AKI

Question 1

What are the risk factors for AKI?

Answer 1

Diabetes
CKD
CCF/CVD
>75 y/o
Sepsis
Medications- ACEi, ARBs, NSAIDs, Abx
Renal transplant
Hypovolaemia
Contrast administration

Question 2

What is the most common cause of AKI?

Answer 2

Dehydration

Question 3

What are some pre renal causes of AKI?

Answer 3

Shock (hypovolaemic, cardiogenic or distributive)
- Hypovolaemia
- Decreased cardiac output e.g. MI
- Decreased effective circulating volume e.g. CCF, liver failure
-Meds- NSAIDS, ACEi, cyclosporin
Renovascular
- Renal a. stenosis

Question 4

What are some intrinsic causes of AKI?

Answer 4

Acute glomerulonephritis
-Dysfunction in the glomeruli
Acute tubular necrosis
-Often from nephrotoxic substances e.g. contrast, medications, rhabdomyolysis
Acute interstitial nephritis
Haemolytic uraemia syndrome or vasculitides
-Vascular cause

Question 5

What are some post renal causes of AKI?

Answer 5

Bladder outlet obstruction
Luminal (e.g. a kidney stone)
Mural (e.g. a tumour of the urinary tract)
Due to external compression (e.g. BPH).

Question 6

The build up of what metabolite in AKI causes confusion? What other symptoms can this cause?

Answer 6

The build-up of urea in the bloodstream can be due to overproduction (e.g. upper GI bleed) or decreased excretion (e.g. AKI, dehydration).
Uraemia causes vague symptoms such as nausea, vomiting, confusion (encephalopathy), seizures and coma. The classic “uraemic tinge” gives the patient’s skin a brown-grey colour.

Question 7

What electrolyte imbalance would indicate an acute rather than chronic kidney failure?

Answer 7

Hyperkalaemia
This is more common in AKI than CKD
Hyperkalaemia in CKD may indicate acute on chronic injury

Question 8

What causes renal artery stenosis?

Answer 8

Most cases of renal artery stenosis are caused by atherosclerosis, although a small proportion are due to fibromuscular dysplasia (with the cardinal case being a young woman).
In elderly think atherosclerosis, in under 50s think fibromuscular dysplasia

Question 9

What investigations can be done for renal a. stenosis? What is the gold standard?

Answer 9

Renal USS shows small kidneys.

Renal angiography is the gold standard investigation.

Question 10

How is renal a. stenosis managed?

Answer 10

Manage the risk factors for atherosclerosis.

Definitive management is with transluminal angioplasty ± stenting.

Question 11

What are tubular casts in the urine indicative of?

Answer 11

Acute tubular necrosis