Renal cortical necrosis and splenic infarction association as a complication of Covid-19

A 76-year-old female patient exhibited no known comorbidities. She was diagnosed with syncope by the emergency service. Moreover, an oropharyngeal PCR swab was performed and she tested positive for COVID-19 pneumonia. Laboratory studies showed leukocytosis (17.8 x 10⁹/L) and neutrophilia (15.6 x 10⁹/L), slightly elevated creatinine (1.14 mg/dl) with an eGFR of 47.1 mL/min/1.73m², and markedly elevated D-Dimer (7051 µg/L DDU). The patient presented no fever and an oxygen saturation level of 85%.

The total-body CT scan was performed after the intravenous administration of a contrast medium under a specific study protocol in order to assess the aorta and vessels of the lower limbs conditions. CT scan demonstrated opacification of the left common iliac artery and a filiform left superficial femoral artery. Reduced opacification of the left femoral vein was observed at a later stage of the research. Moreover, a peripheral hypodense flap of both kidneys was observed during the contrast phases, likely as a result of renal cortical necrosis (Fig.1-2-3-4). In addition, a small area of necrotic hypoperfusion which was located at the upper pole of the spleen was observed as well (Fig. 5-6-7-8). Furthermore, diffuse ground-glass opacity (GGO) can be observed on CT imaging of the lungs (Fig. 9), associated with crazy-paving patterns. The total severity score (according to Chung et al [1]) was 18/20s.

In the first stages, Coronavirus disease 2019 (COVID-19) is characterized by fever, sore throat, cough, dyspnea and different respiratory symptoms. Over time, however, it was discovered that this disease can cause systemic damage. Coronavirus SARS-CoV-2 can in fact lead to diffuse alveolar damage (DAD) with severe capillary congestion and variegated consequences affecting not only the lungs but also other organs. This is likely caused by a vascular dysfunction as a result of an exaggerated inflammatory response. [2] The risk of thrombosis is increased in patients suffering from Covid-19 with an incidence of 31%[3]. There are some cases in which signs of necrosis and abdominal viscera infarction have been found, in addition to common pulmonary embolism. [4, 5 ] Cortical kidney necrosis, as well as spleen infarction, are rare but they should be suspected in patients presenting alterations of blood indices related to renal function or in patients suffering left side abdominal pain. An extremely elevated D-dimer is the most significant alteration of coagulation parameters in severely affected Covid-19 patients. This value is recorded more frequently than other coagulation parameters such as prothrombin time (PT) or aPTT [6]. The increase in the vasoconstrictor angiotensin II, the decrease in the vasodilator angiotensin, and the sepsis-induced release of cytokines can cause a coagulopathy in COVID-19 patients.

The alteration of the coagulation system, which is triggered by a multisystem inflammation, causes systemic damages. Clinical symptoms of abdominal organ damage are not always easy to evaluate in severely affected patients and the alterations in laboratory tests may be due to multiple causes.
A parenchymatous abdominal organs study can be useful in cases of suspected arterial thrombosis in severely affected Covid-19 patients.

These findings are more common in patients with an impaired coagulation cascade and a high D-dimer level; in these cases, the findings of organ damage from imaging procedures can resolve concerns about laboratory abnormalities and determine whether or not organ function is recoverable.

Concerning renal cortical necrosis, contrast-enhanced CT demonstrates a non-enhancing renal cortex and a normal enhancing renal medulla (reverse rim sign).[7]

CT performed during the portal venous phase represents the imaging exam of choice for spleen infarction and typically demonstrates, in case of peripheral infarction, a  wedge-shaped hypoenhancing region.[8]

Diagnosis of thrombosis is often delayed. Early diagnosis and treatment are necessary to prevent infarction of other abdominal organs and to avoid the spreading of this phenomenon to an already affected organ.

MDCT plays a crucial role in early detection of large vessel and intraparenchymal thrombosis.
Timely diagnosis and management of thrombosis can prevent infarction of parenchymal organs and save part of those already affected.