Definition
Perinephric stranding is the attenuation of soft tissues in the perinephric space. It is the manifestation of an increased pressure within the collecting system in the early phase of ureteral obstruction.Perinephric space is a compartment that contains the kidney, adrenal gland, perinephric fat, fibrous bridging septa and a rich network of perineal vessel and lymphatics. Perinephric is a connective fatty tissue that surrounds the kidney. It is an adipose capsule of kidney which is a structure between the renal fascia and renal capsule.
Perinephric space is divided into multiple compartments by fibrous lamellae. These lamellae are known as the bridging septa where some of these structures arise from the renal capsule and extend to the perinephric fascia. Other structures of the bridging septa are attached only to the renal capsule arranged parallel to the renal surface.
Causes and Pathophysiology
Perinephric stranding involves mostly the urinary system especially the kidney. Stranding is known to have result from any acute process of any form of injury to the kidney.The urinary system composed of the kidney, bladder, ureters and urethra. These components are integral in regulating the fluids and electrolytes and acid-base composition of body fluid. The urinary system is also vital in removing the metabolic end products from the blood and regulates blood pressure.
Disruption in the urinary system will lead to various diseases and disorders as it affects the whole functioning system of the body. Acute process and any form of injury to the kidney resulting to perinephric stranding include:
Perinephric Abscess
Infection of the kidney from any offending organism such as Staphylococcus or from hematogenous infection can result to renal abscess extending into the fatty tissue surrounding the kidney. The perinephric abscess is a collection of purulent material in the perinephric space or the kidneys. Onset of manifestation is acute and characterized with chills, fever, and leukocytosis, dull or palpable mass in the flank and abdominal pain with tenderness on palpation.The abscess is located between the capsule of the kidney and the Gerota fascia in which the abscess remained confined. About 30% of perinephric abscess resulted from hematogenous infection of organisms from other site or distal site of infection from other part of the body. Rupture of infection through the Gerota fascia leads to perinephric abscess and even perirenal hematoma can also lead to perinephric abscess.
Management of perinephric abscess is through incision and drainage of the abscess by insertion in the perinephric space until all significant drainage has stopped. Antimicrobial therapy is also prescribed and patient is monitored for sepsis, fluid input and output and the general response of the patient to the treatment.
Ureteral Obstruction
This is a potentially curable form of kidney disease that is a common cause of acute and chronic renal failure as a result of obstruction in the urinary system.Perinephric stranding is a manifestation of an increased intraluminal ureteral pressure as a result of obstruction in the urinary tract at any level. Increased hydrostatic pressure is directly transmitted to nephron tubules with prolonged period of urinary obstruction. Significant pain is associated with most of obstructive uropathies and with sudden decreased in the urine flow which should alert health professionals for further evaluation and treatment. The increased pressure in the collecting system is evident through palpable kidney or bladder in the early phase of ureteral obstruction.
The goal of treatment and management for ureteral obstruction is the reestablishment of the urinary flow and begin treatment of life-threatening complications.
Renal Trauma
The kidneys are normally protected by the rib cage and musculature of the back posteriorly and anteriorly by the cushion of the abdominal wall and viscera. The kidneys are highly mobile and fixed only at the renal pedicle. Traumatic injury can potentially thrust the kidney against the lower ribs which may result to contusion and rupture.Various forms of injuries in the flank, back or upper abdomen can subject the kidneys to bruising, lacerations or actual rupture of the kidney. The injury may be blunt, such as motor vehicle accident, falls and athletic injury, or it may be penetrating such as gunshot wound or stab wound. Massive bleeding can occur even with a fairly small renal laceration as the kidneys receive half of the blood flow from the abdominal aorta.
The immediate management for renal trauma is control of hemorrhage, pain and infection and to preserve and restore renal function to maintain urinary drainage.
Diagnosis
Spiral CT Scan is the imaging modality of choice in diagnosing perinephric stranding as well as in studying and imaging suspected urinary calculi. The advantage of this imaging mode is in accuracy and rapidness in imaging abdomen in a single procedure.Thin images and small stones can be obtained and identified with Spiral CT Scan with the elimination of risk in contrast reaction. The imaging can be performed in less than five minutes obtaining visual of the entire genitourinary tract system including the opposite kidney.
Perinephric stranding is more identified and obtained through Spiral CT Scan which is less commonly seen in intravenous pyelogram.
Treatment
Treatment of perinephric stranding depends on the existing underlying condition. Perinephric stranding is a clinical manifestation arising from any acute process of the urinary system and an injury to the kidney in any form.Preservation and restoration of renal function to gain and maintain optimal health is the purpose of treatment and management. Prevention of life-threatening complication is also geared in treatment and management.
Accurate diagnosis must be obtained prior to administration of therapeutic medication and other medical therapy or procedures to achieve the goal for a continued well being of the patient.
