Sickle Cell Crisis

What happens in a sickle cell crisis

People with sickle cell disease inherit an abnormal hemoglobin, hemoglobin S. When oxygen levels fall, hemoglobin S molecules stick together and distort red cells into a rigid crescent or sickle shape. Sickled cells are sticky, inflexible and short-lived. They jam in small blood vessels, together with white cells and platelets, and inflame the vessel lining.

The result is two kinds of trouble:

• Blocked blood flow (vaso-occlusion): tissue downstream is starved of oxygen, causing severe pain and damage to bone, lungs, spleen, kidneys and brain.
• Red cell breakdown (hemolysis): sickled cells survive about 10 to 20 days instead of 120, causing chronic anemia and jaundice.

A "crisis" is a sudden worsening of either problem. See sickle cell disease for the underlying condition, inheritance and long-term care.

Types of sickle cell crisis

Dactylitis in babies

Often the first sign of sickle cell disease, at 6 months to 2 years old, is painful swelling of the hands and feet (hand-foot syndrome). The baby is irritable, refuses to use the hands or walk, and may have a fever.

Symptoms of a pain crisis

• Sudden, deep, throbbing or stabbing pain, most often in the lower back, legs, arms, chest or abdomen
• Pain that may move or affect several areas at once
• Swelling, warmth or tenderness over affected bones or joints
• Low-grade fever without infection
• Tiredness, poor appetite and difficulty sleeping

Pain varies from mild to among the most severe pain doctors see. People usually recognize their own typical crisis pattern.

Common triggers

Many crises have no obvious cause. Known triggers include:

• infections, including colds, flu and urinary infections
• dehydration, from heat, exercise, vomiting or not drinking enough
• cold exposure, swimming in cold water, wind chill and sudden temperature changes
• low oxygen at high altitude or on unpressurized flights
• physical exertion, emotional stress and poor sleep
• alcohol, smoking and some drugs
• menstruation and pregnancy

How a crisis is assessed in hospital

The team checks oxygen levels, temperature, breathing and spleen size, and asks about the usual pattern and home medicines. Tests usually include a full blood count, reticulocyte count (to detect aplastic crisis), kidney and liver tests, blood cultures if there is fever, and a chest X-ray for chest symptoms. A brain scan is done urgently for stroke symptoms.

Treatment of a sickle cell crisis

At home, for mild crises

• Follow the individual pain plan agreed with your hematology team.
• Take acetaminophen (paracetamol) or ibuprofen as directed. Use NSAIDs only if your team has cleared them for you, because they can strain the kidneys.
• Drink plenty of fluids.
• Use warmth: warm baths, heat pads and warm clothing. Do not use ice, which worsens sickling.
• Rest, and use distraction, relaxation and gentle massage.

In hospital

• Fast pain relief: guidelines recommend that strong pain relief, usually an opioid, be given within about 60 minutes of arrival, with regular reassessment and patient-controlled analgesia when needed.
• Fluids by mouth or IV, avoiding overload.
• Oxygen if levels are low.
• Incentive spirometry: breathing exercises with a simple device to reduce the risk of acute chest syndrome.
• Antibiotics for fever or suspected infection, because people with sickle cell disease have a weak spleen and are vulnerable to serious bacterial infections.
• Blood transfusion or exchange transfusion for acute chest syndrome, stroke, splenic sequestration or aplastic crisis.

Preventing future crises

• Hydroxyurea: a daily medicine that raises fetal hemoglobin, which does not sickle. It reduces pain crises and acute chest syndrome and is recommended for most children from 9 months and many adults.
• L-glutamine and other newer medicines may reduce crises for some people.
• Regular transfusions after a stroke or for high stroke risk found on transcranial Doppler screening in children.
• Stem cell transplant and gene therapy: potentially curative options for selected patients, offered at specialist centers.
• Penicillin in early childhood, routine vaccines, staying warm and well hydrated, and avoiding known triggers.

Complications of repeated crises

Recurrent crises can damage bones (including avascular necrosis of the hip and shoulder), lungs, kidneys, eyes and brain. Chronic pain can develop between crises. Each episode of acute chest syndrome increases the risk of long-term lung disease.

Frequently asked questions

What triggers a sickle cell crisis?

Common triggers are infection, dehydration, cold or sudden temperature changes, strenuous exercise, high altitude, stress and alcohol. Many crises happen without a clear trigger. Drinking plenty of fluids, staying warm and treating infections early reduce the risk.

How long does a sickle cell crisis last?

Most pain crises last from a few days to about a week, with the worst pain in the first 2 to 3 days. Some people have pain for longer. Crises involving the lungs, brain or spleen are emergencies and are treated in hospital.

What does a sickle cell crisis feel like?

People describe deep, throbbing, stabbing or crushing pain, most often in the back, legs, arms, chest or belly. It can move between areas and can be very severe. Children may cry, refuse to walk or use a limb, or have swollen hands and feet.

Can people with sickle cell trait have a crisis?

People with sickle cell trait carry one gene and usually have no crises. Under extreme conditions, such as intense exercise in heat with dehydration or very high altitude, rare serious problems can occur. Normal hydration and gradual training reduce that risk.

When should I go to the ER for a sickle cell crisis?

Go if pain is not controlled by your home plan, or if you have a fever of 38.5 °C (101.3 °F) or higher, chest pain, trouble breathing, stroke symptoms, a prolonged erection, sudden paleness, or a swollen belly in a child. Tell staff you have sickle cell disease.