Incidence

Accounts for 5% of all causes of anemia (1)

• Depends on the underlying etiology of anemia
• Patients can develop leg ulcers, folate deficiency, hemosiderosis, and gallstones
• Can precipitate angina and heart failure in patients with underlying cardiovascular disease

Overall incidence of death is rare

History

• Often suspected after an incidental laboratory finding
• Known family history if hereditary

Signs/Physical Exam

• Generalized pallor (1)
• Pale conjunctiva
• Tachycardia, tachypnea, and hypotension
• Splenomegaly, RUQ tenderness
• Leg ulcer
• Acute chest syndrome (sickle cell disease)

Labs/Studies

• CBC: Low hemoglobin levels; normal MCV. Increased erythrocyte levels may be associated with MCV elevation (1).
• Haptoglobin levels are decreased due to binding with free hemoglobin.
• Reticulocyte counts are increased and reflect the bone marrow's attempt to restore erythrocyte levels.
• LDH levels are elevated due to release into the circulation when erythrocytes are destroyed.
• Bilirubin: Indirect levels are often elevated due to an increased load that "backs up" before being conjugated by the liver.
• Peripheral smears may demonstrate the etiology of hereditary causes.
• WBC and platelet counts may provide information about underlying malignancy or hematologic disease.
• Type and screen for operative procedures where blood loss may occur.
• Type and cross for patients with transfusion dependent anemia or patients with difficult to cross blood due to rare antibodies (always consider in patients with a history of mulitple transfusions).
• CXR if there is concern for hemodynamic compromise or acute chest syndrome (2).

• Avoid oxidative stress (hemolytic crisis) from anxiety and pain by appropriately titrating benzodiazepines and fentanyl in patients with known G6PD deficiency (3).
• Exchange transfusions and appropriate hydration may be performed in sickle cell patients. There is no general consensus regarding preoperative hemoglobin levels, but some clinicians transfuse to maintain a hemoglobin level of 10 g/dL (2).
• for AIHA, controversy exists whether pretreatment with high-dose corticosteroids is beneficial; however, these patients may be on chronic immunosuppression. Consider administering a stress dose of steroids, if appropriate (1).

Patients should be informed about the possible need for blood transfusion.

• Based primarily on the surgical procedure and patient comorbidities.
• Avoid medication that may cause hemolysis under oxidative stress (3).
  • Acetaminophen
  • Antibiotics including penicillin, nitrofurans, isoniazid, and chloramphenicol
  • Sulfa derivatives such as furosemide
  • Antimalarial drugs
  • Miscellaneous including methylene blue, quinidine, vitamin K analogs, probenecid, and possibly nitroprusside.
• Regional and/or neuraxial anesthesia may be considered to optimize postoperative pain control and decrease stress. Significant sedation for these procedures may cause hypoxia and hypercarbia that can precipitate sickling in susceptible patients (2).

• Standard ASA monitors
• Additional invasive monitoring is primarily dictated by the type and length of the surgery as well as comorbid conditions. The necessity for frequent labwork should be considered.
• Foley catheters may be helpful as hemoglobinuria may be visually diagnosed.

• Depends on the surgical procedure
• Avoid hypoxia and hypotension that could provoke sickling or a hemolytic crisis in G6PD deficiency.

• G6PD deficiency. Avoid oxidative stressors such as hypoxia, hypovolemia, and hypothermia as well as select drugs. The use of benzodiazepines, fentanyl, propofol, and ketamine has not been shown to cause a hemolytic crisis (3).
• Sickle cell crises may be avoided with aggressive hydration, avoidance of hypoxia, hypothermia, and acidosis.
• Acute hemolytic transfusion reactions are manifest by hypotension, tachycardia, rash, hyperthermia, and hematuria (1).
  • Immediately stop the transfusion
  • Begin resuscitative measures in the form of hemodynamic support and aggressive hydration and diuresis (to combat acute renal failure, ARF)
  • Send additional donor and recipient blood to be retested in the laboratory.

Careful attention should be paid to adequate pain control and oxygenation to avoid stress that could trigger an acute hemolytic crisis.