Acute Chest Syndrome With Sickle Cell: What Makes It an Emergency

Medically reviewed by Fatima Sharif, MBBS, FCPS

Written by Rashida Ruwa

Posted on October 6, 2026

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Key Takeaways

Acute chest syndrome (ACS) is a serious complication of sickle cell disease that can be life-threatening, and it is actually the most common cause of death in people with the condition.
ACS can look like a cold or pneumonia at first, with symptoms like fever, chest pain, coughing, and trouble breathing, but it can get worse quickly over just a few hours or days. If you or your child has a fever of 101.3 F or higher or trouble breathing, it is important to go to the emergency room right away rather than waiting to see if things improve on their own.
Working closely with your sickle cell care team is a great way to help lower your risk of ACS, which may include staying up to date on vaccinations, managing asthma, avoiding cigarette smoke, and talking with your care team before any planned surgery so they can help you take the right precautions.

View all takeaways

Chest pain, trouble breathing, or fever can be worrying when you have sickle cell disease (SCD) or care for a child with the condition. You may wonder if it’s an infection that will pass, a pain crisis, or a serious complication like acute chest syndrome (ACS).

Although ACS responds well to timely treatment, it can still be life-threatening. In fact, ACS is the most common cause of death in people with SCD. Younger children are more likely to develop ACS, but adults can develop it too. About half of people with SCD experience at least one episode of ACS during their first 10 years of life.

Here’s what to know about ACS, including its causes, symptoms, and when to seek emergency care.

🗳️ Have you or your loved one experienced acute chest syndrome with sickle cell disease?

Yes, once

Yes, more than once

What Causes Acute Chest Syndrome?

The exact cause of ACS isn’t always clear, but it can develop when sickled red blood cells block small blood vessels in the lungs. These blockages can restrict blood flow through the vessels supplying the lungs.

When blood flow is reduced, lung tissue doesn’t get enough oxygen. This can result in lung injury and make it harder for the lungs to work properly.

Several factors can contribute to ACS, including:

Infections — Viral or bacterial lung infections, including pneumonia, commonly cause ACS in children.
A vaso-occlusive crisis — ACS may happen during or shortly after a sickle cell pain crisis.
Fat embolism — A pain crisis can damage bone marrow, allowing fat to enter the bloodstream. If fat reaches the small blood vessels in the lungs, it can cause inflammation and block blood flow.

Sometimes more than one factor may be involved. In many cases, doctors can’t identify a specific cause.

Who’s at Higher Risk for Acute Chest Syndrome?

Although ACS doesn’t always have a single, clear cause, several factors can make it more likely, including:

Asthma
Recent surgery or physical injury
A previous episode of ACS
Age (most common in children ages 2 to 4 years)
A recent respiratory infection, including COVID-19
A sickle cell pain crisis, especially one involving the chest or back
Smoking cigarettes or being exposed to secondhand smoke

Risk factors for acute chest syndrome include being a child, having asthma, being exposed to cigarette smoke, recent infection or surgery, and having had a recent sickle cell pain crisis.

Symptoms of Acute Chest Syndrome

ACS can look a lot like pneumonia, a cold, or the flu at first. This can make it harder to recognize.

Symptoms can vary from person to person, but may include:

Fever
Chest pain
Coughing, sometimes with blood
Fast, shallow breathing
Difficulty breathing
Wheezing

In children, ACS often causes trouble breathing and fever. Adults most commonly experience chest pain, shortness of breath, and a sickle cell pain crisis in the days leading up to an episode.

Although the initial symptoms of ACS may be mild, it can worsen over several hours or days. This makes it important to take new or worsening symptoms seriously.

If you or your child has a fever of 101.3 F (38.5 C) or higher or trouble breathing, go to the emergency room (ER) right away. Don’t wait to see whether it improves on its own.

How Is Acute Chest Syndrome Treated?

Treatment depends on how severe your episode is and what caused it. ACS is treated in the hospital. Here’s what you can expect.

Oxygen and Breathing Support

If your oxygen levels are low, your healthcare team may give you supplemental oxygen. They’ll continue monitoring your breathing and oxygen levels closely throughout your stay.

If breathing becomes difficult or your oxygen levels stay low, you may need noninvasive ventilation, which uses a mask connected to a machine to help you breathe.

In severe cases, you may need a ventilator, which provides breathing support through a tube placed into your windpipe.

Acute chest syndrome is treated in a hospital. You may receive oxygen and breathing support, antibiotics, and pain management. Some people may need intravenous fluids or a blood transfusion.

Antibiotics

Because infections can contribute to ACS, your healthcare provider will likely start you on antibiotics that treat more than one type of bacteria, including Streptococcus pneumoniae and other bacteria linked to pneumonia.

Infection isn’t the cause of every ACS episode, but your healthcare provider may still prescribe antibiotics because bacterial infection is a common cause of ACS. Starting treatment promptly can help prevent the infection from making your symptoms worse.

Pain Management

Your healthcare provider may give you pain medication to help manage your symptoms. Staying comfortable can help you breathe more effectively while they treat the underlying cause of ACS.

However, pain medication has to be used carefully because some drugs, especially opioids, can slow your breathing. Your healthcare provider will monitor you closely and adjust your treatment based on how you respond.

Intravenous Fluids

You may receive intravenous fluids, which are given through a vein, during treatment to help you avoid dehydration. Dehydration can make red blood cells more likely to become sickle-shaped.

Fluids need to be given carefully. People with ACS are more likely to have fluid buildup in the lungs, which can make it harder to breathe.

Your healthcare provider will consider your hydration, breathing, and overall condition when deciding how much fluid you need and how quickly to give it.

Blood Transfusions

Some people with ACS may require a blood transfusion if they have severe anemia or low oxygen levels. A transfusion adds healthy red blood cells that can help carry oxygen more effectively.

If your condition is severe or getting worse, you may need an exchange transfusion instead. This removes part of your blood and replaces it with donor red blood cells. Your healthcare provider will monitor you closely to see how you respond.

Whether you need donor blood depends on your oxygen levels, hemoglobin level, and whether your condition is getting worse.

Other Treatments

If you have asthma and develop ACS, your healthcare provider may give you a bronchodilator to help open your airways. If you don’t have asthma but are wheezing, they may also try a bronchodilator to see whether it helps.

Corticosteroids (steroids) are used more cautiously. Although they may have some benefits during an ACS episode, they can increase the risk of rebound crises and hospital readmission. For children, doctors generally consider corticosteroids only if they also have asthma.

Helping Your Lungs Expand

Your healthcare provider may ask you to take regular deep breaths during treatment. To do so, an incentive spirometer can guide you through the exercise. Using this device as directed may help keep your lungs expanded during recovery.

An older randomized trial involving 29 children and young adults with SCD found fewer lung complications among those who used an incentive spirometer while hospitalized with acute chest or back pain. However, more recent research has had mixed results.

Complications of Acute Chest Syndrome

If it’s not treated immediately, ACS can lead to severe, even life-threatening complications including:

Acute respiratory distress syndrome — Serious lung injury that can lead to respiratory failure and death
Respiratory failure — Lungs unable to provide enough oxygen to the body
Pulmonary hypertension — Very high blood pressure in the pulmonary arteries
Blood clot in the pulmonary artery — Blocked blood flow, causing damage and dysfunction
Scarring — Scarring and thickening of the lungs from recurrent bouts of ACS, making it harder for the lungs to function

Apart from the speed with which it can worsen, these potential complications are another reason to seek treatment as soon as you notice possible symptoms of ACS.

Can Acute Chest Syndrome Be Prevented?

ACS can’t always be prevented, but there’s a lot you can do with your sickle cell care team to help lower your risk. Here are a few ways to lower your risk:

Follow your SCD treatment plan, including disease-modifying treatment such as hydroxyurea if it’s recommended for you.
Manage asthma if you have it, since well-controlled asthma may help lower your risk.
Keep up with recommended vaccinations, including pneumococcal and yearly flu vaccines, because infections are a common trigger for ACS.
If you smoke, work toward stopping, and avoid secondhand smoke.
Use your incentive spirometer as directed during a hospital stay or when your sickle cell care team recommends it.

If you’re having surgery, talk with your sickle cell care team beforehand about whether you need special precautions to lower your risk of ACS.

Surgery can increase the likelihood of an episode, and some people may benefit from a blood transfusion before surgery.

Even when you do everything you can to lower your risk, ACS can still happen. Knowing the warning signs and when to seek emergency care can help you get prompt treatment.

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