Renal subcapsular hematoma with abscess in severe COVID-19

A 53-year-old previously healthy man was admitted to the intensive care unit with respiratory distress due to COVID-19; he needed 10 L/min of oxygen support via a non-rebreather mask. Thoracoabdominal computed tomography (CT) revealed bilateral pneumonia without any abnormal abdominal findings. He was treated sequentially with methylprednisolone pulse therapy, dexamethasone, remdesivir, and tocilizumab. His serum D-dimer level was elevated (10 µg/mL) at the time of admission, so he was started on heparin (200–300 IU/kg/day) for thromboembolism prophylaxis, with a target of 1.5–2.5 times the normal activated partial thromboplastin time.

His respiration generally improved, but on day 8, he developed right-sided abdominal pain and worsening anemia. Abdominal contrast-enhanced CT revealed a right renal subcapsular hematoma (Fig. 1A). CT angiography did not show any active bleeding within the hematoma. Anticoagulants were discontinued and the patient received a blood transfusion.

Fig. 1.

Thoracoabdominal contrast-enhanced computed tomography images. (A) Hematoma of the right kidney on day 8. (B) Infected hematoma of the right kidney on day 30. (C) Disseminated lesions in the right shoulder on day 37.

On day 10, he developed methicillin-sensitive Staphylococcus aureus bacteremia due to a catheter-related infection, and ceftriaxone was started. On day 18, he was transferred to the general ward. Repeat blood culture was negative and follow-up thoracoabdominal CT showed partial hematoma resolution.

On day 30, he developed a spiking fever and ceftriaxone was switched to vancomycin. Thoracoabdominal CT revealed reorganization of the right renal subcapsular hematoma with capsule enhancement, suggesting abscess formation (Fig. 1B). The hematoma/abscess was drained via a percutaneous catheter. The hematoma subsided and the steroids were tapered over 5 weeks; however, a follow-up thoracoabdominal CT on day 37 revealed purulent arthritis in the right shoulder (Fig. 1C). The shoulder abscess was drained and eventually resolved after an 8-week course of antimicrobials.

Subcapsular renal hematomas are rare in clinical practice, and can present with abdominal pain and anemia. The most common causes are tumors, vascular disease, and anticoagulant use. Cases secondary to anticoagulant therapy can usually be treated conservatively [1], [2].

Renal subcapsular hematoma has previously been reported as a complication of coronavirus disease (COVID-19) [3]. Patients with severe COVID-19 are in a constant hypercoagulable state and have an increased risk of thrombosis due to elevated levels of inflammatory cytokines [3], [4]. The standard treatments are anticoagulants and steroids; however, these treatments increase the risk of bleeding and infection, respectively [3], [5]. Hematomas can become infected and form abscesses, resulting in a secondary source of the infection, as in this case. Abscess drainage and antimicrobials are critical [5]. Clinicians should be aware that renal subcapsular hematoma/abscess is a potential complication of COVID-19.

Ethical approval

Ethical approval is not required for case reports.

Consent

Written informed consent was obtained from the patient for publication of this case report and the accompanying images.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

CRediT authorship contribution statement

Hidenori Takahashi: Conceptualization, literature search, Writing – original draft, Writing – review & editing, submission. Kei Morishita: Writing – review & editing. Yasusei Okada: Writing – review & editing, Supervision.

Declaration of Competing Interest

None