Presented by: Arun Rai MD, MBA, MSc
Northwell Health

Introduction

The subcapsular renal hematoma (SRH) is a rare radiologic finding, but one with significant potential risks in the acute and chronic settings. In order to better understand the clinical sequelae and ramifications, the urologic community needs to better understand the clinical course of SRH, and the severity of possible complications during management.

Materials

A natural language processing search algorithm in Nuance mPower Clinical Analytics screened CT and MRI studies for “renal hematomas” across nine Northwell Health hospitals, including a Level 1 Trauma Center from 2011 to 2021. Patients with at least 3 cross-sectional exams to track progression and time to resolution were included. Retrospective chart review assessed etiology of hematoma, interventions and management of clinical sequelae.

Results

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We included 97 patients with acute diagnosis of SRH in the native kidney. Etiologies included traumatic (21%), spontaneous (32%), and iatrogenic causes (47%), as seen in Table 1. Three patients developed Page kidney with hypertension secondary to renin-angiotensin-aldosterone system activation, two of which had solitary kidneys, each requiring new hemodialysis or operative hematoma evacuation. The Page kidney with a contralateral functional kidney was managed conservatively. Six patients developed infected perinephric hematomas, five requiring drainage by interventional radiology (IR) and one requiring nephrectomy, on day 85, on average. 21 patients had perinephric bleeding requiring IR angiography, 17 of which underwent renal artery embolization. One patient had intractable pain, requiring operative hematoma evacuation on day 34. Another patient developed abdominal compartment syndrome requiring decompressive laparotomy. [RA1] 94 patients had repeat imaging within ten months, and 20 (21%) demonstrated hematoma resolution. 18 patients had imaging between 10 and 15 months, of which 8 (44%) had resolved. The average time to resolution was 368 days.

Conclusion

Subcapsular hematoma is a rare finding with only 97 identified in 10 years of a multi-hospital database. 35% of patients required intervention including hemodialysis, embolization and nephrectomy. The most common iatrogenic cause was renal biopsy. One third of spontaneous SRH required embolization, most commonly those with underlying renal masses. Page kidney phenomenon is rare (3%), but possibly more likely in solitary kidney.

Funding

None

Co-Authors

Elizabeth Lynch, MD
Northwell Health

Jacob Gaines, MD
Northwell Health

Justin James, BS
Sophie Davis School of Medicine

Zeph Okeke, MD
Northwell Health

David Hoenig, MD
Northwell Health

Jared Winoker, MD
Northwell Health

Arthur Smith, MD
Northwell Health