Flashcards in 46. Acute tubular necrosis Deck (23):
Acute kidney injury is AKA
acute renal failure
MCC caof acute kidney injury in hospitalized patients
Acute tubular necrosis
can be fata, esp during initial oliguric phase
more than 2%
granular ( muddy brown ( casts
1. inciting event
2. maintenance phase - oliguric
3. Recovery phase - oliguric
duration of maintenace phase
maintenance phase risk for
2. metabolic acidosis
Recovery phase - findings
BUN and creatinine fall
recovery phae - risk for
Acute tubular necrosis can be caused by ... (groups )
1. ischemic factors
2. nephrotoxic factors
ischemic factors - mechanism
2ry to low RBF ( eg hypotension , shock , sepsis , hemorrhage, HF) (often preceded by renala azotemia ) --> reuslts in death of tubular cells that may slough into tubular lumen
areas that are highly susceptible to ischemic injury
2. Thick ascending limb
Nephrotoxic factors - mechanism
2ry to injury resulting from toxic substance ( eg. aminoglycosides radiocontrasts agents. lead, cisplatin ), crush injury ( myoglobinuria), hemoglobinuria
areas tha highly sucseptible to nephrotoxic injury
area that are highlu sucseptible to ischemic injury vs nephrotoxic injury
ischemic injury --> PCT , thick ascending limb
nephrotoxic injury --> PCT
• What is the most common cause of acute kidney injury in hospitalized patients? What happens if it is left untreated?
Acute tubular necrosis—self-reversing in some cases but can be fatal if left untreated
• A septic patient is hypotensive. Urinalysis shows muddy brown casts and the patient is oliguric. What is the cause of this renal pathology?
Decreased renal blood flow, causing ischemic damage to tubular cells (this is acute tubular necrosis)
• What are the two broad categories of acute tubular necrosis?
Ischemia resulting from decreased blood flow and direct nephrotoxicity
• A man with acute renal failure has hematuria, proteinuria, and muddy brown urine casts. Death will most likely occur in which disease stage?
The initial oliguric phase (maintenance, lasting 1–3 weeks) if dialysis is not started (the patient has acute tubular necrosis)
• What are the three stages of acute tubular necrosis?
Inciting event, maintenance (oliguric, hyperkalemia risk), and recovery (polyuric, BUN and serum creatinine fall, hypokalemia risk)
• An addict overdoses and begins seizing; hematuria develops and his creatinine rises sharply. What type of casts do you expect on urinalysis?
Granular "muddy brown" casts (the patient has acute tubular necrosis caused by myoglobinuria that resulted from his seizure)