Kidney stones and calcium Flashcards Preview

Urinary (Semester 3) > Kidney stones and calcium > Flashcards

Flashcards in Kidney stones and calcium Deck (28)
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1
Q

What are the 3 principle organs calcium is found

A

bone, gut, kidneys

2
Q

What is the mechanism of PTH?

A

Increases blood calcium…

  1. acts on DCT to increase resorption
  2. increases osteoclast activity: breaks down bone `
3
Q

After which surgery should you closely monitor calcium levels?

A

A thyroidectomy as by removing the thyroid you may accidentally remove the parathyroid gland

4
Q

Which hormone increases the intestinal absorption of calcium?

A

Calcitriol/Vit D

5
Q

Explain how Vitamin D goes from the sun/food to active calcitriol

A
  1. 7-dehydrocholesterol is in the skin and is converted into D3 cholecalciferol with UV, undergoes 2 hydroxylations:
    D3 travels through circulation bound to transcalciferin, so only a small fraction is free
    First hydroxylated to 25 hydroxyl Vit D in the liver
    Kidney hydroxylates it into final calcitriol
  2. D2 is from yeast and fungi and is converted in the liver and kidney into calcitriol
6
Q

Where does calcitonin come from?

A

Parafollicular cells in the thyroid gland

7
Q

What does calcitonin do?

A

Decreases blood calcium:

  1. Inhibits bone resorption by inhibiting osteoclasts
  2. Decreases kidney resorption
  3. Ensures calcium in the diet is being incorporated into bone
8
Q

Define the following terms:

a) urolithiasis
b) nephrolithiasis
c) renal colic

A

a) urolithiasis: formation of stones anywhere in the upper urinary tract
b) nephrolithiasis: formation of stones in kidney
c) renal colic: the diagnosis of acute and severe pain due to a stone not being passed

9
Q

Try to name 9 risk factors for developing a kidney stone

A
  1. Dehydration
  2. urine pH
  3. Age and gender
  4. FH: 2X increased risk
  5. Obesity
  6. Diet and Drugs: Vit D supplements, protease inhibitors, diuretics can increase calcium concentration in the urine
  7. Anatomical abnormalities; one kidney
  8. Certain diseases that cause hypercalcemia or affect absorption in the bowels, E.G; gout, Crohn’s, hypertension
  9. Renal failure
10
Q

What are the 5 types of stones? What features are associated with each type?

A
  1. calcium salts (80%): low urine volume, raised urine pH, higher urinary concentrations of calcium, phosphate, oxalate, etc. and low concentration of natural inhibitors that might keep urine pH normal (e.g; citrate and magnesium)
  2. Uric acid: associated with hyperuricosuria - lots of uric acid in urine
  3. Struvite stones: magnesium, phosphate and ammonium from bacterial infections that hydrolyzed urea into ammonium - raises urinary pH
  4. Cystine stones: from cystinuria which is a genetic condition
  5. Other substances: e.g; xanthene
11
Q

Describe the pain associated with renal colic

A

Radiates up the loins and flanks, and fluctuates in intensity

12
Q

List 4 other possible symptoms of kidney stones other than pain

A
  1. restlessness
  2. vomiting
  3. hematuria: due to damage to the epithelia
  4. Obstruction can cause infections; leading to fever, sweats, dysuria, etc.
13
Q

List the 3 main locations where a kidney stone can get stuck

A
  1. Ureteropelvic junction: leaving kidney
  2. Mid ureter/pelvic inlet
  3. Ureterovesical junction: entrance to bladder
14
Q

What is the differential diagnosis for kidney stones?

A
  1. Ruptured AAA
  2. If loin pain on R side: appendicitis
  3. If pain on L side: diverticulitis: inflamed pouches in lining of the intestine, common in elderly
15
Q

What 2 investigations might you do in someone presenting with symptoms alike to a kidney stone?

A
  1. Urinalysis: looking for hematuria, nitrites and leukocytes can indicate an infection
  2. Blood test: see if there is urea, creatinine and electrolytes
    FBC
    CRP: c reactive protein indicates inflammation
    Blood cultures
16
Q

When would you admit a patient for kidney stones? (5 things)

A
  1. systemic infections/shock/fever
  2. AKI
  3. pregnancy
  4. dehydrated and can’t take oral fluids (e.g; vomiting)
  5. not responding or worsening pain after an hour of treatment
17
Q

What is the golden standard for imaging a kidney stone?

A

CT KUB

18
Q

What should you equip a patient with kidney stones with when sending them home?

A
  1. Non-steroidal anti-inflammatory drugs, e.g; NSAIDs
  2. Antiemetic can be effective against vomiting and nausea
  3. Explain to them to pee into a sieve as they might pass the stone themselves, and in that cause the stone can be kept and analysed
  4. Follow up appointment in 7 days
19
Q

If there is no access to a CT KUB, what other tools can you use for imaging?

A

MRI, Ultrasound, X ray, ureteroscopy

20
Q

Which stone commonly leads to hydronephrosis and why? What can you do if this develops?

A

Struvite stones as they have a tendency to stick together, a nephrostomy can be done where a tube is inserted into the back which will drain the urine until the stone can be removed

21
Q

What can you insert after a procedure has been done to remove kidney stones to stabilize the ureters? How long does it stay for?

A

A ureteric stent; 4-14 days

22
Q

What drugs may help facilitate a spontaneous passage of stones? What are the criteria for giving these?

A

Alpha-blockers, Ca2+ channel blockers: the patient has to be recently diagnosed, no systemic infection, adequate renal function and a stone <10 mm

23
Q

What is extracorporeal shock wave lithotripsy?

A

Non-invasive outpatient treatment that focuses shock waves to break up the stone until particles are small enough to be passed

24
Q

What does Ureteroscopy do?

A

Camera with use of laser to remove stone

25
Q

What is the most surgical option there is to remove a kidney stone?

A

Percutaneous nephrolithotomy: pass a scope through back of kidney to break up the stone which can be extracted through the nephroscope or removed

26
Q

What is the prognosis for a recurrence and a spontaneous passage?

A

50% will have one more kidney stone and 10% will have multiple more

If the stone is >6mm there is a low chance, and if it is higher up in the ureter. If it is more distal and small, there is a higher chance of it being passed spontaneously

27
Q

What are some complications of having a kidney stone

A
  1. Complete obstruction of urinary flow: reduced GFR, AKI, infection
  2. Ureteric stricture, can damage endothelial layer and bacteria can get into bloodstream = sepsis
28
Q

What can you do to prevent a kidney stone from reoccurring?

A
  1. iIncrease fluid intake
  2. balanced diet; e.g; reduced salt
  3. maintain a healthy weight
  4. to avoid calcium stones: avoid eating oxalate-rich foods; e.g; strawberries and rhubarb
  5. Uric acid stones should avoid excessive dietary intakes of urate rich foods like fish