Urinary L8.2 Flashcards
State uses of calcium
-Calcium hydroxyapatite makes up inorganic component of bone. Compried of calcium and phosphate
-muscle contraction
extracellular funcitions (clotting)
-bound VS free calcium
1) Describe renal handling of calcium?
2) Where does renal calcium reabsorption take place?
3) State a difference between calcium reabsorption in the PCT and DCT
4) Where is phosphate reabsorbed?
1)Ionised Calcium frelly filterted in glomerulus
2) PCT (70%), thick ascending limb (25%), DCT (8%)
3) PCT - paracellular
DCT - transcellular
4) PCT
What are the 3 main hormones that regulate calcium?
- PTH (increase plasma calcium)
- Calcitonon (decrease plasma calcium)
- Calcitriol (increase plasma calcium)
Decribe the formation of calcitriol
RECAP METABOLISM
7-dehydrodrocholesterol converted to Vit D3 in skin via sunlight
Vit D3 converte to 25-hydroxyvitamin D in liver via enzyme (?)
In kidnets, final enzyme (?) converts 25-hydroxyvitamin D into 1,25 dihydroxy vitamin D3 (CALCITRIOL)
Effects of calcitriol
What triggers release of calcitriol?
Increase plasma calcium by
1. Increasing absorption of calcium in intestines
- Increase reabsorption of calcaium in kidney
DECREASED SERUM CALCIUM (enhances action of 1 - alpha hydroxylase in kidney)
1) What is the role of parathyroid gland in calcium level regulation?
2) What is the trigger for PTH release?
1) Chief cells release PTH
PTH increases plasma calcium levels and lower plama phosphate lecels
LOW CALCIUM
Regulation of PTH release
Low extracellular calcium stimulates parathyroid glands to release PTH
PTH binds to steoblasts, inhibiting them and releasing cytokines which activate osteoclasts
Osteoclasts release calcium + phosphatefrom bone
PTH increases reuptake of calcium from kidney
Both of these together act to increase extracellular calcium conc.
This has negatvie feedback effect on parathyroid gland which in turn prevents further release of PTH
Which cells secrete calcitonin?
When is it secreted?
What is its role?
Parafolicular cells in thyroid gland
Secreted in response to high plasma conc
Stimulate osteoblast avtivity, decrease osteoclast activity
Calcitionin decrease plasma calcium conc
State other systemic hormones that regulate plasma calcium
- Glucocorticoids
-inhibit osteoclast activity
-long term: inhibit osteoblast activity and gut absorption of calcium
-important cause of osteoperosis - Oestrogens - inhibit osteoclast activity
Hypercalcaemia pathophysiology
SYMPTOMS
INCREASED PLASMA CALCIUM LEVELS
- PTH seccretion reduces
- Calcitriol synthesis decreases
- Affects kidney and bone
- Decreasing reabsorption in kidney
- Decreased osteoclast activity hence decrease breakdown of bone
- Increased osteoblast activity hence increased bone building
Symptoms
-Bone pain - due to high calcium
-Renal stones
-Polyuria - not as common
-Altered behaviour
What are causes of hypercalemia?
TREATMENT
Hormonal:
-Primary hyperparathyroidism
-Hypervitaminosis
Non Hormonal:
- Malignancy
-Renal failure
IV hydration
Hypocalcemia pathophysiology
Symptoms
Causes
TREATMENT
DECREASED PLASMA CALCIUM LEVELS
-PTH secretion increases
-Synthesis of calcitriol increases
- Increased reabsorption of calcium in kidney
-Increased osteovlast activity, more calcium released from bone
-Decreased osteoblast activity
SYMPTOMS
- Tetany
-Seizures
-Hypotension
-Arrythmia
-PROLONGUED QT INTERVAL: CA responsivle for plateu phase of cardiomyctre contraction. The loner Ca ion channels are open, the longer QT interval
CAUSES
- Hypoparathyroidism
-Hypovitaminosis D
TREATMENT:
Vit D / calcium supplements
Careful monitoring during thyroid surgery
1) What are Renal stones?
2) Who are they more common in?.
3) When are they more common?
1) 80% of renal stones are calcium stones (calcium oxalate, calcium phosphate)
Nephrolithiasis (stone within kidney)
Urothialisis (stone within renal tract)
Renal colic (painful symoptoms caused by urolithiasis)
2) Men
3) Later in life
What are the 3 points of constriction for kidney stones?
Ureteropelvic region
Pelvic inlet
Entrance to bladder
1) What are risk factors for renal stones?
- Dehydration
(reduces circ volume, increase conc of all solutes that can form stones) - Personal history
- Anatomoical structural abnormalities. Some poeple may have more prominent constrictions so stones may be more likely to get lodged,
What are the 4 different types of renal stonnes
1) What are main symptoms of renal stones?
2) If we are suspecting a female patient of suffering with renal stones, what is important to rule out?
- Severe flank loin / groin pain
- Haematuria
Nausea / vomiting
Urinary symptoms
ECOPIC PREGNANCY. Pain will be in similar area
Staghorn Calculus
Large branching stones that occupy majority of renal pelvis. They appear looking like staghorn on X-Ray / urogram. Staghorn calculi are dangerous and require immediate treatment.
Describe management of Kidney stones
NSAIDS - pain releif (naproxen)
IV fluid and analgesia
Surgical treatment
SURGICAL MANEGEMENT:
- Extracorporeal shockwaye lthotripsy
-Uteroscopy
-Urgent drainage with stent
-Percutanous nephrolithotomy
What is Extracorporeal shockwave lithotripsy?
How does it work?
What are the risks
When is it used?
Surgical manegement of renal stones
Machine breaks up stone, using ultrasonic technology. This allows stone to pass.
Risks
-Pain
-Brusing
-Infection
-Bleeding leading to haematuria
Used if stone is less than 10mm
1) What is uteroscopy?
2) Risks?
3) When do we use it?
1) Instrument inserted through ureter to find stone. Camera operated. Surgeon tries to catch stone, breaks stone up and let it pass naturally
2) - pain, bleeding, infection, uretic injury
3) Larger stones 10-20 mm
1) What is percutaneous nephrolithotomy?
2) Risks
3) When is it used?
1) Stone broken down into laser treatmet / ultrasound energy
2) Bleeding, infection
After this, ureter required to be stented.
3) Used for larger stones, over 20mm or STAGHORN CALCULUS
What is metabolic testing?
If patient has risk factors for renal stone formation, and they have first kidney stone, they can be sent off for metabolic testing due to risk of recurrent stones.
Stones looked at for compositional analysis
Management of Renal Stones: Prevention
How is calcium reabsorbed in the PCT?
How is calcium reabsorbed in the thick ascending limb?
How is calcium reabsorbed in the DCT?
