Acute Kidney Injury

Question 1

What is it?

Answer 1

significant deterioration in renal function over hrs or days, clinically manifesting as an abrupt and sustained rise in serum urea and creatinine

Question 2

What are the causes

Answer 2

1. Pre-renal: hypovolaemia, sepsis, CCF, cirrhosis, renal artery stenosis, NSAIDs, ACEi
2. Intrinsic: ATN due to ischaemia or nephrotoxins, aminoglycosides, amphotericin B, tetracyclines, contrast, uric acid crystals, haemoglobinuria (rhabdomyolysis) or myeloma, vasculitis, malignant HTN, cholesterol, HUS, TTP, GN, interstitial nephritis
3. Post-renal: obstruction

Question 3

When should chronic renal failure be suspected over AKI?

Answer 3

Hx of comorbidity (DM, HTN)
Long duration of sx
Prev abnormal bloods
Small kidney (<9cm) on US w increased ethogenicity

Question 4

what would make u suspect that the cause of AKI is obstruction?

Answer 4

• single functioning kidney
• Hx of renal stones, BPH or prev. surgery
• palpable bladder
• complete anuria
• renal US showing dilatation of pelvis + calyces

Question 5

what tests would u do in suspected AKI

Answer 5

1. Bloods - U+E, FBC, LFT, clotting, CPR/ESR, creatinine, ABG, cultures, hepatitis serology
2. Serum Igs, complement levels, autoabs
3. Urine - dipstick, microscopy, MC + S, chemistry
4. CXR - pulm oedema,
5. ECG - signs of hyperkalaemia
6. Renal US

Question 6

What is the immediate management of AKI?

Answer 6

• identify and correct pre-renal and post renal factors
• Urgent US scan, check for palpable bladder
• find and rx exacerbating factors e.g. sepsis
• stop nephrotoxic drugs

Question 7

What are the possible problems u would look out for in AKI and what signs would point to them?

Answer 7

• Vasculitis - epistaxis, haematuria, rash, raised ESR/CRP, autoabs
• Low intravascular volume - reduced turgor and UO, invisible JVP
• Fluid overload - gallop rhythm, raised JVP + BP, lung creps, peripheral oedema

Question 8

What are the potential complications of AKI? how would.u treat them?

Answer 8

1. hypercalcaemia - IV calcium gluconate 10% 10ml, IV insulin + glucose, salbutamol 5mg nebs, calcium resonium, haemodialysis if anuric
2. bleeding (impaired haemostats due to raised urea, made worse by precipitating cause) - give PPIs or H2 antagonists, if active bleeding: FFP + platelets
3. Pulmonary oedema - sit up, high flow O2, IV morphine, (+IV metoclopramide), furosemide, CPAP, venesection (if in extremis)