What are the other Names for this Condition? (Also known as/Synonyms)

• Capillary Leak Syndrome (CLS)
• Clarkson Disease
• SCLS (Systemic Capillary Leak Syndrome)

What is Systemic Capillary Leak Syndrome? (Definition/Background Information)

• Systemic Capillary Leak Syndrome (SCLS) is a condition in which fluid and proteins leak out of tiny blood vessels, into surrounding tissues. This can result in dangerously low blood pressure (hypotension), hypoalbuminemia, and a decrease in plasma volume (hemoconcentration)
• Symptoms may include fatigue, nausea, abdominal pain, extreme thirst, and sudden increase in body weight. Episodes of SCLS vary in frequency, with some people having one episode in their lifetime, and others having several per year. The severity also varies, and the condition can be fatal
• In many cases the cause is not known (idiopathic SCLS). Some people with Systemic Capillary Leak Syndrome report having had an infection (such as a virus) before the episode. Some cases of capillary leak are associated with various conditions of the heart, kidney, or liver
• Treatment during an episode may involve stabilizing the airway and breathing, and infusion of fluids, medications, or blood products. Periodic infusions or the use of certain medications may be used to prevent future episodes

(Source: Systemic Capillary Leak Syndrome;Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Systemic Capillary Leak Syndrome? (Age and Sex Distribution)

• Systemic Capillary Leak Syndrome is a rare condition observed more in adults. It is generally rare in children
• Both males and females may be affected 
• Worldwide, individuals of all racial and ethnic groups may be affected 

What are the Risk Factors for Systemic Capillary Leak Syndrome? (Predisposing Factors)

• Some people with Systemic Capillary Leak Syndrome report having had an infection (such as a virus) before the episode
• Some cases of capillary leak are associated with various conditions of the heart, kidney, or liver

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others. 

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider. 

What are the Causes of Systemic Capillary Leak Syndrome? (Etiology)

• In a majority of individuals, the cause of Systemic Capillary Leak Syndrome is unknown (termed idiopathic Systemic Capillary Leak Syndrome)
• In some individuals, certain underlying illnesses or conditions are believed to be associated with SCLS

What are the Signs and Symptoms of Systemic Capillary Leak Syndrome?

The signs and symptoms of Systemic Capillary Leak Syndrome may include:

• Fatigue
• Nausea
• Abdominal pain
• Extreme thirst
• Sudden increase in body weight
• Very low blood pressure (hypotension)
• Hypoalbuminemia
• Decrease in plasma volume (hemoconcentration)

Episodes of SCLS vary in frequency, with some people having one episode in their lifetime, and others having several per year. The severity also varies, and the condition can be fatal.

(Source: Systemic Capillary Leak Syndrome;Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.) 

How is Systemic Capillary Leak Syndrome Diagnosed?

Systemic Capillary Leak Syndrome is diagnosed on the basis of the following information: 

• Physical examination and evaluation of complete medical history
• Laboratory tests
• Recurrence of symptoms: Recurring episodes are associated with monoclonal gammopathy in the majority of patients (when an abnormal immunoglobin protein is found in blood)
• The diagnosis is supported by ruling out other illnesses with similar symptoms, including secondary capillary leak syndrome or abnormally low levels of protein in the blood (hypoproteinemia)

(Source: Systemic Capillary Leak Syndrome;Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.) 

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Systemic Capillary Leak Syndrome?

The complications of Systemic Capillary Leak Syndrome may include: 

• Very low blood pressure levels
• Severe fatigue
•  SCLS can result in fatalities

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Systemic Capillary Leak Syndrome Treated?

There is currently no cure for Systemic Capillary Leak Syndrome (SCLS).

• Treatment for SCLS during an episode is mainly supportive, aiming to stabilize symptoms and prevent severe complications
• This may involve stabilizing the airway and breathing, taking certain medications, and/or intravenous (IV) infusion of fluids, medications, or blood products. Some have suggested that IV fluids are not recommended because it may worsen swelling (edema) or increase the risk for other complications 
• Once a person begins to recover, diuretics are almost always required
• Periodic infusions or the use of certain medications are used to try to prevent future episodes (prophylactictherapy)
• Having monthly infusions of intravenous immune globulin has been suggested
• A study published in 2017 found that preventive treatment with IVIG was the strongest factor associated with survival in people with SCLS 
• Those who do not improve with IVIG or who cannot tolerate the therapy may have success with theophylline and terbutaline

Research into how SCLS develops and factors that affect its course are underway, in hopes that a better understanding of SCLS will lead to more effective treatment options and a lower mortality rate.

(Source: Systemic Capillary Leak Syndrome;Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can Systemic Capillary Leak Syndrome be Prevented?

• Currently, there are no effective mechanisms available to prevent Systemic Capillary Leak Syndrome
• Further episodes of SCLS may be prevented through appropriate therapy
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Systemic Capillary Leak Syndrome? (Outcomes/Resolutions)

• The prognosis of Systemic Capillary Leak Syndrome is dependent upon the severity of the signs and symptoms and associated complications, if any 
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications 
• Typically, the prognosis may be assessed on a case-by-case basis 

Additional and Relevant Useful Information for Systemic Capillary Leak Syndrome:

Systemic Capillary Leak Syndrome is also known by the following names:

• Capillary Leak Syndrome with Monoclonal Gammopathy
• Periodic Systemic Capillary Leak Syndrome

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/