Pediatric Acute Liver Failure & Antiphospholipid Syndrome
The antiphospholipid syndrome (APS) is an entity on its own (also known
as primary APS) and is also associated with systemic lupus erythematosus
(SLE). Prevalence of APS in SLE is approximately 25%(Singh et al. 2013).
The pathophysiology of this syndrome remains unclear as is the why/when
of antiphospholipid antibodies (aPL) generation. A combination of
genetic and environmental factors play a role. Known triggers are
commonly viral and bacterial infections. Trauma, surgery, immune
abnormalities, anticoagulation withdrawal, parasitic and fungal
infections, along with some malignancies have also been connected to the
etiology of this condition.
APS is defined by presence of aPL and a vascular thrombosis and/or
complication of pregnancy. The thrombotic episodes range from
superficial thrombophlebitis to myocardial infarction, stroke, and
catastrophic APS (CAPS). CAPS may develop in less than 1% of APS
patients and involves multiple blood clots that develop over a short
time frame. These clots impair microcirculation and lead to multisystem
organ injury most commonly in brain, lungs, and kidneys.
More recently, research has shown a coagulopathy associated with
COVID-19, which suggests an immune-mediated pathway reminiscent of APS
and the severe form of CAPS(Serrano et al.
2021). Xiao et al. reported COVID patients with multiple aPL
positivities had a higher incidence of cerebral infarction compared to
patients who were negative(Xiao et al. 2020).
Complement activation has been linked to COVID-19 and contributes to APS
pathogenesis (in murine models); the association between the two needs
further investigation(Fischetti et al.
2005).