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- “Late or delayed complications of renal trauma develop more than 4 weeks after injury and include hypertension, hydronephrosis, calculus formation, and chronic pyelonephritis.”
Kidney in Danger: CT Findings of Blunt and Penetrating Renal Trauma Alonso RC et al. RadioGraphics 2009; 29:2033–2053 - “Posttraumatic renovascular hypertension may occur anywhere from a few weeks to decades fol- lowing injury, but on average occurs within 34 months. Several mechanisms have been proposed for its development, including renal artery occlusion, stenosis (Goldblatt kidney),
or compression; severe renal contusion; arterio-venous fistula or pseudoaneurysm formation; and chronic contained subcapsular hematoma.”
Kidney in Danger: CT Findings of Blunt and Penetrating Renal Trauma Alonso RC et al. RadioGraphics 2009; 29:2033–2053 - “The term Page kidney refers to hypertension secondary to constrictive ischemic nephropathy caused by large chronic subcapsular hematomas, which exert a mass effect on the adjacent renal parenchyma, indenting or flattening the renal margin.This condition may lead to diminished renal perfusion, fibrosis, and scarring.”
Kidney in Danger: CT Findings of Blunt and Penetrating Renal Trauma Alonso RC et al. RadioGraphics 2009; 29:2033–2053 - “At CT, typical findings include a delayed nephrogram
of the kidney and a surrounding fibrotic band that may be calcified. Because spontaneous resolution of posttraumatic hypertension
has been reported in many studies, conservative and pharmacologic treatment is strongly advised. Surgery, including renal revascularization, partial nephrectomy, or even total nephrectomy, is the second step in the management of posttraumatic hypertension.”
Kidney in Danger: CT Findings of Blunt and Penetrating Renal Trauma Alonso RC et al. RadioGraphics 2009; 29:2033–2053 - “Approximately 10% of all significant blunt ab- dominal traumatic injuries manifest with renal injury, although it is usually minor. Contrast- enhanced CT is the imaging modality of choice in the evaluation and management of renal trauma, since it provides essential anatomic and func- tional information. Renal imaging is indicated in cases of (a) penetrating trauma and hematuria; (b) blunt trauma, shock, and hematuria; and
(c) gross hematuria.”
Kidney in Danger: CT Findings of Blunt and Penetrating Renal Trauma Alonso RC et al. RadioGraphics 2009; 29:2033–2053
- When to order a CT in cases of trauma for the kidneys?
- Penetrating trauma and hematuria
- Blunt trauma, shock and hamaturia
- Gross hematuria
- Kidney in Danger:CT Findings of Blunt and Penetrating Renal Trauma Alonso RC et al. RadioGraphics 2009; 29:2033-2053 - AAST Renal Injury Scale: Facts
- Grade I injuries are most common (75-85% of cases)
- Grade 5 is a shattered kidney and means the kidney is in multiple fragments. UPJ avusion can occur and then the patient may have no hematuria
- Most common form of renal pedicle injury is renal artery occlusion - AAST Renal Injury Scale: Grade I
- Normal contusion- microscopic or gross hematuria with normal urologic findings
- Hematoma- nonexpanding subcapsular hematomas with no laceration - AAST Renal Injury Scale: Grade II
- Hematoma- nonexpanding perinephric hematoma confined to the retroperitoneum
- Laceration- superficial cortical laceration less than 1 cm without collecting system injury - AAST Renal Injury Scale: Grade III
- Laceration- renal lacerations greater than 1 cm in depth without collecting system injury - AAST Renal Injury Scale: Grade IV
- Laceration- renal lacerations extending through the renal cortex, medulla, and collecting system
- Vascular injury- injuries involving the main renal artery or vein with contained hematoma, segmental infarctions without associated lacerations - AAST Renal Injury Scale: Grade V
- Laceration- shattered kidney, UPJ avulsions
- Vascular injury- complete laceration (avulsion) or thrombosis of the main renal artery or vein that devascularizes the kidney - AAST Renal Injury Scale
Grade of InjuryType of InjuryI Normal contusion or small hematomaII Hematoma or <1cm lacerationIII Laceration >1cmIV Laceration (deep) or vascular injuryV Laceration (shattered kidney) or vascular injury (avulsion)
- Renal Trauma: AAST Grading System
- Based on surgical findings
- Useful tool to predict outcomes
- The 5 categories "arranged in order of increasing severity according to depth of injury and involvement of the vasculature or collecting system, and correlates well with any abnormalities seen on CT" "The increased use of CT has been partially responsible for a growing trend toward conservative management of renal trauma, except in cases in which extensive urinary extravasation or devitalized areas of renal parenchyma are found and especially in those cases with associated injuries to other abdominal organs."
Kidney in Danger:CT Findings of Blunt and Penetrating Renal Trauma
Alonso RC et al.
RadioGraphics 2009; 29:2033-2053"The reduced radiation CT protocol (30 mAs) resulted in similar detection of renal stones 3.0 mm or larger compared with the standard radiation protocol (100 mAs) while reducing patient exposure by as much as 70%."
Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi
Jin DH et al
Radiology 2010; 255;100-107"Detection of 2.0 mm stones is difficult, even with standard CT protocols by using 5 mm section reconstruction; this may lead to a significant overestimation of sensitivity in clinical studies where a conventional CT scan is used as a reference standard."
Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi
Jin DH et al
Radiology 2010; 255;100-107"Decreasing the tube charge from 100 to 30 mAs resulted in similar detection of renal stones while reducing patient radiation exposure by as much as 70%. Multidetector CT scanning parameters should be tailored to minimize radiation exposure to the patients while helping detect clinically significant renal stones."
Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi
Jin DH et al
Radiology 2010; 255;100-107