Introduction
In December 2019, a sudden outbreak of pneumonia caused by severe acute
respiratory syndrome-coronavirus-2 (SARS-CoV-2) occurred in Wuhan,
China. Later called Coronavirus Disease 2019 (COVID-19), the disease
spread rapidly worldwide and became a pandemic (1). Common clinical
manifestations of COVID-19 are fever, cough, shortness of breath,
fatigue, headache, hemoptysis, loss of taste or smell, and
gastrointestinal manifestations such as nausea, vomiting, anorexia,
diarrhea, and abdominal pain (2). The virus detects
angiotensin-converting enzyme 2 (ACE-2) as its receptor and binds to it.
ACE-2 exists in almost all human tissues including endothelial cells of
arteries, small and large veins, heart, alveolar epithelial cells type 1
and 2 in lungs, nasal mucosa, mouth, nasopharynx, kidney, testis, and
brain (3). Many reports suggest that the introduction of SARS-CoV2 is
associated with decreased ACE-2 activity and that ACE-2 acts as a
negative regulator of the renin-angiotensin-aldosterone (RAAS) system in
critical situations. RAAS is thus boosted in COVID-19 patients and
causes oxidative stress damage to the vascular endothelium (4). In
general, endothelial damage is associated with the pathophysiology of
COVID-19. Activation of von Willebrand factor (VWF), complement
overactivation, excessive neutrophil extracellular traps (NETs)
formation, and mitogen-activated protein kinases may also play a role in
COVID-19-related coagulation. dysregulated innate immune response and
subsequent cytokine storms would also lead to the activation of various
“immunothrombotic” pathways and blood coagulation. COVID-19-related
coagulation affects different organs including pulmonary arteries, lower
limbs, spleen, heart, brain, and kidneys (3). Renal vein thrombosis
(RVT) is a condition in which thrombosis occurs in the renal veins or
their branches. Acute RVT is often due to trauma, severe dehydration,
hypercoagulability, or nephrotic syndrome. RVT is rare and occurs most
often in adults with nephrotic syndrome and newborns with low body fluid
volume or inherited thrombophilia. While it may present with symptoms
such as flank pain, hematuria, or acute kidney injury (AKI), it may also
remain asymptomatic until it leads to pulmonary embolism (PE) or
accidentally diagnosed by imaging studies (5).