summary Sickle cell disease is a common genetic disorder of abnormal hemoglobin synthesis that causes affected blood cells to become "sickle shaped" with an inability to pass through blood vessels efficiently. Patients present with severe bone pain, acute hand swelling, and osteonecrosis. Diagnosis is made with hemoglobin electrophoresis. Treatment is medical management with hydroxyurea for sickle cell crises and monitoring for developing of osteonecrosis and osteomyelitis. Epidemiology Incidence approximately 2 million Americans carry the sickle cell gene 1 in 12 African Americans Etiology Two forms sickle cell anemia sickle cell anemia involves the presence of two abnormal hemoglobin S alleles more severe form sickle cell trait sickle cell trait involves a single copy of the abnormal hemoglobin gene usually asymptomatic increased risk of sudden-death with exertion due to collapse responds early to oxygen, rest, hydration more common Pathophysiology under low oxygen conditions the affected blood cells become "sickle shaped" and are unable to pass through vessels efficiently Orthopaedic manifestations sickle cell crisis (see below) osteomyelitis septic arthritis osteonecrosis of femoral and humeral heads bone infarcts growth retardation / skeletal immaturity dactylitis (acute hand / foot swelling) Imaging General Radiographs recommended AP and lateral standard of involved area findings bone infarcts common biconcave "fishtale" vertebrae MRI recommended for differentiating bone infarction from osteomyelitis obtain gadolinium enhanced T1 sequences which will identify infection Bone Scan helps differentiate infarct from infection Studies General Labs serum CBC, ESR, CRP may be elevated in both osteomyelitis and sickle cell crisis joint aspiration and culture may be necessary to determine if diagnosis is osteomyelitis or sickle cell crisis Sickle Cell Crisis Presentation severe bone pain usually begins near age 2-3 years caused by substance P may lead to bone infarcts Treatment nonoperative hydroxyurea provides pain relief during bone crisis Osteomyelitis Introduction often in diaphysis organism increased incidence of salmonella (may spread from gallbladder infection) staph aureus and salmonella are the most common organisms causing osteomyelits in children with sickle cell disease, although unclear which is more common salmonella osteomyelitis occurs most commonly in children with sickle cell disease Imaging radionuclide bone scan and radionuclide bone marrow scan can differentiate bone infarct from osteomyelitis osteomyelitis: normal marrow uptake, abnormal bone scan infarct: decreased marrow uptake, abnormal bone scan Evaluation aspirate and culture to differentiate from a bone infarct Septic arthritis Sickle cell patients are susceptible to infection due to hyposplenia sluggish circulation decreased opsonization of bacteria Presentation bone pain fever Labs elevated CRP and ESR Studies aspirate joint and culture to identify organism Treatment irrigation & debridement consider preoperative oxygenation and exchange transfusion prior to surgery Avascular Necrosis of Femoral Head Osteonecrosis of the femoral head can be bilateral in sickle cell disease Presentation hip pain with weight bearing Treatment Nonoperative partial weight bearing and range of motion indications initial treatment Operative total hip arthroplasty indications failed non operative intractable pain outcomes results of total joint arthroplasty are poor due to ongoing remodeling of bone
QUESTIONS 1 of 7 1 2 3 4 5 6 7 Previous Next (OBQ13.23) You are the team physician for a collegiate football team and receive weekly injury reports from the athletic trainer. All players with sickle-cell trait are listed at the bottom to remind all on-field personnel that they may need which of the following? QID: 4658 Type & Select Correct Answer 1 Oxygen supplementation and oral or IV hydration 93% (5125/5486) 2 Additonal layers of warm clothes 1% (71/5486) 3 Increased pain medication 1% (37/5486) 4 Avoidance of non-steroidal anti-inflammatory medicines 3% (144/5486) 5 Days of rest due to increased joint pain 2% (91/5486) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ12.39) A 28-year-old African-American male with a history of Sickle Cell Disease complains of progressive left hip pain for the past two years. He denies any causative injuries. His images are shown in Figures A and B. Which of the following mechanisms is most likely responsible for his symptoms? QID: 4399 FIGURES: A B Type & Select Correct Answer 1 Blood disorder due to abnormal hemoglobin S alleles 92% (4597/5009) 2 Progressive slippage of physis though the hypertrophic zone 1% (38/5009) 3 Osteomyelitis most likely due to Salmonella species 5% (246/5009) 4 Accumulation of glycosaminoglycan breakdown products 1% (73/5009) 5 COL5A1 or COL5A2 mutation 1% (27/5009) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ11.77) A 3-year-old African-American child presents with irritability, fever, and a warm, swollen leg. Imaging shows an area concerning for osteomyelitis and trans-cortical biopsy reveals multiple Salmonella species. This child most likely also has which of the following conditions? QID: 3500 Type & Select Correct Answer 1 Osteogenesis imperfecta 0% (8/2931) 2 Child abuse 0% (6/2931) 3 Thalassemia 1% (20/2931) 4 Sickle cell anemia 98% (2887/2931) 5 Renal failure 0% (2/2931) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ09.94) Hematogenous osteomyelitis caused by Salmonella is most common in which of the following patient populations? QID: 2907 Type & Select Correct Answer 1 Neonates 2% (13/845) 2 Intravenous drug abusers 1% (8/845) 3 Patients with sickle cell disease 95% (806/845) 4 Patients with chronic kidney failure requiring dialysis 1% (6/845) 5 Patients with puncture wounds through athletic shoes 1% (7/845) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ06.42) A 12-year-old boy with sickle cell anemia complains of 24 hours of pain in the right thigh. He denies any traumatic injury. The right leg has tenderness with palpation of the mid-thigh. The patient's temperature is 100.2 degrees F, and ESR is 45. Radiographs of the femur are unremarkable. A radionuclide bone scan demonstrates abnormal uptake in the mid-femur. A radionuclide bone marrow scan demonstrates decreased uptake within the marrow. Which of the following is the best step in management? QID: 153 Type & Select Correct Answer 1 Symptomatic care for his pain with NWB crutches, intravenous hydration, and consultation with hematology 66% (577/879) 2 Steroid injection of the quadriceps 0% (2/879) 3 Two weeks of an oral cephalosporin and follow-up radiographs 1% (13/879) 4 Bone biopsy for culture and intravenous antibiotics 21% (183/879) 5 Surgical debridement, culture, and intravenous antibiotics 11% (101/879) L 3 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
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