Nephrology Flashcards
Membranous Glomerulopathy:
histo (light, IF, special stain, EM)
light micro - diffuse GBM thickening without hypercellularity
if - GRANULAR IgG/C3 deposits along GBM
SILVER stain - SPIKE + DOME pattern (spikes of gbm stick out around domes of deposits)
em - irregular SUBEPITHELIAL immune deposits (btwn gbm and podocyte)
Focal Segmental Glomerulosclerosis:
histo - LM, EM
1 nephrotic syndrome in adults
LM - sclerosis is some (focal) glomeruli in only some parts (segmental) of each affected glomerulus; see OBLITERATED CAPILLARIES with HYALIN DEP.
EM - also podocyte FUSION + EFFACEMENT
Membranoproliferative Glomerulonephritis: histo + causes
thickening of GBM with hypercellularity
assoc. with Hep B or C
Mixed cryoglobulinemia
Ab type, organ changes, assoc. disease
IgM in glomerulus > BM thickening + hypercellularity presents as membranoproliferative GNitis
nephritic syn > hematuria and RBC casts
most common in chronic Hep C
Minimal Change Disease
pathophys
1 nephrotic syndrome in kids; idiopathic or after respiratory infection, immunization or insect sting/bite
T-cell production of a GLOMERULAR PERMEABILITY FACTOR (maybe IL-13) > capillary injury with foot process fusion > loss of negative charge causes selective albuminuria
Chronic Kidney Disease Complications
bones? thyroid?
renal osteodystrophy - hyperphosphatemia and hypocalcemia > either osteopenic high-turnover via high PTH or later PTH resistance with osteomalacia
thyroid - uremia inhibits peripheral T4-T3 conversion with HYPOthyroidism
Most common underlying valvular pathology predisposing to infective endocarditis
mitral prolapse
especially with coexistent regurgitation
platelet + fibrin deposits form spontaneously on valve via disturbed flow + endocardial injury
histo of kidney in renal artery stenosis
decreased tubular epithelial size, patchy inflammation and tubulointerstitial / glomerular fibrosis
Acute Interstitial Nephritis: labs + histo
rash, fever, new drug exposure in last 1-3 wks
high creatinine, BUN, oliguria (AKI); eosinophilia + urinary eosinophils; pyuria, hematuria + WBC casts
histo = interstitial infiltrate + edema
Paroxysmal Nocturnal Hemoglobinuria
pathophys, s/s, main organ involved + how?
mutation of PIGA gene > impaired GPI anchor protein > impaired anchoring of CD55 (DAF) and CD56 (MAC inhibitory protein) > complement-mediated hemolysis
hemolytic anemia
pancytopenia
thrombosis - at atypical sites; hepatic, portal + cerebral vv.
kidney - HEMOSIDEROSIS + thrombosis > CKD
Minimal Change Disease
microscopy
light micro - normal
IF - negative for complement and IgG
EM - podocyte effacement + fusion
IgA Nephropathy
syndrome? microscopy?
nephritic syndrome (hematuria + RBC casts)
light micro - segmental glomerular hypercellularity
IF - globular IgA deposits
EM - deposits in mesangium
PSGN
syndrome? microscopy?
nephritic syndrome 2-4 wks after group A strep
LM - cellular proliferation; neutrophils in capillaries
IF - granular deposits of C3 and IgG along GBM
EM - subEPITHELIAL HUMPS (immune deposits)
Anti-GBM disease
syndrome? microscopy?
nephritic syndrome (RPGN usually)
LM - crescent formation
IF - linear C3 and IgG on GBM
EM - GBM breakage, but no deposits seen
Membranous Nephropathy
syndrome? associations?
nephrotic syndrome
viral hepatitis, solid tumors, lupus
AD Polycystic Kidney Disease
mutation? presentation / cyst location/#?
PKD-1 or PKD-2 mutation > tubular cell proliferation + fluid secretion
cysts at ANY point in nephron; <5% nephrons affected
microscopic cysts at birth enlarge over decades, compress parenchyma > atrophy + fibrosis
mostly asymptomatic; flank pain, hematuria + hypertension; end-stage kidney by age 70
liver cysts and cerebral aneurysms
AR Polycystic Kidney Disease
differentiation from AD?
bilateral flank masses at birth or during 1st year (AD occurs later)
cysts in DCT or collecting duct (AD is anywhere in nephron)
US at birth shows large kidneys + cysts are visible if > 1 cm
Multicystic Dysplastic Kidney
kidney appearance/abnormalities?
multiple cysts of varying size; absence of pelvocaliceal system
ureteral or ureteropelvic atresia
affected kidney is nonfunctional; may be bilateral > Potter sequence
abdominal US of fetus / newborn for dx
Potter syndrome
renal abnormalities in fetus (ARPKD, bilateral renal agenesis, etc.) cause oligohydramnios
results in: pulmonary hypoplasia Potter facies (flat nose, recessed chin, epicanthal folds, low ears) limb defects CV abnormalities
Paraneoplastic syndromes in renal cell carcinoma
Hypercalcemia - via parathyroid hormone-related peptide (or prostaglandin overproduction > resorption)
Erythrocytosis - ectopic EPO
(Hepatic dysfunction - unrelated to liver mets)
Specific risk factors for BLADDER and RENAL cancers
renal - smoking, obesity, hypertension; toxin exposure (HEAVY METALS, PETROLEUM)
bladder - smoking, OCCUPATIONAL EXPOSURES (rubber, plastics, aromatic amine dyes, textiles, leather) SCHISTOSOMA haematobium and CYCLOPHOSPHAMIDE
Kidney injury in rhabdomyolysis
mechanism? labs?
Heme pigment release from myoglobin degradation in glomeruli > direct cytotoxicity + vasoconstriction > ACUTE TUBULAR NECROSIS
high CK
myoglobinuria = UA pos for blood, neg for RBCs
AKI - high BUN + creatinine
high K / P / Urate, low Ca
Renal Cell Carcinoma
cell origin + histo? gross appearance?
from PROXIMAL TUBULE cells of cortex; cuboidal/polygonal cells with abundant clear cytoplasm + “chicken wire” vasculature
spherical mass; renal vein invasion common; GOLDEN-YELLOW tissue (high lipids) with NECROSIS + hemorrhage
Renal Cell Carcinoma
presentation + paraneoplasia? risks?
hematuria, flank pain + palpable mass
polycythemia (EPO) or hypercalcemia (PTHrP)
smoking, hypertension + obesity
toxins (heavy metals, petroleum)
mostly in pts 60-70
Renal Oncocytoma
cell origin? gross morpho?
rare COLLECTING DUCT cell tumor
homogenous brown tumor with CENTRAL STELLATE SCAR visible on imaging
PSGN immunofluorescence:
Deposition pattern + location? Molecules deposited?
Subepithelial granular deposits
deposits of IgG, IgMandC3b
Lupus Nephritis
Mechanism? Most common histo pattern?
T3 HS rxn - deposits can be mesangial, subendothelial, and/or subepithelial
Diffuse proliferative glomerulonephritis is #1 type
proteinuria + RBC casts
Calcium Oxalate stones
how to prevent? 2 ways
- Thiazides - increase calcium reabsorption from tubular fluid
- Urine ALKALIZATION - via POTASSIUM CITRATE (also prevents uric acid stones)
(Acetazolamide also alkalinizes urine, but metabolic acidosis result > Ca and Pi mobilization from bone > actually increases Ca stone risk)
Stages of acute tubular necrosis
Initiation - 24-36 hrs
Maintenance - 1-3 weeks
Recovery - months
First stage of ATN
timing, causes (2 categories)
24-36 hours
- Ischemia - hemorrhage, MI, shock, sepsis
- Cytotoxins - contrast, aminoglycosides, myoglobin
Second stage to ATN
timing, presentation
1-3 weeks
Oliguric failure - low GFR, low urine, volume overload
high creat/BUN, high K, metabolic acidosis
Third stage of ATN
timing, presentation, complications
months
Gradual urine output increase > diuresis
Continued tubular impairment causes ELECTROLYTE WASTING (K, Mg, P, Ca)
Maintenance (2nd) stage of ATN
tubular function parameters (3)
low osmolality (<350 mOsm/kg) high sodium (> 30 mEq/l) high fractional excretion of sodium (>1%)
Water Deprivation Testing Method + Results
normal pt?
central DI pt?
partial / complete nephrogenic DI?
primary polydipsia?
pt deprived of water for 4 hours with hourly checks of serum + urine osmolality; ADH is administered after several hours
normal - urine starts around 500, raises on its own, and does not raise much more after ADH
central DI - urine starts around 100, doesn’t raise much on its own, and raises sharply after ADH
partial/complete NDI - urine starts around 100 and raises slowly to ~ <500 with little change via ADH (partial) or doesn’t raise at all (complete)
primary polydipsia - urine starts around 100, and raises on its own
Post-Obstructive Diuresis
what is it? when does it happen?
kidneys act to normalize fluid volume + solute levels after urinary obstruction
occurs in a patient who is catheterized after obstruction (as in BPH)
TTP-HUS
pentad
- fever
- neurological sx - progressive lethargy
- renal failure
- anemia
- thrombocytopenia
in setting of antecedent GI illness
Turner syndrome
internal abnormalities (not musculoskeletal) + their consequences
CV - bicuspid aorta or COARCTATION
renal - HORSESHOE kidney
repro - STREAK OVARY, infertility, amenorrhea
AR Polycystic Kidney Disease
mutation?
PKHD1 gene for FIBROCYSTIN (in renal tubules + bile ducts); mutation can be spontaneous too
can cause renal insufficiency, nephromegaly and hypertension
if oligohydramnios occurs > Potter sequence
