++
Inherited anemias stem from abnormal hemoglobin structure or production or from abnormal RBC structure or metabolism. Anemia occurs when destruction of red blood cells exceeds production. Most patients with dyshemoglobinemia are aware of their status.
++
Most patients with sickle cell disease (SCD) (homozygous (HbSS)) or sickle trait (heterozygous (HbAS)) present with symptoms related to vasoocclusive crisis, or with pain, weakness, or infections. Physical examination findings commonly include pallor, venous stasis changes, jaundice, hepatosplenomegaly, cardiac flow murmurs, cardiomegaly, and high-output congestive heart failure (CHF).
++
Painful vasooclusive crisis in the musculoskeletal system or, in some cases, organ-specific symptoms are the most common presentation to the ED. Crisis occurs when sickled RBCs mechanically obstruct blood flow, causing ischemia, organ damage, and infarction. Crisis-causing stresses include fever or infection (especially encapsulated organisms Haemophilus influenzae or Pneumococcus), cold exposure or high altitude, dehydration or overexertion, medication noncompliance, or drug use.
++
Acute symptomatic anemia results from splenic sequestration, bone marrow failure (aplastic crisis), or hemolysis due to infection and presents with fatigue, weakness, dyspnea, chronic heart failure, or shock.
++
Life or limb-threatening events seen in SCD patients include acute chest syndrome (vasoocclusive pulmonary insult), stroke, renal infarct, mesenteric infarcts, sepsis, avascular necrosis, osteomyelitis, pneumonia, or priapism.
+++
Diagnosis and Differential
++
The degree of illness guides the evaluation of an acute crisis. Although workups should be individualized, the more common, vague complaints (pain, weakness, fever) must include a search for an underlying, treatable event. See Table 136-1.
++