Covid -19 pandemic, is an ongoing global pandemic which is caused by SARS-CoV-2. Currently more than 190 million cases have been confirmed with more than 4 million deaths, making it one of the deadliest pandemics in the history. Up to now, no effective treatment was detected and nearly 14 % of the world population were vaccinated 1.

A literature review of 28 scientific papers which published the autopsy findings of patients died from Covid-19 with total number of cases is 341, concluded that the major histological findings in the lung is diffuse alveolar damage with hyaline membrane formation, and microthrombi in small pulmonary vessels 2.

It appears that there is a high incidence of deep vein thrombosis of an estimated %14.8% among the hospitalized patients which are risky for pulmonary embolism.

Pulmonary thromboembolism signifies the presence of severe covid-19, may lead to respiratory failure and necessitates patient hospitalization and if multiple will suggest bad prognosis 3.

Small vessels thrombosis may be followed by large vessel thrombosis or recurrent pulmonary thromboembolism. The estimated mortality rate in cases with recurrent pulmonary thromboembolism was about 45%.

Multiorgan damage frequently detected and was associated with hyperinflammatory response and fibrinous thrombi of the small vessels of liver, kidneys, heart and bowel 2.

An immune related thromboembolism in patients with Covid-19 was associated with hypercoagulability state, platelet dysfunction, platelet aggregation and vascular endotheliitis 4.

D-dimer and ventilation /perfusion scan are of high sensitivity and low specificity in the detection of pulmonary thromboembolism.

Computed tomography pulmonary angiography (CTPA) can’t evaluate the microcirculation. Nephrotoxicity, radiation exposure and the patient critical condition are considered limitations to the use of CTPA. CTPA can detect only large and medium pulmonary vessels thrombosis and subsequent pulmonary infarction 35.

Echocardiography can show sequalae of massive pulmonary embolism by detecting right ventricular dilation, tricuspid valve regurge, pulmonary hypertension and Rt ventricular apical dyskinesia 6.

So, radiologists are in urgent need to an effective imaging modality capable of detecting micro vessels thrombosis with subsequent ischemia and infarctions.

Contrast enhanced ultrasound is an imaging modality which was used recently to detect small vessels thrombosis with subsequent organ ischemia and infarction in patients of Covid-19 showing promising results 57891011.

Small vessels thromboembolism is frequently undetected by means of radiological and laboratory investigations, in spite being a main feature of Covid-19 proved by the few radiology trials of using the ultrasound contrast enhancement and the autopsy findings of patients died from Covid-19 27891011.

Small vessels thromboembolism is multifactorial, caused by coagulopathy, thrombocytopathy and endotheliopathy associated with severe Covid -19.

Endotheliitis can be resulted from direct viral infection of the endothelial cells or immune hyperinflammatory reaction. The hypothesis of direct viral infectivity was opposed by the recent findings of scanty ACE- 2 receptors on the endothelium cells and the recent study which showed inability of the virus to infect cultured endothelium cells, raising the possibility of being subsequent of the hyperinflammatoy reaction 15.

Abnormal coagulation profile and platelet dysfunction in patients with severe Covid -19 in conjunction with endotheliopathy will lead to the frequent finding of small vessels thromboembolism among the patients 415.

The United Kingdom SARS corona virus-2 variant was found to be associated with high incidence of vasculopathy compared with the old variants with high incidence of vasculitis and perivascular fat planes inflammation. The mortality rate in hospitalized patients with vasculopathy was three-fold higher than patients without vasculopathy. The mortality rate in patients who received dexamethasone therapy was three times less than in patients who didn’t receive dexamethasone. The estimated hazard ratio in patients with vasculopathy and didn’t receive dexamethasone was 8.24 compared with those without vasculopathy 16.

The forementioned findings demonstrate the success of dexamethasone in management of vasculitis.

Management of small vessels thromboembolism was assumed to depend on the use Gluco-corticosteroid (Dexamethasone) therapy, antiviral drugs and anticoagulants.

In ophthalmology Cytomegalo-virus corneal endotheliitis was successfully managed with antiviral drugs, and topical corticosteroids 17.

Endotheliitis in covid -19 patients can be treated with corticosteroid therapy, anticoagulant and antiviral therapy. Prostacycline fatty acid derivative of Arachidonic acid can be useful as it promotes the healing of endothelium, vasodilator and prevent platelets aggregation (4).

Omega -3 fatty acid can be helpful as it promotes the healing of endothelium, inhibit the platelet aggregation and can switch off the cytokines storm 18.

Small vessels thromboembolism is an essential feature of Covid-19 which is frequently undetected by means of radiological and laboratory investigations, mainly caused by endotheliitis, coagulopathy and thromocytopathy. Prevention and early management will help greatly to reduce the severity of the disease and mortality rate.

Funding: None