Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Semester 3 > Urinary 5 renal stones > Flashcards

Urinary 5 renal stones Flashcards

1
Q

How much dietary calcium is absorbed and how is it controlled?

A

20-40% (25mmol), increases in growing children, pregnancy, lactation and decreases with advancing age
Under control of 1, 25-(OH)2D
Complexing calcium reduces absorption
2-5 mmol secreted back into gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How much calcium is filtered through and reabsorbed in the kidney per day?

A

250mmol filtered
95-98% reabsorbed - 65% in PCT, associated with Na and water intake, 20-25% recovered in ascending limb of loop, 10% recovered in DCT under parathyroid hormone (PTH) control
24hr urinary calcium excretion <10mmol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How much calcium is excreted in the faeces and urine?

A

faeces - 800mg

Urine - 200mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What forms of calcium are in the plasma?

A

Ionised - active but not measured 45%
Protein bound (80% o albumin) 45%
Complexed (citrates, phosphate, etc) 10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the ionised calcium reference range and the total adjusted calcium ref range?

A

ionised: 1.1 - 1.3 mmol/L
total adjusted: 2.10 - 2.60 mmol/L

aCalcium = mCalcium + 0.02(40 - mAlbumin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the major factors associated with plasma calcium homeostasis?

A 
PTH
Bone
Intestine
Kidney
25-OHD
1,25-(OH)2D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are good sources of vitamin D/calciferol?

A

Solar UVB
Oily fish
Egg
Cereal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is the active form of vitamin D created?

A

vitamin D -> 25-(OH) vit D (25-hydroxylase)

-> 1,25-(OH)2 vit D (active form)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the reference ranges for 25-OH vit D?

A

adequate 50-150 nmol/L

Severe deficiency <15nmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the risk factors for fit D insufficiency and deficiency?

A

Pigmented skin
Lack of sunlight exposure or atmospheric pollution
Exclusively breast fed
Multiple, short interval pregnancies
Elderly, obese or institutionalised
Vegetarian (or other non-fish eating) diet
Malabsorption, short bowel or cholestatic liver disease
Use of anticonvulsants (induce enzymes in the liver that break down fit D) rifampicin, cholestyramine, highly active antiretroviral treatment (HAART) or glucocorticoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where is 1,25(OH)2D created?

A

Kidney

25-OHD in liver…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the actions of 1,25-(OH)2D on bone?

A

Increases the availability of calcium and phosphate via intestinal uptake
Promote osteoblast activity and maturation of osteoclast precursor cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the action of 1,25-(OH)2D on the kidney?

A

Inhibition of renal 1 alpha hydroxyls by intestinal absorbed phosphate
Promotes synthesis of 24,25-(OH)2D
Small effect on renal calcium and phosphate reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What functions of cells and tissue does 1,25-(OH)2D regulate?

A

Cell differentiation and proliferation
May decrease proliferative activity of some tumour cells
inhibition of cellular growth
Stimulation of insulin secretion
Modulation of immune and haemopoietic systems
Inhibitor of renin production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What chronic diseases are associated with fit D deficiency?

A 
Osteoporosis
Osteoarthritis
Falls
Insulin sensitivity
Pregnancy outcomes
Periodontal disease
Various cancers
TB
Hypertension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the actions of PTH on bone?

A

Aids bone remodelling by stimulation of osteoclast activity, increasing plasma calcium and phosphate
Slowly stimulate osteoblast activity

17
Q

What are the actions of PTH on the kidney?

A

Increase calcium and magnesium reabsorption
Decrease phosphate and bicarbonate reabsorption
Stimulates conversion of 25-OHD to 1,25-(OH)2D by 1 alpha hydroxylase

18
Q

What factors influence bone growth and turnover?

A

Calcium phosphate and magnesium metabolism
PTH and 1,25(OH)2D
Other hormones and factors e.g. Thyroid hormone, oestrogen, androgens, cortisol, insulin etc

19
Q

What are the main cause of hypercalcaemia?

A

Primary hyperparathyroidism
Haematological malignancies
Non-haematological malignancies
Others

20
Q

What are the clinical manifestations of hypercalcaemia?

A

GI - anorexia, nausea/vomiting, constipation, rarely acute pancreatitis
CV - hypertension, shortened QT interval on ECG, enhanced sensitivity to digoxin
Renal - polyuria and dipsia, occasional nephrocalcinosis
Central nervous system - cognitive difficulties and apathy, depression, drowsiness, coma

21
Q

What are the differences between hypercalcaemia of malignancy and primary hyperparathyroidism?

A

Malignancy - >3.5mmol, weeks/moths, rapid increase, renal canaliculi rare, plasma PTH suppressed, decreased bone formation

Primary hyperparathyroidism: <3.5mmol/L, moths/years, slow increase, renal canaliculi common, plasma PTH raised, increased bone formation

22
Q

What is the difference between primay, secondary and tertiary hyperparathyroidism?

A

1 and 3 raised plasma calcium, 2 low or normal

23
Q

What causes hypercalcaemia of malignancy?

A

Parathormone-related peptides (PTHrP) - amino acid homology with N-terminal of PTH (active portion of PTH)
Cytokines eg Tumour necrosis factor, interleukin-1
Transforming growth factor alpha (TGFalpha)
Prostaglandins

24
Q

How is acute hypercalcaemia managed?

A

General measures - hydration, loop diuretics
Specific measures - biphosphonates, calcitonin, glucocorticoids
Treat underlying condition

25
Q

What is the lifetime risk for renal stone formation?

A

Approx 20% men and 5-10% women will develop renal stones
50% recurrnece rate within 5 yr
After 8yrs, 63% men and 18% women form additional stones
Racial differences in stone formation

26
Q

What are the manifestations of renal stones?

A

Need not produce symptoms - incidental finding on abdominal x-rays
Haematuria
Pain and associated complications of an obstruction in the renal tract

27
Q

What is the distribution of renal stones by type?

A 
Calcium 70-80%
Magnesium Ammonium Phosphate 5-20%
Urate 5-10%
Cystine 2-5%
Rare forms <1%
28
Q

What factors are involved in renal stone formation?

A 
Low urine volume
Hypercalcuria
Primary hyperparathyroid
Hyperoxaluria
Hyperuricosuria
Hypomagnesuria
29
Q

What medical conditions are associated with stone formation?

A 
Hypercalciuria
Increased oxalate consumption
Enteric hyperoxaluria
Ileostomy
Primary hyperparathyroidism
Renal tubular acidosis
Hyperuricaemia
Urinary infection
Cystinuria
30
Q

When are stones formed?

A

Urine supersaturation with respect to calcium oxalate

At low urine pH uric acid stone formation is favoured and may promote calcium oxalate stones

31
Q

What reduces the risk of stone formation?

A

Ionic strength reduces risk of crystals forming

Low pH reduces urine citrate by enhancing renal tubular re-absorption and reducing synthesis of citrate

32
Q

What are promoters of calcium oxalate and calcium phosphate stones?

A

Organic matrix

Tamm-Horsfall mucoproteins

33
Q

What are inhibitors of calcium oxalate and calcium phosphate stones?

A 
Citrate
Pyrophophate
Clycoaminoglycans
RNA fragments
Acidic glycoproteins
Magnesium
34
Q

What is the management of renal stones?

A

Increased fluid intake: urine output >2L daily
Dietary restriction of oxalate and sodium for all
Consider dietary restriction of calcium and animal proteins

35
Q

What would blood screening show in evaluation of someone with renal stone formers?

A 
Ca
PTH
PO4
Urate
U/Es and acid base status
36
Q

What urine screening would be don e to evaluate a patient with renal stones?

A

Urinalysis: pH, sediments
Culture: urea-splitting organisms

37
Q

What would a radiograph tell you about a patient with renal stones?

A

Type:
Radiopaque: calcium oxalate, calcium phosphate, struvite, cystine
Radiolucent: Urate, xanthine, 2 hydroxyadenine

38
Q

What investigations would be carried to out to diagnose renal stones?

A 
History
Blood screen
Urine screen
Radiograph
Biochemical stone analysis

Semester 3 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions