chronic renal failure

Question 1

5 causes

Answer 1

Glomerulonephritis
DM
Hypertension/renovascular
PCKD
Reflux nephropathy

Question 2

3 points of pathophysiology

Answer 2

Persistence of underlying insult (e.g PCKD) will accelerate the decline of renal function
If GFR < 30%, CRF will progress despite this because remaining nephrons will one by one cease to function under the increased workload
Hypertension, nephrotoxic drugs, and other renal insults contribute to this progressive loss of renal function

Question 3

9 clinical features

Answer 3

Uraemia (malaise, lethargy, anorexia, malnutrition, hiccups) - failure of excretory function
Nocturia (early) –> dehydration - loss of urinary concentrating ability
Hypertension (various factors e.g. failure to excrete sodium)
Hypotension (damage to renal tubules –> sodium loss)
Hyperkalaemia
Metabolic acidosis (failure of acid secretion)
Bone problems (abnormal levels of calcium, vitamin D, phosphorus, PTH)
Anaemia (failure to secrete erythropoietin)
Medications - altered metabolism of medications excreted by kidneys

Question 4

definition and grading of CRF

Answer 4

Normal GFR is 90-120, CKD is defined as 90 - increased risk for CKD (e.g. diabetes, hypertension) OR kidney damage but normal GFR
60-90 - kidney damage and mild GFR reduction
30-60 - moderate GFR reduction
15-30 - severe reduction
<15 - kidney failure

Question 5

rx

Answer 5

Define and treat the underlying cause
Educate and refer to nephrology
Avoid nephrotoxins (e.g. NSAIDs, ACEIs)
Manage hypertension aggressively (target 120-25/80-85)
Manage fluid volume (avoid severe overload, maintain circulating blood volume)
Manage complications: anaemia (give erythropoietin + ferrous sulphate), bone disease (restrict phosphorus, phosphate binders +/- activated vitamin D)
Diet: fluid/salt restrict, maintain nutrition - may need daily multivitamin supplementation + folic acid, control protein intake, may need potassium reduction
Commence renal replacement therapy if required

Question 6

Types of renal replacement therapy

Answer 6

Haemodialysis
Peritoneal dialysis
Transplant

Question 7

Issues with dialysis

Answer 7

Only partially replaces some of the functions of the kidneys
Technique failure (e.g. failed vascular access or peritoneal failure)
Progression of comorbidities (especially CVD)

Question 8

Transplant - better quality of life but 3 issues:

Answer 8

Immunosuppression (infection/malignancy)
CVD
Availability of donor organs

Question 9

Occupational implications

Answer 9

Ascertain physical nature of work activities - some people can tolerate anaemia well, and thus return to work
Employer needs to make reasonable adjustments to allow time away for dialysis
Need to protect fistula site from damage (e.g. avoid manual handling –> may need more sedentary work)
Support of a partner will be important in reducing combined stresses of ongoing treatment, care of family, and return to work

Question 10

ix

Answer 10

Blood (standard): FBE (normochromic, normocytic anaemia), UEC (raised creatinine and urea), LFT (raised ALP due to renal osteodystrophy), CRP/ESR
Blood (additional): CMP (low calcium, raised phosphate), glucose (DM), PTH (raised)
Urine: MCS, dipstick, 24h urinary protein
Imaging: Renal ultrasound, DTPA scan, CXR (cardiomegaly, pleural/pericardial effusions, PO) bone x-rays (renal osteodystrophy)
Renal biopsy (if cause unclear + normal sized kidneys)

Question 11

reversible causes

Answer 11

CHF or low CO syn (tamponade, myxedema)
Infection
Dehydration
Nephrotoxins - superimposed ATN or AIN
Electrolyte disarray - Ca++,  K+, Na+
Obstruction
Malignant HTN and/or its Rx

Question 12

haemodialysis - requirements and risks

Answer 12

requires vascular access, stable hemodynamics & systemic heparin. Risks - dysequilibrium syndrome, shock, bleeding, catheter site infection and/or sepsis, air embolism

Question 13

peritoneal dialysis - requirements and risks

Answer 13

requires intact abdomen without ileus and ICU care. No heparin needed; continuous Rx. Risks - failure to drain, impaired respirations, shock, bleeding, peritonitis, bowel perforation, and hyperglycemia

Question 14

causes of CRF with normal/large kidneys

Answer 14

DM, PCKD

Amyloidosis, myeloma, systemic sclerosis, asymmetric renal vascular disease

Question 15

indication for renal replacement therapy

Answer 15

renal failure advanced and symptoms

significant or when renal function has declined to low levels (creatinine clearance ~10 ml/min).