What is Acute Chest Syndrome?
Acute chest syndrome is a serious issue that can happen to people with sickle cell disease, where a new dense spot appears on the chest x-ray, often along with trouble breathing or a possible fever. The reason why this happens is that certain factors in people with sickle cell disease can cause blood vessels in the lungs to get blocked. Anyone with sickle cell disease can experience acute chest syndrome but it mostly happens in people with a particular type, HbSS. This condition can worsen rapidly and is the top cause of death in patients with sickle cell disease. Therefore, detecting it early and beginning treatment immediately can enhance the chances for a positive outcome.
What Causes Acute Chest Syndrome?
Acute chest syndrome is a condition with various causes and many times its exact root cause isn’t clear. Generally, in adults, it’s thought to be triggered by fat or bone marrow particles. These particles are often found in air sacs in the lungs of people who passed away due to sickle cell disease. In situations when the supply of blood to the bone marrow is interrupted, these particles can be unleashed into the bloodstream. They can then travel to the lungs, causing blood vessels to close off, which can lead to acute chest syndrome.
There are other factors that can cause acute chest syndrome as well, including infection, asthma, low oxygen levels, too much sedation, and complications after surgery. In children, infections often spark the condition. Asthma-related narrowing of the airways can cause low oxygen levels, which leads to abnormalities in red blood cells. Patients with both sickle cell disease and asthma stand a risk of getting acute chest syndrome two to four times higher than those with sickle cell disease alone.
A condition of low oxygen levels is repeatedly noticed in people having both sickle cell disease and asthma, particularly in children during the night. Even if these patients show normal oxygen levels during the day, they might develop low oxygen levels during the night which can lead to red blood cell irregularities. After surgery, patients might not breathe deeply due to pain or sedating medications, which can lead to these abnormalities in the lungs and result in acute chest syndrome.
It’s also important to point out that people with sickle cell disease are more likely to develop blood clots in their lungs than having them travel from elsewhere in the body. Still, if a patient shows signs of a deep vein blood clot in their limbs or symptoms indicating a potential lung blood clot, these possibilities should be considered.
Risk Factors and Frequency for Acute Chest Syndrome
Acute chest syndrome is a serious lung condition that frequently affects people with sickle cell disease. About half of the people with this disease will experience more than one episode of Acute Chest Syndrome. It is most common in children between the ages of 2 and 4. In adults, 78% of these episodes happen following episodes of vaso-occlusive pain, a complication associated with sickle cell disease. Acute chest syndrome is the leading cause of death in people with sickle cell disease, making up about 25% of all deaths. The death rate for adults with this condition is 4.3%, while for children it’s 1.1%.
- Acute chest syndrome is the most common serious lung condition for people with sickle cell disease.
- About 50% of people with sickle cell disease will have more than one episode.
- It is most common in children aged between 2 and 4 years old.
- In adults, 78% of episodes occur after episodes of vaso-occlusive pain, a type of severe pain commonly seen in sickle cell disease.
- Acute chest syndrome is the leading cause of death in people with sickle cell disease, causing about 25% of all deaths.
- The risk of death for adults with this condition is 4.3%, and for children it’s 1.1%.
Signs and Symptoms of Acute Chest Syndrome
Acute chest syndrome is a medical condition that can show up differently in kids and adults. In children, it’s often caused by infection. The most common symptoms in kids include wheezing, coughing, difficulty breathing, and fever. Adults, however, often experience chest pain, pains in the limbs, shortness of breath, or signs of vaso-occlusive crises (blocked blood flow) in other parts of the body, such as priapism (long-lasting erections).
- Symptoms in kids:
- Wheezing
- Coughing
- Difficult breathing
- Fever
- Symptoms in adults:
- Chest pain
- Pain in the limbs
- Shortness of breath
- Signs of vaso-occlusive crises, like priapism
Testing for Acute Chest Syndrome
Acute chest syndrome is a serious condition that needs to be accurately diagnosed using a blend of medical images and an assessment of symptoms. To confirm someone has acute chest syndrome, two main criteria need to be met:
- The person must exhibit new signs of disrupted lung activity (this is known as a pulmonary infiltrate) seen on a chest x-ray or CT scan, which involves at least part of one lung. This disruption should not be due to the collapse of part or all of a lung (a condition known as atelectasis). Along with this, they must experience one or more of the following symptoms:
- Chest pain
- A fever that exceeds 38.5 C
- Fast breathing, wheezing, crackling sounds when breathing, coughing, or visible struggle with breathing
- A decrease in blood oxygen levels (more than a 2% drop from their normal levels when breathing in room air, or a measure of oxygen in the blood—known as PaO2—below 60 mmHg).
The challenge here is that these criteria are not specific only to acute chest syndrome—they could also be signs of pneumonia. This is why it is extremely important to get a chest x-ray for any person with sickle cell disease who comes in with breathing problems. Acute chest syndrome can start subtly but can turn serious quickly. Starting treatment as soon as possible can effectively manage this condition.
There are several known risk factors that increase the chances of developing acute chest syndrome. These include:
- Having a low level of fetal hemoglobin (HbF), a type of hemoglobin that carries oxygen in the blood
- Being young in age
- Having asthma or another type of lung disorder
- Being a smoker
- Having recent trauma or surgery.
Treatment Options for Acute Chest Syndrome
Clinicians should be on high alert for acute chest syndrome, a severe lung-related complication of sickle cell disease, particularly during a painful sickle cell crisis. Early identification and prompt treatment can lower the risk of death, shorten hospital stays, reduce healthcare costs, and decrease the chances of the condition recurring. The treatment needs to be aggressive due to the quick progression of this disease.
Pain control, intravenous fluids, antibiotics, supplemental oxygen, and blood transfusions all play a part in managing acute chest syndrome. To manage pain in children, doctors typically start with the drug ketorolac, as it won’t cause drowsiness or slow down breathing like opioid pain medications can. In adults, pain management can also start with ketorolac. However, if ketorolac and the over-the-counter pain reliever acetaminophen don’t adequately control the pain in either adults or children, opioid pain medication may be needed. This medication is usually given through a device that allows patients to control their medication, called patient-controlled analgesia (PCA). This balance between relieving pain, which can prevent lung collapse, and preventing over-sedation is crucial in successfully managing acute chest syndrome.
Drinking plenty of fluids is also crucial, especially in cases where a patient is dehydrated. However, large amounts of intravenous fluid are no longer recommended, as too much fluid can lead to lung fluid build-up and further respiratory problems. The goal of managing fluids is to restore and maintain adequate hydration levels without causing fluid overload.
The use of broad-spectrum antibiotics in all patients with acute chest syndrome is also recommended due to the increased risk of infections, particularly in children. These drugs can combat a wide range of bacteria. If there’s a concern about a certain type of bacteria, known as MRSA, another antibiotic, vancomycin, may be added to the treatment plan.
In order to prevent air sac collapse within the lungs, “incentive spirometry,” a technique to encourage deep breathing and lung expansion should be performed every two hours while the patient is awake.
Supplemental oxygen is suggested to correct low oxygen levels in patients with acute chest syndrome. In severe cases, supplemental oxygen may be administered through a machine that helps with breathing (BiPAP) or, in very extreme cases, a machine that function like an artificial lung (ECMO).
Transfusions of packed red blood cells can help improve oxygen levels within the blood and are usually indicated when the hemoglobin level is lower than usual, when diagnostic imaging shows worsening signs, or symptoms have worsened.
Other possible treatments for acute chest syndrome include using bronchodilators in cases where asthma is contributing to the condition. However, routine use has not shown any measureable benefits in treating this syndrome. Additionally, steroids can help decrease the length of hospital stays, but their usage is linked to a higher rate of repeat sickle cell crises, higher readmission rates, and an increased risk of fat blockages in blood vessels. If acute chest syndrome doesn’t respond to standard treatment, bronchoscopy (a procedure that looks inside the lung airways) with bronchoalveolar lavage (a procedure that washes out the airways) may be considered.
What else can Acute Chest Syndrome be?
When someone is experiencing signs of acute chest syndrome, it could be due to various possible causes. You should consider:
- Acute coronary syndrome: This includes conditions like unstable chest pain and heart attacks, with symptoms such as chest discomfort, breathlessness, and other heart-related issues
- Pulmonary embolism: This condition often causes sudden chest pain, trouble breathing, and can be life-threatening
- Pneumothorax: This condition, also known as a collapsed lung, often causes immediate sharp chest pain and difficulty breathing
- Pneumonia: Symptoms include a cough that produces mucus, fever, chest pain, and trouble breathing
- Pleural effusion: This condition, which is fluid buildup around the lungs, may cause chest pain, breathlessness, and lack of normal breath sounds when a doctor listens to your lungs
- Empyema: This infection in the area between the lungs and chest wall can cause chest pain, fever, a cough that brings up mucus, and difficulty breathing
- Aortic dissection: This serious condition often leads to severe chest pain that can extend into the back
- Acute respiratory distress syndrome (ARDS): This lung condition often leads to difficulty breathing, low oxygen levels in the blood, and unusual findings on a chest X-ray
Remember, it’s essential for doctors to look into all these health problems and perform necessary tests to make a correct diagnosis.
What to expect with Acute Chest Syndrome
Acute chest syndrome is a common and potentially serious issue for people with sickle cell disease. About half of the patients will have an episode at some point. It is a significant problem as it is responsible for about a quarter of the deaths in people with sickle cell disease. In adults, the risk of dying from an acute chest syndrome episode can be as high as 9%.
In terms of children, acute chest syndrome tends to happen again, especially in kids under the age of four. Several factors can lead to a child being hospitalized again for this condition. These can include a history of asthma, breathing difficulties, and long stays in the hospital when first diagnosed with acute chest syndrome.
Long-term issues arising from acute chest syndrome may include having repeated episodes, a lung condition known as interstitial lung disease, and high blood pressure in the lungs.
Possible Complications When Diagnosed with Acute Chest Syndrome
Acute chest syndrome, a severe complication of sickle cell disease, can result in a range of health problems. These include the following:
- ARDS: This is a serious condition where the lungs become severely inflamed and filled with fluid, causing difficulty with oxygen uptake and potentially leading to respiratory failure.
- Respiratory failure: This occurs when the lungs can no longer bring enough oxygen into your body, or remove carbon dioxide from your body. It is a direct result of extensive lung damage.
- Pulmonary infarction: This happens when a blood clot gets lodged in a lung artery, causing tissue damage and impaired lung function.
- Pulmonary fibrosis: This results from repeat episodes of acute chest syndrome. It involves the scarring and thickening of lung tissue which impairs lung function and causes long-term respiratory issues.
- Pulmonary hypertension: This is high blood pressure in the lungs due to chronic damage from acute chest syndrome. It puts a strain on the heart and impairs cardiac function.
- Severe pain
- Death
Preventing Acute Chest Syndrome
For long-term management of acute chest syndrome, there are a few different strategies doctors might use. These include a medication called hydroxyurea, a procedure known as packed red blood cell transfusions, and another procedure known as hematopoietic cell transplants.
Hydroxyurea is a drug that has been shown to reduce instances of acute chest syndrome by half in adults, and by a third in children. It does this by increasing the amount of a type of protein called HbF in red blood cells. It’s the only medication proven to decrease instances of this condition.
If hydroxyurea is not effective, or if someone is recovering from a severe episode of acute chest syndrome, doctors might use chronic red blood cell transfusions. This is particularly common during high-risk times, like winter. However, it’s important to note that this procedure does have risks, which can include infections, too much iron in the body, and allosensitization, which is a reaction of the immune system.
For patients with a particular type of genetic disorder called sickle cell disease, who have had multiple episodes of acute chest syndrome, a hematopoietic cell transplant may be an option. This requires a perfectly matched sibling donor and involves a process that destroys bone marrow, which brings its own risks. However, this procedure has been successful in over 80% of sickle cell disease cases.
