Sickle Cell Disease Overview
Sickle cell disease (SCD) is a genetic disorder affecting hemoglobin, the oxygen-carrying protein in red blood cells. Normal red blood cells are round and flexible, allowing them to flow easily through small blood vessels. In sickle cell disease, abnormal hemoglobin (hemoglobin S) causes red blood cells to become rigid and crescent-shaped ("sickled") under conditions of low oxygen, dehydration, cold, or stress. These sickled cells cannot pass through small blood vessels, causing blockages that lead to tissue ischemia and severe pain.
SCD primarily affects people of African, Mediterranean, Middle Eastern, and South Asian descent. In the United States, approximately 100,000 people have sickle cell disease. These patients frequently utilize EMS services during acute crises and represent a population that requires specific knowledge for optimal prehospital care.
Vaso-Occlusive Crisis (Pain Crisis)
The vaso-occlusive crisis (VOC) is the most common reason sickle cell patients seek emergency care. Sickled cells block small blood vessels, causing ischemia and intense pain. Common sites include the bones, chest, abdomen, and joints. The pain is often described as deep, throbbing, and excruciating, and it can mimic other emergencies (appendicitis, heart attack, pulmonary embolism). Triggers include dehydration, cold exposure, infection, stress, and high altitude.
Management of VOC in the field centers on aggressive pain control. These patients are often undertreated for pain due to provider bias. Sickle cell pain crises are genuinely severe, and patients who report high pain levels should be believed and treated accordingly. Administer analgesics per protocol (opioids are typically required), provide supplemental oxygen if the patient is hypoxic (routine oxygen for normoxic patients is no longer recommended), establish IV access, and administer warm fluids. Keep the patient warm and transport in a position of comfort.
Acute Chest Syndrome
Acute chest syndrome (ACS) is a life-threatening complication of SCD characterized by a new pulmonary infiltrate (on chest X-ray) with at least one of the following: chest pain, fever, or respiratory symptoms. It is caused by a combination of vaso-occlusion in the pulmonary vasculature, fat embolism from bone marrow infarction, and infection. Patients present with chest pain, cough, dyspnea, fever, and hypoxia. ACS can rapidly progress to respiratory failure and is a leading cause of death in sickle cell patients.
Other Sickle Cell Emergencies
Additional emergencies in sickle cell patients include splenic sequestration (sudden pooling of blood in the spleen causing acute anemia and hypovolemic shock, most common in children), aplastic crisis (temporary cessation of red blood cell production, often triggered by parvovirus B19 infection, causing severe anemia), and stroke (sickle cell patients have a significantly increased stroke risk, especially children ages 2 to 16). For any sickle cell patient with altered mental status, focal neurological deficits, or signs of stroke, treat as a stroke alert and transport immediately to a stroke center.