Sickle Cell Disease: New Approaches and Guidelines

Developed as part of a collaboration of CCNC, the NC Division of Public Health, the comprehensive sickle cell centers at Carolinas Health Care, Duke University, East Carolina University, University of North Carolina at Chapel Hill, Mission, and Wake Forest University and primary care physicians across North Carolina. Adapted from the NIHLBI guidelines

Objectives

 Provide basic overview of Sickle Cell Disease  Understand recommendations for care based on 2014 NHLBI guidelines  Health Maintenance  Acute Problems  Introduce tools to facilitate adoption of recommendations  Foster specialist and primary care collaboration in care of patients with sickle cell disease

Sickle Cell Disease (SCD)

 SCD refers to a group of disorders characterized by a predominance of HbS   SCD affects 1 in 375 African American live births, as well as other populations Includes HbSS, HbSC, HbS/ b thalassemia ( b 0 b +) , HbS/Other  Sickle Cell Anemia (SCA)   Subset of genotypes with often more clinical severity and anemia Includes HbSS, HbS/ b 0 thalassemia

Brief Pathophysiology

     Mutation at sixth position of beta globin chain changes glu → val With deoxygenation, the HbS molecule polymerizes within the RBC leading to characteristic shape changes Sickled erythrocytes are rigid and obstruct small blood vessels leading to tissue ischemia Deformed sickle cells adhere to endothelium & macrophages  induces hemolytic process Inflammation and ongoing adhesion

Manifestations of Sickle Cell Disease

 Chronic anemia  Hemolysis   Jaundice Cholelithiasis (bilirubinate) anemia pulmonary HTN gall stones

Hemolysis

 Acute complications  Pain, priapism, stroke  Acute chest syndrome (ACS)   Splenic sequestration infection leg ulcers nephropathy AVN

Vaso-Occlusion

 Chronic organ damage  Spleen, brain  Kidneys, lung, bones, eyes asplenia ACS stroke pain

Recommendations and Tools

  Health Maintenance  Pediatric and Adult Problem-focused– Acute and Chronic  Fever  Respiratory Symptoms/Hypoxia  Anemia  Neurological  Pain  Tip Sheet - New Recommendations and Clinical Pearls

Health Maintenance

Routine Health Maintenance

 General co-morbidities to address and control  Asthma  Obstructive Sleep Apnea  Dental Caries  Screen for retinopathy/retinal infarct  By history (age 0-2 yrs)  By vision screen (3-10yrs)  By comprehensive eye exam (10 yrs+)  Screen for renal disease  Proteinuria starting age 10y

Routine Health Maintenance

 Screen for CNS problems (strokes, moyamoya)  Annual Trans-Cranial Doppler (2-16y) for HbSS/HbS b 0  By specialist  History of neurocognitive symptoms/decline (headaches, changes in school or work performance)  No longer routine Pulmonary Hypertension Screen (EKG, ECHO, CXR)  Anticipatory guidance to include risk of priapism

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Routine Health Maintenance

PenVK 125mg BID <3y; 250mg BID >3y  Until age 5 yrs for HbSS/S b 0 , if no splenectomy or invasive bacterial infection  Typically to age 3 yrs for other genotypes, but weak recommendation to consider no prophylaxis  13-valent pneumococcal vaccine (Prevnar) as per recommendations for general population  23-valent pneumococcal age 2 and 7 years  MenHibRix or Menveo at 2, 4, 6, and 12-15 months  MCV4/Menactra – 2 dose primer at age 2, booster at age 5, and then every 5 years

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Routine Health Maintenance Hydroxyurea (HU)

Original use – anti-cancer drug   Increases fetal hemoglobin in the blood  Prevents sickling of red cells  RBCs survive longer in the bloodstream Daily doses reduce:  Frequency of painful crises  Frequency of acute chest syndrome  Need for blood transfusions/severe anemia  Mortality

Effects of Hydroxyurea in SCA

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Expanded Recommendations for Hydroxyurea

ALL children > 9 months with SCA (HbSS, HbS b 0 thal)  Adults with SCA:  3+ painful crises in 12 months  Sickle cell pain or severe symptomatic chronic anemia that interferes with daily activities or quality of life  History of ACS  Consider in other populations (e.g. SCD and chronic kidney disease, HbSβ+thal/HbSC and recurrent painful crises)

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Initiation and Monitoring

Starting dose  Children - 20 mg/kg/day  Adults - 15 mg/kd/day (5-10 mg/kg/day if CKD)  Increase by 5 mg/kg/day q8w to maximal tolerated dose (max 30-35 mg/kg/day)  Monitor CBC, reticulocyte count every 4 weeks during initiation and every 3 months while on a stable dose  Maximum tolerated dose to keep  ANC >2,000/µL– 4,000/µL  Platelets >80,000  ARC >80,000

Initiation and Monitoring

 Initiation and titrating typically done by specialist  Monitoring could be done in collaboration with PCP, if more accessible for the patient  Similar to anti-convulsant levels and titrating

Reproductive Counseling

 Discuss importance of knowing partners’ hemoglobin genotype for genetic counseling  Hydroxyurea (HU) is a teratogen  Long Acting Reversible Contraceptive (LARC) is recommended while on HU  Progesterone-only contraception may be preferable  Current recommendation is to discontinue HU before pregnancy and while breastfeeding

Acute and Chronic Problems

 Fever  Respiratory Symptoms  Anemia  Neurological Symptoms  Pain

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Management of Fever in SCD

Prompt evaluation for any fever > 38.5

° C (101.3

° F)  Age < 1 year (any fever > 38 ° C (100.5

° F)  CBC, Blood Culture, retic, ± CXR ± Ucx  Immediate administration of IV/IM Ceftriaxone Recommend hospital admission for:          Age < 1 year Temp > 39.5

° C, 103.1

° F Allergy to Cephalosporins Surgical splenectomy/history of pneumococcal sepsis Unsure follow-up Toxic appearance, low BP Infiltrate on CXR WBC < 2000, > 30,000 x 10 9 /L Hb < 2 g/dl from baseline or < 6g/dl

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Respiratory Symptoms Biggest worry-Acute Chest Syndrome

Number One cause of death Any new infiltrate with clinical symptoms (e.g. fever, dyspnea, chest pain, hypoxia, increased WBC) CXR may be negative in first 24 hours Lower lobes most commonly involved; 1/3 bilateral May be caused by infection, sickling, fat embolism, atelectasis

Neurological Symptoms

 Acute focal neurological deficits  Risk of acute stroke  Immediate, emergency evaluation and treatment  Headaches  Risk of Moyamoya - Stenotic arteries in Circle of Willis/basal ganglia with network of collaterals (“puff of smoke”)  Referral to specialist

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Neurological Symptoms “Silent” Cerebral Infarcts

Cerebral ischemia on MRI without focal neurological symptoms 20-30% patients with HbSS Associated with neurocognitive deficits/decline Increased risk of overt stroke Progression shown to be decreased with chronic transfusion therapy Consider referrals for neuro/neuropsych/sickle cell specialist/learning eval/IEP Pegelow

Blood

, 2002; Kwiatkowski

BJH

2009; DeBaun

Blood

, 2012

Pain Acute Chronic

Acute Painful/ Vaso-occlusive ‘crisis’

 Most prominent manifestation  Variable frequency (none to daily)  May be precipitated by illnesses, stress, dehydration  Pain in the extremities, Headache, Chest, Abdomen  Abdominal pain may mimic surgical condition

Acute/Vaso-occlusive

 Assess for other complications (e.g. aplastic crisis, neuro event, priapism, sepsis, fever, ACSD, abdominal, ortho, etc)  Keep warm, hydrated  Assure following home pain plan  Home plan fails → emergency treatment

Chronic Pain

    Major Causes – Avascular necrosis of hips/shoulders, leg ulcers, chronic bony pain, priapism, neuropathic pain/hyperalgesia Assess effect on activity, functional status, quality of life, depression Involve pain management specialist, sickle cell provider, ortho as indicated Controlled, coordinated pain management    Best if one provider manages chronic pain medications Pain Agreement Check CSRS/Provider Portal for medication/prescriber history

Thank you

Acknowledgment for part of slide content: Jennifer Rothman, MD Director, Pediatric Comprehensive Sickle Cell Program, Duke University Medical Center