Acute kidney failure resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:

Overview

Acute Renal Failure is an abrupt reduction in kidney function defined as at-least one of the following: 1. an absolute increase in the serum levels of creatinine of 26.4 μmol/L(0.3mg/dl) or more; 2. a percentage increase in the serum levels of creatinine of more than 50%(1.5 fold increase from baseline); or 3. a reduction in volume of urine output(oliguria <0.5 ml/kg hourly for >6 hours. Acute renal failure is increasingly common, particularly in elderly population, hospital inpatients, and critically ill patients and it carries a high mortality. The most common cause of in-hospital acute renal failure in acute tubular necrosis resulting from multiple nephrotoxic insults such as sepsis, hypotension, and use of nephrotoxic drugs or radio-contrast media. Patients at risk include elderly people, diabetics, patients with hypertension or vascular disease, and those pre-existing renal impairment.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Life threatening cause 1
• Life threatening cause 2
• Life threatening cause 3

Pre Renal Causes

• Hypovolaemia

* Haemorrhage

* Volume depletion(for example vomiting, diarrhea, burns, inappropriate diuresis)

• Renal Hypoperfusion

* Non-steroidal anti-inflammatory drugs/selective cyclo-oxygenase 2 inhibitors

* Angiotension converting enzyme inhibitors/angiotension receptor antagonist

* Abdominal aortic aneurysm

* Renal artery stenosis/occlusion

* Hepatorenal syndrome

• Hypotension

* Cardiogenic shock

* Distributive shock(for example sepsis, anaphylaxis)

• Oedematous States

* Cardiac failure

* hepatic cirrhosis

* Nephrotic syndrome

Intrinsic Renal Causes

• Glomerular disease

* Inflammatory- post-infectious glomerulonephritis, cryoglobulinaemia, Henoch-Schonlein purpura, systemic lupus erythematosus, antineutrophil cytoplasmic antibody associated glomerulonephritis, anti-glomerular basement membrane disease

* Thrombotic- disseminated intravascular coagulation, thrombotic microangiopathy

• Interstitial Nephritis

* Drug Induced- Non-steriodal anti-inflammatory drugs, antibiotics

* Infiltrative- Lymphoma

* Granulomatous- Sarcoidosis, Tuberculosis

* Infection related- post-infective, Pyelonephritis

• Tubular Injury

* Ischemia- prolonged renal hypoperfusion

* Toxins- drugs(such as aminoglycosides), radiocontrast media, pigments(such as myoglobin), heavy metals(such as cisplatinum)

* Metabolic- hypercalcemia, immunoglobin light chains

* Crystals- urate, oxalate

• Vascular

* Vasculitis(usually associated with antineutrophil cytoplasmic antibody)

* Cryoglobulinaemia

* Polyarteritis nodosa

* Thrombotic microangiopathy

* Cholesterol emboli

* Renal artery thrombosis/renal vein thrombosis

Post Renal Causes

• Intrinsic

* Intra-luminal- stone, blood clot, papillary necrosis

* Intra-mural- urethral stricture, prostatic hypertrophy or malignancy, bladder tumor, radiation fibrosis

• Extrinsic

* pelvic malignancy

* retroperitoneal fibrosis

Diagnosis

Shown below is an algorithm summarizing an step by step approach to diagnosis the cause of Acute Renal Failure to aid in the management.

Patient presenting features ❑ Oliguria (sudden or gradual) ❑ Anuria ❑ Edema ❑ Hypotension ❑ Hematuria ❑ loin pain ❑ renal colic ❑ fever

Medical History and Risk Factors ❑ inquire about previous similar episodes ❑ co-morbidities ❑ Diabetes-long standing poorly controlled diabetes can precipitate ARF ❑ Hypertension ❑ Heart Failure ❑ Vascular disease(such as Renal Artery stenosis ❑ Inquire about drug history ❑ ACE inhibitors- can precipitate ARF in Renal artery stenosis ❑ NSAIDs-associated with interstitial kidney disease ❑ Penicillins-associated with renal papillary necrosis ❑ inquire about recent hospitalization-rule out Acute Tubular Necrosis ❑ Inquire about recent trauma/surgery-rule out sepsis-look for fever and hypotension/rule out hemorrhage and hypovolemia ❑ Age factor-elderly people-rule out Benign Prostate hypertrophy/prostate cancer ❑ history of kidney stones ❑ Social history-Alcohol use/tobacco use/drug abuse ❑ history of autoimmune disorders- Systemic Lupus Erythromatosus, Good Pasture syndrome

Treatment

Shown below is an algorithm summarizing the treatment of [[disease name]] according the the [...] guidelines.

Do's

• The content in this section is in bullet points.

Don'ts

• The content in this section is in bullet points.

References

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