Renal Failure

Question 1

ways to measure excretory renal function 4

gfr= glomerular filtration rate

Answer 1

• plasma/ serum creatinine
• estimated GFR: MDRD formula (sex, age, race, creatinine)
• creatinine clearance
• isotope GFR (usually Cr15 EDTA)

Question 2

problems with serum/plasma creatinine 4

Answer 2

• related to muscle mass (more muscle, more creatinine so normal has big range)
• may not be elevated above ‘normal’ until 50% GFR lost
• changes within normal range are significant
• artefacts: muscle damage, drugs

Question 3

what kind of creatine measurements are most useful

Answer 3

serial

Question 4

write modified MDRD formula

Answer 4

eGFR (ml/min/1.73m2)= 2.107x serum creatinine (umol/l)-1.154 x age -0.203

Question 5

normal GFR range

Answer 5

100-200

Question 6

define acute kidney injury AKI and outcome

Answer 6

rapid loss of renal excretory function (over hours or days rather than weeks)
reversible if underlying condition is treated

Question 7

define chronic kidney disease CKD

Answer 7

slowly progressive loss of excretory renal function. original cause often unknown, usually irreversible (management aimed at slowing progression)

Question 8

3 causes of AKI

Answer 8

• pre-renal: problem in blood supply to kidney (thrombosis, dec bp)
• intrarenal: direct damage to kidneys due to inflammation/ toxins/ drugs/ infection/ reduced blood supply
• post-renal: obstruction to urine flow eg prostate enlargement, kidney stones, bladder, tumour, injury

Question 9

4 causes of pre renal AKI

Answer 9

• salt and water depletion (diarrhoea, vomiting, diuretics, fever, poor fluid intake)
• haemorrhage (esp gastrointestinal)
• hypotension (heart failure, drugs, sepsis, shock)
• renovascular disease

Question 10

types of renal AKI and % 3

Answer 10

85% tubular necrosis (mostly due to pre renal factors eg low bp)
10% interstitial nephritis
5% glomerulonephritis

Question 11

how to diagnose kidney disease

Answer 11

• urine dipstick

- renal biopsy (interstitial nephritis, acute glomerulonephritis

Question 12

8 causes of toxic AKI

Answer 12

• antibiotics eg aminoglycosides, amphotericin
• radiographic contrast media (inc non-ionic)
• chemotherapy agents esp cis-platinum
• rhabdomyolysis
• intravascular haemolysis
• tumour lysis
• solvents (inc ethylene glycol, carbon tetrachloride)
• hepatorenal syndrome

Question 13

3 common causes of post renal AKI

Answer 13

• obstruction to outflow from both kidneys or to outflow from a single functional kidney esp prostate in males, cervix in females
• retroperitoneal fibrosis, neurogenic bladder
• intra-renal obstruction eg crystals or casts (esp myeloma)

Question 14

what does prognosis of post renal AKI depend on 2

Answer 14

• underlying condition

- duration of obstruction

Question 15

causes of chronic kidney disorder 5

Answer 15

• diabetic neuropathy MOST COMMON
• genetic causes (esp polycystic kidney disease) 10%
• vascular disease
• chronic glomerulonephritis
• chronic urinary outflow obstruction

Question 16

classification system of chronic kidney disease

Answer 16

5 stage according to eGFR

1: normal kidney function with some other evidence of kidney disease
5: eGFR less than 10-15 ml/min ie need for renal replacement

Question 17

consequences of renal failure 7

Answer 17

-accumulation of 6: K+, urea, creatinine, H+, water, PO4
-deficiency of 2: erythropoitin–> anaemia
1 alpha vitamin D3 –> hypocalcaemia, hyper parathyroid hormone, bone disease
-delayed drug excretion
-pulmonary oedema
-xerostomia
-uraemic stomatitis (white/ grey on FOM)
-brown tumour

Question 18

outcome of K+ accumulation

Answer 18

changes polarisation of cells –> large T waves –> cardiac arrythmias –> sudden death

Question 19

how to control potassium

Answer 19

diet (eg less bananas)

Question 20

explain renal bone disease

Answer 20

less calcium –> less vit D activation –> non calcified osteoid –> bone resorption

Question 21

4 tx for renal replacement therapy

Answer 21

• dialysis/ transplantation
• erythropoietin
• 1 alpha vitamin D
• sodium bicarbonate

Question 22

normal blood Hb levels

Answer 22

130-150g/l

Question 23

how does a haemodyaliser work

Answer 23

contains small plastic ‘capillaries’ surrounded by dialysis fluid for filtration

Question 24

explain arterial-venous fistula

Answer 24

sew artery to vein –> blood flows in to vein –> dilates vein –> can put needles in to vein for dialysis

Question 25

why are anticoagulants used in dialysis and examples 3

Answer 25

stops blood clotting during dialysis - heparin for dialysis - warfarin for access patency - aspirin

Question 26

what does CAPD stand for and how does it work

Answer 26

Continuous Ambulatory Peritoneal Dialysis needle and dialysis in to peritoneum (space between organs) --> fluid exchanged over peritoneal membrane continuously/ 4 times per day

Question 27

6 general consequences of immunosuppression

Answer 27

- infection (correlation with corticosteroid dosage) - viral transmission with transplant esp CMV - malignancy (esp viral eg lymphoma, skin, cervix. UV exposure and skin type important) - hypertension - dyslipidaemia - osteopaenia

Question 28

2 main causes of gingival hyperplasia

Answer 28

- cyclosporin (immunosuppression) | - calcium blockers (dipines)

Question 29

5 adverse effects of cyclosporin

Answer 29

- nephrotoxicity - tremor - hirtuism - gingival hypertrophy (worsened by nifedipine) - interactions (esp macrolides, diltiazem)

Question 30

4 important drug interactions

Answer 30

- cyclosporin and macrolides (erythromycin, clarithromycin) - cyclosporin and diltiazem - cyclosporin and enzyme inhibitors - azatioprine and allopurinol

Question 31

5 considerations for dental care after renal transplantation

Answer 31

- good OH essential - gingival hypertrophy (cyclosporin, nifedipine) - inc susceptibility to infection - antibiotic prophylaxis - drug interactions esp erythromycin etc

Question 32

6 normal functions of kidneys

Answer 32

- excretion of salt/ water/ waste products of metabolism (via urine) - regulation of acid-base (H+) in tubules - regulation of blood pressure (with renin) - production of erythropoetin (stimulates RBCs) - activation of vit D (1 alpha hydroxylase) - excrete water soluble drugs/ metabolites

Question 33

order blood moves around kidney

Answer 33

afferent arteriole --> glomerulus -> vasa recta

Question 34

order of nephron system kidneys

Answer 34

bowmans capsule --> proximal convoluted tubule -->loop of henle --> distal convoluted tubule --> collecting duct

Question 35

increase in serum creatinine in AKI stage 1 2 3

Answer 35

1: 1.5-2 2: 2-3 3: >3 or >354umol/L with acute increase of >44umol/L

Question 36

most common known cause of kidney failure in pts starting renal replacement therapy in UK

Answer 36

diabetes

Question 37

% of people in england with diabetes

Answer 37

7.4%

Question 38

proportion of people with diabetes who have kidney disease

Answer 38

18%-30%

Question 39

% of patients having tx/ dialysis whose kidney disease was due to diabetes

Answer 39

14%

Question 40

categories of GFR

Answer 40

``` G1: normal/ high GFR G2:mildly decreased G3a: mild-mod decreased G3b: mod-severely decreased G4: severely decreased G5: kidney failure ```

Question 41

what is a. normal GFR b/ GFR in kidney failure

Answer 41

a. normal GFR: >90ml/min/1.73m2 | b. GFR in kidney failure:

Question 42

presentation/ symptoms of chronic kidney disease

Answer 42

often asymptomatic until CKD4/5 (GFR

Question 43

3 lab changes of CKD

Answer 43

anaemia disordered bone mineral metabolism acidosis

Question 44

AKI/ CKD consequeneces: a. accumulation of (6) b. deficiency of (2) and consequences c. delayed (1)

Answer 44

a. accumulation of (6): K+, urea, creatinine, H+, water, PO43- b. deficiency of (2) and consequences: erythropoietin --> anaemia. 1alpha vit D3 --> hypocalcaemia, hyperPTH, bone disease c. delayed (1): drug excretion

Question 45

what does uraemic stomatitis look like

Answer 45

white-grey pseudomembranous lesion on tongue and FOM