Pathology Cheat Sheet
Follow the Interstitium
Renal interstitial and vascular disease for NEET-PG: pyelonephritis, reflux nephropathy, papillary necrosis, benign vs malignant nephrosclerosis, and HUS.
MedNext Academy | 3 min read
Follow the Interstitium
Renal interstitial and vascular disease for NEET-PG: pyelonephritis, reflux nephropathy, papillary necrosis, benign vs malignant nephrosclerosis, and HUS.
Tubulointerstitial diseases including pyelonephritis, and the vascular diseases of the kidney.
High-yield lines
- Acute pyelonephritis is bacterial infection of the kidney with neutrophils filling the tubules and interstitial abscesses.
- Ascending infection from the lower urinary tract, often by Escherichia coli, causes most pyelonephritis.
- Vesicoureteric reflux predisposes to pyelonephritis and reflux nephropathy in children.
- Chronic pyelonephritis shows coarse cortical scars over blunted calyces and thyroidisation of tubules.
- Acute interstitial nephritis is often drug-induced and shows interstitial eosinophils with a rash and eosinophilia.
- Analgesic nephropathy causes papillary necrosis, also seen in diabetes and sickle cell disease.
- Benign nephrosclerosis from hypertension causes hyaline arteriolosclerosis and finely granular kidneys.
- Malignant hypertension causes hyperplastic onion-skin arteriolosclerosis with fibrinoid necrosis and a flea-bitten kidney.
- Renal artery stenosis causes renovascular hypertension through renin release.
- Thrombotic microangiopathy in the kidney occurs in haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura.
- Haemolytic uraemic syndrome in children classically follows Shiga toxin-producing Escherichia coli infection.
- Renal cortical necrosis is bilateral ischaemic necrosis seen in obstetric emergencies and severe sepsis.
Mapped competency codes
- PA28.8
- PA28.10
- PA28.11
Continue into the full chapter
This summary maps to PA28-urinary-tract.
Frequently Asked Questions
What is the typical cause and histology of acute pyelonephritis?
Ascending Escherichia coli infection producing neutrophilic infiltration of tubules and interstitial microabscesses, often with vesicoureteric reflux as a risk factor.
What characterises chronic pyelonephritis?
Coarse asymmetric cortical scars overlying blunted deformed calyces, with tubular atrophy and eosinophilic casts giving a thyroidisation appearance.
How does malignant hypertension affect the kidney?
It causes hyperplastic onion-skin arteriolosclerosis with fibrinoid necrosis, producing petechial haemorrhages that give a flea-bitten kidney.
What triggers haemolytic uraemic syndrome in children?
Shiga toxin-producing Escherichia coli, which causes thrombotic microangiopathy with anaemia, thrombocytopenia, and acute kidney injury.
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