Mechanisms of Disease Exam II
Terms
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- creatinine clearance
- (U x V)/ P then divide by minutes in day (1400)
-
a. normal urine output
b. oliguria
c. anuria
d. polyuria -
a. 750-2000 mL/day
b. <500
c. <100
d. >2500 - fractional excretion of urea
- (Una x Pcre)/ (Pna x Ucre) then x 100
- prerenal azotemia
-
anything that creates inadequate blood flow to kidneys
-secretion of ADH = ocnc urine
Una <10meq/L, 350-400 mOsm - renal azotemia
-
nephrons don't do work, Na lost to urine
Una>40meq/L, <350 Osm - causes renal azotemia
-
glomerulonephritis
acute tubular necrosis
pyelonephritis - diff b/t uremia and azotemia
-
azotemia- increased plasma creatinine and BUN with NO symptoms
uremia- increased WITH symptoms (many) - prerenal ARF caused by:
-
1. hypotension (sepsis, dehydration, hemorrhage)
2.edematous states (CHF, cirrhosis, nephrotic syndrome) -
nephrotic syndrome leaks...
nephritic syndrome leaks... -
>3g protein/day
<3g protein/day (post-infectious glomerulonephritis) - intrinsic RF caused by:
-
-acute tubular necrosis = ischemia= tubules sick
-nephrotoxic drugs (aminoglycosides, radiocontrast)
-heavy metals =injure tubules, necrosis
-glomerulonephritis
interstitial nephritis (drugs)
-infectious int. neph (usually E.Coli)
-vasculitis (vessels disrupted by IC deposition) - post RF/ obstructive RF caused by:
-
commonly nephrolithiasis/urethrolithiasis, usually uric acid stones --> gout or CHEMO
-also tumors, BPH - universal early sn that kidney function is compromised by whatever cause
- increased BUN and Pcre
- GFR in chronic renal failure
- goes to 10 mL/min and below
- NL Pcre
- <1.3 mg/dl
- Total urinary creatinine per day
- 1-2 g
- BUN
- 8-20 mg/dl
- NL BUN/Pcre ratio
- 10-15
- BUN/Pcre in prerenal azotemia
- >/= 20
- FEna
-
NL <1-5%
prerenal azotemia <1%
contrast agent prerenal azo <1%
renal azotemia >1%
postrenal azotemia >1% (>4%) - Prerenal azotemia values
-
Una <10 mEq/L
Uosm >450 mOsm/kg
FEna <1%
BUN/Pcre >20 - Renal azotemia values
-
Una >40 mEq/L
Uosm <450
FEna >1%
BUN/Pcre <20 - Postrenal azotemia FEna
- FEna >4%
- hypokalemia
- <3.5 mEq/L
- hyperkalemia
- >5.5 mEq/L
- NL total urinary protein per day
- 150 mg
- minimal proteinuria
- <0.5 g/day
- moderate proteinuria (nephritic syndrome)
- .5-3.5 g/day
- marked proteinuria (nephrotic syndrome)
- >3.5 g/day
- NL urinary protein/ creatinine on "spot" urine
- <0.2
- NL urine osmolality on "spot" urine after 12 hr fluid restriction
-
>800 mOsm/kg
<400 = renal impairment - spot urine for myoglobin- + indicates:
-
crush injury
polymyositis
recent surgery
rhabdomyolysis
electrical burn - hematuria
- >5 cells per hpf
- pyuria (WBC's)
- >5 cells per hpf
-
dysmorphic RBCs or RBC casts (even one) in urine is
PATHGNOMONIC for: - glomerulonephritis
- WBC casts in urine indicate
- pyelonephritis
- epithelial casts in urine indicate
- acute tubular necrosis
- fatty casts (oval fat bodies) in urine indicate
- nephrotic syndrome
- waxy casts indicate
- chronic renal failure
- urine dip should be negative for:
-
-protein
-glucose
-ketones
-RBC's
-bilirubin
-nitrite
-leukocyte esterase - on microscopic analysis, urine should be negative for:
-
-bacteria
-casts: RBC, WBC, waxy or fatty - NL to see these in urine under microscope:
- an occasional hyaline or epithelial cell cast
- urine dip = + for blood but no cells on microscopic analysis?
- Hb or Mb in urine
- kidneys regulate blood flow by 3 different mechanisms:
-
1. myogenic mech- main way, so partially responsible for GFR maint. too = afferent arteriole constricts
2. tubuloglomerulo feedback- JGA regulates GFR against momentary changes in BP
3. glomerulotubular balance - keep amt. filtered solute (NaCl) constant during time that GFR might be increased by change in BP-maintains constant fraction being filtered - parts of juxtaglomerular apparatus
-
1. macula densa
2. granular cells
3. extraglomerular mesangial cells (secrete chem. junk)
4. sympathetic nerves (no para in kidney!) - macula densa detects:
- increase in flow rate-->sends signal to granular cells-->causes afferent arteriole to constrict-->decrease GFR
- release of NE by sympathetic nerves on alpha-1 receptors causes:
-
vasoconstriction
-receptors found on renal arterioles - release of NE by sympathetic nerves on beta-1 receptors causes:
-
release of renin
-receptors found on granule cells in JGA - release of NE by sympathetic nerves in renin tubule causes:
- increase in Na reabsorption
- CO2 causes
- arteriole vasodilation (more blood can flow to exercising muscles)
- 2 mechs that regulate BP long term:
-
1. angiotensin II induced vasoconstriction
2. aldosterone and ADH mediated regulation of circulatory fluid volume - 3 detectors to control renin secretion:
-
1. hi pressure baroreceptors in carotid sinus/aortic arch- detect decrease, increase symp activity, triggers granular cells to release renin...
2. intrarenal baroreceptors (granular receptors= stretch receptors)
3. macula densa cells - decrease release of chem junk that inhibits renin from being released by gran cells - besides vasocontriction, angiotensin II ALSO CAUSES:
-
1. aldosterone secretion by zona glomerulosa of adrenal glands-->increased renal Na absorption-->increased fluid volume-->increased BP
2. release of ADH from posterior pituitary -->increased water reabsorption in collecting duct - % Na reclaimed by kidneys and H2O equivalent
-
2% reclaimed by aldosterone
= 3.6 extra L fluid -
treatment for CHF:
(to fight kidney's cycle of vasoconsriction and increased fluid vol.) -
1. diurectics
2. Ca channel blockers, ACE inhibs, ARB's - glucose in urine if... (=renal clearance of glucose)
- plasma load causes filtered load to exceed Tm (amount filtered in is more than the 375 mg/min max can reabsorb back into bloodstream- whatever is over 375 goes into urine)
- glucose cotransported with:
-
-Na
-amino acids (Bence Jones proteins cause max to be exceeded, released in urine) -
a.) if you dilate AFFERENT arteriole, GFR will _____
b.) if you constrict afferent arteriole, GFR will ____ - increase, decrease
- crush efferent arteriole, GFR will______
- pressure will back up, GFR increases
- ACE inhibs dilate the ______ arteriole
- EFFERENT
- H2CO3 is a ______ acid. these are eliminated by the ____
-
volatile, lungs
(emphysema= CO2 builds up, pH drops) - nonvolatile acids
- H2SO4 (result of metab), H3PO4
- kidney response if plasma/body pH decrease
- inc. H= secretion/excretion, increase reabsorb of bicarbonate, increase creation of new bicarb.
- Na/H antiporters where?
-
proximal tubule
-secrete H into tubular fluid, reabsorb Na - intercalated cells where?
-
collecting duct of nephrons
-proton pumps pump H out interstitium into tubular fluid a/g gradient - buffers in tubular fluid
-
NH3- H+ goes with NH3 to form NH4 which can bind to Na
HPO4 2- --> takes on 2 H+ ions and remove from tub fluid - primary glomerulopathies
- PIGN (nephritic), IgA nephropathy (berger's disease, nephritic), Goodpasture's (antiGBM GN, nephritic), minimal change disease (nephrotic)
- secondary glomerulopathies
-
DM, SLE, amyloidosis
-larger systemic disease that usually causes glomerulopathy, usually nephritic - nonglomerular diseases
-
1. tubulo interstitial nephritis (drug rxns)
2. infectious tubulointerstitial nephritis = pyelonephritis
3. tubular injuries...acute tubular necrosis from drugs, ischemia, heavy metals - proximal renal tubular acidosis symp:
- glucosuria, aa uria, uricosuria
- distal renal tubular acidosis
- salt wasting, hypercholemia, hyponitremia
- medullary area injured
- polyuria- inability to concentrate urine
- anemia differential dx:
-
Chronic fatigue
COPD
Congestive Heart Failure
Hypothyroidism
Anemia
Lupus
Infectious mononucleosis
Depression - COPD symptoms:
-
-history of smoking, chronic SOB
-abnormal chest diameter
-faint breath & heart sounds (hyperinflated lungs)
-exhaling >6 sec.
-percussion hyperresonant - CHF:
-
-smoking, HTN, MI, CAD, valve/myocarditis
-SOB/DOE
-JVD
-chest heave over R/L ventricle
-PMI enlarged, displaced
-heart murmur
-hepatosplenomegaly/ascites
-HJR
-rales in LVF, pedal edema in RVF
-cardiomegaly on CXR
-azotemia due to renal failure
-**inc plasma BNP (brain natriuretic peptide) - hypothyroidism:
-
-h/o cold intol, const, absence sweating, menorrhagia
-hoarseness, dry puffy skin, hard pitting edema
-possible goiter
-slow speech, delayed DTR's
-blood TSH inc. in primary, dec. in secondary
-T4 usually low - Lupus
-
-fever, anorexia, weight loss
-raynaud's
-malar rash
-joint pain
-RF, generic ANA's, anti-dsDNA Ab's, anti-smith ab's - Mono
-
-fever, sore throat, anorexia, myalgia
-pharynx may look like strep
-possible rash
-lymphadenopathy
-enlarged tender spleen
-positive monospot
-lymphocitosis w/ atypical (large) lymphocytes - female anemia hematocrit, Hb
- <37%, <12 g/dl
- male anemia H + H
- <41%, <13.5 g/dl
- used to describe and detect anemia:
-
RBC count, HCT, Hb <--calc from these are:
MCV, MCH, MCHC, RDW, blood smear - normal blood values:
-
RBC- 4.2-6.1 X 10^6 microliters
MCV- 80-100 fL
blood smear- normocytic, normochromic, no unusual shapes - used to detect response to infection, allergy, cancer (normal values):
-
WBC- 4.5-11 x 10^3/ microliter
and differential:
neutrophils - bands (immature), segs (mature) 54-62%
lymphocytes, monocytes, eosinophils, basophils
platelets - 150-450 x 10^3 - H + H =
- total red cell MASS - indirect measure of RBC count
- Decreased RBC production(decreased Hb synth anemias):
-
-Fe-deficiency
-thalassemia
-anemia of chronic disease
-B12 deficiency
-folate def
-alcohol - intrinsic hemolysis:
-
-hereditary spherocytosis = membrane
-sickle cell = Hb defect
-G6PD deficiency = oxidation - extrinsic hemolysis:
-
-autoimmune
-microangiopathic = mech. cardiac valve
-hypersplenism = spleen eats - if MCV is normal:
- normocytic anemia
- if MCV is increased:
- macrocytic anemia/ megaloblastic
- if MCV decreased:
- microcytic anemia
- microcytics
-
Fe def
thalassemia
chronic disease
hereditary spherocytosis
hypersplenism - macrocytics
-
alcohol
B12 (mega)
folate (mega) - serum ferritin below ____ means absent Fe stores
- 30 microliters
- TIBC (total iron binding capacity)
-
-measure of how much iron can be added and bound by various proteins
-increased with 70% Fe def patients = further proof of deficiency - 4 main kidney functions
-
1. reabsorb filtered nutrients (proximal tubule)
2. secretion
3. eliminate/conserve H2O - adjust urine osmolality
4. adjust pH of plasma- secrete H+ ions and make/conserve bicarbonate ions - kidney converts ______ to _____
- 25 (OH)Vit D, 1.25(OH) Vit. D (active form)
- ADH
-
released from post pit in response to dehydration
-increased H2O reabsorp in collecting duct - dehydration value
- plasma osmolality too high - above about 290 millimoles/liter
- what monitors plasma osmolality?
- preoptic/periventricular nuclei of hypothalamus
- mesangial cells
-
-contractile
-phagocytic
-respond to complement cascade by secreting chemical junk (this can affect rest of cells + decrease function)
-also secret mesagial matrix (supports glomerular tuft) - triple layer of glomerulus
-
-glomerular capillary endothelial cells
-basement membrane
-visceral epithelial cells (podocytes) - what composes most of the plasma's negative charge?
- albumin
- average GFR
- 125 mL/min
- effective renal plasma flow
-
total amount plasma going to kidneys and thru glomeruli
-all plasma flow in ALL afferent arterioles over 1 minute
-not all blood filtered thru each pass thru glom- some escapes thru efferent artery but might be filtered on next pass - renal flow thru kidney:
- afferent arteriole -> glomerular capillaries -> Bowman's capsule -> proximal convoluted tubule -> descending loop -> loop of Henle -> ascending loop -> distal convoluted tubule -> collecting duct
- blood flow in glomerulus:
- capillaries -> fenstrae (holes permit leakage) -> basement membrane -> foot processes of visceral podocytes -> fluid falls into Bowman's Space (or other blood exits glom cap's via efferent arterioles which branch into peritubular cap's)
- amt excreted =
- amt filtered + amt secreted - amt reabsorbed
- H2O is passively reabsorbed in thin ______ loop of Henle, Na+ is passively reabsorbed in thin _____ loop of Henle
- descending, ascending (traps Na+ at bottom loop of Henle interstitium
- counter-current multiplier of Henle's loop creates ____osm fluid
- 1200
- in the ascending limb ___ is pumped out, ___ passively follows it
- Cl-, Na+
- plasma creatinine value
- should be 1.2 mg/mL - higher than that indicates poor renal function
- renal clearance
-
(Udrug x V)/ Pdrug
how many individual mL of blood are cleared of the solute they are carrying
= mL/min not mg/min - nephron
- anatomic unit of kidney - each human has ~ 1 mil.
- glomerulus
-
tuft of cap's
-lined by endothelial cells
-covered by epithelial cells (podocytes)
-glomerular basement membrane in the middle
-continuous layer with those of bowman's capsule - mesangium
-
space b/t cap's in glomerulus- extension of basement membrane
-intrinsic glomerular cells and tissue macrophages - both respond to cytokines - podocytes
- epithelial cells on glom basement membrane
- tubuloglomerular feedback
- if inc. in Na+, sensed by macula densa-->afferent arteriole vasoconstriction- this dec. GFR so smaller. amt solute per unit time-->Na+ more efficiently reclaimed
- medullary oxygen consumption
-
redistribute blood from cortex to medulla
-constriction of some vascular beds, dilation of others - loss of nephrons
- compensatory glomerular hyperfiltration and renal hypertrophy -->progression to chronic renal failure begins
- causes of renal artery stenosis:
-
-atherosclerosis in renal arteries (usually 45+ y.o.)
-fibromuscular dysplasia - things to look for in dx of renal artery stenosis:
-
-refractory HTN (BP uncontrolled even w/ 3meds)
-new onset of HTN
-ARF upon starting ACE inhib
-bruit - fibromuscular dysplasia
-
women 25-45
unexplained HTN
fibromuscular struc crowds lumen of arteriole
*beads on a string* in renovascular system
angioplasty/stint - primary hydronephrosis
- blockage occurs at uteropelvic junction
- secondary hydronephrosis
- blackage anywhere lower in urinary tract
- polycystic kidney disease
-
genetic autosomal- chr 16
cysts take over
polycystin present (to fight or the cause?)
enlarged kidneys
approx 40 y.o.
hematuria, HTN
increased UTI
cysts in liver
dialysis, transplant - general symptoms of chronic renal failure:
-
-inc. BUN and creatinine due to inc. GFR
-N/V, fatigue, anorexia, disrupted sleep all due to toxin buildup
-dec seizure threshold, peripheral neuropathy (restless legs)
-HTN, pericarditis from uremia-->cardiac tamponade
-bone pain, patholog fx, soft tissue calc.
-GI bleeding - causes of CRF:
-
-diabetes (10+ yrs)
-HTN (nephrosclerosis)
-glomerulonephritis (primary or secondary)
-interstitial nephritis (drugs, heavy metals)
-polycystic kidney disease
-injury to any part - consequences of RF:
-
1. dec ability to secrete or excrete Na+
2. dec. ability to handle water (hyponatremia or hypernatremia)
3. become hyperkalemic- heart dysrhythmias
4. acidemia (increased H+, bicarb not being formed, not enough ammonia)
5. no conversion to active form vit. D -->hypocalcemia
6. drug doses larger b/c not clearing as fast - which tubules handles potassium?
- distal tubule
- what fits in glomeruli:
-
things <2.5 nm (glucose, water, urea)
things >4 nm won't fit
-albumin is 3.6 = borderline, but - charge repels - components of protein in urine
-
40% albumin
40% Tamm-Hursfall proteins (from thick ascending limb)
rest = IgG, IgA, light chains - causes of minimal proteinuria (<.5 g/day)
- exercise, fever, postural, HTN, UTI, polycystic kidney disease, renal tub dysfunction
- cause of moderate (.5-3 g/day)
- glomerulonephritis, preeclampsia, CHF, mild diabetec nephropathy, multiple myeloma (bence jones)
- marked proteinuria causes:
- glomerulonephritis, severe diabetic nephropathy, lupus, amaloidosis
- orthostatic proteinuria
-
</= 2g day, normal at night
tenns/ young adults
at night, lying down= BP dec, goes away - functional proteinuria
- high fever, cold exposure, strenuous exercise
- mech of pathologic proteinuria
-
1. loss charge = albuminuria (MCD)
2. loss size barrier (RA, SLE, diabetes, amaloidosis)
3. overload proteinuria (multiple myeloma, hemolysis in vascular spaces)
4. proximal tubule dysfunction