Renal pathology Flashcards
What are renal calculi?
Stones that form within the renal tract. Most stones are made from calcium (radiopaque) but others are made from struvite and uric acid crystals (radiolucent).
Signs and symptoms of renal calculi
- Asymptomatic
- Pain (suprapubic and loin pain that can radiate to the genital region)
- Dysuria
- Urinary tract infection
- Haematuria
Causes of renal calculi
- Idiopathic
- Hypercalcaemia
- Hyperuricaemia
- Hyperoxaluria
- Recurrent UTI
- Drugs eg loop diuretics
- Hereditary conditions increase risk eg polycystic disease
Renal calculi investigations
- 24 hour urine analysis: assess levels of calcium, uric acid, oxylate and citrate
- CT kidney, ureter, bladder (KUB) for radiopaque stones
- Ultrasound and IVU can also be utilised
- Chemical analysis of stone composition
Complications of renal calculi
- Recurrent UTI
- Recurrent calculi
- Obstruction
- Trauma to ureter / uretric stricture
Conservative treatment of renal calculi
Prevent cause: low calcium diet
Medical treatment of renal calculi
- Pain - anagesia and tamsulosin
- Dehydration - IV and oral fluids
- Nausea and vomiting - Antiemetics
- ↑ calcium - low calcium diet and stop thiazide diuretics if possible
- ↑ oxalate - low oxalate diet
- ↑ uric acid - allopurinol
Radiology treatment for renal calculi
- Nephrostomy insertion
- Antegrade ureteric stent insertion
Surgical treatment for renal calculi
- Antegrade or retrograde removal of large stones or staghorn calculus
- Extracorporeal shock wave lithotripsy (ESWL) for the treatment of larger stones (>0.5cm)
Signs and symptoms of lower urinary tract infection
- dysuria
- frequency
- urgency
- suprapubic pain
Signs and symptoms of upper urinary tract infection
- fever
- flank pain
- haematuria
Risk factors for UTI
- female gender
- sexual intercourse
- catheterisation
- pregnancy
- menopause
- diabetes
- genitourinary malformation
- immunosupression
- urinary tract obstruction
UTI causative organisms
- Escherichia coli: leading cause of UTI in the community and also nosocomial infection
- Staphylococcus saprophyticus: 2nd leading cause in sexually active females
- Klebsiella pneumonie: 3rd leading cause
UTI investigations
- Urine dipstick: positive for leucucytes and nitrates
- Urine culture: for diagnosis of causative organism (>10^5 organisms per mL of midstream urine)
- Radiology: consider ultrasound scan or cystoscopy if UTI occurs in children, in men or if UTI recurrent
UTI treatment
- Trimethoprim twice daily
- Consider prophylactic antibiotics if UTI recurrent
- If recurrent ie >4 times per year, seek to exclude anatomical variant or abnormality of the renal tract
UTI complications
- Pyelonephritis
- Renal failure
- Sepsis
Give examples of congenital kidney abnormalities
HERD
- Horseshoe kidney
- Ectopic kidney
- Renal agenesis
- Duplex ureters
What is a horseshoe kidney?
This occurs during development when the lower poles of both kidneys fuse, resulting in the formation of one horseshoe shaped kidney. This cannon ascend to the normal anatomical position due to the central portion catching the inferior mesenteric artery.
Signs and symptoms of horeshoe kidney
- Asymptomatic
- Recurrent urinary tract infection
- Renal calculi
- Obstructive uropathy
Investigations for horseshoe kidney
Ultrasound is diagnostic
Horseshoe kidney complications
- Susceptible to trauma
- Renal calculi formation
- Increased risk of transitional cell carcinoma of the renal pelvis
What is an ectopic kidney?
This is a congenital abnormality in which the kidney lies above the pelvic brim or within the pelvis
Signs and symptoms of an ectopic kidney
Usually asymptomtic
Causes of ectoptic kidney
- Genetic abnormalities
- Poor development of the metanephrogenic diverticulum
- Teratogen exposure
Investigations for ectopic kidney
Ultrasound scan is diagnostic
Treatment for ectopic kidney
None, treat symptoms should they develop
Complications of ectopic kidney
- UTI
- Renal caluli
What are duplex ureters?
This occurs when the ureteric bud splits during embryonic develpment and results in the development of two ureters, which drain one kidney.
Signs and symptoms of duplex ureters
- Asymptomatic
- Recurrent UTI
Investigations for duplex ureters
Ultrasound scan and excretory urography is diagnostic
Treatment for duplex ureters
Treatment of complications
Complications of duplex ureters
- Vesicoureteral reflux
- Ureterocele
- UTI
What is renal agenesis?
Bilateral and unilateral absence of the kidney
Signs and symptoms of bilateral absence of kidneys
Potter’s syndrome
- Low set ears
- Limb defects
- Receding chin
- Flat, broad nose
Signs and symptoms of unilateral absence of kidneys
- hypertension
- increased risk of respiratory failure
- proteinuria
- haematuria
Investigations for renal agenesis
Antenatal screening
Treatment for bilateral renal agenesis
- Neonates usually die a few days after birth
- If they survive they require chronic peritoneal dialysis
