Sickle cell crisis

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(A) normal red blood cells flowing freely through a blood vessel. (B) abnormal, sickled red blood cells sticking at the branching point in a blood vessel. Cross-section shows long polymerized sickle haemoglobin (HbS) strands stretching and distorting the cell.

Precipitating Factors

Clinical Features

Vaso-Occlusive Crisis[1]

See Vaso-occlusive pain crisis

Bony infarction

  • More debilitating and refractory pain than past episodes
  • Localized bone tenderness, elevated WBC


  • Tender, swollen hands/feet
  • May have low-grade fever
  • Occurs in <2yr old, extremely rare >5yr old
  • Radiographs will show soft tissue swelling in the acute phase. Recurrent episodes can lead to a mottled appearance of hand and feet small bones on radiography. [2]

Avascular necrosis of femoral head


  • Due to occlusion of blood vessel lumens, which causes microfractures, leading to collapse of cancellous bone and the articular surface
  • Occurs in 30% of patients by age 30yr, prevalence increases with age
  • Patients present with afebrile, inguinal pain with weight-bearing but can be asymptomatic
    • Decreased ROM and pain with ambulation or passive ROM
  • Other common sites of involvement are the humeral head and the area above the knee

Respiratory distress and chest pain

Abdominal pain


  • Across all ages, infection is leading cause of death
  • Children aged 6mo to 3yr at greatest risk for sepsis
  • Parvovirus B19
    • Can cause several different syndromes:
      • Erythema infectiosum ("slapped cheeks" rash)
      • Gloves and socks syndrome
        • Well-demarcated, painful, erythema of hands and feet
          • Evolves into petechiae, purpura, vesicles, skin sloughing
      • Arthropathy - symmetric or asymmetric, knees and ankles
      • Aplastic crisis
        • Reticulocyte count drops 5d post-exposure, followed by hemoglobin drop
        • Can cause serious anemia which lasts for 2wk

Musculoskeletal infection

  • Patients with SCD have increased rates of bone and joint infection
    • Difficult to distinguish from bony infarcts
      • High fever is more typical of infection
      • Limited range of motion is much more typical of infection
      • Left shift is unique to infection
      • ESR is unreliable
      • May require bone scan or MRI to definitely distinguish infection from infarct

Splenic sequestration

  • Major cause of mortality in <5yr old
  • Labs: hemoglobin drop, no change in bili, normal to increased retic count

Neurologic disease

  • CVA is 250x more common in children with SCD
    • 10% of children suffer clinically overt stroke
    • 20% found to have silent CVA on imaging
  • Increased rate of cerebral aneurysm and ICH


  • Priapism
    • Occurs in 25% by age 20
  • Papillary necrosis

Differential Diagnosis

Sickle cell crisis


Algorithm for the Evaluation and Management of Sickle Cell Crises


Based on clinical presentation, but may include:

  • CBC (assess for significant anemia)
  • Reticulocyte count (<0.5% suggests aplastic crisis - rare in adults), calculating reticulocyte index
    • Laboratory value is a percentage, and absolute count corrects for level of anemia
    • Absolute retic count = % retics x (pt Hct / normal Hct)
    • Retic index = absolute retic count / maturation factor[4]
      • ≥35%, maturation factor 1.0
      • 25 to <35%, maturation factor 1.5
      • 20 to <25%, maturation factor 2.0
      • <20%, maturation factor 2.5
    • Reticulocyte index ≥2 means adequate response
    • Reticulocyte index <2 suggests hypoproliferation
  • Metabolic panel, lipase (if abdominal pain)
  • CXR (if cough, shortness of breath, or fever)
  • ECG
  • VBG
  • Urinalysis
  • Pregnancy test
  • CT brain (if symptoms of CVA)
    • Note that if patient is anemic, CT non-contrast is unreliable in ruling out hemorrhagic stroke, subarachnoid hemorrhage[5]
    • Will need CTA, MRI, and/or MRA


  • Generally a clinical diagnosis
  • Certain syndromes require imaging/labs for confirmation (see below)


  • Only use supplemental oxygen for patients who are hypoxic (<92%)
  • Reserve IVF bolus for patients who are hypovolemic
    • Over hydration may cause atelectasis which may precipitate Acute Chest Syndrome and hyperCl acidosis which could lead to further sickling \
    • Make sure to use hypotonic fluids: 1/2NS, D5-1/2NS


Vaso-occlusive pain crisis

  • Analgesia
  • Hydration
    • Controversial
      • Dehydration promotes sickling
      • IVF bolus may lead to atelectasis, pulmonary edema, and acute chest syndrome. Hyperchloremic metabolic acidosis due to normal saline may further precipitate sickling. [8] [9] [10]
      • There are no randomized controlled trials that have assessed the safety and efficacy of different routes, types or quantities of fluid.[11]
  • O2 if hypoxia; otherwise may inhibit erythropoiesis

Acute Chest Syndrome

  • O2; titrate to pulse oximetry >92%
  • Incentive Spirometer
  • Hydration: Oral hydration preferred, IV hydration with hypotonic fluid if patient unable to tolerate PO
  • Analgesia: pulmonary toilet is important but avoid excessive sedation
  • Bronchodilators
  • Antibiotics: 3rd generation cephalosporin + macrolide
  • Transfusion (leucocyte depleted); consider transfusion to goal of hemoglobin 11 / hematocrit 30 for:
    • O2 Sat <92% on room air
    • hematocrit 10-20% below patient's usual hematocrit or dropping hematocrit
  • Exchange transfusion; consider for:
    • Progression of acute chest syndrome despite simple transfusion
    • Severe hypoxemia
    • Multi-lobar disease
    • Previous history of severe acute chest syndrome or cardiopulmonary disease


Neurologic disease

Splenic sequestration


  • Any fever of ≥38.5C requires empiric antibiotics (regardless of well appearance or any localized infection found)
  • Ceftriaxone 50mg/kg (maximum single dose 2g)


Consider admission to the hospital

Consider discharge

  • Pain is under control and patient can take oral fluids and medications
  • Ensure appropriate oral analgesics are available
  • Provide home care instructions
  • Ensure resource for follow-up

See Also


  1. Lovett P. et al. Sickle cell disease in the emergency department. Emerg Med Clin North Am. 2014 Aug;32(3):629-47
  2. George, A., DeBaun, M., & DeBaun, M. (2021, April 28). Acute and chronic bone complications of sickle cell disease. Retrieved April 20, 2022, from
  3. George, A., DeBaun, M., & DeBaun, M. (2021, April 28). Acute and chronic bone complications of sickle cell disease. Retrieved April 20, 2022, from
  4. Poorana PP and Subhashree AR. Role of Absolute Reticulocyte Count in Evaluation of Pancytopenia-A Hospital Based Study. J Clin Diagn Res. 2014 Aug; 8(8): FC01–FC03.
  5. Lyon M et al. Approach to the diagnosis and treatment of acute subarachnoid hemorrhage in a patient with sickle cell disease. Am J Emerg Med. 2015 Mar;33(3):481.e3-4.
  6. *Lyness, D., & Motov, S. (2016, July 7). CERTA Opioid Alternatives and Analgesics. Retrieved July 25, 2016, from
  7. *Lyness, D., & Motov, S. (2016, July 7). CERTA Opioid Alternatives and Analgesics. Retrieved July 25, 2016, from
  8. Glassberg, J., Evidence-based management of sickle cell disease in the emergency department.Emerg Med Pract, 2011. 13(8): p. 1-20
  9. Carden, M.A., et al., Variations in pediatric emergency medicine physician practices for intravenous fluid management in children with sickle cell disease and vaso-occlusive pain: A single institution experience.Pediatr Blood Cancer, 2018. 65(1)
  10. Carden, M.A., et al., Normal Saline Bolus Use in Pediatric Emergency Departments is Associated with Worse Pain Control in Children with Sickle Cell Anemia and Vaso-occlusive Pain.Am J Hematol, 2019.
  11. Okomo U, Meremikwu MM. Fluid replacement therapy for acute episodes of pain in people with sickle cell disease. Cochrane Database of Systematic Reviews 2015, Issue 3. Art. No.: CD005406. DOI: 10.1002/14651858.CD005406.pub4