When an SCLS episode occurs, treatment focuses on controlling blood pressure. Following diagnosis, your doctor may recommend treatments to reduce the risk of another episode.
This article looks at the symptoms and causes of SCLS and secondary capillary leak syndrome. It also discusses treatment options, when to seek medical help, and more.
There are two main types of capillary leak syndrome: systemic capillary leak syndrome (SCLS) and secondary capillary leak syndrome.
SCLS is also known as idiopathic systemic capillary leak syndrome or Clarkson’s disease. It refers to recurrent episodes where there is no identifiable cause.
Secondary capillary leak syndrome refers to when something triggers the condition. This can include another medical condition, an infection, or some medical treatments.
The first symptoms you may experience before a capillary leak syndrome episode are nasal congestion and a cough. These may be due to a viral upper respiratory infection. This occurs during a phase known as the “prodromal phase.” This phase may not be present in idiopathic SCLS.
Other initial symptoms can include:
- malaise or generally feeling unwell
- lightheadedness
- headache
- nausea
- feeling faint
- swelling
- abdominal pain
Once fluid leaks from the capillaries, signs of capillary leak syndrome
- severe hypotension or low blood pressure
- hemoconcentration, which refers to thickened or highly concentrated blood
- hypoalbuminemia, which refers to low levels of the protein albumin
- hypovolemic shock, which means that the heart cannot pump enough blood due to extreme fluid loss
This phase can last for several days at a time. An SCLS episode can occur anywhere from once every 3–5 days to once every 10 years, according to research.
Hypotension
Symptoms of hypotension include:
Hypovolemic shock
Symptoms of hypovolemic shock can include:
- thirst
- muscle cramps
- abdominal pain or chest pain
- lethargy
- agitation
- confusion
Learn more about hypovolemia and hypovolemic shock.
The exact cause of idiopathic SCLS is unknown.
More than half of people experiencing SCLS have a monoclonal protein in their blood. However, the level of this protein is typically low.
Researchers do not yet understand the role the monoclonal protein may play in triggering SCLS. Although, suggested explanations include an autoimmune response and something in the blood causing damage to cells lining the capillaries. More research is needed to fully understand this link.
Secondary capillary leak syndrome
Secondary capillary leak syndrome occurs when something triggers the condition. Researchers have identified various triggers that may cause this to happen.
The most common trigger is viral infection, such as from SARS-CoV-2, the virus that causes COVID-19. Other possible triggers include:
- stem cell transplantation
- some anti-cancer treatments
- physical exertion
- snake bites
- malignant hypertension
- COVID-19 vaccine
The first phase of treatment for an acute episode of SCLS typically takes place in an intensive care setting. It usually involves intravenous fluid replacement, which is administered through a vein.
During the second phase of treatment, your doctor may recommend:
- diuretics, in case of excess fluid
- glucocorticoids, to reduce capillary leak
- intravenous albumin and colloids, to increase blood flow to vital organs
Your doctor may then recommend treatments to reduce your risk of another SCLS episode. This typically involves intravenous immunoglobulins once per month.
Other medications that may be helpful in preventing further episodes include terbutaline and theophylline. You may require regular blood tests so your doctor can monitor your theophylline levels.
In some cases, medications such as leukotriene inhibitors and ACE inhibitors may be beneficial. However, because the condition is rare, there is a lack of controlled trials. As a result, more research is needed to determine the effectiveness of these medications.
There have been fewer than 500 reported cases of SCLS worldwide since it was initially described in 1960.
Among 134 cases diagnosed between 2010 and 2016, 71 were people assigned male at birth and 63 were people assigned female at birth.
The median age at the time of diagnosis was 48 years.
Contact your doctor as soon as you have concerns about capillary leak syndrome. The condition can be serious and may require immediate medical attention.
To make a diagnosis, your doctor may ask about your medical history and symptoms and perform a physical exam.
The three main signs your doctor may look for if they suspect capillary leak syndrome are:
- low blood pressure
- increased hematocrit, which refers to the volume of red blood cells in your blood
- hypoalbuminemia, which refers to low protein in your blood
- acute renal failure
To find this information, your doctor will take your blood pressure reading and order blood tests.
Blood tests may also reveal a sharp decrease of serum albumin levels and a sharp increase of hemoglobin levels. This can help to confirm the diagnosis. These changes can occur when fluid loss causes the blood to become more concentrated.
Identifying the presence of a monoclonal protein can confirm the diagnosis. However, your doctor may still diagnose capillary leak syndrome without the presence of the monoclonal protein.
Capillary leak syndrome can be a serious condition that may lead to severe complications without treatment.
Possible complications include:
- multiple organ dysfunction syndrome
- hypercoagulability, which is an increased tendency for thrombosis
- anasarca, which refers to body-wide swelling
- acute renal failure
- pulmonary embolism
- pericardial effusions, which is a buildup of fluid around the heart
- disability due to rhabdomyolysis, which is the breakdown of muscle
Seek medical help as soon as you have concerns about capillary leak syndrome. Receiving treatment early and following the plan your doctor prescribes may help reduce your risk of complications.
As the cause of SCLS is unknown, it may not be possible to prevent the condition. However, after one episode, your doctor may prescribe medication to help to reduce the risk of another episode. This may include monthly intravenous immunoglobulins.
For secondary capillary leak syndrome, you may be able to prevent the condition by avoiding the known trigger. For example, if a specific medication caused the episode, your doctor may recommend switching to another medication.
It is important not to stop any medications you are currently taking before consulting with your doctor. They can advise on steps you can take to taper off or switch to another medication.
Here are some more frequently asked questions about capillary leak syndrome.
How long can you live with capillary leak syndrome?
Because capillary leak syndrome is a rare condition, there is limited data on survival rates. However, in a small study
Receiving maintenance therapies may improve your outlook. Talk with your doctor about the outlook for your specific condition.
Is capillary leak syndrome serious?
Capillary leak syndrome can be a serious condition. It can result in numerous complications that may cause disability. It is important to contact your doctor as soon as you have concerns about the condition. They can advise on treatments to help reduce the risk of more episodes.
What drugs can cause capillary leak syndrome?
Some medications may trigger secondary capillary leak syndrome. These
If you believe your medication is causing capillary leak syndrome, inform your doctor right away. They may advise changing your medication or lowering your dosage.
Capillary leak syndrome is a rare condition in which fluid leaks from the capillaries. Idiopathic systemic capillary leak syndrome refers to recurrent episodes with no known cause. Secondary capillary leak syndrome is caused by a trigger, such as an infection or medical treatment.
Capillary leak syndrome may cause extremely low blood pressure, low levels of the protein albumin, highly concentrated blood, and hypovolemic shock. You may also experience symptoms a few days before an episode, such as malaise, nausea, headache, and feeling faint.
The main treatment for capillary leak syndrome is fluid replacement therapy. Your doctor may recommend monthly intravenous immunoglobulin treatment to reduce the risk of another episode.
Contact your doctor as soon as you have concerns about capillary leak syndrome. It can be a serious condition that may lead to serious complications. Your doctor can perform tests to confirm the diagnosis and recommend treatments.