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Flashcards in Renal Deck (281)
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What does the appearance of hazy, smoky, or foamy urine implicate?

Hazy: presence of cells or crystals
Smoky: acute glomerulonepritis
Foamy: protein


What is specific gravity and what is normal for urine?

Specific Gravity: ratio: weight of vol. of urine / weight of vol. of distilled water

Normal: 1.003-1.035


Define osmolality

number of solute particle dissolved in 1kg of water


What effect does protein have on urine pH?

high protein diet -> acidic urine (lower pH)

Vegetarian diet -> alkaline urine


What infection should be considered w/ very high (>8) urine pH?

Urea splitting microbes (ex. Proteus)


What is the cutoff size for protein filtration at the glomerulus?

25,000 daltons
Albumin: 69,000 - will not normally be filtered


How much protein is usually excreted in urine /day and what level will register as positive on a dipstick test?

250mg /day -> positive dipstick test


What is Tamm-Horsfall protein?

Glycoprotein Secreted by TALH
Constitutes the majority of protein excreted in urine
Can gel in lumen and produce urinary casts


4 sources of protein in urine

Tubular disorder: most filtered protein is taken up and degraded by proximal tubule. If damaged -> increased urine protein
Glomerular disease: increased filtration
Overflow state: excessive systemic production (ex. Ig light chain in multiple myeloma)
Contamination: semen, vaginal secretion, pus, blood, mucus


In a chemical test for blood in urine, what substances are detected?

RBC, Hb, Myoglobin


What is renal glycosuria? Causes?

glucose in urine due to reduction in reabsorption at PCT (normal blood glucose level)
-Fanconi's syndrome, interstitial nephritis, pregnancy


In urine, how many RBCs are normally visible /HPF?



What does the presence of dysmorphic RBCs on urinalysis indicate?



What are oval fat bodies seen in urinalysis?

tubular epithelial cells with fat droplets in cytoplasm
indication of NEPHROTIC syndrome
maltese-cross pattern of cholesterol / cholesterol ester


7 types of urinary casts

hyaline: may be normal w/ exercise or dehydration (Tamm-Horsfall)
RBC: glomerulonephritis
WBC: inflammation of tubular interstitium (nephritis / pyelonephritis)
epithelial: tubular injury (acute tubular necrosis)
granular: fine - may be normal; coarse (muddy brown) - tubular necrosis
fatty: nephrotic
waxy: renal failure casts - advanced CKD


What is a renal lobule?

A group of nephrons draining into a common collecting duct


What type of collagen makes up the glomerular basement membrane?

Type IV


What is a filtration slit?

space between foot processes of podocyte (visceral epithelium of glomerulus)
Nephrin: filtration protein: allows small things through


What is Heymann Nephritis?

Experimental model demonstrating possible mechanism behind in situ immune complex formation
Rats immunized with PCT brush border Ag develop Ab that is cross reactive w/ podocyte


Primary membranous glomerulonephropathy

In situ immune complex formation
Ab against unknown Ag in glomerular basement membrane


What determines the location of Ag or immune complex deposition in the glomerulus?

neutral: deposit in mesangium
anion: subendothelial (bet. endothelium and GBM
cation: subepithelial (bet. GBM and podocyte


What is focal segmental glomerulosclerosis?

damage to glomeruli increase stress on other glomeruli -> endothelial injury, podocyte injury, coagulatin, inflammation, messangial cell proliferation and increased ECM


What is tubulointerstitial fibrosis?

glomerulosclerosis -> proteinuria and tubular ischemia -> injury and activation of tubular cells -> cytokines and growth factors -> interstitial inflammation and fibrosis


global vs. segmental

level of the glomerulus
global: entire glomerulus
segmental: portion of glomerulus


What morphological feature is associated with rapidly progressive glomerulonephritis?

Crescent formation
-form of hypercellularity. severe glomerular damage -> leakage of cytokines, procoagulant into bowman's space -> parieal epithelial proliferation and leukocyte infiltration


Calculation for plasma osmolality and normal values

Plasma osmolality = 2 * [Na+] + ([glucose]/18) + (BUN/2.8)

Normal = 288
Na = 140
glucose = 100
BUN = 10


Describe water distribution in terms of body weight, ECF and ICF

TBW = 0.6 * lean body weight
ECF = 1/3 TBW
ICF = 2/3 TBW


2 causes of pseudohyponatremia

1: lab artifact: elevated plasma protein expands plasma volume -> appearance of decreased [Na] (hyperlipidemia and hypergammaglobulinemia)
2: hyperosmolal hyponatremia: elevated glucose -> increased osm -> fluid shift from icf to ecf -> lowered [Na]


In the setting of elevated blood glucose, how is the post-correction [Na] estimated?

Post glucose correction [Na] = add 1.6 mM for every100 mg/dL blood glucose is over 200mg/dL to plasma [Na]


what effect does elevated BUN have on distribution of water?

None. Urea even distributes between ICF and ECF