Week 4 - Urology Cases of the Week - ACUTE kidney injury (protocol for investigations)

Question 1

What are the two changes in creatinine that aid in the diagnosis of acute kidney injury?

Answer 1

Serum creatinine greater than 26micromole per litre change in the past 48 hours or Serum creatinine has increased greater than 50% over the past 7 days

Question 2

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Answer 2

Likely diagnosis would be Acute kidney injury

Question 3

1) What other blood samples would you take? now that creatinine has been measured

Answer 3

FBCs LFTs Measure urea and electrolytes Get a cross matching and coagulation screen

Question 4

Why is the patient likely to be in acute kidney injury from her history? (ie pre, intrinsic or post renal cause)

Answer 4

Patient is hypoperfused and likely to be a prerenal cause

Question 5

What is given to treat the hypoperfusion?

Answer 5

Probably give saline initially Haemoglobin concentration will now drop – so would be good to give bloods

Question 6

At gastroscopy, she is found to have a duodenal ulcer, which is bleeding, and is injected. Later, she tells the doctor that although her general health is good, she has had sore joints recently, and has been taking ibuprofen twice daily for the last 2 weeks. What factors have contributed to the acute kidney injury? (describe how)

Answer 6

The NSAIDs have inhibited the COX 1and2 enzyme leading to decreased prostoglandins This causes decreased bicarbonate in the stomach leading to ulceration and bleeding NSAIDs also cause vasconstriction of the afferent arteriole which causes a decreased perfusion of the kidney

Question 7

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Answer 7

pH - 7.35-7.45 pCO2 - 4.7-6 HCO3 - 23-27 pO2 - 11-13

Question 8

 Creatinine 760 mol/L.  Urea 42mmol/L.  Potassium 6.8mmol/L  Haemoglobin 79g/L.  WBC 11.4 x 109 /L.  Platelets 475 x 109/L  Arterial blood gases: pH 7.31. PCO2 4.2kPa. PO2 6.9kPa.  HCO3 – 14mmol/L Base on these values what does the patient have and what is the treatment?

Answer 8

Patient has a metabolic acidosis with compensation

Question 9

What is the normal potassium range? What would you say about the patinets oxygen and potassium levles?

Answer 9

3.6 to 5.2 millimoles per liter (mmol/L). Patineet is hyperkalaemic and hypoxic

Question 10

What would the inital emergency treatment of the patient be?

Answer 10

For oxygen Give non-rebreather mask 15l/min o Treatment depends on severity Mild cases (K+ >5.5-6.0 mmol/l) • Calcium resonium (orally or rectally) Moderate cases (K+ > 6.5 mmol/l) • Calcium resonium • Dextrose + insulin Severe cases (K+ > 7.0 mmol/l) • IV calcium chloride or gluconate (to stabilise the myocardium) • Bollus of 50ml 50% dextrose and 10 units soluble insulin • Salbutamol nebulisers High flow oxygen

Question 11

Why is salbutamol also given in hyperkalaemia?

Answer 11

B-agonists have shown to drive potassium into the cells

Question 12

Note that none of these measures remove potassium from the body,so their effect on serum potassium is temporary What will almost certainly be required?

Answer 12

Haemodialysis will almost certainly be required

Question 13

2) What are the likely causes of his acute kidney injury?

Answer 13

The patient could have a vasculitis or goodpasture’s syndrome

Question 14

What other investigations would you request?

Answer 14

Would request for an ANCA antibody and a anti-GBM antibody in the blood A renal biopsy may also be carried out

Question 15

What would the treatment be if the patient had a systemic vasculitis or goodpastures’ syndrome? What vasculitis do you think it could be?

Answer 15

Could be MPA or GPA Treat both with oral steroids and cyclophosphamide

Question 16

Which antibodies would show in MPA and GPA?

Answer 16

MPA - mircoscopic polyangiitis - would show MPO-ANACA (p-ANCA against MPO) antibodies GPA - granulomatosis with polyangiitis - Wegener’s granulomatosis - would show PR3-ANCA (c-ANCA against PR3)

Question 17

If the patient is ANCA positive and granuloma is present, what are the two options? If the patient is ANCA positive and granuloma is not present, what is the option??

Answer 17

Granuloma present - GPA or EGPA (Churg-Strauss) Granuloma absent - MPA