Acute renal failure Flashcards Preview

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Flashcards in Acute renal failure Deck (13):
1

Definition

Deterioration in kidney function over days/hours, demonstrated by + in urea and creatinine.

1. Increase in serum creatinine by ≥26.5 micromol/L (≥0.3 mg/dL) within 48 hours; or

2. Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days; or 3. Urine volume <30ml/hour

2

Life threatening consequences

1. Fluid overload

2. Hyperkalemia

3. Metabolic acidosis

3

Etiology

1. Pre-renal Hypovolemia Hemorrhage Sepsis Third spacing Overdiuresis Heart failure Hepatorenal Renal artery stenosis NSAIDs, ACEi

2. Intrinsic Glomerular->GN Tubules->Toxins, ATN Interstitium->infection Vascular->vasculitis, TE, malignant HTN, HUS, TTP

3. Post-renal Urinary tract obstruction

4

Nephrotoxins

1. Aminoglycosides

2. Amphotericin

3. Radiological contrast

4. Uric acids

5. Haemoglobinuria/Myoglobinuria

5

Most common cause of acute kidney injury

Acute tubular necrosis due to ischemia

6

Pathophysiology

1. Prerenal->reduced perfusion->+RAAS, vasoconstriction, salt and water reabsortion

2. ATN->ischemia, free radicals, complement, inflammation, necrosis

3. Obstruction->Pressure, ischemia, atrophy

7

Three important questions to ask

Is this chronic or acute? Is this due to obstruction? Is there a rare cause of ARF?

8

Features suggestive of CRF

1. Comorbidities->DM, HTN, long duration of symptoms

2. Previously abnormal blood results

3. Small kidneys on USS

4. Anaemia and phosphate+->not distinguishing as can occur within days, absence does suggest AKI

9

History

1. In pre-renal

Hemorrhage,

GIT loss,

sweating,

fluid replacement

Sepsis,

pancreatitis

Thirst, dizziness, tachyC, oliguria, anuria

Orthopnea/PND

2. Intrinsic

Rash

Hematuria, Edema w/ HTN

Myeloproliferative

Medicine/contrast NSAIDs

Rhabdomyolysis->muscle tender, seizure,

drug abuse, alcohol abuse, ++exercise, limb ischemia

3. Post

Urgency, frequency, hesitancy

Hx of malignancy, nephrolithiasis, previous surgery

Flank pain, hematuria

10

Physical examination

1. HypoT, HTN

2. pulmonary edema, peripheral edema

3. Asterixis, mental state

4. Hydrations

5. Sepsis

6. Pancreatitis

6. HTN, edema, proteinuria, hematuria

7. Rash, petechiae, eccymoses

8. Abdominal bruit, Abdominal distension,

9. +bladder

Prostate enlargement

11

Investigations

1. Bloods/urine

UEC->+urea/creatinine, +potassium, metabolic acidosis Ratio

Urinalysis->RBC, WBC, casts, nitrite, bacteria Urine MCS

FBC->anaemia, leukocytosis, thrombocytopenia (HUS, TTP)

VBG->metabolic acidosis

CK->rhabdoM

Clotting, LFTs

Urine osmolarity

2. Unclear cause:

ANA, ANCA, anti-dsDNA, antiGBM, ASOT, hepatitis, bence jones

3. Imaging

Renal USS->dilation, reduced size

CXR->pulmonary edema, cardiomegaly

ECG->peaked T waves, +PR, wide QRS if hyperkalemia

12

Management

1. Specialist help

2. Catheterise, start fluid chart

3. Assess IV volume->BP, JVP, skin turgor, fluid balance

4. Attach ECG.

5. Examine for palpable bladder

6. 2 large bore IV cannulae->Investigations: UEC, CMP, FBC, ESR/CRP, INR. LFT, CK, LDH, protein electroP, hepatitis serology, ANA/ANCA/complement, anti-GBM, ASOT, blood cultures Urgent urine MCS USS ECG, CXR

7. Assess and treat hyperkalemia: calcium gluconate IV, insulin + glucose, salbutamol, calcium resonium

8. Treat the treatable

9. If dehydrated/hemorrhage->fluid 250-500ml NS bolus/transfusion

10. Stop nephrotoxic medications

11. Treat pulmonary edema: sit up, high flow, morphine + metoC, frusemide.

12. May need hemodialysis, IV nitrates

13. Manage hemorrhage: PPI, FFP/PLTs, blood transfusion

14. Reassess

15. Continue IVF to maintain urine output

16. If fluid overloaded->consider urgent dialysis. Nitrate, frusemide, dopamine in short term.

17. Treat sepsis

18. Admit

19. Regular monitoring->BP, urine, pulse

20. Daily weights, fluid balance, input/output

21. Nutrition

13

Indications for dialysis

Refractory pulmonary edema Persistent hyperkalemia Severe metabolic acidosis Uremic encephalopathy Uremic pericarditis