Kidney disease

Question 1

What are the main functions of the kidney?

Answer 1

• Metabolise and excrete drugs
• Maintain normal body volumes
• Acid-base balance (producing bicarbonate and excreting H+)
• Calcium homeostasis
• Produces erythropoietin (RBC production)
• Produces renin - involved in regulating blood pressure

Question 2

How does the kidney metabolise calcium?

Answer 2

Vitamin D is produced from sunlight absorption and diet.
Vitamin D is carboxylated twice (in liver and kidney).
Vit D then is involved in calcium through increasing absorption from bone and increase in bone turnover.

Question 3

How does the kidney maintain blood pressure?

Answer 3

• Kidneys secrete renin as blood pressure drops which leads to an increase in angiotensinogen from the liver to form angiotensin 1 and converted to angiotensin 2
• Angiotensin 2 increases blood pressure by causing vasoconstriction and also acting on adrenal glands to cause the glands to release aldosterone which causes sodium retention by the kidneys

Question 4

How do ACE inhibitors and angiotensin 2 receptor antagonists work to lower blood pressure?

Answer 4

ACE Inhibitors = inhibit angiotensin converting enzyme

Angiotensin 2 receptor antagonist = blocks the angiotensin 2 receptors to stop vasoconstriction and actions on adrenal gland

Question 5

What is the normal GFR (glomerular flow rate)?

What GFR indicates kidney disease?

Answer 5

Male = 130
Female = 120

GFR < 90

Question 6

What are causes of chronic kidney disease?

Answer 6

• Hypertension
• Diabetes
• Prostatic hypertrophy
• Myeloma
• Use to anti-inflammatory drugs overly due to affect on prostaglandin production
• NSAIDS
• Renal pathology

Question 7

What are the effects of kidney disese?

Answer 7

1 - hypertension due to no control of level of blood volume

2 - peptic ulcer

3 - anaemia in blood due to decrease in erythropoietin

4 - affects bone marrow causing fibrosis leading to lymphopenia or neutropenia

5 - renal osteodystrophy due to affects on calcium metabolism and low calcium levels increase bony turnovers

Question 8

How do we treat kidney disease?

Answer 8

Haemodialysis - removes excess water at a dialysis unit. Clean blood put back into patient.

Continuous Ambulatory Peritoneal dialysis = the patient’s peritoneum acts as a semipermeable membrane and that has a port created in the abdominal wall into which the dialysis fluid is injected. Water and metabolites diffuse through the peritoneum into the solution which patient changes regularly.

Question 9

Some patients get a renal transplant, how does this change our treatment?

Answer 9

1) Immunosuppressants to prevent rejection
2) Steroids taken as immune-suppressants
3) Give antibiotic cover for 3 years post transplant
4) Liaise with renal physician

Question 10

What do we need to be aware of dentally when a patient has kidney disease?

Answer 10

1. Bleeding risk - tend to have low platelets and reduced function. Patients tend to be on heparin for dialysis so treat between dialysis days.
2. Increased risk of infection - increases risk due to low white blood cells count and on immunosuppressants
3. Often the patient is taking bisphosphonates
4. Never give NSAIDS
5. Caution with IV sedation (enhanced sedative effect and for longer)
6. Decrease dose of amoxicillin and erythromycin

Question 11

What blood tests are required for kidney disease diagnosis?

Answer 11

1) FBC to check platelet levels, white blood cells, neutrophils and lymphocytes
2) Urea and electrolytes test (renal screen) - to check GFR

Question 12

What GFR does a patient need dialysis?

Answer 12

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