Acute Chest Syndrome

Acute chest syndrome is a serious complication of sickle cell disease (SCD) where sickle cells get stuck in small blood vessels in your child’s lungs. This blockage creates a vaso-occlusive crisis — when oxygen-rich blood can’t reach body tissues.

The condition can get worse quickly and become fatal. It’s an emergency and the most common cause of death in people with sickle cell disease.

People with sickle cell disease have red blood cells with a crescent or sickle shape. These can’t pass through blood vessels easily. That means hemoglobin (a protein in red blood cells) can’t carry enough oxygen throughout your child’s body.

Acute chest syndrome is common in people with sickle cell disease, especially between ages 2 and 4. This syndrome can also happen again once you’ve had it. It happens more than once in 1 out of 2 people with SCD.

Symptoms of acute chest syndrome

Acute chest syndrome symptoms may vary. They happen because of inflammation and blood vessel blockages in the lungs. People often have symptoms like:

• Cough
• Fever of 100.4 degrees Fahrenheit (38 degrees Celsius)
• Shortness of breath (dyspnea)
• Low oxygen in your blood (hypoxemia)
• Fast, shallow breathing (tachypnea)
• Wheezing
• Chest pain (adults only)
• Acute pain (especially in an adult’s arms, legs and back) from blocked blood flow (vaso-occlusive crisis)
• Fluid buildup in an adult’s lungs and chest (pleural effusion)

Acute chest syndrome causes

Scientists aren’t entirely sure what causes acute chest syndrome. But they believe it’s related to an embolism or infection in your child’s lungs. With an embolism, a blood clot, fat or a piece of dead bone marrow tissue can get stuck in a blood vessel and block blood flow. It may lead to acute chest syndrome, especially in adults.

Infections like viral or bacterial pneumonia can cause acute chest syndrome. This is the most common cause of the syndrome in children.

Risk factors

People with both SCD and asthma are two to four times more likely to have an episode of acute chest syndrome than people with only SCD.

Other risk factors include:

• Age between 2 and 4 years
• Low oxygen levels (like after surgery or trauma)
• Low levels of fetal hemoglobin
• Smoking or secondhand smoke

How to lower your child’s risk

If your child has sickle cell disease, talk to your healthcare team about ways to reduce their risk of acute chest syndrome. They may suggest:

• Staying current with asthma treatments
• Getting vaccinations for flu, pneumonia and COVID-19
• Blowing into a bottle frequently to clear your child’s airways and reduce fluid buildup around their lungs
• Getting regular physical activity to strengthen their lungs
• Getting regular blood transfusions
• Taking hydroxyurea or L-glutamine to reduce pain and avoid hospitalization

Complications of this condition

Without immediate treatment, people who develop acute chest syndrome may have complications, like:

• Acute respiratory distress syndrome (ARDS), a life-threatening lung injury
• Altered mental status
• Kidney injury
• Interstitial lung disease
• Pulmonary hypertension
• Liver dysfunction
• Multi-organ failure
• Respiratory failure
• Severe pain

How doctors diagnose acute chest syndrome

Acute chest syndrome criteria include abnormal substances building up in your child’s lungs (lung infiltrates) and either chest pain, cough, wheezing, fever or low oxygen levels. A healthcare provider might grade their case as mild, moderate or severe.

A provider can make an acute chest syndrome diagnosis based on your child’s symptoms, exam, history and results from the following tests:

• Pulse oximetry to check your child’s oxygen level
• Arterial blood gases analysis to measure acidity (pH), oxygen and carbon dioxide in the blood
• Blood tests, including complete blood count (CBC), which evaluate red blood cells, white blood cells and platelets and look for infections
• Chest X-ray to look for infection or abnormal substances (infiltrates) in the lungs
• Bronchoscopy to check for certain kinds of infections
• CT angiogram to look for a pulmonary embolism
• Ultrasound of the legs to check blood flow

How is it treated?

Early treatment is essential to keep your child alive. Acute chest syndrome treatment may include medications and treatments, like:

• Medications for pain relief (ketorolac or opioids) or infections (antibiotics or antivirals)
• Blood transfusion, which replaces some of your child’s blood with donated blood or blood products
• IV fluids to prevent dehydration, which can worsen sickle cell disease and increase pain
• Incentive spirometer, a device that encourages your child to take deep breaths, which helps to keep parts of their lungs from collapsing
• Supplemental oxygen therapy

When should I see my healthcare provider?

Seek immediate medical attention at a hospital if your child has sickle cell disease and develops symptoms of acute chest syndrome. Tell the healthcare providers in the emergency room that your child has SCD. Ask for an X-ray right away to determine whether they have this syndrome so that providers can start treatment quickly. Diagnosing acute chest syndrome promptly can save your child’s life. It can also lessen the chance of another episode.

You may want to ask your provider:

1. How often should my child use the spirometer?
2. How often do they need blood transfusions to lower my risk of this syndrome?
3. Can you tell me what triggered acute chest syndrome?
4. When do they need a follow-up visit with you?

What can I expect if my child has acute chest syndrome?

Acute chest syndrome is usually more severe in adults than in children. A worse outcome may be more likely in adults with low platelet counts. But most people with this condition can recover if they get treatment quickly.

Even after successful treatment for acute chest syndrome, a person with SCD can have another episode in the future. Acute chest syndrome is one of the more common reasons for hospital stays in adults with sickle cell disease.

The death rate among adults with acute chest syndrome is about 4 out of 100. It’s about 1 in 100 for children.

Can this be prevented?

Healthcare providers can prevent acute chest syndrome from developing during an SCD-related hospital stay. If your child is getting treatment for SCD in the hospital, their healthcare team should monitor and test them regularly. They can make sure they’re getting the medicines they need for pain and asthma, along with the oxygen and fluids they need. They’ll also want your child to do their part by breathing into a spirometer every two hours.