12 - Renal Function and Co-morbidity Risk

Question 1

What can lead to CKD?

Answer 1

• Diabetes
• Glomerulonephritis
• Hypertension

Question 2

Relationship Diabetes to CKD

Answer 2

• Damages small blood vessels in kidneys and other organs
– Proteins begin to leak into the urine
– Ability to filter waste decreases
– Waste products begin to build up
– Kidneys may fail
– May need dialysis or transplant to live

Question 3

Normal kidney morphology and structural changes in diabetes mellitus.

Answer 3

thickening of the glomerular basement membrane
fusion of foot processes
loss of podocytes with denuding of the glomerular basement membrane
mesangial matrix expansion.

Question 4

Proteins in Urine

Answer 4

• The results of structural changes alter the charge on the GBM and the arrangement and size of the pores within the GBM so that larger (positively charged ) proteins may enter the urine
• Albumin – main plasma protein (approx. 65kD in size, usually retained in the bloodstream)
• Others
• Immunoglobulins and /or Bence-Jones
• Tamm-Horsfall
• Lysozyme
• Myoglobin and/or Haemoglobin
• Bacterial origin
• Peptides

Question 5

Micro- and Macro-albuminuria

Answer 5

• Normally, albumin stays in the body and little/no albumin is found in the urine.
• Less than 30 mg of albumin are excreted in a 24 hr period in a healthy individual.
• Microalbuminuria is the presence of a slightly elevated concentration of albumin in the urine: 30 – 300 mg per 24 hr period
• Macroalbuminuria: > 300 mg per 24 hr period

Question 6

Issues around measuring protein in urine

Answer 6

• Different proteins have different measurement responses with the same method
• A given protein has a different response in different methods
• Variable influence of interfering substances on different methods
• No standard reference material for calibration

Question 7

Investigation approach

Answer 7

• All patients
– Measurement of blood pressure
– eGFR calculation using serum creatinine
– Albumin / Creatinine Ratio (ACR)
– Urine sediment dipstick for RBC, WBC

Question 8

CKD and Carotid Atherosclerosis

Answer 8

• CKD is an independent risk factor for cardiovascular disease
• The work of Tanaka et al looked at the presence of atherosclerotic plaques in the carotid artery in patients with impaired real function
• A strong correlation was found between kidney dysfunction and carotid atherosclerosis.
• In more recent studies, other arteries of CKD patients have also shown similar atherosclerotic plaque depositions.