Acute Chest Syndrome

What is acute chest syndrome? Acute chest syndrome is a complication of sickle cell disease (SCD). It involves chest pain, cough, fever, low oxygen levels and abnormal substances accumulating in the lungs (lung infiltrates). The condition can progress quickly and is the most common cause of hospitalization and death in people with sickle cell disease. Sickle cell disease is a genetic disorder that affects hemoglobin, a protein in red blood cells. If you have SCD, your red blood cells are shaped like crescents or sickles, rather than round as they should be. Sickle-shaped cells can’t pass through your blood vessels easily, so hemoglobin can’t carry enough oxygen throughout your body.

How common is acute chest syndrome? Acute chest syndrome is common in sickle cell disease. Half of people with SCD will have acute chest syndrome at least once. It’s more common in children with SCD ages 2 to 4 years, but the complication is usually more severe in adults than in children. People with both SCD and asthma are more likely to have an episode of acute chest syndrome than people with only SCD.

What causes acute chest syndrome? Scientists aren’t entirely sure what leads to acute chest syndrome. But they believe it’s related to one or more of the following factors: Bone marrow necrosis: Bone marrow is the spongy tissue inside most bones. If bone marrow dies (necrosis), particles can travel into your blood and circulate. Particles that reach your lungs may contribute to acute chest syndrome. Fat embolism: Bone marrow necrosis can also cause a fat embolism. This is a piece of fat that gets stuck in a blood vessel and blocks blood flow. It may lead to acute chest syndrome. Infection: Infections such as viral or bacterial pneumonia can cause acute chest syndrome. In children, infection is the most common cause of acute chest syndrome. In adults, the complication is often caused by fat embolism.

What are the symptoms of acute chest syndrome?

Signs of acute chest syndrome may vary, especially between children and adults.

Children with acute chest syndrome often display signs of infection:

- Cough.

- Fever.

- Low concentration of oxygen in the blood (hypoxemia).

- Abnormally rapid breathing (tachypnea).

- Wheezing.

Adults may have similar symptoms, plus:

- Chest pain, especially during breathing.

- Acute pain (especially in your arms, legs and back) from blocked blood flow (vaso-occlusive crisis).

- Fluid buildup in your lungs and chest (pleural effusion).

- Trouble breathing (dyspnea).

How is acute chest syndrome diagnosed?

Diagnosing acute chest syndrome quickly can save a person’s life. If you have SCD and are in the hospital, you should be monitored and tested regularly.

Tests that can help healthcare providers diagnose the complication include:

- Arterial blood gases analysis to measure acidity (pH), oxygen and carbon dioxide in your blood.

- Blood tests, including complete blood count, which evaluate red blood cells, white blood cells and platelets.

- Chest X-ray to look for infection or abnormal substances (infiltrates) in your lungs.

- Cultures, which can test the blood, spit or other body fluids for various infections.

- Based on the test results and your symptoms, your healthcare provider might grade acute chest syndrome as mild, moderate or severe.

How is acute chest syndrome treated?

Early treatment is essential to prevent serious complications of acute chest syndrome. Treatments may include:

- Blood transfusion, which replaces some of your blood with donated blood or blood products.

- IV fluids to prevent dehydration, which can worsen sickle cell disease and increase pain.

- Medications for pain relief, such as ketorolac or opioids.

- Incentive spirometer, a device that encourages you to take deep breaths, helps to keep your lungs clear.

- Supplemental oxygen therapy.

 - Antibiotics for bacterial infection.

- Antivirals for viral infection.

        How can I reduce my risk of acute chest syndrome?

        If you have sickle cell disease, talk to your healthcare team about possible options to prevent acute chest syndrome. They may suggest:

·     - Blowing into a bottle frequently to clear your airways and reduce fluid buildup  around your lungs.

·     - Exercising regularly to strengthen your lungs.

·     - Getting regular blood transfusions.

·     -Taking hydroxyurea or L-glutamine to reduce pain and avoid hospitalization.

        What’s the outlook for someone with acute chest syndrome?

People who develop acute chest syndrome need immediate treatment to prevent complications such as:

·     - Acute respiratory distress syndrome (ARDS), a life-threatening lung injury.

·     - Altered mental status.

·     - Kidney injury.

·     - Liver dysfunction.

·     - Multi-organ failure.

·     - Respiratory failure.

·     - Severe pain.

·     - Death.

The death rate among adults with acute chest syndrome is approximately 4%. It’s about 1% for children.

Can acute chest syndrome come back?

Even after successful treatment for acute chest syndrome, a person with SCD can have another episode in the future.