Tubules- Pathology Flashcards
This is the most common cause of acute renal failure where there is an acute decline in renal fxn often with morphologic evidence of tubular injury.
Acute Kindey Injury (AKI)
What are the 4 causes of AKI?
- Ischemia
- Direct toxic injury
- Acute tubulointerstitial nephritits
- Urinary obstruction
What do u see in the urine in AKI?
Dirty brown granular casts
What happens to the GFR in AKI?
↓ because of an ↑ backpressure from the plug
What 2 segments of the nephron are susceptible to ischemic AKI?
PCT and medullary segment of thick ascending limb.
In ischemic AKI, waht protein is seen in the eosinophilic hyaline casts?
Tamm-Horsfall protein
What area is susceptible to toxic AKI?
PCT
What causes nephrotoxic AKI?
Aminoglycosides, heavy metal (lead, Slayer), myoglobinuria (crush injury), ethylene glycol, radioconstrast, urate (tumor lysis syndrome)
What are the names of the 3 stages for AKI?
Initiation, Maintenance, and recovery
In the initiation phase, what happens the BUN in addition to the slight decline in urine output?
↑ BUN (azotemia)
In the maintenance phase of AKI, there are sustained decreases in urine output, salt and water overload, rising BUN, and what changes in [K] and [H]?
hyperkalemia
metabolic acidosis
What happens to [K] in the recovery phase?
hypokalemia
What is the Tx to AKI?
Dialysis
This is a drug-induced hypersensitivity rxn of the interstitum and tubules, leading to ARF.
Acute interstitial nephritits (AIN)
What are the Sx to AIN?
fever, eosinophilic, rash, renal abnormalities, azotemia
What are the 3 drug classes to cause AIN?
NSAIDs
PCN
Diuretics
Which WBC do u see in the urine in AIN?
Eosinophils
What type of hypersensitivity rxn is AIN?
Type I
Case: pt presents with headache, anemia, GI Sx and HTN. Biopsy shows chronic tubulointerstitial nephritis and renal papillary necrosis. What has this pt been doing to cuase this?
Taking a ton of analgesics
Renal papillary necrosis is a result of what 4 things?
chronic analgesic abuse (phenacetin or ASA use), diabetes mellitus, sickle cell trait or disease, severe acute pyelonephritis
What are the 4 forms of renal injury from NSAID use?
1 hemodynamically induced ARF (↓ prostaglandins)
- acute hypersensitivity interstitial nephritis
- acute interstitial nephritis and minimal-change disease.
- membranous nephropathy
Who is susceptible to acute uric acid nephropathy?
Chemo pts
Who is susceptible to chronic urate nephropathy?
gout pts
What forms in the kidney in chronic urate nephroapthy?
monosodium urate crystals which form a tophus with giant cells and a fibrotic rxn
Nephrocalcinosis is a result of what?
Disorders that are associated with hypercalcemia
Who is at risk for acute phosphate nephropathy?
People drinking that horrible crap b4 a colonoscopy
This is the condition where nonrenal malignant neoplasms (myelomas) cause tubulointerstitial problems from the tumor or the therapy itself.
Light-chain cast nephropathy
What is the main cause of renal dysfxn in Light-chain cast nephropathy?
Bence Jones (light chain) proteinuria
What is the morphology of the masses that fill the tubular lumens in Bence Jones nephropathy?
pink-blue amorphous masses that are surrounded by giant cells
This is sclerosis of renal arterioles from hyaline arteriolosclerosis from extravasation of plasma proteins or medial and intimal thickening as a response to hemodynamic changes
Benign nephrosclerosis
This is when dramatic HTN can cause vascular damage to kidneys, leading to fibrinoid necrosis of arterioles and small arteries. This has onion skinning pattern on exam.
Malignant HTN
This is an uncommon cause of HTN where the renal artery is stenosed, which increases renin (cuz it thinks there is hypotension), and HTN develops
Renal artery stenosis
Why is HTN from renal artery stenosis easy to treat?
Just cut away the stenosed renal artery
These are a group of disorders characterized clinically by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure, and morphologically by thrombotic lesions in capillaries and arterioles in various tissue beds, including those of the kidney
Thrombotic microangiopathies
This microangiopathy is from consuming food with contaminated bacteria producing Shiga-like toxins.
Typical HUS
This microangiopathy is associated with inherited mutations of complement-regulatory proteins or diverse acquired causes of endothelial injury
Atypical HUS
This microangiopathy is associated with inherited or acquired deficiencies of ADAMTS13, which regulates the fxn of von Willebrand Factor (vWF)
TTP
After eating contaminated food, what are the Sx to typical HUS?
start diarrheal and move with a sudden onset of bleeding manifestations (especially hematemesis and melena), severe oliguria, and hematuria.
is atypical HUS easy or hard to treat?
hard
What is the pentad of Sx in TTP?
fever, neurological Sx, microangiopathic hemolytic anemia, thrombocytopenia, and renal failure
What is the Tx of TTP?
This is from autoantibodies against ADAMTS13, so treatment is with immunosuppressive therapy
What morphology of the kidneys shows in the acute stage in the microangiopathies?
patchy or diffuse cortical necrosis and subcapsular petechiae. The glomerular capillaries are occluded by thrombi