on 14-Apr-2016 (Thu)

Question

Sigmund Freud wrote: "By accepting the existence of these two (or three) psychical systems,
psycho-analysis has departed a step further from the descriptive
"psychology of consciousness" and has raised new problems and acquired a new content."
What did he mean by that and what problems are likely to arise because of that?

Answer

He meant that lack of resistance equals acceptance.
As long as either analysand accepts analyst's content or analyst accepts analysand's, analysis proves successful,
however, both parties could be trapped in circulus in probando, logical fallacy known as circular reasoning.

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#nephrology

Question

Approach to AKI

Answer

Causes:
1) pre-renal
2) renal
3) post-renal

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Question

What are pre-renal causes of AKI?

Answer

↓ renal blood flow d/t:

1) ↓ ECF volume (volume depletion)
2) ↓ effective ECF volume (volume overloaded - CHF - but not getting to kidneys; fluid shift to interstitial space - liver ds)
3) disruption of hemodynamics/autoregulation​
-drugs (NSAIDs, RAAS blockers)
-endogenous mediators (accumulation of vasoactive compounds in liver failure - hepatorenal syndrome)

NB: could be losing Na or ↓ intake

Tags

#exam #nephrology

Question

What is a renal cause of AKI?

Answer

inj d/t dysfn of renal parenchyma.

look for:
-systemic ft's (ds could also be affecting kidneys)
-HTN (NB: hypo for pre-renal)
-mild to mod ECF volume overload
-anemia/thrombocytopenia
-***abn urine sediment (RBC, WBC, protein, abn casts)***

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#nephrology

Question

What is a cause of post-renal AKI?

Answer

inj secondary to not passing urine from kidneys (urine backs up)

dx = imaging (kidney & bladder u/s)

Tags

#exam #nephrology

Question

What are 2 methods of urine evaluation?

Answer

1) dip stick → **alb, Hg, WBC**, others (glu, pH, urobilinogen, specific gravity)
2) microscopy → cells, crystals, casts

Tags

#exam #nephrology

Question

What are 3 types of renal AKI causes?

Answer

1) tubulo-interstitial → acute tubular necrosis (atn), allergic/acute interstitial nephritis (ain), tubular obstruction
2) glomerular → prolif ds, non-prolif ds (rarely causes aki)
3) vascular → arteries (renal a stenosis, vasculitis), arterioles (atheroembolic ds, vasculitis), capillaries (thrombotic microangiopathies, vasculitis), veins/venules (thrombosis)

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Question

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	[...]	[...]
urine microscopy	normal	hemegranular casts
urinary [Na]	<20mmol/L	>20mmol/L
FENa	<1%	>1%

Answer

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	normal	hemegranular casts
urinary [Na]	<20mmol/L	>20mmol/L
FENa	<1%	>1%

Tags

#nephrology

Question

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	[...]	[...]
urinary [Na]	<20mmol/L	>20mmol/L
FENa	<1%	>1%

Answer

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	normal	hemegranular casts
urinary [Na]	<20mmol/L	>20mmol/L
FENa	<1%	>1%

Tags

#nephrology

Question

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	normal	hemegranular casts
urinary [Na]	[...]	[...]
FENa	<1%	>1%

Answer

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	normal	hemegranular casts
urinary [Na]	<20mmol/L	>20mmol/L
FENa	<1%	>1%

Tags

#nephrology

Question

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	normal	hemegranular casts
urinary [Na]	<20mmol/L	>20mmol/L
FENa	[...]	[...]

Answer

pre-renal aki vs atn:

Test	pre-renal	atn
urine dipstick	normal	Hg +/- alb
urine microscopy	normal	hemegranular casts
urinary [Na]	<20mmol/L	>20mmol/L
FENa	<1%	>1%

Tags

#exam #nephrology

Question

What is ATN (acute tubular necrosis)?

Answer

• 2nd most common cause of AKI
• d/t ischemia/toxins
• look for signs of ↓ volume (pre-renal hypotension can cause ATN)
• **hemegranular casts** = dx

Tags

#exam #nephrology

Question

What is allergic/acute interstitial nephritis (ain)?

Answer

interstitial inflm d/t:

• usually allergic rxn to drugs (abx, NSAIDS, PPIs, etc)
  • usually present 7-10d post-exposure
  • urine → RBC, WBC, protein, **WBC casts**
• autoimmune ds
• inf's

Tags

#exam #nephrology

Question

What is prolif glomerulonephritis?

Answer

• too many cells in glomerulus so can't filter → AKI
• present w/:
  • rapid ↓ in GFR
  • ​HTN, anemia
  • ↑ inflm markers
  • other systemic ft's (if 2ndary)
  • ECF volume full/mildy overloaded
• urine → **RBC casts** (nephrologic emerg)

Tags

#nephrology

Question

What is non-prolif glomerular ds?

Answer

structural problem - rarely causes AKI - just see proteinuria

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#nephrology

Question

What are causes of thrombotic microangiopathies?

Answer

TTP, hemolytic uremic syndrome (HUS), hypertensive emerg

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#nephrology

Question

How do you manage AKI?

Answer

general

• prevent additional nephrotoxins (drugs, contrast)
• rx ECF volume status
• avoid complications
  • ECF volume overload (↓Na intake, ↑ diuretics)
  • avoid ↑K (↓ intake, diuretics, laxatives, shift into ICF)
  • renally dose meds

​pre-renal aki

• improve hemodynamics
  • ↑ ECF w/ IV fluids
  • ↑ cardiac output

​renal AKI

• ATN → time
• AIN → remove offending agent, consider corticosteroids
• glomerulonephritis → maybe immunosuppresive therapy (urgent)

Tags

#nephrology

Question

Drugs with Renal Effects

Answer

• Renin‐Angiotensin‐Aldosterone System (RAAS) blockers
• Diuretics
• Antidiuretic Hormone (ADH)

Question

Angiotensin II stimulation causes:

Answer

↑ aldo
vasoconstriction
↑ Na reabsorption

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#nephrology

Question

Direct renin inhibitors (i.e. aliskiren) do what?

Answer

Blocking Renin Action

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Question

ACE inhibitors do what?

Answer

Blocking Angiotensin II production

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Question

Angiotensin receptor blockers do what?

Answer

Blocking Angiotensin II action

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Question

Spironolactone/Eplerenone does what

Answer

Blocking action of Aldosterone

NB: spironolactone = K+ sparing diuretic

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Question

Diuretics do what?

Answer

• ↓ Na to ↓ ECF volume
• can cause over-diuresis
• if acts prox to CCD = K wasting
• if acts @ CCD = K sparing

Tags

#nephrology

Question

Weak diuretics..

Answer

• work at prox tubule
• carbonic anhydrase inhibitors (not used much as diuretics) - blocks reabsorption of HCO3 (Na stays out with it)

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Question

Potent diuretics..

Answer

loop diuretics (furosemide, bumetanide)
work on asc limb of loop
blocks NKCC2
can add to thiazide diuretics

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Question

Thiazides..

Answer

hydrochlorothiazide (HCTZ), Chlorthalidone, Indapamide, Metolozone
works on DCT (distal convoluted tubule)
imp s/e:

• Dyslipidemia
• Hyponatremia
• Hyperuricemia
• Hypercalcemia

Tags

#nephrology

Question

Potassium Sparing Diuretics..

Answer

weak
2 mechanisms:

• block aldosterone from binding its receptor (spironolactone, epeleronone)
• bind ENaC

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Question

ADH..

Answer

aquaporin insertion in CD
VAPTANS (new)

• Competitive inhibitors for ADH

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Question

Nephrotoxic drugs contributing to pre-renal AKI

Answer

diuretics → ↓ ECF volume d/t ↑ Na loss
RAAS blockade → Block either the formation or action of AngII (which maintains GFR) → efferent vasodilation
NSAID → Inhibit the formation of prostaglandins (which vasodilate afferents)

Tags

#nephrology

Question

What are tubulo-toxic drugs causing ATN?

Answer

Aminoglycosides Antibiotics (Gentamicin, Tobramycin, Amikacin)
Amphotericin B (antifungal)
Cisplatin (chemo)
IV radiocontrast dye

Tags

#nephrology

Question

medications implicated with AIN

Answer

Acute interstitial nephritis:

• NSAIDS
• abx
• PPI
• allopurinol

Chr interstitial fibrosis:

• lithium (most common), etc