Sickle Cell Crises

Overview

Sickle cell crises are acute episodes of severe illness that occur in patients with sickle cell disease. These episodes are typically caused by vaso-occlusion, hemolysis or bone marrow suppression.

• Triggers
  • Infection (the most common trigger)
  • Extreme temperatures
  • High altitude
  • Hypoxia
  • Acidosis
  • Dehydration
  • Physical or emotional stress
  • Trauma or surgery
  • Pregnancy
  • Menstruation
  • Alcohol and smoking
• Main types of crises
  • Vaso-occlusive (pain) crises
  • Splenic sequestration crisis
  • Aplastic crisis
  • Hemolytic crisis
  • Acute chest syndrome
  • Stroke
  • Pulmonary embolism
  • Priapism
  • Multi-organ system failure

Vaso-occlusive crisis

A vaso-occlusive crisis is caused by acute occlusion at various points in the circulation of an organ. It is characterised by pain, which varies in intensity according to the level of ischemia or necrosis of the organ.

• Signs and Symptoms
  • Severe pain
    • Triggered by cold, dehydration, infection or hypoxia
    • Affects the hands and feet in young patients – dactylitis
    • An acute abdomen can be due to mesenteric ischemia
  • Seizures
  • Strokes
  • Cognitive defects
  • Myocardial infarction
• Treatment
  • Supplemental oxygen to maintain SpO2 >95%
  • Ample analgesia
    • IV Morphine – patient controlled analgesis if possible
  • Antiemetics if there is nausea
  • Antihistamines, if there is pruritus
  • Intravenous fluids
    • Give 50% more maintenance fluid
  • Transfusion for a very severe crisis
  • Empiric antibiotics if the temperature is > 38 C, unwell, or acute chest syndrome

Acute Chest Syndrome

Acute chest syndrome is a serious complication of sickle cell disease caused by vaso-occlusion of the pulmonary circulation. It is the most clinically significant vaso-occlusive crisis.

• Signs and Symptoms
  • Cough
    • Productive or non-productive
  • Wheeze
  • Fever
  • Dyspnea
  • Tachycardia
  • Chest pain
    • Acute chest pain
    • Worse with breathing
  • Respiratory distress with clinical signs of consolidation
  • Hypoxia (SpO2 <95% on room air)
  • Cyanosis
• Treatment
  • Ample analgesia
  • Supplemental oxygen to maintain SpO2 >95%
  • Empirical IV antibiotics (ceftriaxone + gentamicin) until sputum culture returns
  • Bronchodilators (salbutamol) if wheezing or obstructive PFTs
  • Gentle intravenous hydration
    • Enough to ensure the hydration status is OK
    • Avoid overhydration due to the risk of pulmonary oedema
  • Transfusion for severe acute chest syndrome
  • Incentive spirometry
  • Long-term hydroxyurea to prevent recurrence

Splenic sequestration crisis

A splenic sequestration crisis is an acute, painful enlargement of the spleen, which can lead to circulatory collapse.

• Signs and symptoms
  • Hepatosplenomegaly
  • Severe anemia
  • Hypotension
  • Tachycardia
  • Tachypnoea
• Treatment
  • Admit
  • Supplemental oxygen
  • Intravenous fluids
  • Urgent Transfusion
  • Ample pain medications
  • Antibiotics (third or fourth-generation cephalosporins)

Severe Anaemia or Aplastic Crisis

Aplastic crisis is an acute aplastic anaemia that is characterised by a haemoglobin concentration of < 5 g/dL or an acute drop of > 2g/dL from the steady state. It is triggered by infection with the Parvovirus B19 or malaria.

• Signs and symptoms
  • Feeling weak and tired
  • Breathlessness
  • Palpitations
  • Pallor
  • Fatigue
  • Hypotension
  • Tachycardia
• Treatment
  • Usually self-limited. Resolves in < 2 weeks.
  • Transfusion

Stroke in Sickle Cell Disease

Sickle cell disease can cause progressive stenosis of cerebral arteries, which increases blood flow velocity. Transcranial Doppler (TCD) can be used to quantify the velocity.

• Investigations
  • Non-contrast enhanced CT, MRI, or MRA: to confirm stroke. Screening > 16 years
  • Transcranial Doppler: detects blood flow velocity in the MCA, PCA, ACA, Basilar artery, vertebral artery, distal ICA and ophthalmic artery. Routine screening is done for children 2 – 16 years
    • Increased velocity in stroke (> 200 cm/s) in the MCA/ICA increased stroke risk
    • Low or absent flow signal in vessel occlusion (ischemic stroke)
    • Microembolic signals (silent infarcts)
    • Vasopasm (secondary complication)
• Treatment of stroke in SCD
  • Pharmacologic management of cerebral edema and seizures
  • Surgical repair of ruptured aneurysms
  • Emergency exchange transfusion to reduce HbS < 30% of total hemoglobin
    • This stops occlusion and sickling
  • Routine exchange transfusion reduces stroke incidence by > 90%

Priapism

Priapism is a persistent penile erection that is unrelated to sexual stimulation and lasts for more than 4 hours. It is usually triggered by sexual activity or a full bladder and can result in impotence.

• Signs and symptoms
  • Acute fulminant erection
    • Lasting more than 4 hours
    • Repeated (stuttering) painful erections lasting more than 30 minutes and up to 4 – 6 hours
• Treatment
  • Intravenous fluids
  • Analgesia and anxiolysis with diazepam
  • Catheterise and attempt micturition
  • Encourage walking and warm baths to avert early priapism
  • Exchange transfusion
  • Surgery

Multi-Organ System Failure (MOSF) in Sickle Cell Disease

MOSF should be suspected if there is typical vaso-occlusive pain that is followed by deterioration, within 3 – 4 days of admission

• Treatment of Acute Multi-Organ System Failure in SCD
  • ICU/HDU care
  • Pain management
  • Hydration
  • Oxygenation
  • Blood Cultures + empiric broad-spectrum antibiotics
  • Monitor electrolytes and fluids
  • Intubate if needed
  • Dialysis if needed
  • Aggressive transfusion (simple or exchange) if Hb is dropping rapidly – target Hb of > 10g/dL.