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Renal Pathology (parts 3 & 4)

What causes a granular surface on the kidneys?
benign nephrosclerosis-->patchy ischemic atrophy-->focal loss of parenchyma-->granular surface
common in diabetics, also dt HTN


Where to renal artery emboli usually come from?
the heart (enlarged L atrium, plaques in aorta, etc)

What is the classic clinical triad of HUS?
acute renal failure, microangiopathic hemolytic anemia, thrombocytopenia

What are the four types of renal calculi?
oxalates, phosphates, uric acid, carbonates

Which kind of kidney stones forms when the urine is alkaline?
phosphates aka struvite stones, magnesium ammonium phosphate stones
dt infx w/ urea splitting bact, may form staghorn in renal pelvis

What renal tumor may appear under a microscope to have fernlike "fronds"?
papillary adenoma

What tumor shows polygonal cells and numerous prominent mitochondria by electon microscopy?
oncocytoma

What is the most common primary renal tumor in childhood?
Wilm's tumor, most dx'd age 2-5, assoc w/ xsome 11 defect, presents w/ abdom enlargement

What's the major risk factor for renal cell carcinoma?
tobacco use

What's the most common type of renal cell carcinoma??
clear cell carcinoma (75-85%)

What are the two categories of acute tubular necrosis?
toxic or ischemic

What's a common toxin that kills dogs by acute tubular necrosis?
ethylene glycol: antifreeze

What do toxic tubules look like?
cells lack nuclei, have eosinophilic staining homogenous cytoplasm
cellular debris in lumen of tubule forms into protein casts

How does ATN present?
decreased urine output
acute renal failure

What's the prognosis with toxic ATN?
good if the basement membrane is sill alive
the tubular cells will be replaced
full recovery is possible if toxin is removed

How do you recognize ischemic acute tubular necrosis?
loss of perfusion causes skip lesions, possible pie shaped infarcts
flank pain, hematuria
usudt renal artery stenosis or circulatory shock

What is AIN?
acute interstitial nephritis
edema, inflam in parenchyma w/ accompanying tubulary injury
usudt allergic response to drug, infx agent or toxin (lead)
transplant rejection
suspect when acute renal dz onset after new med or recent infx incl URI, GI

How does AIN present?
2-40 days after exposure
fever, rash, aches, pains
hematuria, oliguria
eosinophilia in serum and urine
40-50% of cases present with acute renal failure
Dx: kidney biopsy
R/O: Wegener's
Tx: discontinue problematic meds

What are some drugs linked to the development of AIN?
ibu, NSAIDS, acetaminophen
penicillin, cephalosporin, cimetidine
thiazide (diuretics), cyclosporine

What infections are likely causes of AIN?
legionella, CMV, streptococcus

What toxins?
lead, cadmium, radiation

What is the supposed mechanism for acute interstitial nephritis?
drug or infx agent acts as a HAPTEN-->binds cytoplasmic or extracellular membrane
immune response to hapten causes injury, type I or type IV

What causes chronic interstitial nephritis?
after acute that persists in spite of discontinuing drug-->scarring of interstitium-->decr tubule fx
hematological malignancies: lymphoma, multiple myeloma
chronic exposures: lead

What is yet another name for the same thing?
Seems like all these conditions overlap

What are the two two drugs that cause analgesic nephropathy?
aspirin and acetaminophen
because they inhibit prostaglandin synthesis, predisposing the papilla to ischemic injury
acetaminophen is a metabolite of phenacitin, covalently binds to papilla causing secondary oxidative damage

How much do you have to take to hurt your kidneys?
a lot over a long time

What happens when you get atherosclerosis of the renal arteries?
the glomerulus isn't getting as much blood pressure as it is designed for
so it reduces excretion
small arteries become thick & narrow
"benign nephrosclerosis" occurs dt HTN and DM, too

When does the kidney surface get a characteristic granular surface?
benign nephrosclerosis-->patchy ischemic atrophy-->focal loss of parenchyma-->granular surface

What causes malignant nephrosclerosis?
malignant hypertension
see focal hemorrhages in kidney
renal arteries & arterioles hyperplastic, onion ring appearance
medical emergency says the notes, though this kind of hyperplasticity takes time to form
incr renin-->incr adrenal ALD and incr conversion of angiotensin I-->II

What would you suspect if you hear a bruit on the mid-back or flank, over the kidney?
rental artery stenosis, a common cause of HTN

What two conditions cause widespread thrombosis in capillaries and arterioles?
hemolytic uremic syndrome (HUS) and thrombocytic thrombocytopenic purpura (TTP)

What's the hallmark of thrombotic angiopathy?
widespread formation of hyaline thrombi in microcirculations
thrombi composed of platelets and fibrin
seems to be initiated by endothelial injury

What can trigger endothelial injury in capillaries?
bacterial endotoxins and cytotoxins: E. Coli 0157, Shigella, typhoid, septicemia
verocytotoxin often present in kids, it affects ECs, RBCs and PLTs
cytokines
viruses
drugs
endothelial antibodies
may be idiopathic
LUPUS tops the noninfectious list

What is the classic clinical triad of HUS?
acute renal failure, microangiopathic hemolytic anemia, thrombocytopenia
sudden onset after GI or flu-like infx
one of the main causes of ARF in kids
renal sx: hematuria, hemolytic anemia, severe oliguria, 50% of kids have HTN
E. Coli 0157:H7 is the most common bacteria implicated, amoxycillin tx may also trigger
kids will present with diarrhea and fever, systemic vasoconstriction
adults with HUS often show signs of TTP, may have SLE, scleroderma, antiphospholipid Ab
or be pregnant
Tx: peritoneal dialysis
Prog: good

What's the pronosis with post-partum HUS/TTP syndrome?
poor

Where to renal artery emboli usually come from?
the heart (enlarged L atrium)
also ruptured aortic plaques
cholesterol crystals may obliterate artery lumen, cleft spaces visible where crystals were

What are the usual compositions of renal calculi?
oxalates, phosphates, uric acid, carbonates

Which kind makes six sided crystals?
cystine
rare, dt hereditary issue
precipitate out in acidic urine
stones multiple and recurrent

Which makes "casket top" shape?
triple phosphate

Which kind of kidney stones are most common?
calcium oxalate (about 75%)

Which kind are also known as struvite stones?
magnesium ammonium phosphate stones
dt UTI with urea-splitting bact ie proteus or pseudomonas, some staph
urine alkaline
can make bigguns: staghorn calculi in pelvis of kidney, no peeing this out

What conditions increase the odds of uric acid crystals?
gout
acute febrile illness
Lesch Nyhan syndrome (retarded kids injure selves chewing on extremities)
any dz with rapid cell turover ie: leukemia, chemo & radiation
urine pH of 5.5 or less, shapes may be various

How do you find out that someone has a benign tumor of the kidney?
usually incidental finding on autopsy, quite common, most are small
adenoma most common, has fronds, fernlike

What renal tumor may appear under a microscope to have fernlike "fronds"?
papillary adenoma

What tumor shows polygonal cells and numerous prominent mitochondria by electon microscopy?
oncocytoma

What is the most common primary renal tumor in childhood?
Wilm's tumor, most dx'd age 2-5, assoc w/ xsome 11 defect, presents w/ abdom enlargement

What's the most common renal malignancy overall?
renal cell carcinoma (80-85% of primary renal, 2% of all visceral)
originate in cortex
usually in 60's-80's
present with hematuria, no pain, nonspecific sx
25% have mets by dx by US: deadly

What triad suggests advanced RCC?
flank pain, hematuria, palpable mass

What's the major risk factor for renal cell carcinoma?
tobacco use
other risks: cadmium, asbestos, benzene, alkylamines
ctd: obesity, HTN, Estrogen therapy unopposed, prior radiation to same area
ctd: cystic dz dt dialysis (5-6% develop RCCA), males
NOT elevated risk in folks with polycystic kidney dz

What's the most common type of renal cell carcinoma??
clear cell carcinoma (75-85%)
What other cancer is caused by asbestos?
mesothelioma in lung

Where does RCC metastasize to?
lung, lymph nodes, bone, liver, brain, ipsilateral adrenal gland, contralateral kidney
invades via the renal vain and may ascend or descend within the vena cava
causes hydronephrosis
if tumor has obstructed gonadal vein: scrotal varicocele that doesn't empty when recumbent
L gonadal vein comes from renal vein
R gonadal vein from inferior vena cava
so more on left

What hormones may be produced by RCC?
erythropoeitin, parathyroid related protein, renin, insulin, glucagon, HCG
may cause SIADH, DM, hyperPTH, etc

Where do mets to the kidneys usually originate?
lung, breast, uterus, ovaries, stomach, intestine, pancreas
leukemia, lymphoma

Who is most likely to present with ureteropelvic junction obstruction (congenital)??
male infants & children

What does UPJ obstruction commonly cause?
hydronephrosis in infants/children

Who is most likely to have diverticuli of the ureters?
girls

Hydroureter may be congential or acquired in people with what condition?
benign prostatic hyperplasia

What is the most common primary malignancy of the ureter?
transitional cell carcinoma

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