Chronic Kidney Disease

Question 1

Definition

Answer 1

Chronic kidney disease (CKD) describes a progressive deterioration in renal function:
Abnormalities of kidney function or structure present for more than 3 months, with implications for health. This includes all people with markers of kidney damage and those with a GFR <60 on at least 2 occasions separated by a period of at least 90 days (with or without markers of kidney damage).

Question 2

Epidemiology

Answer 2

Afro-Caribbean’s
Age
Males

Question 3

Risk Factors

Answer 3

Diabetes
Smoking
HTN
Autoimmune conditions: SLE, RA, Sjogren’s
Nephrotoxic Drugs: NSAIDS
BPH
Renal artery stenosis
Glomerulonephritis

Question 4

Aetiology

Answer 4

Diabetes (MC)
Hypertension
Age related decline
Glomerulonephritis
Polycystic kidney disease
Meds: NSAIDS, PPI, Lithium

Question 5

Pathophysiology

Answer 5

Diabetes (MC) cause:
- Excess glucose sticks to endothelium of efferent arteriole (glycation) = gets stiff and narrow + fibrosis = blood is less able to leave glomerulus = increases pressure in glomerulus = hyperfiltration = in response, mesangial cells secrete more ECM = GLOMERULOSCLEROSIS
HTN:
- Walls of afferent arteriole thicken to withstand the pressure = narrow lumen = can lead to encephalopathy (asterixis seen) + pericarditis. Urea also effects platelet function = bleeding. Can also develop uraemic frost = urea crystals develop in skin
Hyperkalaemia = Arrhythmias
Normally kidneys activate Vit D which increases absorption of Ca2+ in the gut. Less Vit D = hypocalcaemia = PTH increases = bone resorption (renal osteodystrophy)
Low fluid entrance to kidney = RAAS = hypertension = worsens CKD
Kidneys produce less EPO = anaemia

Question 6

Signs

Answer 6

HTN
Fluid overload = raised JVP + oedema
Uraemic sallow = yellow. or pale brown skin colour
Uremic frost
Cardiac arrhythmias
Peripheral neuropathy
(Butterfly rash in SLE)

Question 7

Symptoms

Answer 7

Increased bleeding
Lethargy
Loss of appetite (due to uraemia)
Nausea
Muscle cramps
Anorexia
Frothy urine
Swollen ankles
Pruritus
Bone pain

Question 8

Diagnosis

Answer 8

FIRST LINE: Urine dipstick = proteinuria + haematuria
Urine albumin: creatinine ratio (ACR): >3mg/mmol = clinically significant proteinuria
U&Es: serum creatinine can be used to calculate eGFR and quantify the severity of CKD; patients may also develop electrolyte disturbances such as hyperkalaemia
FBC: normocytic normochromic anaemia secondary to reduced erythropoietin production; usually apparent when GFR is < 35 ml/min
Bone profile and PTH: patients are at risk of hypocalcaemia, hyperphosphatemia, and secondary or tertiary hyperparathyroidism
Renal ultrasound: to exclude a structural defect. In CKD, there is bilateral kidney atrophy, possible hydronephrotic or stones

Question 9

G score

Answer 9

> 90 ml/min = STAGE 1
60-90 ml/min with some sign of kidney damage = STAGE 2
45-59 ml/min a moderate reduction in kidney function = STAGE 3A
30-44 ml/min a moderate reduction in kidney function = STAGE 3B
15-29 ml/min a severe reduction in kidney function = STAGE 4
Less than 15 ml/min established kidney failure - dialysis or a kidney transplant may be needed = STAGE 5

Patient needs an eGFR of at least < 60ml/min on at least two occasions separated by period of 3 months or proteinuria for at least 3 months to diagnose CKD

Question 10

A score

Answer 10

A1 = < 3mg/mmol
A2 = 3-30 mg/mmol
A3 = 30 mg/mmol

Question 11

Management

Answer 11

Lifestyle =
- Smoking cessation, exercise, drinking alcohol in moderation
- Avoid nephrotoxic medications; e.g. NSAIDs
- Dietary advice: low salt and potassium diets, with fluid restriction if there is evidence of overload
CKD-mineral bone disease:
- Vit D
- Phosphate binders (calcium acetate)
Cardiovascular risk factors:
CVD
- Aspirin 75mg
- Atorvastatin 20mg
HTN
- ACE-I = Ramipril
- ARB = Candesartan
Anaemia:
- Target Hb: 10-12 g/dl, as per NICE [4]
- Iron replacement: either orally or intravenously, prior to commencing ESAs; particularly important in patients on haemodialysis
Erythropoiesis stimulating agents (ESAs): e.g. erythropoietin (EPO) or darbepoetin
Renal replacement therapy:
- Typically performed when eGFR is in single digits (CKD stage 5) or there are signs of uraemia
- Dialysis is usually commenced first, followed by renal transplantation if the patient is eligible

Question 12

Complications

Answer 12

Cardiovascular
- Cardiovascular disease is the leading cause of death in CKD
- Heart failure: due to fluid overload and anaemia
Musculoskeletal
- CKD-metabolic bone disease
Endocrine
- Secondary hyperparathyroidism
- Tertiary hyperparathyroidism occurs after a prolonged period of secondary hyperparathyroidism
Haematological
- Anaemia: usually normocytic and normochromic and is multifactorial; predominantly due to low EPO, but also reduced erythropoiesis due to uraemia, reduced iron absorption and anorexia due to uraemia
Metabolic
- Uraemia
- Hyperkalaemia
- Metabolic acidosis