COVID-19 News: Scientists Warn Of Systemic Capillary Leak Syndrome That Can Affect Post COVID And Post Vaccinated Individuals
: Scientist are warning that many Post COVID and Post vaccinated individuals could be prone to a serious condition known as Systemic Capillary Leak Syndrome (SCLS).
Systemic capillary leak syndrome happens when fluid leaks from your small blood vessels into surrounding tissues. It requires immediate treatment to prevent a drop in blood pressure and other serious complications. Capillary leak syndrome can't be cured, but you can reduce episodes by taking medications as prescribed.
Scientist from Kermanshah University of Medical Sciences-Iran, Shahid Beheshti University of Medical Sciences-Iran, Babol University of Medical Sciences-Iran, O. O. Bogomolets National Medical University, Kyiv-Ukraine, Tehran University of Medical Science-Iran and Mayo Clinic, Arizona-USA conducted a review to understand the correlation between capillary leak syndrome and post-SARS-CoV-2 infections and post COVID-19 vaccinations.
SCLS or systemic capillary leak syndrome is an uncommon, potentially life-threatening disorder defined as recurrent attacks of pseudo-shock, whose frequency, severity, and duration are variable, with each bout lasting 24-48 hours. On the other hand, SCLSs are classified into acute or chronic and primary or secondary, based on the relapses of attacks, the severity of manifestations, and the presence of precipitating factors.
The primary, spontaneous, or idiopathic SCLS is Clarkson’s disease, while secondary cases occur due to certain precipitating factors, including hematologic malignancies, immune disorders, trauma, toxins or chemicals, medication, surgery, transplantation, and infections.
It has been known that among the aforementioned precipitating factors, immune disorders such as Sjögren’s syndrome, systemic sclerosis, and juvenile dermatomyositis, malignancies, such as monoclonal gammopathies, lymphoma and myeloproliferative disorder, and medications such as G-CSF, interferons, rituximab and chemotherapeutic agents such as checkpoint inhibitors as the most commonly reported triggers of SCLS in the literature.
In the case of infections responsible for SCLS, influenza is the the most common along with respiratory syncytial virus (RSV) with West Nile virus (WNV), hantavirus, rotavirus, brucellosis, meningococcemia, malaria, Zika, Ebola, and dengue fever as the less prevalent ones.
To date, It has been demonstrated that viruses, like the influenza virus, causing upper respiratory tract infections are predominantly responsible for SCLS; coronaviruses are also believed to lead to this complication.
There has been a number of case reports of SCLS following SARS-CoV-2 infection that have been reported in various COVID-19 News
It has also been found that vaccination is another crucial trigger for SCLS.
SCLS had been reported following influenza vaccination.
Worryingly, the introduction of SARS-CoV-2 vaccines has brought about several new or exacerbated cases of SCLS.
To date, most cases of SARS-CoV-2 vaccination-induced SCLS have been reported with adenoviral vector and mRNA vaccines.
SCLS or systemic capillary leak syndrome occurs due to the disruption of endothelial cells, which leads to increased vascular permeability, causing intravascular fluid to leak into the extravascular space and albumin to be retained in the interstitial space.
Significantly, this phenomenon can lead to hypovolemia, peripheral hypoperfusion, and acute renal insufficiency.
It has been found that in viral infections, this condition can be triggered by direct viral toxicity on the endothelial barrier of massive inflammatory mediators secretion.
This inflammatory response in the lungs leads to pulmonary capillary leak syndrome, which manifests as progressive hypoxemic respiratory failure and acute respiratory distress syndrome (ARDS).
Also, the elevation of proinflammatory cytokines and chemokines, like CCL2, IL-1, IL-6, IL8, IL-12, and TNF-α during the SARS-CoV-2 infection has a critical role in damaging the respiratory system and other organs. The most significant injury occurs in angiotensin-converting enzyme 2 (ACE2) rich areas, which are entry gates of the virus.
The occurrence of SCLS in the settings of COVID-19 vaccines can be attributed to the SARS-CoV-2 spike glycoprotein encoded by the RNA or the viral vector].
According to the study team, in any patient presenting with generalized edema, hypotension, hemoconcentration, or hypoalbuminemia shortly after being infected with SARS-CoV-2 or after receiving a SARS-CoV-2 vaccine, SCLS should be considered.
To date, there are no specific diagnostic criteria and tests for SCLS. Therefore, the diagnosis of capillary leak syndrome is that of exclusion. After ruling out other causes of hypovolemic shock, the diagnosis of SCLS can be considered on the presence of the classical triad of hypotension, hemoconcentration, and hypoalbuminemia. For example, the pulmonary capillary leak syndrome diagnosis is based upon clinical and radiologic findings and exclusion of heart failure.
However, in deceased patients, postmortem electron microscopy examinations of lung tissues, showing loosening of inter-endothelial junctional complex and increase in protein concentrations and cytokine levels of the bronchoalveolar fluid (BALF), retrospectively confirms the diagnosis.
The review was published on a preprint server and is currently being peer reviewed.
The study team also highlighted the similarities between SCLS and Kawasaki disease (KD) in the context of COVID19 is to the extent that it is sometimes known as SARS-CoV-2–induced Kawasaki-like hyperinflammatory syndrome (SCiKH syndrome).
COVID-19-related multisystem inflammatory syndrome (MIS) is another similar condition that predominantly occurs in the pediatric population. It usually occurs in the late phase of SARS-CoV-2 infection, is manifested by elevated inflammatory biomarkers, and is managed with anti-inflammatory agents such as corticosteroids and IV immunoglobulins (IVIg).
Sepsis is another condition commonly mistaken for SCLS. However, procalcitonin levels, blood cultures, and evidence of active infection on the chest or abdominal imaging can help in differentiating it from other differential diagnoses.
The study team advised that other conditions that can present with hemoconcentration, hypoalbuminemia, and hypotension include nephrotic syndrome, malnutrition, cirrhosis, angioedema, and anaphylaxis, which should be excluded on clinical and paraclinical findings.
The study team concluded that SCLS is among the most important immune diseases triggered by the SARS-CoV-2. According to existing evidence, SARS-CoV-2 infection and COVID-19 vaccination could cause this life-threatening condition.
Furthermore, SCLS could lead to severe complications like thromboembolism (caused by hemoconcentration and hyperviscosity), renal failure, pericardial effusions, tamponade, and cardiac arrest. Since there are no specific diagnostic criteria and tests for determining SCLS, the diagnosis is excluded. After excluding other causes of hypovolemic shock, the diagnosis of SCLS can be considered on the presence of the classical triad of hypotension, hemoconcentration, and hypoalbuminemia. A wide range of conditions can be listed as the differential diagnosis for cases of suspected SCLS. The most important ones are septic shock, nephrotic syndrome, anaphylaxis, hereditary angioedema, drug reactions, exudative enteropathy, and ovarian hyperstimulation.
The study team advocates that early stages of SCLS should primarily be managed conservatively with osmotic drugs, diuretics, colchicine, renal replacement therapy, hemofiltration, and albumin transfusion.
In later phases, surgical drainage might be needed to extract the accumulated fluids from body cavities to restore vital organs’ function. Since SLCS has been observed in association with SARS-CoV-2 infection and COVID-19 vaccination, it should be considered a possible diagnosis in COVID-19 patients, and it is advisable to be very cautious and weigh the risks and benefits of vaccination of people with a history of this syndrome.
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