Renal disease + AKI

Question 1

Pre-renal causes

Answer 1

Hypovalaemia:

• septic shock
• cardiogenic shock
• CHF and liver failure - ascites and peripheral oedema

Vascular:

• Renal artery stenosis
• Toxins: NSAIDs, ACEi, Cyclosporine
• Thrombosis

Question 2

Renal causes

Answer 2

Glomerulonephritis
Acute Tubular Injury - nephrotoxins, ischaemia
Vasculitis

Question 3

Post-renal causes (SNIPIN)

Answer 3

Diseases of renal papillae, pelvis, ureters, bladder or
urethra

• Stone
• Neoplasm
• Inflammation: stricture
• Prostatic hypertrophy
• Infection: TB, schisto
• Neuro: post-op, neuropathy

Question 4

Presentation of renal disease

Answer 4

Uraemia - pruritis
Fluid overload + HTN
Less bicarb reabsorption - Metabolic acidosis - breathless + confusion
Hyperkalaemia - arrhythmia + palpitations
Less EPO production - anaemia
Vitamin D deficiency - fatigue
Less calcium resorption - osteomalacia

Question 5

AKI

Answer 5

Significant decline in renal function over hrs or days

manifesting as an abrupt and sustained ↑ in Se Creatinine

Question 6

Volume asessment - dehydrated

Answer 6

Postural hypotension
↓ JVP
↑ pulse
Auscultate lungs - pulmonary oedema 
Peripheral oedema 
Poor skin turgor, dry mucus membranes
Urine output vs input

Question 7

Ix

Answer 7

Bloods:

• FBC - anaemia
• U+E
• HbA1c - diabetes
• Bone profile - Ca, PTH, ALP, phosphate
• CRP
• CK - rhabdomyolysis
• Haematinics - Fe, Folate, B12

VBG: hypoxia (oedema), acidosis, ↑K+

GN screen: if cause unclear

Urine:

• dipstick - protein and blood - MCS
• chemistry - U+E, PCR, osmolality, Bence Jones proteins

ECG: hyperkalemia

CXR: pulmonary oedema

Renal USS: Renal size, hydronephrosis

Question 8

AKI stages

Answer 8

Stage I

• ↑Cr x1.5 baseline
• UO <0.5ml/kg/h x 6h
• > 26.5micromol/l increase

Stage II

• ↑Cr x 2
• <0.5ml/kg/h x 12h

Stage III:
- ↑Cr x 3
- <0.3ml/kg/h x 24h, or
anuria x12h

Question 9

Mx

Answer 9

Identify and tx pre-renal or post-renal causes
Urgent USS
Tx exacerbating factors: e.g. sepsis
Stop nephrotoxins: NSAIDs, ACEi, gentamycin, vancomycin
Stop metformin if Cr > 150mM

Question 10

Monitor

Answer 10

Catheterise and monitor UO
Consider CVP
Fluid balance
Weight - indication of fluid

Question 11

Hyperkalaemia ECG

Answer 11

Tall tented T waves 
Flattened P waves
↑ PR interval
Widened QRS
Sine-wave pattern → VF

Question 12

Mx of hyperkalaemia

Answer 12

Calcium gluconate
Glucose + Actrapid
Salbutamol nebulizer
Calcium resonium

Question 13

Indications for Acute Dialysis

Answer 13

1. Persistent hyperkalaemia (>7mM)
2. Refractory pulmonary oedema
3. Symptomatic uraemia: encephalopathy, pericarditis
4. Severe metabolic acidosis (pH <7.2)
5. Poisoning (e.g. aspirin)

Question 14

Renal tubular acidosis

Answer 14

Impaired acid excretion → hyperchloraemic metabolic acidosis

Both → RAS activation → K+
wasting and hypokalaemia

Type 1 (Distal) - Inability to excrete H+

Type 2 (proximal) - Defect in HCO3 reabsorption in PCT

Question 15

Bartter’s Syndrome

Answer 15

Blockage of NKCC2 reabsorption in loop of Henle - (as if taking furosemide)

• hypokalaemia and metabolic alkalosis

Question 16

Gitelman Syndrome

Answer 16

Blockage of NaCl reabsorption in DCT (as if
taking thiazides)

• hypokalaemia and metabolic alkalosis

Question 17

Polycystic Kidney Disease pathology

Answer 17

Autosomal dominant
PKD1 on Chr16
PKD2 on Chr4

• Large cysts arising from all parts of nephron
• Progressive decline in renal function
• 70% ESRF by 70yrs

Question 18

Mx of PCKD

Answer 18

General:

• ↑ water intake, ↓ Na, ↓ caffeine
• Monitor U+E and BP

Genetic counselling
MRA screen for Berry aneurysms

Medical

• HTN control
• Mx infections aggressively

Surgical:
- Laparoscopic cyst removal or nephrectomy.

Question 19

Risk factors for AKI

Answer 19

Diabetes
CKD
IHD/CCF
Elderly >75
Sepsis
Medications – ACEi, ARBs, NSAIDs, gentamycin, vancomycin 
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