What Is Acute Kidney Injury?

Acute kidney injury is also referred to as kidney trauma or kidney injury. After violent action on the injured kidney, it causes structural changes in the kidney tissue.

Acute kidney injury

Acute kidney injury is also referred to as kidney trauma or kidney injury. After violent action on the injured kidney, it causes structural changes in the kidney tissue.

Chinese name

Acute kidney injury

Foreign name

Acute renal injury

Meaning

Violence in the kidneys, structural changes in the tissues

Classification

Open and closed injuries

Renal trauma is divided into open injury and closed injury. Open injuries are seen in bullet, bayonet, and dagger injuries. There are many reasons for closed injuries, such as direct violent impacts, falls, traffic accidents, and being hit by others or balls during sports. In addition, spontaneous rupture and iatrogenic kidney injury under renal pathological conditions are all closed injuries. According to the degree of kidney injury, kidney trauma is divided into 4 types: Renal injury can be divided into: renal contusion. The main changes are edema and small focal hemorrhage in the renal parenchyma; incomplete renal laceration, renal parenchyma and pelvic laceration are partial, and there may be intrarenal hematoma or subcapsular hematoma; complete renal laceration, that is, parenchyma Penetrating laceration. In severe cases, the kidney ruptures into several pieces of tissue. The renal pelvis is severely lacerated. There is often a large amount of bleeding inside and outside the kidney and extravasation of urine. Renal pedicle injury is the rupture or rupture of renal pedicle blood vessels.

In addition to having a history of trauma, the following symptoms can occur:

1. Low back pain: It is pain on the injured side of the waist or upper abdomen, which can be accompanied by tenderness and throbbing pain, and severe injuries can have lumbar muscle tension and rigidity.

2. Lumbar lump: Caused by perrenal hematoma and / or extravasation of urine.

3. Hematuria: It is the most common and important symptom, the incidence rate is as high as 80% -100%. Including microscopic hematuria and gross hematuria.

4 Shock: Occurs during severe injury.

5. Others: such as bloody ascites (caused by kidney rupture and rupture into the abdominal cavity) and combined injuries of other organs.

1. Urography: It is the main examination method for patients with kidney injury. However, the angiography is often without obvious abnormalities or poor imaging, and the surrounding conditions of the kidney cannot be directly displayed. Only when there is a laceration of the renal pelvis, it can be seen that the contrast agent penetrates into the parenchyma or even around the kidney. Occasionally due to intrahepatic hematoma, compression and deformation of the renal pelvis and pelvis can be seen.

2. Angiography: If there is a blood vessel rupture, the angiographic arterial phase can show extravasation of intravascular contrast agent. When there is a renal parenchyma, the renal parenchyma shows irregular kidney defects or dissociation into fragments; if there is an intrarenal hematoma, the branch of the blood vessel can be dislodged; if the subcapsular hematoma is seen, the capsule capsule is separated from the kidney, The contour is arc-shaped. Angiography can also confirm post-traumatic aneurysms and arteriovenous fistulas.

3.B-ultrasound performance: renal contusion: slight enlargement of the outline of the kidney, limited hyperechoic bands or smaller hypoechoic areas in the superficial layer of the renal parenchyma. A small subcapsular hematoma can produce a corresponding echo. Renal laceration: The kidneys often have diffuse enlargement, the renal capsule bulges outward, there is no echo zone under the capsule, and the renal parenchyma shows irregular hypoechoic margins. The renal sinus can be deformed, enlarged, and the boundary with the renal cortex is unclear. There is blood in the renal pelvis, which shows that the renal pelvis and calyx are separated to different degrees. expansion. Those who completely break or break into several pieces are mixed with hematoma and blood clot in the renal lipid sac, and the structure is fuzzy. Renal pedicle injury: The ureter is broken at the junction with the renal pelvis, and a large amount of urine accumulates in the renal hilum, forming a hypoechoic area, but sometimes the B-ultrasound is not easy to show the fracture opening.

4. CT manifestations: Renal contusion can indicate that the kidney is large, and the substantial enhancement is delayed or not strengthened after enhancement. Partial or complete laceration of the kidney, CT can clearly show the location, scope, and presence or absence of hematoma. Fresh hematoma is high density, and extravasation is low density. Depending on the location, hematomas can be distinguished in the kidney, under the kidney capsule, or around the kidney. The latter can have a mixed density due to the presence of fibrous spaces and fat in the perirenal space. If the contrast scan shows extravasation after the enhancement, it indicates that the laceration extends to the collection system. A few days after the injury, the hematoma became low density as hemoglobin was gradually absorbed. Subrenal or perrenal hematomas are often shown as extrarenal crescent or semilunar low-density shadows surrounded by a renal envelope or a perifacial fascia. Extrarenal urocysts can also show similar extrarenal low density shadows.

5. MR manifestations: The diagnostic principles are basically similar, but the manifestations of subacute and chronic hematomas are more characteristic than CT.