to hepatitis A and B.

• Continue prophylactic penicillin if applicable.

Iron Chelation:

• Initiation of chelation with deferoxamine should be considered after ³ 1 year of chronic transfusions and/or when serum ferritin is increased to ³ 1500-2000 m g/L. Hepatic iron content >4 mg/gm dry wt liver tissue (as determined by liver biopsy) also has been used as an indication for beginning iron chelation. Initial dose is 40-50 mg/kg/d s.c. in at least 8-10 cc sterile water infused over 10-12 hr, 5-6 nights per week. Measurement of 24 hr urinary iron excretion in response to a single dose of deferoxamine can help document drug efficacy. Generally, the mean daily dose of deferoxamine (mg/kg) divided by the serum ferritin concentration (m g/L) should not exceed 0.025. Skin irritation can be reduced by diluting the deferoxamine in a larger volume (12cc H₂0/gm deferoxamine) and/or adding 5 mg hydrocortisone to infusate. Use of serial erythrocytapheresis for chronic transfusions may delay or limit the duration or avoid entirely the need for chelation.

• Counsel regarding avoidance of excess dietary iron.

• Consider vitamin C supplementation, 100-250 mg/d, only at start of each dose of deferoxamine.

Monitoring:

• Audiology evaluation if any symptoms present (e.g. tinnitus, difficulty hearing)

• Ophthalmology consultation for any new visual symptoms

• Prior to each transfusion:

• CBC, reticulocyte count, type and cross, antibody screen. Consider serum ferritin and Hb S quantitation

• Every 3-6 months

• Height, weight, history, physical exam

• Hb electrophoresis, ferritin, ALT

• Assess acceptance and compliance of patient and family with deferoxamine therapy.

Yearly Monitoring

• Liver function tests including ALT. Consider Hepatitis C, HIV, and HTLV I-II serology, calcium, phosphorus, alkaline phosphatase, thyroid profile, fasting glucose, and other endocrine studies as indicated.

• Audiology evaluation

• Ophthalmology examination

• Consider CXR, EKG, echocardiogram

• Consider 24 hr urinary iron excretion with 12 hr dose of subcutaneous deferoxamine (usually 40-50 mg/kg).

• Consider metaphyseal and spinal radiographs.

• Consider liver biopsy for histology and quantitative iron.

• Consider CNS evaluation including MRI, MRA, and/or neurocognitive testing for patients with stroke

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References

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Copyright © 1997 Sickle Cell Information Center
Last modified: November 01, 2002