Question | Answer |
Where is phosphorus handled in kidney (what segment) | only proximal tubule. |
T/F PTH affects gut absorption of mineral \s. | FALSE. It does not directly, but activates/anactivates vitamin D which then affects calcium & pos absorption (NaPi2b stimulated by vitD). |
What is mean stimulus for PTH release? | hypocalcemia |
Main effects of PTH? | raise serum calcium: stimulate bone resorption, stimulate VitD production (whihc then enhances GI Ca & phs absor), i nhibits calciuria, Stimulates phosphaturia. |
What influences Vitamin D? | PTH stimulates & FGF23 inhibits vitD |
What are main effects of vitamin D? | regulate G.I. Absorption of calcium and phosphorus. VitD increases absorption both. Inhibits PTH. Stimulates FGF23. Stimulates alpha 24-hydroxylase |
Effects of FGF23? | lower serum phosphorus by stimulating phosphaturia. Inh VitD and PTH. Stimulated by high phosphorus and VitD |
What affects vitamin D synthesis? | PTH increases VitD synth where is FGF 23 lowers it. |
What affects FGF23 synthesis? | high phosphorus level and vitamin D increase synthesis. |
HyperCa + nl Phos + hi-nl PTH + hypOcalciuria + hi vitD | FHH. Must confirm with 24 hr urine to document low calcium excr ( UCa high in hyperPTH) |
HypoCa + hyperPhos + low PTH + low vitD + hi UCa | AD hypoparathyroidism |
HypoCa + hypoPhos | vit D deficiency |
HypoCa + hypoPhos + hi PTH , nl25 vitD, undetectable 1,25D | 1 alpha deficiency ~ rickets |
S/S calciphylaxis | SC nodules, primarily in areas of fat (breast, abdomen, thigh) can progress to alterations then Eschar. |
Pathology of calciphylaxis is _____. | septal panniculitits |
Predisposing factors to develop calciphylaxis? | Hi Ca, hi Phos, hi PTH, DM, SC injections, DM, warfarin, |
Rx calciphylaxis is _____. | sodium thiosulfate. Note this is an acid and will lower HCO3 by ~4. |
Beta-2 microglobulin is better removed with ___ flux dialysis. | HIGH. Note it still accumulates. |
T/F incidence of hip fractures remains stable depending on dialysis vintage. | FALSE. Hip fractures increased longer patient remains on dialysis. |
T/F extremes of PTH are associated with increased risk of fractures. | True |
T/F cinacalcet use his decreased incidents of fractures. | false. There's no evidence fractures have fallen w/ cinacalcet use . |
Indications for parents are actually? | PTH> 800 responsive to medical therapy associated with severe hyperCa, fractures, bone pain, refractory itching, Progressive calcification, calciphylaxis, Tendon rupture, unexplained myopathy. |
Preparing urine for microscopy? | 10 ML's spun for five minutes at 3000 RPM. Remove 9.5 cc of the supernatant. Suspend fillet in remaining volume. Aspirate 0.1 point one ML's with pipette in place on glass slide, Covered with Cover slip. |
Define hematuria? | >3 RBCs/HPF on two separate samples |
Renal tubular epithelial cells on microscopy are seen with? | acute tubular injury/ATN. Look for tiny hook like protrusion. |
WBC's in urine appearance? | look for multiple nuclei. (compared to renal tubular epithelial cells they have single nucleus). |
Urine positive for WBC cast Plus AKI usually from? | acute interstitial nephritis. UTI can cause casts, but Usually not with renal disease unless have sepsis. |
How do casts form? | Tamm-Horsfall proteins precipitate out in a low flow states and trap debris (cells, etc.) |
Waxy casts are associated with? Appearance? | CKD or late ATN cause waxy casts, that look like melted candle wax. |
Microscopy showing fat globules in renal tubular epithelial (or macrophages) cells + Maltese crosses on polarization? | oval fat bodies from nephrotic syndrome. |
Appearance of calcium oxalate crystals (monohydrate vs dihydrate) | calcium monohydrate are needle or dumbbell shaped; calcium dihydrate look like squares/diamonds with X in center (“envelope) |
Enteric hyperoxaluria is caused by? | calcium is saponified by fat, Which allows oxalate absorption. Causes: orlistat, gastric bypass, malabsorption. |
Calcium phosphate crystals look like? | triple phosphate (magnesium ammonium phosphate) look like coffins. Calcium phosphate look like starbursts or needles. |
Hexagon shaped crystals are from? | Cysteine |
Rectangular or shaped like crystals are from? | cholesterol |
Sulfamethoxazole crystals look like? | Needles |
Sulfa based crystals look like? | Fans |
Fan shaped crystals are from? | Sulfa, indinavir |
Needlelike crystals are from? | Atazanavir, indinavir (form fans), some calcium phosphate, calcium oxalate monohydrate, acyclovir, cipro ( form starburst) |
The Appearance of methotrexate crystals? | amorphous debris in clusters |
A low-calcium diets promote ______ absorption. | oxalate |
hyperpPhos causes what effect on regulating hormones? | PTH and FGF23 are both stimulated; they then have off-opposite effects on vitD |
what influences vitamin D | 1-alpha OHase has opposing effects oh PTH and FGF23; hi vitD inhibits PTH and stimulates FGF23 |
effect on PTH and FGF23 on phos secretion? | both induce phosphaturia |
Imaging of medullary sponge kidney shows what findings? | Dilated collecting ducts on retrograde urography with parenchymal calcifications. Contrast tends to pool and give brush like appearance. |
Medullary sponge kidney is associated with? | Ectasia of collecting ducts, urine stasis, lo Ucitrate, distal RTA. Asymptomatic hematuria common, some develop flank pain. RX citrate. |
Papillary necrosis presentation? | Asymptomatic or gross hematuria, pain, obstruction. |
Treatment of calcium stones? | thiazide for hyperclciuria, citrate if hypocitraturia |
Treatment of uric acid stones? | raise pH > 6.5 w Kcitrate or K bicarbonate. may benefit from lowering UCa, xanthine oxidate inh? weight reduction? |
Treatment of cysteine stones? | penicillamine |
Treatment of oxalate stones? | often from enteric hyperoxaluria —> restrict in diet, CaCitrate & Kcitrate |
Medullary sponge kidney consequences? | Calcium phosphate nephrolithiasis + mild RTA. |
Medullary sponge kidney (MSK) | characterized by recurrent episodes of calcium phosphate and calcium oxalate nephrolithiasis; associated with hypercalcuria, hypocitrituria, and mild metabolic acidosis. Rx: high-fluid intake associated with alkali therapy (potassium citrate). |
Magnesium oxide has been used along with pyridoxal phosphate to treat ________ stones. | oxalate |
(stone type) nephrocalcinosis is seen with Crohn's disease? | Calcium oxalate stones, but it does not develop without a colon! |
Renal effects of Triamterene? | urinary crystals but not stones |
If you see NEEDLE shaped crystals, think what drugs? | acyclovir & indinavir, ca-oxalate monohydrate |
Gastric bypass and malabsorption can cause Ca-ox crystal by___. | With fat malabsorption, calcium is saponified by the fat, allowing free oxalate to be reabsorbed. |
If you see dumbbell shaped crystals, think what drugs? | SULPHONAMIDE |
If you see ENVELOPE shaped crystals, think what? | calcium oxalate dihydrate |
If you see HEXAGONAL shaped crystals, think what? | cysteine, Rx cysteine crystals is po α-mercaptopropionylglycine, increase H2O & urine pH. |
Rx cysteine | Oral α-mercaptopropionylglycine, increase H2O & urine pH. |
If you see Coffin shaped crystals, think what? | calcium phosphate crystals |
If you see amorphous brown-colored precipitates, think what? | methotrexate forms amorphous brown-colored precipitates |
How and what type of crystals/stones are see w fat malabsorption? | Calcium is saponified by the malabsorbed fat, allowing free oxalate to be reabsorbed; this leads to hiserum oxalate—>hyperoxaluria—>acute oxalate nephropathy. |
Which crystals polarize positively, are seen within the tubular lumens and are the cause of the AKI? | calcium oxalate |
Drugs assoc w ca-oxalate? | Orlistat (induces malabsorption), topiramate (CA inh causes low urine citrate and high urine pH) |