20 Tubulointerstitial Disease

• like heart attack

• cat scan
• multiple myeloma: bence jones protein

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

• 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

• 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

• 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

• longterm NSAIDS exposure

NSAIDS

• 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

• 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

• i in cortical stands for ICU and DIC: critically ill
• caused by massive tissue destruction

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