Acute kidney failure resident survival guide

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


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. To aid the diagnosis and management, it is important to find out the underlying cause, whether its pre-renal, renal or post renal. Initial workup should be carried out as soon as the patient is encountered and any life threatening situation should be treated promptly.


Life Threatening Causes

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

Common Causes

Acute renal failure
Pre-renal causes
Intrinsic renal causes
Post-renal causes
Glomerular disease
Tubular injury
Interestitial nephritis
Vascular diseases
Inflammation (vasculitis)
Inflammation (glomerulonephritis)
Oclusion (thrombosis or embolism

Pre Renal Causes

  • Hypovolaemia
  • Renal Hypoperfusion
  • Hypotension
  • Oedematous States

Intrinsic Renal Causes

  • Glomerular disease
  • Interstitial Nephritis
  • Tubular Injury
  • Vascular

Post Renal Causes

  • Intrinsic
  • Extrinsic


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
❑ bone pain

❑ fever
Medical History and Risk Factors

❑ inquire about previous similar episodes
❑ co-morbidities

Diabetes-long standing poorly controlled diabetes can precipitate ARF
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

❑ elderly patient with bone pain-Myeloma?

❑ history of kidney stones<br ❑ Associated symptoms

❑ Nasal stuffiness/epistaxis-suggest Wagener's Granulomatosis?
❑ recent sore throat-streptococcal Glomerulonephritis

❑ Social history-Alcohol use/tobacco use/drug abuse
❑ history of autoimmune disorders- Systemic Lupus Erythromatosus, Good Pasture syndrome

Initial work-up

❑ Basic Blood

❑ full blood count with differentials
❑ blood glucose
❑ urea and electrolytes
❑ coagulation screen
❑ inflammatory markers
❑ urea/electrolytes
❑ liver function test
❑ calcium and phosphate
❑ blood culture if infection suspected
❑ Arterial blood gases or venous bicarbonate

❑ Urine analysis
❑ Urine microscopy/urine sediment/culture
❑ Renal ultrasound
❑ chest radiograph
❑ Electrocardiogram
❑ renal biopsy may be indicated if intrinsic cause is suspected

Draw a conclusion

❑ Treat any life threatening features first—shock, respiratory failure, hyperkalaemia
❑ Is this acute or chronic renal impairment?
❑ A full drug history (current, recent, and alternative medication) is vital
❑ Is there a pre‐renal cause? What is the patient's current fluid status?
❑ Could this be obstruction?
❑ Is intrinsic renal disease probable—what does urine analysis show?


Renal failure diagnostic approach
Is this acute or chronic renal failure
❑ History and physical examination
❑ Previous creatinin measurement
❑ Small kidneys on ultrasound except in diabetes
Has obstruction been excluded?
❑ Complete anuria
❑ Palpable bladder
Renal ultrasound
Is the patient euvolemic?
❑ Check pulse, JVP, orthostatic hypotension, daily weights, fluid balance
❑ Check for BUN/Cr ratio
❑ Check for urinary sodium
❑ Do fluid challeng test
Does evidence of renal parenchymal disease exist? (other than ATN)
❑ History and physical examination (clinical features)
❑ Check urine dipstick and microscopy for RBC, WBC, and protein sodium
Has a major vascular occlusion occurred?
❑ Ask for a history of atherosclerotic vascular disease
❑ Check for renal asymmetry
❑ Check for loin pain
❑ Check for macroscopic hematuria
❑ Check for complete anuria


Definitive Management depends upon the underlying cause; however, the initial approach is directed to treat any life-threatening feature attempting to halt or reverse the decline of the renal function, and if unsuccessful providing support by renal replacement anticipating a renal recovery. Hyperkalemia, pulmonary edema, and severe acidosis require immediate attention.


Severe hyperkalemia is a medical emergency and should be immediately treated with infusion of calcium. Treatment with calcium is a temporizing measure “buying time” while measures are started to reduce the serum potassium through increasing cellular uptake. Overall these measures will bring the potassium back to normal; however, still the body will be in excess. If pure pre-renal failure, measures can be taken to excrete the potassium through the kidney by giving resins. Ultimately, if hyperkalemia is refractory to all the above measures, hemodialysis ca be started.

Serum potassium>6.5 is a medical emergency
Immediate action
Reduction in plasma potassium concentration
Removal of potassium from the body
Calcium gluconate or carbonate
If pure pre-renal failure, renal excretion will serve to return the whole body levels to normal
to stabilize the myocardium and prevent cardiac arrythmias
Ion exhange resins calcium polystrene or sodium polystrene
Hemodialysis for refractory hyperkalemia
Insulin with glucpse
beta-2 agonist
Sodium bicarbonate


Pulmonary oedema is often the result of excessive fluid resuscitation, and can be anticipated in many patients—especially those with known cardiac dysfunction, the elderly, and those who appear volume replete at the outset—and hopefully avoided by more judicious intravenous fluid therapy. If respiratory failure, intubate the patient and start mechanical ventilation.While these measures are being undertaken, pharmacological treatment to offload the decompensated heart can be started. If these measures fail, hemodialysis or hemofiltration can be used.

Respiratory failure
Pharmacological treatment
I/V opioids(diamorphine)
I/V infusion of glyceryl nitrate
provoke diuresis with large doses of diuretics such as furesemide
Supplemental oxygen OR intubate and mechanically ventilate


Severe metabolic acidosis (blood pH <7.2) often accompanies ARF and arises through a variety of mechanisms, related both to reduced renal function and the underlying cause of the patient's illness. Systemic acidosis impairs cardiac contractility, induces bradycardia, produces vasodilatation, and augments hyperkalemia, among other effects. Reversing acidosis through the administration of an alkaline solution—sodium bicarbonate—would seem to be sensible, but there is very little evidence to show that it provides benefit. Isotonic (1.26%) solutions may have a role as fluid replacement therapy in stable patients with a moderate to severe acidosis and a requirement for fluid replacement, in whom dialysis is not imminent. Haemodialysis or haemofiltration will usually be required to treat severe acidosis in oligoanuric patients.


General Measures
❑ Fluid Balance-normal saline preferred but avoid fluid overload
❑ Relief of Obstruction-Bladder outflow obstruction if suspected should be relieved by passage of urethral catheter
❑ Uremic Platelet Dysfunction-Renal replacement therapy may improve but DDAVP and cryoprecipitate may be required
❑ Carbohydrate and protein requirement should be tailored individually and ideally delivered by enteral route
❑ Practice good infectious control
❑ Care of pressure areas
❑ DVT prophylaxis if prolonged immobility


  • Normal Saline is the preferred fluid for resuscitation.
  • Treat acute renal failure keeping in mind the cause behind it.
  • Start Dialysis when needed.
  • Correction of coagulopathy if needed with DDAVP and cryoprecipitate.
  • DVT prophylaxis if needed.
  • Avoid pressure ulcers.



[1] [2]

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  2. Hilton R (2006). "Acute renal failure". BMJ. 333 (7572): 786–90. doi:10.1136/bmj.38975.657639.AE. PMC 1601981. PMID 17038736.