CASE 18489 Published on 14.03.2024

Acute renal cortical necrosis in a patient with post-surgical hypovolemic shock

Section

Uroradiology & genital male imaging

Case Type

Clinical Case

Authors

Elia Lecumberri de Fuentes Jokin Zabalza Unzué, Daisy Johanna Guapisaca, Ainhoa Clemente-Idoate, Cristina Sánchez Amaya

Hospital Universitario de Navarra, Pamplona, Spain

Patient

66 years, female

Categories
Area of Interest Kidney ; Imaging Technique CT
Clinical History

A woman aged 66, with complex surgery of the aortic arch involving the reimplantation of supra-aortic trunks, developed acute ischemic supra and infratentorial lesions, depicted on a cranial CT done 24 hours after the intervention. Blood analyses conducted 48 hours later demonstrated multiorgan failure, and thus, a thoracoabdominal CT was requested to discard treatable complications.

Imaging Findings

An angio-CT was performed. The arterial phase proved patency of the renal arteries and displayed no enhancement of the kidneys (Figure 3: videoclip). In the venous phase, significant diffuse cortical hypodensity and medullary hyperdensity were demonstrated (Figures 1 and 2).

Besides, mucosal thickening and hypodensity of the colonic wall, involving the transverse and ascending colon, was shown (Figure 1). This was consistent with colitis, likely of ischemic origin, given the clinical context. Another finding, not present in previous studies and suggestive of infarction, was the appearance of a small triangular morphology hypodensity in segment III of the liver (Figure 1). Partially thrombosed thoracoabdominal aneurysm remained without changes (Figures 1 and 2).

Discussion

Renal cortical necrosis (RCN) is a rare but potentially fatal cause of acute renal failure, typically resulting from sudden but prolonged insufficient blood supply to the renal cortex [1–3]. Several underlying causes can contribute to it, including obstetric complications (>50%), shock, sepsis, disseminated intravascular coagulation or toxins [2]. It usually affects both kidneys, although only compromise of the grafted kidney has been seen in cases of renal transplantation.

The distinct vascular architecture and blood flow control between the medullary and the cortex predispose the medullary to be relatively insensitive to most vasoconstrictor factors that participate in this condition [1,2].

RCN is clinically manifested with hypertension, oliguria or anuria, increased creatine and blood urea nitrogen levels, abdominal pain and other laboratory abnormalities [3].

Histology remains the gold standard for diagnosing RCN. However, biopsies are invasive and might be contraindicated in critical patients [1,2]. Therefore, imaging studies play a crucial role in the assessment of RCN, helping to visualise structural changes in the kidneys.

The chosen imaging modality will depend on the clinical scenario and the suspected cause of RCN. Ultrasounds may reveal a hypoechogenic renal cortex [4]. CT demonstrates no enhancement of the renal cortex. MRI could provide valuable information for diagnosis and kidney prognosis [1]. Additionally, subtraction angiography would reveal abnormalities in renal blood flow, such as thrombosis or stenosis. Recently, contrast-enhanced ultrasound scans have been performed for early diagnosis of RCN [3].

The mentioned non-enhancement of the renal cortex, with simultaneous enhancement of the medulla, is well-known as the “reverse rim sign”, and it is radiologically characteristic for the diagnosis of RCN [1,2]. Excepting transplanted kidneys and sustained situations of low cardiac output, a preserved lineal halo enhancement of the subcapsular outer cortex can be associated, reflecting the “cortical rim sign” [2]. The latter corresponds to preserved subcapsular outer-cortex blood supply by capsular arteries.

In the course of patients with a history of RCN, an atrophic renal evolution and cortical nephrocalcinosis may be identified [3].

Acute treatment focuses on addressing the underlying cause and providing supportive care. The prognosis varies depending on the severity of the underlying condition and the extent of kidney damage [3].

Take home message

Imaging studies provide valuable information. Final diagnosis of RCN often requires a combination of clinical, laboratory and imaging findings. In some cases, a kidney biopsy may be necessary to confirm the diagnosis and identify the underlying cause.

Interpreting imaging findings in the context of the patient’s clinical history is crucial for accurate diagnosis and appropriate management of RCN.

All patient data have been completely anonymised throughout the entire manuscript and related files.

Differential Diagnosis List
Renal infarction
Renal vein thrombosis
Acute tubular necrosis
Acute cortical renal necrosis
Pyelonephritis
Paroxysmal nocturnal hemoglobinuria with renal hemosiderosis
Final Diagnosis
Acute cortical renal necrosis
Case information
URL: https://eurorad.org/case/18489
DOI: 10.35100/eurorad/case.18489
ISSN: 1563-4086
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