20 Tubulointerstitial Disease

ATN

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• like heart attack

• cat scan

• multiple myeloma: bence jones protein

• Rusty downspout draining muddy water: acute tubular necrosis (ATN)

• muddy cast on urinalysis

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• epithelial cells squeeze through nephron and form casts

• phase 1: clinically silent

• maintenance: acute RF, a few days later

• metabolic acidosis: can't excrete acids

• phase 3: fast urine output, drop K with urine

• know hyperkalemia in phase 2 and hypo in phase 3

AIN

Acute

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• Kidney bag with little blue candies: interstitial nephritis

• Blue star clusters in kidney nebula: drug-induced interstitial nephritis

• Baseball-filled kidney containers: NSAIDs can cause acute interstitial nephritis

• Kidney filled with blue tickets: loop diuretics can cause interstitial nephritis (blue cells on histology )

• Kidney sharps: IV acyclovir can cause interstitial nephritis or crystalline nephropathy

• don't need to know individual bacteria

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• WBC casts: inflammation of nephron

• no bladder symptoms (frequency, urgency, burning urination) association with pyelonephritis (ascending infection from bladder to kidney)

• eosinophilia: allergic reaction

Chronic

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• longterm NSAIDS exposure

NSAIDS

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• Constricted proximal end of hose: NSAIDs cause afferent arteriole vasoconstriction, decreasing GFR

• Bursting from high pressure: NSAIDs can increase blood pressure due to COX inhibition in the kidney, decreasing sodium excretion

• Baseball-filled kidney containers: NSAIDs can cause acute interstitial nephritis

• Sloughing off cleat spikes: NSAIDs can cause renal papillary necrosis (sloughing of renal papillae)

• Elevated “lift-ium” balloons: NSAIDs can increase serum lithium concentrations

• Depleted mineral mine: NSAIDs can cause hypoaldosteronism (decreased mineralocorticoids)

• Big K: NSAID induced hypoaldosteronism can cause hyperkalemia. Type 4 RTA

Papillary Necrosis

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• Gray-white or yellow necrosis of the distal two-thirds of the renal pyramids is seen macroscopically and corresponds microscopically to coagulation necrosis with preserved tubule outlines; cortical surface scars can develop subsequently as inflammatory foci are replaced by fibrous depressions.

• Symptoms are due to sloughed papillae (sometimes visible in urine as tissue flecks) and include dark or bloody urine and colicky flank pain (due to ureteral obstruction).

• phenacetin: analgesic no longer used

• Baseball-filled kidney containers: NSAIDs can cause acute interstitial nephritis

Cortical Necrosis

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• i in cortical stands for ICU and DIC: critically ill

• caused by massive tissue destruction

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• kidney diseases as either glomerular diseases (biopsy) or tubulointerstitial diseases (clinical diagnosis)