Capillary leak syndrome was associated with more severe multisystem inflammatory syndrome in children during the COVID-19 pandemic.

AIM: This population-based study investigated the occurrence of capillary leak syndrome (CLS) in children with multisystem inflammatory syndrome in children (MIS-C), associated with COVID-19. We also examined associations between CLS and MIS-C disease severity. METHODS: All eligible individuals aged 0-18 years, who were diagnosed with MIS-C in Skåne, southern Sweden, from 1 April 2020 to 31 July 2021, were studied. They were all included in the Pediatric Rheumatology Quality Register and clinical and laboratory data were compared between patients with and without CLS. RESULTS: We included 31 patients (61% male) with MIS-C in the study. The median age at diagnosis was 10.6 years (range 1.99-17.15) and 45% developed CLS. All six patients who required intensive care had CLS. Patients with CLS also had a higher incidence of reduced cardiac function, measured as low ejection fraction. The CLS group exhibited significantly higher C-reactive protein values (p < 0.001) and N-terminal pro-B-type natriuretic peptide levels (p < 0.001), as well as lower platelet counts (p = 0.03), during the first week of treatment. Individuals with CLS also received more intense immunosuppression. CONCLUSION: CLS was a common complication of MIS-C in our study and these patients had a more severe disease course that required more intensive treatment.

Capillary leak syndrome: State of the art in 2021.

Capillary leak syndrome (CLS) is an increasingly acknowledged multifaceted and potentially lethal disease. Initial nonspecific symptoms are followed by the intriguing CLS hallmark: the double paradox associating diffuse severe edema and hypovolemia, along with hemoconcentration and hypoalbuminemia. Spontaneous resolutive phase is often associated with poor outcome due to iatrogenic fluid overload during leak phase. CLS is mainly triggered by drugs (anti-tumoral therapies), malignancy, infections (mostly viruses) and inflammatory diseases. Its idiopathic form is named after its eponymous finder: Clarkson's disease. CLS pathophysiology involves a severe, transient and multifactorial endothelial disruption which mechanisms are still unclear. Empirical and based-on-experience treatment implies symptomatic care during the acute phase (with the eventual addition of drugs amplifying cAMP levels in the severest cases), and the prophylactic use of monthly polyvalent immunoglobulins to prevent relapses. As CLS literature is scattered, we aimed to collect and summarize the current knowledge on CLS to facilitate its diagnosis, understanding and management.

Capillary leak syndrome: etiologies, pathophysiology, and management.

In various human diseases, an increase in capillary permeability to proteins leads to the loss of protein-rich fluid from the intravascular to the interstitial space. Although sepsis is the disease most commonly associated with this phenomenon, many other diseases can lead to a "sepsis-like" syndrome with manifestations of diffuse pitting edema, exudative serous cavity effusions, noncardiogenic pulmonary edema, hypotension, and, in some cases, hypovolemic shock with multiple-organ failure. The term capillary leak syndrome has been used to describe this constellation of disease manifestations associated with an increased capillary permeability to proteins. Diseases other than sepsis that can result in capillary leak syndrome include the idiopathic systemic capillary leak syndrome or Clarkson's disease, engraftment syndrome, differentiation syndrome, the ovarian hyperstimulation syndrome, hemophagocytic lymphohistiocytosis, viral hemorrhagic fevers, autoimmune diseases, snakebite envenomation, and ricin poisoning. Drugs including some interleukins, some monoclonal antibodies, and gemcitabine can also cause capillary leak syndrome. Acute kidney injury is commonly seen in all of these diseases. In addition to hypotension, cytokines are likely to be important in the pathophysiology of acute kidney injury in capillary leak syndrome. Fluid management is a critical part of the treatment of capillary leak syndrome; hypovolemia and hypotension can cause organ injury, whereas capillary leakage of administered fluid can worsen organ edema leading to progressive organ injury. The purpose of this article is to discuss the diseases other than sepsis that produce capillary leak and review their collective pathophysiology and treatment.

Idiopathic systemic capillary leak syndrome (Clarkson disease).

In 1960, Dr Bayard Clarkson described a woman experiencing sporadic recurrent episodes of shock and anasarca. Plasma from an acute attack induced a shock-like syndrome when injected into rats. The enigmatic systemic capillary leak syndrome (SCLS) named for Dr Clarkson is characterized by transient and severe but reversible hemoconcentration and hypoalbuminemia caused by leakage of fluids and macromolecules into tissues. Although less than 500 cases of SCLS have been reported in the literature since 1960, the condition is probably underdiagnosed because of a lack of awareness and a high mortality without treatment. Allergists should be vigilant of this diagnosis because its presentation can resemble more common plasma leakage syndromes, including angioedema or systemic anaphylaxis. Although the precise molecular cause of SCLS remains unknown, substantial advances over the last 5 years have increased our understanding of SCLS pathogenesis.

Epidemiology, risk factors, and prognosis of capillary leak syndrome in pediatric recipients of stem cell transplants: a retrospective single-center cohort study.

CLS involves sudden loss of intravascular fluids into the interstitial spaces. CLS was described as a possible complication after SCT. Few studies report the incidence of CLS in pediatric populations. We aimed to assess CLS incidence, its risk factors, and impact on the survival. The clinical charts of patients <18 years of age transplanted at our institution between 2002 and 2012 were reviewed. CLS was defined by weight gain >3% in 24 hours and positive intake balance despite furosemide administration. In total, 234 patients underwent 275 allogeneic SCT procedures in the analyzed time frame. Fifteen patients developed CLS (5.4%). The probability of developing CLS was significantly increased in patients suffering from sepsis (14.3% vs 0.6%, P<.001). Patients with CLS exhibited an increased risk of acute GvHD in the first 30 days after SCT (10.8% vs 1.8%, P=.002). Ten of the patients with CLS required intensive care. CLS strongly impacts OS at day +100 after SCT and is a predictive factor of TRM at the same date (42.9% vs 5%, P<.0001). The biological relation among sepsis, GvHD, and CLS development in terms of cytokine release and endothelial damage warrants further studies.

Clinical and pathological findings of a fatal systemic capillary leak syndrome (Clarkson disease): a case report.

Systemic capillary leak syndrome (SCLS) is a rare disorder with episodes of hypotension, hypoalbuminemia, and hemoconcentration. During attacks endothelial hyperpermeability results in leakage of plasma proteins into the interstitial space. Attacks vary in severity and may be lethal.A 49-year-old previously healthy man was admitted to hospital for hypovolemic shock, anasarca with pleuropericardial effusion, muscle fatigue, and oliguria occurring after a flu-like syndrome. Laboratory data showed an increase in hematocrit (65%), leucocytes (24.590 µ/L), creatinine (2.5 mg/dL), creatine phosphokinase (10.000 U/L), and a decrease in serum albumin (17 g/L) without proteinuria. Immunoglobulins of class G/λ monoclonal gammopathy were detected (1.3 g/L). The initial suspicions addressed to a protein-loosing syndrome or to an effort-related rhabdomyolysis. Initial therapy was based on steroids, albumin, and high molecular weight plasma expanders (hydroxyethyl starch). Because of high hematocrit, phlebotomy was also performed. The patient had complete clinical remission and a diagnosis of SCLS was finally made. He received prophylactic therapy with verapamil and theophylline that was self-stopped for intolerance (hypotension and tachycardia). He had a new crisis 2 days after a physical effort, and was admitted in intensive care unit. The patient died for severe hypovolemic shock with multiorgan failure and sudden cardiac arrest 15 hours after hospital admission. Postmortem investigation revealed massive interstitial edema of main organs with myocardial hyperacute ischemia.Studies on SCLS are limited for the rarity of the disease and its unpredictable course. Both prophylactic and acute crisis treatments are empirical and optimal management of severe attacks is still lacking.

[Clinical risk factors for capillary leak syndrome in children with sepsis].

OBJECTIVE: To investigate the clinical features of capillary leak syndrome (CLS) in children with sepsis, and to analyze its risk factors. METHODS: Clinical data of 384 children with sepsis was studied retrospectively. They included 304 cases of general sepsis, 54 cases of severe sepsis and 26 cases of septic shock, and were divided into non-CLS (n=356) and CLS groups (n=28). Univariate analysis was performed for each of the following variables: sex, age, malnutrition, anemia, coagulation disorders, white blood cell count, C-reactive protein (CRP), procalcitonin (PCT), tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, blood glucose, lactic acid, Pediatric Risk of Mortality (PRISM) III score, pediatric critical illness score (PICS), severe sepsis and number of failed organs≥3. The statistically significant variables (as independent variables) were subjected to multivariate logistic regression analysis. RESULTS: The incidence rate of CLS in children with septic shock, severe sepsis and general sepsis were 42.3%, 20.1% and 1.3%, respectively, with significant differences among them (P<0.01). There were significant differences in anemia, coagulation disorders, CRP, PCT>2 ng/mL, TNF, IL-1, IL-6, blood glucose, lactic acid, PRISM III score, PICS and number of failed organs≥3 between the non-CLS and CLS groups (P<0.05). Severe sepsis/shock and PRISM III score were the independent risk factors for CLS in children with sepsis. CONCLUSIONS: The severity of sepsis and PRISM III score are positively correlated with the incidence of CLS in children with sepsis. Early monitoring of such factors as infection markers and blood glucose in children with severe sepsis and high PRISM III score may contribute to early diagnosis and effective intervention, thus reducing the mortality from CLS in children with sepsis.

Capillary leakage in travelers with dengue infection: implications for pathogenesis.

Dengue hemorrhagic fever is characterized by the presence of a capillary leak syndrome. Its pathogenesis is presumed to differ from that of classical dengue fever (DF) and to be associated with secondary dengue infection. Returning travelers given a diagnosis of DF were evaluated for capillary leakage with abdominal sonography. Data were compared between travelers with primary/secondary infection defined by epidemiologic and serologic parameters. A total of 12 (34.3%) of 35 patients had sonographic signs of capillary leakage. Most (85%) patients with capillary leakage had classical DF. Capillary leak was diagnosed in 32% of primary dengue cases and in 40% of secondary dengue cases (P = 0.69). The two patients given a diagnosis of dengue hemorrhagic fever had primary infections. The high prevalence of capillary leakage among travelers, most of them with primary exposure to dengue, calls into question the importance of secondary infection in causing capillary leakage in dengue infection.

The systemic capillary leak syndrome: a case series of 28 patients from a European registry.

BACKGROUND: The systemic capillary leak syndrome (SCLS) is a rare disease characterized by life-threatening attacks of capillary hyperpermeability. OBJECTIVE: To describe the clinical characteristics, laboratory findings, treatments, and outcomes of patients with SCLS who were not previously reported in the literature. DESIGN: Case series. SETTING: Patients referred to a European multicenter SCLS registry between January 1997 and July 2010. PATIENTS: 28 patients with SCLS. MEASUREMENTS: Frequency, severity of attacks, and vital status were assessed every 6 months, from diagnosis to the end of the study. RESULTS: 13 men and 15 women referred to the registry who were not previously reported in the literature had 252 attacks. Median age at disease onset was 49.1 years (range, 5.4 to 77.7 years), and median annual frequency of attacks was 1.23 (range, 0.13 to 21.18) per patient. Monoclonal IgG gammopathy was observed in 25 patients (89%). Preventive treatment included intravenous immunoglobulin (n = 18), terbutaline (n = 9), and aminophylline (n = 10). Eight patients died (29%); 1-year survival was 89%, and 5-year survival was 73%. Death was directly related to SCLS attacks in 6 of 8 cases (75%). In 10 patients with a prediagnosis period greater than 6 months who received preventive treatment, the annual frequency of attacks after diagnosis decreased by a median of 1.55 (range, 0.14 to 8.84) per patient. Five years after diagnosis, survival was 85% in 23 patients who had received prophylactic treatment and 20% in 5 patients who had not. LIMITATION: The benefits of preventive treatment could not be precisely ascertained because of the small sample size and because most patients received several treatments. CONCLUSION: Clinical experience with these 28 patients with SCLS suggests that prophylactic treatment with ß(2)-agonists or intravenous immunoglobulin may reduce the frequency and severity of attacks and may improve survival. PRIMARY FUNDING SOURCE: Université Pierre et Marie Curie, Paris, France.

Idiopathic systemic capillary leak syndrome (Clarkson's disease): the Mayo clinic experience.

OBJECTIVE: To determine clinical features, natural history, and outcome of a well-defined cohort of 25 consecutive patients with idiopathic systemic capillary leak syndrome (SCLS) evaluated at a tertiary care center. PATIENTS AND METHODS: Records of patients diagnosed as having SCLS from November 1, 1981, through April 30, 2008, were reviewed. Descriptive statistics were used to analyze patient demographics, clinical features, complications, and therapeutic interventions. RESULTS: Of the 34 patients whose records were reviewed, 25 fulfilled all diagnostic criteria for SCLS. The median age at diagnosis of SCLS was 44 years. Median follow-up of surviving patients was 4.9 years, and median time to diagnosis from symptom onset was 1.1 years (interquartile range, 0.5-4.1 years). Flulike illness or myalgia was reported by 14 patients (56%) at onset of an acute attack of SCLS, and rhabdomyolysis developed in 9 patients (36%). Patients with a greater decrease in albumin level had a higher likelihood of developing rhabdomyolysis (p=.03). Monoclonal gammopathy, predominantly of the IgG-κ type, was found in 19 patients (76%). The progression rate to multiple myeloma was 0.7% per person-year of follow-up. The overall response rate to the different therapies was 76%, and 24% of patients sustained durable (>2 years) complete remission. The estimated 5-year overall survival rate was 76% (95% confidence interval, 59%-97%). CONCLUSION: Systemic capillary leak syndrome, a rare disease that occurs in those of middle age, is usually diagnosed after a considerable delay from onset of symptoms. The degree of albumin decrement during an attack correlates with development of rhabdomyolysis. A reduction in the frequency and/or the severity of attacks was seen in nearly three-fourths of patients who were offered empirical therapies. The rate of progression to multiple myeloma appears to be comparable to that of monoclonal gammopathy of undetermined significance.

[Idiopathic capillary leak syndrome]. / Syndrome de fuite capillaire idiopathique.

Idiopathic capillary leak syndrome (ICLS) is a rare and poorly known condition. Since the first description in 1960, about hundred cases have been reported. A French register that was initiated in 1997 provides a better knowledge of the natural course of the disease and highlights some therapeutic issues. ICLS mainly affects middle-aged adults. The prognosis is poor with a 10-year mortality rate around 34%. Severe crisis and complications occurring in intensive care units account for 80% of the mortality. Diagnosis relies on an almost pathognomonic association: recurrent attacks of hypotension and hemoconcentration with paradoxical hypoalbuminemia. A monoclonal gammopathy is found in about 80% of patients. Physiopathology still remains unclear. Paraprotein toxicity has never been demonstrated. As a result, no evidence-based treatment is available neither for acute crisis nor for prophylaxis. Management of acute episodes is mainly symptomatic. Fluid infusion must be cautious because it can induce complications during the recovery phase. Patient education is a major measure to prevent recurrent attacks. Beta-2 stimulants were reported to reduce the frequency and severity of episodes and were considered as the recommended prophylactic measure. However, early data from the French register suggest that intravenous immunoglobulins are more effective in reducing both frequency and severity of the attacks. Inclusion of patients with ICLS in a register is crucial to improve the knowledge about aetiology and treatment of this disorder.

Risk factors for capillary leakage syndrome after bone marrow transplantation.

Age, hematopoietic growth factors, cyclosporin A, mode of bone marrow transplantation (BMT) (autologous, allogeneic-related, unrelated), and underlying disease were assessed as potential risk factors for capillary leakage syndrome (CLS) in 96 patients after BMT. CLS was defined as unexplained weight gain of > 3% within 24 h and nonresponsiveness to furosemide. CLS occurred in 9/21 patients after unrelated compared with 2/33 after allogeneic-related BMT (p = 0.0017) for hematopoietic disorders (n = 54) and in 6/7 patients after allogeneic-related compared with 3/35 after autologous BMT (p = 0.001) for solid tumors (n = 42). Hematopoietic growth factors and cyclosporin A were no significant risk factors on their own. We conclude that unrelated BMTs or high-intensity conditioning regimens used in combination with allogeneic-related BMT are the main risk factors for CLS.

Marrow engraftment and clinical manifestations of capillary leak syndrome.

A capillary leak syndrome occurs frequently in bone marrow transplant patients in addition to graft-versus-host-disease and infection. The underlying pathology is poorly understood but the clinical manifestations of excessive weight gain, ascites, and edema associated with kidney and liver abnormalities suggest a common injury to multiple organs. The clinical courses of 55 allogeneic and autologous marrow transplant recipients were retrospectively reviewed with regard to the presentation of a capillary leak syndrome (CLS). Twenty-nine patients (53%) developed non-cardiogenic pulmonary edema with or without concurrent pleural effusions; the incidence was comparable in allogeneic and autologous recipients. Pulmonary features were accompanied by hepatic dysfunction in 28, renal dysfunction in 22, and central nervous system abnormalities in 17. There was a strong correlation between time of engraftment and the first manifestations of CLS, both of which occurred earlier in allogeneic than in autologous transplant recipients. These data confirm that CLS occurs in both allogeneic and autologous transplant recipients and suggest a pivotal contribution by circulating leukocytes.