Tubulointerstitial Diseases I/II Flashcards
What is ATN? How does it present?
subset of AKI, representing the worst cases
What are the common causes/types of acute tubular necrosis (ATN)?
- Ischemic (~75% of ATN cases; usually ischemia is due to shock–esp septic shock)
- Nephrotoxins (radio contrast)
What is the gross pathology of ATN?
- Enlarged (up to 30% larger than normal)
- Pale cortex
- Congested medulla, especially at cortico-medullary junction
The portions of the renal tubules most vulnerable to acute ischemic necrosis are:
(Why these portions?)
(1) Proximal straight tubule and
(2) Ascending thick limb of the loop of Henle
*these are the 2 parts of the tubule in the outer medulla at corticomedullary junction, which is the area that becomes congested in ATN
What are 2 early ischemic change noted in the microscopy pathology of renal tubules?
- Blebbing of luminal side of cell membranes
2. Diffuse edema of tubular cells (seen as vacuolization of cytoplasm
What 5 microscopic pathologic findings are seen in ATN?
- loss of brush borders
- flattening of epithelium
- necrosis & sloughing of epithelial cells
- formation of proteinaceous casts
- apoptosis
What casts are seen in ATN? Why is finding these casts significant?
pigmented, brownish, coarsely granular casts (“muddy brown”)
they can be used to diagnose ATN
The apoptotic renal tubular epithelial cells are most likely have decreased cytoplasmic activity of:
BCL2
Vacuolization and calcium oxalate are related to ingestion of what substance?
Ethylene glycol
What is the immediate treatment for potassium over 7 mmol/L?
Intravenous calcium gluconate Intravenous insulin (+ glucose)
What causes the cortical hemorrhages present in ATN?
when cells undergo ischemia/necrosis, dead cells of basement membrane slough off into the tubular lumen. This creates an obstruction. This (somehow) leads to hemorrhage, and more cells are damaged by the ROS involved in reperfusion
When is ATN a medical emergency?
when K is >7
How is ATN reversible and necrotic simultaneously?
ATN is reversible at the level fo the patient, even though the individual cells which are affected die
Gross pathology of acute pyelonephritis?
Areas of dark red congestion
Areas of light tan suppurative inflammation
Some necrosis
Some abscesses may form
Microscopic pathology of acute pyelonephritis?
Congestion with some mild hemorrhage
Heavy infiltration by leukocytes
Acute pyelonephritis is characteristically abscessing because it produces:
Liquefactive necrosis
Microscopic Pathology of Renal Abscesses:
severe acute inflammation
necrosis
no liquefaction
Why are renal abscesses so blue under the microscope?
Nuclear debris from breakdown of dead cells, especially neutrophils.
What are possible complications of acute pyelonephritis?
- pyelonephrosis
- perinephric abscesses
- acute papillary necrosis
- healing by scar formation and calyx deformation
Learning gross pathology of kidneys will be most helpful for future
radiologists
you never know what bizarre questions he’ll ask
Pyelonephritis can cause
- necrosis
2. subsequent scarring, which visible on the cortical surface
What are 2 sources of infection causing pyelonephritis? What bacteria is usually responsible?
from bladder
blood
E. Coli
Gross Pathology of Chronic Pyelonephritis:
scarring, causing depression of cortical surface
Microscopic Pathology of Chronic Pyelonephritis:
- inflammation (lymphocytes & plasma cells), primarily interstitial
- fibrosis
- tubules distended (with inspissated urine)
What is the relationship between
acute interstitial nephritis (AIN)
and drug reactions?
Drug reactions are a subset/cause of AIN, accounting for 75% of cases of AIN
(note: most drug rxns do not cause AIN)