- What is acute renal failure? H90
- What is the RIFLE classification/consensus criteria of ARF? H91
Etiology and Pathophysiology
- What are the common causes of ARF? H88
- A 30-year-old man presents with loose motion and vomiting for 2 days. On query he admitted, he did not pass any urine for last 24 hours. What is your impression? H87
- How can you treat the patient of ARF following diarrhea? H89
What is acute renal failure?
Acute renal failure (ARF; also referred to as acute kidney injury, or AKI) describes a sudden and usually reversible loss of renal function, which develops over days or weeks and is usually accompanied by a reduction in urine volume.
*Pre-exam preparation for medicine, HN Sarker; Davidson’s Principles and Practice of Medicine, 22nd edition
Sudden deterioration in renal function, occurring within weeks or months (<3 months), biochemically detected by high urea and creatinine level. This is usually reversible.
*Long Cases in Clinical Medicine, ABM Abdullah
What is the RIFLE classification/consensus criteria of ARF?
|Grade||GFR criteria||UO criteria|
|Risk||SCr × 1. 5 UO||< 0. 5 mL/kg/hours × 6 hours|
|Injury||SCr × 2 UO||< 0. 5 mL/kg/hours × 12 hours|
|Failure||SCr × 3 or SCr > 350 μmol/L with an acute rise > 40 μmol/L||< 0. 3 mL/kg/hours × 24 hours
UO < 0. 3 mL/kg/ hours × 24 hours
|Loss||Persistent ARF > 4 weeks|
|ESKD||Persistent renal failure > 3 months|
*Pre-exam preparation for medicine, HN Sarker
* Davidson’s Principles and Practice of Medicine, 22nd edition
Etiology and Pathophysiology
What are the causes of acute renal failure?
Causes of ARF:
- Prerenal: (Impaired perfusion)
- Fluid loss due to diarrhea, vomiting, dehydration, etc
- Blood loss due to hemorrhage.
- Plasma loss in burn
- Hypotension due to myocardial infarction, shock, vasodilator drugs, heart failure
- Hemolytic uremic syndrome
- Hepatorenal syndrome
- Renal artery occlusion or stenosis
- Disease affecting arterioles.
(Under perfusion to the kidney initially causes rapidly reversible changes. Subsequently, acute tubular necrosis or other changes cause long lasting but usually temporary intrinsic renal failure.)
- Renal (intrinsic renal disease):
- Glomerulonephritis e.g. MCGN, IgA nephropathy
- Small-vessel vasculitis
- Acute tubular necrosis
- Prolonged hypotension
- Interstitial nephritis
- Drugs (NSAIDs, ciprofloxacin, allopurinol, sulfonamide, cyclosporine).
- Inflammatory disease such as SLE, rheumatoid arthritis, systemic sclerosis, multiple myeloma, vasculitis
- Post renal:
- Urethral— meatal stenosis/phimosis, paraphimosis, stricture/valves, stone, blood clot, slaughed papilla.
- Bladder neck—benign prostatic enlargement, malginancy (prostate cancer, cervical cancer (?)), stone.
- Bilateral ureteric—calculus, following surgery, pelvic tumor, uterine prolapse, retroperitoneal fibrosis (due to radiation, methysergide, idiopathic).
*Long Cases in Clinical Medicine, ABM Abdullah; Davidson’s Principles and Practice of Medicine, 22nd edition
A 30-year-old man presents with loose motion and vomiting for 2 days. On query he admitted, he did not pass any urine for last 24 hours. What is your impression?
This patient develops acute renal failure (ARF) due to
How can you treat the patient of ARF following diarrhoea?
Correction of dehydration by appropriate fluid (e.g. cholera saline). Restoration of blood volume will restore kidney function and produce urine output.
If no urine output after rehydration, it indicates established ARF. So management of oliguric phase should be given—
- Hyperkalemia (a plasma K+ concentration > 6 mmol/L) must be treated immediately, to prevent life-threatening cardiac arrhythmias.
- Fluid—Daily fluid intake should equal to urine output plus an additional 500 mL to cover insensible losses.
- Protein and energy intake— In patients in whom dialysis is likely to be avoided, accumulation of urea is slowed by dietary protein restriction (to about 40 gm/day).
- Infection control.
- Drugs—Vasoactive drugs such as NSAIDs and ACE inhibitors and nephrotoxic drugs should be avoided.
- Renal replacement therapy.
*Short and Long Cases in Clinical Medicine, HN Sarker