A Clinical Guide to Urologic Emergencies

Hunter Wessells, Shigeo Horie, Reynaldo G. Gómez, Hunter Wessells, Shigeo Horie, Reynaldo G. Gómez

• Publisher: Wiley-Blackwell
• Year: 2021
• ISBN:
  9781119021490
• Edition: 1
• Topic: Medicina
• Subtopic: Urología

A Clinical Guide to Urologic Emergencies

A Clinical Guide to Urologic Emergencies

An ageing population and a predicted shortfall in the number of urologists means that, increasingly, the management of complex urological problems will fall to hospital emergency departments and the surgeries of primary care physicians. With many doctors and medical students now having less exposure to urology, there is a real and urgent need for accessible and practical guidance in managing urologic emergencies.

A Clinical Guide to Urologic Emergencies offers practical guidance to the best practices in diagnosis, treatment and management of patients with urgent urological conditions. Designed to be an extremely useful tool to consult in the clinical setting, it will be a vital source of information and guidance for all clinicians, irrespective of their level of urologic knowledge.

Edited by an outstanding international editor team, this book is particularly aimed at physicians, advanced practice providers, and urology and emergency medicine trainees managing patients in diverse healthcare settings across the globe.

A Clinical Guide to Urologic Emergencies is accompanied by a website featuring video content at www.wiley.com/go/wessells/urologic

Section I
Upper Urinary Tract

1
Blunt Renal Injuries

Lindsay A. Hampson and Nnenaya Mmonu

Department of Urology, UCSF School of Medicine, San Francisco, CA, USA

Epidemiology, Etiology, Pathophysiology

Epidemiology and Etiology

Kidneys are the most injured genitourinary organ in external trauma, and it is estimated that 1–5% of all traumas and 10% of abdominal traumas sustain a renal injury [1–4]. In a series consisting purely of blunt abdominal trauma mechanism, 15% of patients were found to have an injury to the kidneys [5]. Of all patients who sustain genitourinary trauma, over half of them involve the kidney [6]. A population‐based study found the incidence of renal trauma to be 4.9 per 100 000 population ≥16 years of age in the United States [4]. The majority of these patients were young and male, with 72% between the ages of 16 and 44 and 75% male. In an analysis of pediatric genitourinary injuries, renal injuries were found to make up 3.5% of the cohort, but the incidence has not been defined [7].

There is variation in the etiology of renal trauma based on geographical location; series from Low and Middle‐Income Countries (LMIC) suggest that the rates of penetrating trauma are high, with the majority of blunt trauma caused by road traffic accidents, assault, and falls [8–11]. In the More Economically Developed Countries (MEDC), the vast majority (90–95%) of renal injury is sustained by blunt trauma, which is caused by motor vehicle collisions (63%), falls (14%), sports injuries (11%), pedestrian accidents (4%), motorcycle crashes (2%), assault (2%), and the remaining from other causes [6, 12, 13]. In a recent blunt renal trauma series, 80% of injuries were found to be grade I–II renal injuries, 9.5% grade III, 8.1% grade IV, and 2.7% grade IV [5]. Thus, imaging all renal injuries is unnecessary, and criteria have been developed (see below). Table 1.1 summarizes the large (n > 100) series with emphasis on blunt injuries.

Table 1.1 Demographics of renal trauma.

SERIES ^a	[6]	[14]	[15]	[1] ^b	[4]	[16]	[5] ^b	[17]	[18]	[19]
Year published	1984	1986	1995	2001	2003	2012	2012	2013	2013	2014
Renal injury (N)	154	132	2254	227	6231	1505	221	338	9002	105
Renal injury (%)	2.9	3.25	n/a	1.4	1.2	n/a	n/a	n/a	n/a	n/a
Blunt (%)	93.5	95.4	89.8	93.4	81.6	95.0	100	96.2	82.0	96.1
Penetrating (%)	6.5	4.6	10.2	6.6	18.4	5.0	0	3.9	17.8	3.9
Grade IV–V (%)	n/a			14.6			10.9	29.3	21.1	23.5
Initial non‐operative management among all trauma (%)		92.6	92.6	n/a	88.6	94.5	n/a	92.6	86.8	98.0
Initial non‐operative management among blunt trauma (%)			98.3	89.5/92.9?	96.3		92.3	92.6	94.4
Nephrectomy (%) among all trauma	3.8	3.2			7.9	3.1	n/a	7.1	8.6	1.9
Nephrectomy (%) among blunt trauma			0	7.2	3.3		5.4	7.4	4.7

Blank cells indicate missing data.

^a Series with N < 100 not included.

^b Data showing grade and management of blunt renal injuries only.

Pathophysiology

Blunt trauma injury to the kidney is thought to occur as a result of kinetic energy transmission, often as a consequence of rapid deceleration forces or direct interaction of structures in the environment with the soft tissues and bones of the flank and then the kidney. Studies using animal models have shown that the kidney has viscoelastic properties and that damage occurs as a result of stresses that cause tissue deformations exceeding an impact energy threshold of 4 J [20, 21]. A three‐dimensional animal model also demonstrated that the primary site of load‐bearing, where injuries result from, is the junction between the renal pelvis and the renal cortex [21]. Research has also demonstrated that the kidney with a fluid‐filled structure (i.e. ureteropelvic junction obstruction, hydronephrosis, or renal cyst) may be more prone to rupture due to the hydrostatic pressure and resulting distribution of forces within the kidney [20, 22].

Children may have a higher risk of significant renal injury from blunt trauma and this is thought to be related to the proportionately larger kidney for their body size as compared to that of adults, the possibility of children retaining fetal lobulations that may predispose to parenchymal disruption, and the pediatric kidney having less protection due to lower perirenal fat content, weaker abdominal muscles, and less ossification of the rib cage [23, 24].

The proportion of patients with renal trauma found to have congenital anomalies varies, depending on different series, ranging from 1 to 23% [23]. One series that reviewed 193 pediatric renal trauma patients found that just over 8% of patients had a congenital anomaly [25]. Data regarding renal trauma and congenital a...