Genitourinary: Part 1 Flashcards
1
Q
Name 6 functions of the kidney
A
- Filter or secrete waste/excess substances
- Retain albumin and circulating cells
- Reabsorb glucose, amino acids and bicarbonates
- Control BP, fluid status and electrolytes
- Actiates 25-hydroxy vit D (hydroxylates hit to 1,25 dihydroxy vit D)
- Synthesises erythropoietin
2
Q
Define GFR
A
Volume of fluid filtered from the glomeruli into Bowman’s space per unit time (minutes)
3
Q
What is th normal GFR in the body
A
120ml/min
4
Q
What percentage of the cardiac output does each kidney receive
A
20%
5
Q
What is the eGFR
A
Predicts creatinine generation (produced by muscle and only eliminated from the kidneys) - from age,gender and race
6
Q
What factor is required for a normal GFR
A
- Everything is at a steady rate and extremes of muscle mass may be misleading (Body builders or amuptees)
7
Q
Where do sugars, amino acids and bicarbonates get reabsorbed
A
PCT
8
Q
Where is 70% of Na reabsorbed
A
Pct with water
9
Q
What pathology can effect the PCT
A
Ischaemic injury resulting in acute tubular necrosis
10
Q
What part of the kidney is most vulnerable to damage
A
PCT
11
Q
What is Fanconi Syndrome
A
EFFECTS PCT
- Glycosuria
- Acidosis with failure of urine acidification
- Phosphate wasting resulting in rickets/osteomalacia
- Aminoaciduria
12
Q
What causes fanconi syndrome
A
Cystinosis
Wilson’s
TENOFOVIR (used in HIV)
13
Q
What is reabsorbed at the Loop of Henle
A
25% Na and water
14
Q
What transporters are founding the loop of Henle
A
Na2KCl - more active here
15
Q
Where do most diuretics work
A
Loop Of Henle as 25% of Na is filtered here
16
Q
What is reabsorbed at the DCT
A
Na and water (5%)
17
Q
What constitutes the juxtaglomerular apparatus
A
Macula Densa cells
Juxtaglomerular cells
18
Q
Role of Macula dense cells
A
Sensitive to NaCl
Too much NaCl accumulate at macula dense, then afferent arterioles are CONSTRICTED to reduce GFR rate (less gradient)
19
Q
When does the juxtaglomerular apparatus release RENIN
A
When it detects high solutes
20
Q
What regulates re-absorption of solutes at the collecting duct
A
Aldosterone
21
Q
How does aldosterone effect the collecting ducts
A
Increases transcription of enact channels which absorb Na+ in exchange for K+
22
Q
What is secreted by the collecting duct into the urine
A
K+ and H+
23
Q
How is water re-absorption handled i the collecting ducts
A
Water re-absorbed by aquaporin 2 channels
24
Q
What is hyperaldosteronism
A
LOTS of Na reabsorption resulting in a negative lumen, K+ and H+ rush in causing hypokalaemic alkalosis
25
In what condition is hyperkalaeimc acidosis seen in
Addison's
26
How is hyperkalaemic acidosis treated
Sodium bicarbonate
27
What causes hyperkalaemic alkalosis
Loop diuretics
28
Where is K+ absorbed
PCT and Loop of Henle
29
Where is K+ secreted
DCT
30
What governs secretion of K+
NA conc
| Aldosterone
31
What compounds drive cellular K+ uptake
Insulin and Catecholamines
32
Way causes hypokalaemia
Loop Diuretics
| Thiazide diuretics
33
What causes hyperkalaemia
```
Spironolactone (aldosterone antagonist)
Amiloride (acts on eNAC channels)
ACEI
ARB
Trimethoprim (acts on enact channels but milder)
```
34
Are diuretics NEPHROTOXIC
No
35
How do diuretics cause nephrotoxic effect
They cause hypovolaemia
36
What two medications are extremely effective in advanced kidney disease
Thiazide and loop diuretics
37
What organ is responsible for maintaining plasma tonicity
Kidney
38
What detects water conc
Osmoreceptors in th hypothalamus
39
What is released in response to high conc in plasma
VASOPRESSIN
40
Role of vasopressin
Binds to V2 receptors and increases insertion of Aquaporin-2 in apical membrane
41
Where is vasopressin produced
Suprachiasmatic nucleus
42
In which part of th kidney is erythropoietin produced
Renal cortex - acts as an oxygen sensor, blood flow and oxygen
43
At what eGFR level is anaemia usually seen
<30
44
When is erythropoietin production stimulated
In response to tissue hypoxia
45
Why is there a drop in Ca during kidney failure
Kidney cannot hydroxylate and there is a drop in Ca (less re-absorption in the gut)
46
Actions of calcitriol
Increases Ca and phosphate absorption from the gut
Increases phosphate absorption
Suppresses PTH
47
What disease is caused by calcitriol deficiency
Secondly hyperparathyroidism
48
Consequences of secondary hyperparathyroidism
1. Low Vit D results in low Ca and phosphate resulting in increased PTH which causes Ca and phosphate leeching out of the bones
2. High PTH acts on osteoclasts increasing activity and reducing bone quality
49
What consists of the upper urinary tract
Kidneys
| Ureters
50
What does the LUT consist of
Bladder
Bladder neck
Prostate gland
Urethra and urethral sphincter
51
Function of LUT
Convert the continuous process of excretion to an intermittent, controlled volitional process - micturition
52
Essential features of the LUT
1. Low pressure and storage of urine to adequate capacity
2. Prevent leakage of urine stored
3. Allow rapid, low-pressure voiding at an appropriate time and place
53
What MAP drives filtration in Bowman;s capsule
60-70 mmHg
54
Physiology of Voiding
1. Pontine micturition stimulates excitatory control to detrusor nucleus and inhibits ONUF's nucleus
2. Signal transmitted from root S3,4,5 via parasympathetic nervous system and results in contraction of detrusor muscles and relaxation of the urethraa
55
How is urination stopped
1. Pontine store .centre sends inhibitory signals to detrusor muscles and excitatory to onus's
2. Signal transmitted from T10, L1 and 2 via sympathetic nervous system = relaxation of th bladder and contraction of the urethral sphincter
56
Describe the sacral micturition centre
initiates voiding when bladder is full automatically - inhibited VOLUNTARILY
57
Consequence of cutting cord above S2,3,4
Only urinate when bladder is full, not voluntarily inhibited anymore
58
Storage of th ebladder
500 ml
59
What lines the bladder
Urothelium
60
How many cells thick is urothelium
3-7 cells thick
61
What stops reabsorption of urine
Umbrella cells
62
Why do men have a greater voiding pressure
Longer urethra - more likely to develop retention
63
Why do women have a lower voiding pressure
Shorter urethra - more likely to develop incontinence
64
What do renal stones consist of
Crystal aggregates, stones from in collecting ducts and may be deposited anywhere from pelvis to urethra:
Consist of calcium oxalate and phosphate
65
What are the there places renal stones tend to cause narrowing
1. Pelvicureteric junction
2. Pelvic brim
3. Vesicoureteric junction
66
Peak incidence of renal stones
20-40
67
What gender are renal stones common in
Males
68
Chances of recurrence after having a renal stone
50%
69
Risk factors for renal stones
1. Trauma/anatomical abnormalities
2. Chemical composition of urine that favours stone crystallisation
3. Dehydration - conc urine
4. Infection
5. Hypercalcaemia, hyperoxaluria, hypercalciuria and hyperuricaemia
6/ Primary renal disease
7. Drugs (diuretics, antacids, corticosteroids and aspirin + allopurional)
8. Diet
9. Gout
10. Fam History
70
What is supersaturation of urine
When urine solvent contains more solutes than it can hold in solution)
Heterogeneous nucleation occurs more rapidly than homogenous nucleation (where crystal must grow in a liquid medium with no surface on which a crystal can grow)
Requires less energy - cells adhere to renal papilla causing a seed crystal to grow
71
What do most renal stones consist of
Calcium oxalate (60-65%)
Calcium phosphate (10%)
72
Where are stones located
Collecting system or renal parenchyma
73
Consequence of stones
Hydronephrosis - combination of obstruction and dilatation of renal pelvis that causes lasting damage to kidneys
74
What causes hypercalciuria
1. Hyperparathyroidism = hypercalacaemia
2. Excessive intake of Ca
3. Idiopathic hypercalciuria = increased absorption in gut
4. Primary renal disease such as polycystic kidneys or medullary sponge kidney
75
What causes hyperoxaluria (increased oxalate in urine)
1. High dietary intake of oxalate rich food (spinach, rhubarb and chocolate)
2. Low dietary ca resulting in decreased binding of oxalate so increased oxalate absorption and urinary excretion
76
What causes uric acid stones to form
Hyperuricaemia with or without gout
Dehydration
Patients with ileostomies are at risk from dehydration and bicarbonate loss from GI secretion - acidic urine
77
Uric acid is soluble in what pH
alkaline than acidic
78
What are infective renal stones made of
Magnesium ammonium phosphate and calcium
79
What causes infective stones
UTI:
| Proteus mirabilis
80
how do proteus mirabilis cause UTIs
Hydrolyse urea to ammonium hydroxide
Increased ammonium ions and alkalinity favour stone formation
81
What causes cystine stones
Cystinuria - autosomal recessive condition affecting cysteine (AA) in epithelial cells of renal tubules and GI treat
Excessive urinary excretion and formation of cysteine stones
82
Clinical presentation of renal stones
1. Asymptomatic
2. RENAL COLICS
3. LOIN PAIN
4. Fluid and diuretics make pain worse as peristaltic flow increases (if UT is obstructed)
5. Dysuria/strangury (burning)
6. Recurrent UTIs
7. haematuria
8/ Reduced bowel sounds
9/ BP low
10. SOCRATES
83
What is dysuria
Difficulty peeing
84
Clinical presentations associated with renal colics
1. Rapid onset
2. Pain resulting from upper urinary tract obstruction
3. Excruciating ureteric spasms
4. Pain from loin to ground comes and goes in waves as ureters peristalsis
5. Nausea and vomiting
6. Worse with fluid loading
7. radiates to going and ipsilateral testis/labia
8. can't lie still
85
Differential diagnosis of renal stones
1. Vascular accident (ruptured aortic abdominal aneurysm) if over 50 years - until proven otherwise
2. Bowel pathology (diverticulitis or appendicitis)
3. Ectopic pregnancies or ovarian cyst torsion (do uric pregnancy test)
4. Testicular torsion (loin pain and nothing else!!)
86
How is renal stones diagnosed
1. Vit D conduction - hypercalcaemia, recurrent UTIs and lots of rhubarb and tea
2. Urine dipstick (positive for blood)
3. Mid-stream specimen of urine sent for culture and sensnitivit y
4. FBC
Kidney Ureter bladder x-ray
5. Non-contrast computerised tomography
6. Ultrasound
87
FBC result for renal stones
1. Urea, electrolyte, creatinine and claim raised
88
First line intervention for renal stones
X-ray
89
What does x-ray show in renal stones
Stone in line of renal tract
90
What is the gold standard for renal stones
Non-contrast computerised tomography (99% sensitive for stones)
91
Pros of NCCT
1. No contrast so doesn't cause renal damage
92
Con of NCCT
No functional info
| Gives radiation dose equivalent to 18 months background radiation
93
Role of ultrasound in kidney stones
1. Kidney stones and renal pelvis dilatation well but ureteric stones can be missed
94
What is ultrasound sensitive for
Hydronephrosis
95
Cons of ultrasound in kidney stones
Poor at visualising stones in ureter
96
When is ultrasound good for looking for kidney stones
Pregnancy or younger recurrent stone-formers (nor radiation risk)
97
Treatment for kidney stones
1. Strong analgesic for colics - IV DICLOFENAC
2. Antibiotics for infection (IV GENTAMICIN or CEFUROXIME)
3. Antiemetics
4. Observe for sepsis
5. Stones less than 5mm can pass
98
What medication is given for stones greater than 5mm with pain
1. ORAL NIFEDIPINE or alpha blocker (TAMULOSIN) - promotes expulsion and reduces analgesia requirement
```
If this still does not work: EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY
Endoscopy with YAG
Percutaneous nephrolithotomy (keyhole surgery to remove stones )
```
99
How are recurrent kidney stones prevented
1. Over hydration
2. Normal low ca dietary intake
3. Low salt diet
4. Reduce BMI
5. Reduce animal proteins
6. Active lifestyle
7. Uric acid stones: Caused by long term allopurinol use
Only form in acid urine
Deacidification of urine - ORAL SODIUM BICARBONATE to alkalinise urine
Cysteine stones: OVERHYDRATION
Urine alkalisation
Cysteine binders
100
Name a cysteine binder
CAPTOPRIL
101
Id hyperclacaemia is present in recurrent kidney stones what can be given for treatment
ORAL BENDROFLUMETHIAZIDE to increase ca excretion
