10.31 Flashcards by Joseph Marvin

What is the most common cause of acute renal failure (ARF)?

Acute Tubular Necrosis (ATN)

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What are the two patterns of ATN?

Ischemic

Nephrotoxic

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What happens to tubular epithelial cells during ATN?

Swelling, loss of polarity, etc. (reversible)

Necrosis and apoptosis (lethal)

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What allows recovery from ATN?

Patchiness of tubular necrosis

Intact BM

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How does ATN start?

Decline in urination
Increased BUN
Lasts ~36hrs…if survive this then outcome is good

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What is the recovery process like for ATN?

Increase in urine volume (up to 3L/day)–> overcompensation–> hypokalemia

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What is the difference between acute and chronic forms of Tubulointerstitial Nephritis (TIN)?

Acute has PMNs/Eos, edema

Chronic has fibrosis and tubular atrophy

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What are the symptoms of TIN?

Polyuria
Nocturia
MIld metabolic acidosis

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What causes TIN?

Lots of things…

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What causes acute pyelonephritis?

Bacterial infection (gram-)

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What causes chronic pyelonephritis?

Includes bacterial infection…but also reflux or obstruction

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What are some complications of acute pyelonephritis?

Papillary necrosis (diabetics and pt. with obstruction)--yellow necrosis
Pyonephrosis
Perinephric abscess (suppurative inflammation extends through the renal capsule into adjacent tissue)

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What causes damage to the calyces?

Chronic pyelo and analgesic neuropathy

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What causes chronic pyelonephritis?

Chronic reflux or chronic obstruction

Usually bacterial infection, but not always

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What might be the morphology of chronic pyelonephritis?

Deformed calyx(es)
Thyroidization

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How do drugs cause TIN?

Trigger an interstitial immunologic reaction (methicillin)
Cause acute renal failure
Slow injury to tubules over many years–> CRI (analgesic abuse nephropathy)

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What needs to be ingested in order for a person to develop analgesic nephropathy?

2 or more of the following for ~7yrs:

Aspirin, caffeine, acetaminophen, codeine, phenacetin

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What distinguishes analgesic nephropathy from DM nephropathy?

In analgesic nephropathy, papillae in various stages of necrosis, with calcification and sloughing

In DM, they’d all be in the same stage

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What is a concern with analgesic nephropathy?

Urothelial carcinoma of the renal pelvis

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How do NSAIDS cause ARF?

Inhibition of PG synthesis–>vasoconstriction–> decreased blood volume

Hypersensitivity

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Besides ARF, what else can NSAIDS cause?

Acute interstitial nephritis
MCD
MGN

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Who is susceptible of getting urate nephropathy?

Chemo patients–acute uric acid nephropathy

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What causes renal insufficiency in patients with multiple myeloma (a plasma cell neoplasm)?

Bence Jones proteinuria–Ig light chains

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How does Bence Jones proteinuria cause renal insufficiency?

Directly toxic to tubules

Combine with Tamm-Horsfall proteins–>cast formation–>obstruction and inflammation

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What are the gross features of benign nephrosclerosis?

Normal/small kidneys | Fine granular surface

What causes the sclerosis?

Hyalinization of the walls of arterioles and small arteries

Is benign nephrosclerosis bad?

Not typically

Who is most likely to have benign nephrosclerosis?

Black diabetics with HTN

What is associated with malignant hypertension?

Malignant nephrosclerosis

Who has the greatest risk of developing malignant nephrosclerosis?

Young black men

What are the gross features of malignant nephrosclerosis?

Pinpoint petechial hemorrhages...otherwise smooth

What are the micro features of malignant nephrosclerosis?

Fibrinoid necrosis of arterioles | Onion-skinning of vessels

What are the symptoms of malignant nephrosclerosis?

Headache N&V Visual impairments (scotomas--flashing lights)

Other than HTN, how else can renal artery stenosis?

A bruit

What is the primary cause of renal artery stenosis?

Occlusion via a atheromatous plaque

What are Hemolytic Uremic Syndrome (HUS) and Thrombotic thrombocytopenic Purpura (TTP)?

Thrombotic microangiopathies...systemic thrombi

What initiate HUS/TTP?

Endothelial injury and activation | Platelet aggregation...unusually large von Willebrand factor multimers

What causes classic (childhood) HUS?

Verocytotoxin producing E. coli--causes endothelial lysis

What is the typical outcome of childhood HUS?

Recovery with dialysis (weeks) | Some develop CRF

What causes adult HUS?

Lots of things: ``` Infection Antiphospholipid syndrome Pregnancy Vascular renal diseases Drugs (chemo and immunorepressive)...treat with plasma exchange ```

What causes familial HUS?

Deficient Factor H...50% mortality rate (treated with plasma exchange and corticosteroids)

What causes the symptoms of TTP?

Defect in protease that cleaves large von Willebrand multimers

What are the symptoms of TTP?

Fever NEUROLOGICAL symptoms (NOT seen in HUS) Hemolytic anemia Purpura

Who is most likely to get TTP?

Women under 40yo

What are the gross features of HUS/TTP?

Patchy or diffuse renal cortical necrosis

What are the micro features of HUS/TTP?

Glomeruli w/ thickened cap walls Fibrin deposits in cap lumens, subendo, and mesangium Fibrinoid necrosis of arterioles w/ thrombi

What are the gross features of acute renal infarcts?

Solitary White Wedge shaped

What are the gross features of chronic renal infarcts?

Depressed | Gray-white scars w/ a V shape

What are the micro features of renal infarcts?

Ischemic coagulative necrosis

What are two kinds of benign renal tumors?

Angiomyolipoma | Oncocytoma

What are angiomyolipomas associated with?

Tuberus sclerosis--auto domininant syndrome...lots of different -omas

What does a oncoctyoma look like w/o magnification?

Mahogany brown

What does a oncoctyoma look like under a microscope?

Large, eosinophilic cells with round nuclei | EM shows lots of mitochondria

Where do oncocytomas develop?

Collecting ducts

What is the most common adult renal cancer?

Renal cell carcinoma (1-3% of ALL cancers)

What is the biggest risk factor for renal cell carcinoma?

Smoking

What is Von Hippel-Lindau syndrome?

Type of renal cell carcinoma Auto dominant disorder Hemangioblastomas of the cerebellum and retina Renal cysts and renal carcinoma VHL gene encodes a tumor suppressor gene

What is the most common form of renal cell carcinoma?

Clear cell carcinoma

What is lost in almost all clear cell carcinomas?

Losses on chromosome 3p...in region of VHL gene

What does a clear cell carcinoma look like?

Bright yellow tumor | Possibly necrotic

What is associated with trisomy 7, 16, and 17 and loss of Y?

Papillary carcinoma (10-15% of RCC)

What are the micro features of papillary carcinomas?

Cuboidal cells with a papillary growth pattern | Foam cells in papillary cores

What carcinoma has vegetable-like cells?

Chromophobe carcinoma (5% of RCC...good prognosis)

What is the typical progression of RCC?

Invade/grow along renal vein Flank pain, palpable mass, hematuria (10%) Asymptomatic Metastases (lung then bone...other) 5 year survival is 45%

How can RCC be treated prior to metastases?

Nephrectomy

What are urothelial carcinomas of the renal pelvis?

Transitional cell carcinomas (often occur with bladder TCC)

Are urothelial carcinomas really bad?

Only if high grade/invasive