Chronic kidney disease

Question 1

Define CKD

Answer 1

Reduction in kidney function or structural damage (or both) present for >3 months, with implications for health.

Question 2

Causes of CKD

Answer 2

Diabetes - most common
Hypertension
Glomerular disease 
PKD
Pyelonephitis 
Other e.g. nephrotoxic drugs, toxins, SLE, vasculitis, myeloma, HIV

Question 3

Consequences + complications of CKD

Answer 3

AKI
Anaemia (reduced EPO production)
Hypertension (increased renin due to falling GFR)
Osteodystrophy (low calcium due to not activating vit D, causes PTH release and so bone resorption –> secondary hyperparathyroidism)
Hyperkalaemia (kidneys normally excrete potassium)
Azotemia (high urea)

Dyslipidaemia
Cardiovascular disease 
Peripheral neuropathy and myopathy
Malnutrition
Malignancy
End-stage renal disease 
All-cause mortality

Question 4

Signs/symptoms/consequences of high urea

Answer 4

Nausea and loss of appetite
Encephalopathy - asterixis, coma, death
Pericarditis
Bleeding (urea makes platelets less sticky), Uremic frost (crystals deposit in skin)

Question 5

How does hypertension lead to CKD?

Answer 5

Walls of artery supplying kidney become narrow

• -> less blood + oxygen to kidney
• -> ischaemic injury to glomeruli
• -> Immune cells (macrophages and foam cells) secrete growth factors
• -> mesangial cells secrete extracellular matrix
• -> glomerulosclerosis
• -> nephrons have diminished ability to filter blood

Question 6

How does diabetes lead to CKD?

Answer 6

Excess glucose

• -> non-enzymatic glycation
• -> efferent arteriole becomes stiff and narrow
• -> more difficult for blood trying to leave glomerulus
• -> increased pressure within glomerulus, causing hyperfiltration
• -> mesangial cells produce more and more matrix
• -> glomerulosclerosis
• -> nephrons have diminished ability to filter blood

Question 7

CKD should be diagnosed in people with…?

Answer 7

1) Markers of kidney damage e.g. urinary albumin:creatinine ratio (ACR) >3 mg/mmol, urine sediment abnormalities, electrolyte and other abnormalities due to tubular disorders, abnormalities detected by histology, structural abnormalities detected by imaging, and a history of kidney transplantation

AND/OR

2) A persistent reduction in renal function
e. g. eGFR <60

Question 8

What to ask in history?

Answer 8

PC/HPC - lethargy, itch, SOB, cramps, sleep disturbance, bone pain, loss of appetite, vomiting, weight loss, taste disturbance
ROS - urine output, mood
PMH - previous AKI, risk factors for CKD, previous CVD/stroke
DH - any nephrotoxic drugs?
FH - renal disease e.g. ADPKD
SH

Question 9

Signs of CKD on examination

Answer 9

Uraemic odour (ammonia-like smell of the breath, may be present in advanced disease).
Pallor
Cachexia
Cognitive impairment
Dehydration or hypovolaemia
Tachypnoea (fluid overload, anaemia, or co-morbid ischaemic heart disease)
Hypertension
Palpable bilateral flank masses with possible hepatomegaly (polycystic kidney disease)
Palpable distended bladder (obstructive uropathy)
Peripheral oedema (renal sodium retention, hypoalbuminaemia, or co-morbid heart failure)
Peripheral neuropathy or myopathy
Frothy urine (may indicate proteinuria)

Question 10

Define G1

Answer 10

eGFR >= 90

Question 11

Define G2

Answer 11

eGFR 60-89

Question 12

Define G3a

Answer 12

eGFR 45-59

Question 13

Define G3b

Answer 13

eGFR 30-44

Question 14

Define G4

Answer 14

eGFR 15-29

Question 15

Define G5

Answer 15

eGFR <15

Question 16

Define A1

Answer 16

Urinary ACR <3 mg/mmol

Question 17

Define A2

Answer 17

Urinary ACR 3-30 mg/mmol

Question 18

Define A3

Answer 18

Urinary ACR >30 mg/mmol

Question 19

Investigations for CKD

Answer 19

Serum creatinine and eGFR
Early morning urine sample for urinary ACR
Urine dipstick for haematuria + MSU if positive
–> Repeat within 3 months to diagnose + classify CKD

Check nutritional status, BMI, BP, HbA1c, lipid profile

Consider renal tract ultrasound if indicated

Question 20

What is accelerated progression of CKD?

Answer 20

Sustained decrease in eGFR of 25% or more from baseline and a change in CKD category within 12 months; or a sustained decrease in eGFR of 15 mL/min/1.73 m2 within 12 months.

Question 21

How to monitor CKD?

Answer 21

Monitor creatinine, eGFR and urinary ACR - how often depends on their stage and trajectory
FBC if stages 3b, 4, 5
Serum calcium, phosphate, vit D, PTH if stages 4 or 5

Question 22

When to refer to nephrology?

Answer 22

eGFR < 30
Accelerated progression
ACR of 70 or more
ACR of 30 or more + persistent haematuria
Uncontrolled HTN with four drugs
Suspected/confirmed rare or genetic cause e.g. PKD
Suspected renal artery stenosis
Suspected complication of CKD

Question 23

How to manage in primary care

Answer 23

Assess for and manage risk factors and co-morbidities
Assess for hypertension - use lisinopril or losartan if ACR > 30 or diabetic, TARGET IS 140/90 or 130/80 if ACR >70 or if diabetic
Optimise diabetic control
Statin
Antiplatelet drug
Immunisations - flu and pneumococcal disease

Question 24

Management of CKD bone/mineral disorders

Answer 24

Reduced dietary intake of phosphate
Phosphate binders - calcium based binders, sevelamer (non-calcium based)
Vitamin D: alfacalcidol, calcitriol
Parathyroidectomy may be needed in some cases

Question 25

Dietary requirements of patients with advanced CKD

Answer 25

Healthy diet, reduce alcohol
May be asked to cut down on fluids
Reduced salt
May be advised to have low potassium diet or a low phosphate diet