Week 109 - Renal Colic Flashcards
In L/min what is the approximate Renal blood flow?
1.5L/min
Fluid and electrolyte balance takes place by the glomerulus and tubular resorption, what are the four controlling mechanisms?
ADH, Aldosterone, Macula Densa and Renin.
How does ADH control resorption of water?
- ADH is secreted by the posterior pituitary gland.
- It binds to Vasopressin II receptors on the wall of the collecting duct.
- This triggers a cascade; Adenylate Cyclase converts ATP>cAMP, the increased levels of cAMP trigger aquaporin-2 channels to move into the membrane allowing for greater reabsoprtion.
What triggers the secretion of ADH and where from?
• From the posterior pituitary gland, due to an increase in plasma osmolality or a decrease in plasma volume. And stimulation by Angiotensin II.
Where are the pressure receptors that detect reduced plasma volume?
In the carotids, veins and atria.
What receptors detect change in plasma osmolality and where are they located?
Osmoreceptors in the hypothalamus.
Where is Aldosterone secreted from and what causes it’s secretion?
Adrenal Cortex, Increased plasma levels of Angiotensin II and III and stretch receptors in the atria of the heart.
What does Aldosterone do?
It is the principle regulator of salt and water balance in the body. It binds to receptors in the distal tubule and collecting duct and upregulates the Na/K pumps, pumping K into the urine and Na into the blood, it causes a retention of water.
Where is the macula densa and what does it detect?
Specialised cells in the walls of the distal tubule, detect Na levels in the distal tubule.
When macula densa detects a low Na level what two actions does it take?
- Dilates afferent arterioles, decreasing resistance of the afferent arterioles, causing greater flow to the glomerulus.
- Releases prostaglandins that cause juxtaglomerular cells to release Renin.
Where is Renin synthesised, stored and secreted?
Juxtaglomerular cells that are mainly in the walls of the afferent arterioles of the nephron.
Renin is secreted for juxtaglomerular cells in response to which 3 stimuli?
1) A decrease in arterial blood pressure detected by baroreceptors.
2) Protaglandins secreted by the macula densa.
3) Sympathetic stimulation.
What does Renin do?
Renin, also known as angiotensinogenase, hydrolyses angiotensinogen into angiotensin I.
What converts angiotensin I into angiotensin II?
Angiotensin-converting Enzyme (ACE)
What is ACE and what does it do?
Angiotensin-converting Enzyme, converts angiotensin I into angiotensin II.
Where is ACE secreted from?
Mainly from the lungs but also the kidneys.
What are the five actions of Angiotensin II?
1) Increase in sympathetic activity.
2) Tubular Na,Cl resorption; K excretion; water retention.
3) Increased secretion of Aldosterone.
4) Vasoconstriction > Increased blood pressure.
5) Increased ADH secretion.
There are three types of significant Haematuria what are they?
1) Visible haematuria
2) Symptomatic non-visible haematuria (sNVH)
3) Persistant asymptomatic non-visible haematuria.
What are the initial investigations for Haematuria?
1) Exclude UTI or other transient causes.
2) Plasma creatinine/ eGFR
3) Proteinurea
There are three types of patient that should have a urological referral with haematuria, what are they?
1) Any patient with visible haematuria.
2) Any patient with sNVH.
3) Patient >40yrs with aNVH.
What are some of the causes of haematuria?
Stones, UTI, Trauma, Urothelial Malignancy, Benign prostate hypertrophy, Bladder Tumour, Prostate cancer, Kidney tumours, Nephrological causes.
What is the most common type of Kidney cancer and how much does it account for?
Renal Cell Carcinoma, 85%.
What is a definition of Renal Colic?
‘Kidney Pain’ begininning in the abdomen and often radiating to the hypochondrium or groin. Is often ‘colicky’ due to peristalsis but can be constant.
What initial investigations (excluding imaging) should be performed for renal colic?
Urine dipstick, Midstream urine for microscopy and culture, Blood tests, Pregnancy test (if of reproducing age.)
What is the gold standard of imaging for renal colic?
Non-contrast CT.
Non-contrast CT is the gold standard for investigating Renal Colic, what are the advantages?
- Quick
- Almost all stones are visible
- High sensitivity and specificity
- Can identify non-urological pathology.
What imaging tests are recommended for investigation of Renal Colic?
- KUB X-ray - simple but 10% of stones are radiolucent.
- IVU - Intravenous Urogram - Depends on renal function and allergy may occur to dye (interaction with metformin)
- USS - Ultrasound - Quick and widely available but easy to miss stones.
Referral to the metabolic clinic is recommended in some patients, what six types of patient?
1) All recurrent stones.
2) All non-calcium stones.
3) Family History.
4) Age <25 years
5) Disease associated with stones.
6) Single kidney and any stone event.
For uncomplicated stone disease, what will the metabolic clinic look at?
Stone analysis, blood analysis and urine dipstick.
In complicated stone disease the metabolic clinic looks at the same as uncomplicated stone disease (stone analysis, blood analysis and urine dipstick) and which additional test?
Urine analysis; Ca, oxalate, citrate, urate, magnesium, phosphate, urea, sodium, potassium, creatinine, volume.
What are the three common sites of obstruction for renal stones?
1) Pelviureteric junction.
2) As the ureter arches over the iliac vessels.
3) Vesicoureteric junction.
If a patient had a urinary stone but with no sign of obstruction what would the management be?
NSAIDS, depends on size of stone.
6mm 10% pass spontaneously, intervention likely.
If a patient had an obstructed ureter but no sign of sepsis what would the management be?
NSAIDS, Admission, may be allowed home for trial passing. Depends on size of stone.
6mm - 10 % pass spontaneously.
If a patient had an obstructed ureter and signs of sepsis, what would the management be?
- NSAIDS
- 1g IV ampicillin
- IV Gentamicin
- Nephrostomy or uteric stent.
Removing a stone (Renal): What method is used for 85% of stone removals?
Extracorporeal shock wave Lithotrpisy.
Removing a stone (Renal): What type of removal is ideal for distal stones?
Ureteroscopy.
Removing a stone (Renal): What type of procedure is used for removing calyceal, staghorn/large renal stones?
Percutaneous Neprolithotomy (PCNL) - keyhole procedure, a nephrostomy is needed afterwards.
Urgent drainage via a stent or nephrostomy is sometimes needed in which four cases?
1) Acute obstruction.
2) Infected obstructed kidney.
3) Non-progression on conservative management.
4) Persistant pain.
Which type of stone accounts for 70% of all urinary stones?
Calcium oxalate.
Accounting for 15-20% of stones what is the second most common type of urinary stone?
Infective stones - Struvite (Magnesium Ammonium Phosphate) caused by infectious agents converting urea to ammonia.
What are the four types of stone, what is their prevalence and what is their cause?
1) Calcium Oxalate (70%) - Higher calcium concentration in urine, but unclear.
2) Struvite - (15-20%) Magnesium Ammonium Phosphate - caused by infective agents converting urea into ammonium.
3) Uric Acid (5-10%) - 50% caused by hyperuricaemia)
4) Cystine (1-2%) - Caused by a genetic defect.
