Renal Failure

Question 1

what are the normal functions of the kidneys ?

Answer 1

excretion of salt, water and waste products of metabolism via urine,
regulation of acid-base (H+),
regulation of blood pressure (renin),
production of erythropoietin, activation of vitamin D (1alpha OHase),
excrete water soluble drugs and metabolites

Question 2

how is excretory renal function measured ?

Answer 2

plasma/serum creatinine,
estimated GFR, MDRD formula (sex, age, race, creatine),
creatinine clearance,
isotope GFR

Question 3

what are the issues with serum/plasma creatine ?

Answer 3

related to muscle mass,
may not be elevated above normal range until 50% GFR lost,
changes within the normal range are significant,
artefacts - muscle damage, drugs,
serial measurements most helpful

Question 4

what is the modified MDRD formula ?

Answer 4

eGFR (ml/min/1.73m2) = 2.107 x serum creatinine (umol/l) - 1.154 x age - 0.203 (x 0.742 if female and x 1.21 if african american

Question 5

how should GFR levels from plasma creatine be interpreted ?

Answer 5

in the context of the individual. serial measurements most helpful

Question 6

what term is sued to describe acute renal failure ?

Answer 6

acute kidney injury

Question 7

what term is used to describe chronic renal failure ?

Answer 7

chronic kidney disease

Question 8

what is the definition of AKI ?

Answer 8

rapid loss of renal excretory function over hours or days

implies reversibility if underlying condition can be successfully treated

Question 9

what are the causes of pre-renal AKI ?

Answer 9

salt and water depletion - diarrhoea, vomiting, diuretics, fever
haemorrhage esp gastrointestinal
hypotension - heart failure, drugs, sepsis, shock
renovascular disease

Question 10

what are the causes of renal AKI ?

Answer 10

tubular necrosis 85%
interstitial nephritis 10%
acute glomerulonephritis 5%

Question 11

what are the causes of toxic AKI ?

Answer 11

antibiotics esp aminoglycosides and amphotercin 
radiographic contrast media inc non ionic 
chemotherapy agents esp cis platinum 
rhabdomyolysis 
intravascular haemolysis 
tumour lysis 
solvents 
hepatorenal syndrome

Question 12

what are the causes of post renal AKI ?

Answer 12

obstruction to outflow from the kidneys
retroperitoneal fibrosis
neurogenic bladder
intra renal obstruction eg crystals

Question 13

what is the definition of CKD ?

Answer 13

slowly progressive loss of excretory renal function

original cause often unknown, usually irreversible

Question 14

what are the causes of CKD ?

Answer 14

diabetic neuropathy
genetic
vascular disease, chronic glomerulonephritis, chronic urinary outflow obstruction

Question 15

what causes GFR to decline ?

Answer 15

increasing age

Question 16

what is the presentation and symptoms of CKD ?

Answer 16

often asymptomatic,

symptoms emerge stage 4 or 5 (GFR

Question 17

what are the consequences of AKI and CKD ?

Answer 17

accumulation of K+, urea, creat, H+, water, PO43-
deficiency of erythropoietin - anaemia,
deficiency of 1 alpha vitamin D3 - hypocalcaemia, hyper PTH, bone disease,
delayed drug excretion,
xerostomia,
uraemic stomatitis

Question 18

what is involved in renal replacement therapy ?

Answer 18

erythropoietin, vit D (one-alpha), sodium bicarbonate, dialysis and transplantation

Question 19

what are the consequences of immunosuppression ?

Answer 19

infection 
viral transmission with transplant
malignancy 
hypertension 
dyslipidaemia
osteopaemia

Question 20

what are the adverse effects of cyclosporin ?

Answer 20

nephrotoxicity,
tremor,
hirsutism,
gingival hypertrophy,
interactions esp macrolides, dilitaizem, enzyme inhibitors, azatioprine, allopurinol

Question 21

how does renal transplantation affect dental care ?

Answer 21

good OH essential,
gingival hypertrophy, 
increased susceptibility to infection,
antibiotic prophylaxis,
drug interactions esp erythromycin