Painful microvascular vaso-occlusive crisis

Specialty: Hematology.

• Painful sickle cell crisis
• painful sickle cell crisis
• vasoocclusion due to sickle cell red blood cells

Why it occurs

• Sickle cell anemia / Sickle cell disease (polymerization of hemoglobin S under conditions of hypoxia, dehydration, acidosis or cold; rigid sickle erythrocytes adhere to the activated endothelium, forming cell aggregates that occlude capillary microcirculation of bones, joints and parenchymal organs, causing acute tissue ischemia and microvascular infarction)
• Beta-thalassemia and hemoglobin S overlap syndrome (sickling syndrome)
• SC hemoglobinopathy (compound heterozygous variant with high viscosity and propensity for vascular occlusive phenomena)
• Polycythemia vera with uncontrolled hematocrit (extreme blood viscosity that slows capillary flow causing diffuse tissue ischemia).

Initial workup

Complete blood count (monitor acute decrease in hemoglobin due to accelerated hemolysis, reactive leukocytosis that is associated with a worse prognosis and platelet count); absolute reticulocyte count (to assess marrow regenerative capacity and rule out concomitant aplastic crisis induced by Parvovirus B19); peripheral blood smear (evidence of abundant sickle cells, dianocytes, marked polychromasia, and circulating erythroblasts); immediate chest x-ray (provided there are respiratory symptoms or fever) and x-ray of the affected bone (to rule out bacterial osteomyelitis associated with Salmonella or S. aureus as a differential diagnosis); determination of lactate dehydrogenase (LDH), total and indirect bilirubin and serum creatinine.

Standard management

• Morphine / Fentanyl — potent opioid analgesics administered intravenously or by patient-controlled infusion - PCA; pillar of immediate symptomatic treatment in the hospital setting, and the dose must be adjusted individually and aggressively to relieve severe pain
• Hydroxycarbamide / Hydroxyurea — oral disease-modifying drug for chronic daily use; increases fetal hemoglobin - HbF which interferes with the polymerization of HbS, reducing the frequency and severity of vaso-occlusive crises
• Crizanlizumab — monoclonal antibody directed against P-selectin; blocks cell adhesion to the endothelium, reducing the frequency of painful vaso-occlusive crises
• L-glutamine — oral supplement that reduces oxidative stress in sickle erythrocytes
• Intravenous fluid therapy with hypotonic solutions (such as one-third glucosaline serum to rehydrate erythrocytes and reduce viscosity, avoiding overhydration that predisposes to acute chest syndrome).