PKD/CKD/AKI

Question 1

What happens to K+ in the collecting duct (intercalated cells and principal cells)?

Answer 1

Intercalated cells —> K+ is re-absorbed into the blood (and H+ is excreted).

Principal cells—-> K+ is secreted into the collecting duct (in urine).Leaves via ROMK or BK channels or K+/Cl- co-transporters

K+ secretion (by principal cells) OUTWEIGHS K+ re-absorption (by intercalated cells)

Question 2

What is type 1 renal tubular acidosis?

Answer 2

Is when the distal tubule cannot excrete H+ ions resulting in metabolic acidosis and high urinary pH as well as hypokalaemia.

Question 3

What are some causes of type 1 renal tubular acidosis?

Answer 3

Genetic (there are both autosomal dominant and autosomal recessive forms)

Systemic lupus erythematosus

Sjögren’s syndrome

Primary biliary cholangitis

Hyperthyroidism

Sickle cell anaemia

Marfan’s syndrome

Question 4

What is the treatment for type 1 and 2 renal tubular acidosis?

Answer 4

Oral bicarbonate

Question 5

What is type 2 renal tubular acidosis?

Answer 5

Occurs when proximal tubule cannot re-absorb HCO3-.Results in high urinary pH, metabolic acidosis and hypokalaemia

Question 6

What is type 4 renal tubular acidosis?

Answer 6

Is also known as hyperkalaemic RTA. It is caused by reduced aldosterone—-> reduced K+/H+ excretion in the DCT.

Question 7

What can cause low aldosterone seen in type 4 renal tubular acidosis?

Answer 7

Adrenal insufficiency
Diabetic nephropathy
Medications (e.g., ACE inhibitors, spironolactone or eplerenone)

Question 8

How do you manage type 4 RTA?

Answer 8

Management is targeted at the underlying cause. Fludrocortisone (a mineralocorticoid steroid) may be used in aldosterone deficiency. Oral bicarbonate and treatment of hyperkalaemia may also be required.

Question 9

What is the choice of investigation for RELATIVES of a patient with ADPKD?

Answer 9

Abdominal ultrasound

Question 10

What genes are affected if a patient has autosomal dominant polycystic kidney disease? What are the two?

Answer 10

In 85% of cases —> PDK1 gene on chromsome 16 is affected

In 15 % of cases —-> PDK2 gene on chromsome 4 is affected

Question 11

What are some extra-renal presentations of ADPKD?

Answer 11

Cerebral aneurysms

Hepatic, splenic, pancreatic, ovarian
and prostatic cysts

Mitral regurgitation

Colonic diverticula

Question 12

What are some complications of polycystic kidney disease?

Answer 12

Chronic loin/flank pain
Hypertension
Gross haematuria can occur with cyst rupture (usually resolves within a few days)
Recurrent urinary tract infections
Renal stones
End-stage renal failure occurs at a mean age of 50 years

Question 13

What should a patient avoid if they have ADPKD?

Answer 13

Contact sports –> due to the risk of cyst rupture

NSAIDs and anticoagulants

Question 14

What is the primary medication used for managing ADPKD?

Answer 14

Tolvaptan (a vasopressin receptor antagonist)

Slows cyst development and progression of renal failure

Question 15

What causes autosomal RECESSIVE polycystic kidney disease?

Answer 15

A mutation in the PKHD1 gene on chromosome 6

Question 16

Renal failure is defined as …..

Answer 16

a glomerular filtration rate of less than 15ml/min

Question 17

What medication is needed when patients are on haemodialysis?

Answer 17

Anticoagulation (to avoid blood clotting in the machine and during the process).

Heparin or citrate

Question 18

What are the sites to do an AV fistula?

Answer 18

1. Radiocepahlic fistula at the wrist (radial artery to cephalic vein)
2. Brachiocephalic fistula (at the antecubittal fossa—→ brachial artery to cephalic vein)
3. Brachiobasilic fistula (at the upper arm—> is less common and more complex operation)

Question 19

What are some complications of an AV fistula?

Answer 19

Aneurysm
Infection
Thrombosis
Stenosis
STEAL syndrome
High-output heart failure