(BMJ 2008;337:a1397)
Approach
• Start O2 if pt hypoxemic or having pain
• Pain medication: Start early, check w/ hematologist for dose
• Abx: If infection is suspected, particularly w/ fever (many pts are functionally asplenic)
Definition
• Pathophysiology: Recessive β-globin mutation → structurally abnl HbS → deoxygenate form polymerizes → RBC sickles → hemolysis/microvascular occlusion
• Anemia: Chronic (hemolysis 2/2 sickling), acute (parvovirus B19, splenic sequestration)
• Microvascular occlusion: Pain crisis, acute chest syndrome, stroke, splenic sequestration, renal necrosis, aseptic necrosis, priapism
• Infection: Sepsis from encapsulated organisms (S. pneumoniae, N. meningitidis, H. influenzae) after splenic infarction & osteomyelitis (Salmonella, S. aureus)
History
• CP, SOB, bone pain (back, extremities)
Findings
• Bone tenderness, tachypnea, ±fever, r/o stroke, priapism
Evaluation
• CBC w/ differential (compare to baseline), chemistries, reticulocyte count (if concern for aplastic crisis or severe hemolysis), LFTs, bilirubin
• CP crisis: CXR (consolidation), ABG, ECG
• Consider other x-ray/MRI (osteomyelitis), CTA chest (PE); CTA/MRI (stroke) prn
Treatment
Acute
• ↓ sickling: O2, IVFs, analgesia w/ opiates (contact hematologist for doses)
• Treat infection w/ abx
• Transfusion for aplastic anemia, splenic sequestration, priapism
• Exchange transfusion: For acute stroke, severe acute chest syndrome
Chronic
• Hydroxyurea: ↑ HbF & ↓ pain crises, frequency & duration of hospitalizations, & risk of acute chest syndrome (NEJM 1995;1332:1317), ↓ mortality (NEJM 2003;1289:1645)
Disposition
• Home: If pain is well controlled
• Admit: Concern for sepsis, acute chest, or hemolytic crisis
Pearl
• Acute chest syndrome: Vaso-occlusion of pulmonary vasculature → pulmonary infarct, consolidation, PNA that resembles ARDS