Renal disease: post-renal Flashcards
(39 cards)
What is post-renal disease?
Post-renal disease refers to a condition that occurs distal to the nephron, involving the intrarenal collecting system, ureter, bladder, prostate, or urethra.
What is the main cause of post-renal disease?
The main cause of post-renal disease is obstruction, which can lead to the development of hydronephrosis and/or hydroureter.
What are the consequences of acute ureteric obstruction?
Acute ureteric obstruction can result in dilatation of the afferent arteriole, increased glomerular filtration rate (GFR), increased tubular pressure, reduced flow at the macular densa, release of renin, and the production of prostaglandins (PgI, PgE) and nitric oxide.
What happens during Phase 1 of acute ureteric obstruction?
Phase 1, which occurs within the first 0-90 minutes, is characterized by increased tubular pressure, reduced flow at the macular densa, release of renin, prostaglandins (PgI, PgE), and nitric oxide, as well as dilatation of the afferent arteriole and increased GFR.
What happens during Phase 2 of acute ureteric obstruction?
Phase 2, which occurs between 90 minutes to 4 hours, is characterized by sustained increased tubular pressure, reduced filtration pressure, and decreased glomerular filtration rate (GFR). There is no further dilatation of the afferent arteriole.
What occurs during Phase 3 of acute ureteric obstruction?
Phase 3, which takes place from 4 hours to 18 hours, involves afferent vasoconstriction, shunting of blood flow from the outer to inner cortex, lack of perfusion of many glomeruli, reduced glomerular colloid osmotic pressure, and reduced tubular pressure. Glomerular shutdown and decreased GFR are also observed.
What are the consequences of chronic obstruction in the urinary tract?
Chronic obstruction can lead to dilatation of tubules, interstitial fibrosis, relatively preserved glomeruli, damage to collecting ducts and distal tubules in the medulla, and obstructive atrophy. In dogs, nephron loss occurs after 4-7 days, and little recoverable renal function is observed after 1 month.
What are the symptoms of urinary tract obstruction?
Symptoms of urinary tract obstruction include flank pain, urinary tract infection with flank pain, pain after drinking, haematuria (blood in urine), exercise-induced haematuria, and it can also be a chance finding.
What are the functions affected by chronic obstruction in the distal tubules?
Chronic obstruction can affect the concentration of urine, excretion of H+ (hydrogen ions), and excretion of K+ (potassium ions) in the distal tubules.
Is urinary tract obstruction considered an emergency?
Yes, urinary tract obstruction is considered an emergency.
What are the initial investigations for urinary tract conditions?
Initial investigations may include renal function tests, a full blood count, prostate-specific antigen (PSA) test (for males), urinalysis, urine culture, blood gases, and imaging.
What imaging techniques are used for urinary tract evaluation?
Ultrasound scan and CT scan are commonly used for imaging the urinary tract. Ultrasound scan can detect dilated renal pelvis, while a non-contrast CT scan (CT KUB) is used to identify stones in the upper right ureter. However, it is important to note that stones can be missed on contrast CT scans.
What is dynamic renography and what does it measure?
Dynamic renography is a technique that involves the use of Technetium-99m labeled MAG3 (Mercapto Acetyl Tri Glyceride) to measure blood flow and assess obstruction. The initial uptake of the tracer is used to measure blood flow, and the area under the curve is calculated to evaluate kidney function. The rate of washout quantifies the degree of obstruction.
What is MAG3?
MAG3 is a radiopharmaceutical used in dynamic renography for evaluating kidney function and assessing obstruction in the urinary tract.
What should be considered when performing a CT scan for urinary tract evaluation?
When performing a CT scan, particularly for identifying stones, it is important to be aware that stones can be missed on contrast CT scans.
What is MAG3 renography used for?
MAG3 renography is a diagnostic imaging technique used to evaluate kidney function and assess obstruction in the urinary tract.
How is acute obstruction in the urinary tract treated as an emergency?
The emergency treatment of acute obstruction may include relieving the obstruction through measures such as ureteral stenting or nephrostomy tube placement to restore urine flow and relieve symptoms.
What are the causes of obstruction in the urinary tract?
Obstruction in the urinary tract can be classified based on the location of the obstruction. It can occur in the lumen of a tube (e.g., stones), within the wall (e.g., tumors, strictures), or outside the wall (e.g., lymph nodes, tumors, retroperitoneal fibrosis). Obstruction can also occur at different levels, including the pelviureteric junction, ureter, or bladder outflow.
What are the common types of urinary tract stones?
The most common types of urinary tract stones are calcium oxalate and phosphate stones, often mixed together. Staghorn stones, which are large and fill the renal pelvis, are typically composed of triple (calcium, magnesium, ammonium) phosphate and are associated with infection. Uric acid stones are associated with gout and acidic urine. Cystine stones are rare and associated with a genetic disorder called cystinuria.
What are the common symptoms of ureteric colic?
Ureteric colic is characterized by severe pain, nausea and vomiting, intermittent waves of pain, restlessness, pain radiating from the loin to the groin, urinary frequency (strangury), and blood in the urine.
What are the treatment options for urinary tract stones?
The treatment options for urinary tract stones include extracorporeal shockwave lithotripsy (ESWL), ureteroscopy, and cystolitholapaxy.
What is extracorporeal shockwave lithotripsy (ESWL)?
Extracorporeal shockwave lithotripsy (ESWL) is a non-invasive procedure used to break down urinary tract stones into smaller fragments using shockwaves generated outside the body. It is typically used for the treatment of kidney stones or larger stones in the upper urinary tract.
What is ureteroscopy?
Ureteroscopy is a procedure that involves inserting a thin tube with a camera (ureteroscope) into the ureter to visualize and remove or break down urinary tract stones. It may be combined with laser stone fragmentation or the use of ureteric baskets to remove or extract the stone fragments.
What is cystolitholapaxy?
Cystolitholapaxy is a procedure used for the fragmentation and removal of bladder stones. It involves inserting instruments through the urethra to access and break down the bladder stones.
