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Flashcards in Nephrology Deck (327)
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1

Primary d/o

Dec'd HCO3 (met acidosis) -> dec'd PCO2 (resp alk compensation) -> 1.3(change in HCO3) +-2

Inc'd HO3 (met alkalosis) - -> inc'd PCO2 (resp acidosis compensation) -> 40+0.7 (change HCO3)

Inc'd PCO2 (resp acidosis) -> Inc'd HCO3 (met alkalosis compensation)-> Acute 1 HCO3 for 10 PCO2, Chronic 3.5 HCO3 for 10 PCO2

Dec'd PCO2 (resp alkalosis) -> dec'd HCO3 (met acidosis - compensation)-> Acute 2 HCO3 for 10 PCO2, Chronic 5HCO3 for 10 PCO2

2

Acid/base Method

1. Check pH >7.4 alkalotic - met if bicarb inc, resp if CO2 dec
met if bicarb dec, resp if CO2 inc
2. Check AG - Na+- (Cl+HCO3)
3. Compensation
5. Met Acidosis with AG - 1:1 rule - change in AG = change bicarb (only if doing AG met acidosis)

3

Non gap metabolic acidosis causes?

Lower GI losses (diarrhea) /ureteral diversion (like diarrhea)
RTA
Prox: MM, acetazolamide, lead, topamax,
Distal: Sjogrens, lupus, amphote, foscarnet, toluene

4

RTAs

Proximal RTA (II) - pH=5, urine AG neg (not able to reclaim bicarb) - spills bicarb - UpH alkaline at first but then acidifes in functional distal tubule
Distal RTA (I) pH>5.5 - pos Urine AG (inappropriately alkaline urine in setting of systemic acidosis) - a/w CaPO4 kidney stones

Diarrhea - pH=5 - tubules are working - diarrhea gets rid of lots of bicarb in blood - kidneys still get rid of ammonium and hydrogen to compensate - pH of urine still acidic - neg AG urine

Hyporenin hypoaldo (IV) - no aldo, can't get rid of K -> get hyperkalemia - alkaline pH

5

Confirm RTA

Urine anion gap = negative (normal) - measure for urine - when can acidify urine/diarrhea ammonium (unmeasured cation)
When AG + -> not dumping ammonium

6

Proximal RTA vs diarrhea

check products that would be dumping due to prox RTA (AA, glucose, phosphate) - not diarrhea if see these

7

Anion Gap metabolic acidosis

M ethanol
U remia
D iabetic ketoacidosis
P ropylene glycol, paraldehyde
I sonazid (INH)
L actate
E thylene glycol, ethanol
S alicylates - ** also causes respiratory alkalosis

8

Metabolic gap acidosis with Osmolar gap

AG and Osmolar Gap
Methanol
Propylene glycol
Ethylene glycol, ethanol
Osmolar gap=

9

Ketosis without acidosis in substance AG normal bicarb normal

Isopropyl etoh

10

Metabolic alkalosis
PCO2 inc'd = 0.6(change in bicarb)

MC acid base abnormality - everyone on diuresis and vomiting (bicarb up, lose hydrogen) - maintained cuz pre-renal - can't get bicarb out
pH high - high bicarb level
PCO2 inc'd = 0.6(change in bicarb)
Chloride responsive (to saline) - Ucl 20 (hyperaldo)
Mineralocorticoid excess
Diuretic (recent)
Gittleman - like HCTZ dec K, normal BP, UCl>15
Barter's syndrome - like lasix, normal BP Ucl ?15
Little's/licorice ingestion - high BP, Ucl>15, dec'd K

11

Respiratory Acidosis

not breathing - too much PCO2 (chest wall injury, obstruction, CNS resp depression, COPD (chronic)
Acute 1 inc HCO3 for 10 inc PCO2
Chornic 4 inc HCO3 per 10 inc PCO2

12

Respiratory Alkalosis

Hyperventilating - PE, high altiutde, PNA, sepsis
Acute - dec 2 HCO3 per 10 dec PCO2
Chronic - 5 dec HCO3 per 10 dec PCO2

13

Glue sniffing

distal RTA (alkalotic urine)

14

Serum Osm=

2(Na+) + BUN/2.8+Gluc/18

15

Osm gap=
Ethylene glycol->glycolic acid->CaOx crystals->ATN

Measured serum osm-calculated Osm
if osm gap>50 needs HD
if osm gap <50

16

Non-gap Met acidosis

Loss of bicarb or unable to excrete H+
RTA
Diarrhea
Ureterosigmoiostomy
Early renal failure
Post hyperventillation (blowing off PCO2 - kidney dumps bicarb, absorbs Cl-)

17

Toner fluid/acetone/isopropyl etoh

NOT converted to acid
converts to ketone - not acidic
No AG
inc'd serum osm

18

Dec'd transportaion defect in ascending loop of henle

Bartter's syndrome (Lasix), low BP, low K, UCl>15

19

Dec'd transportationd ef in deistal tubule

Gitelman's (HCTZ) low BP, low K, UCl>15

20

INc'd (aldo independent) transport in distal tubule

Liddle's syndrome (high BP) low K, UCl>15

21

Pt p/w ingestion unknown substance pH7.18, PCO2 23, Bicarb 8, Na 136, Cl 100 HCO3 10 - Ca Ox crystals

Gap metabolic acidosis
Ethylene glycol
tx: ethanol if Osm Gap 20
HD if osm gap >50

22

pt brought in with confusion, convulsions and blindness after injesting uknown substance - pH 7.24, PCO2 28, HCO3 14 Na 136, Cl 100 HCO3 15 dx?

Methanol poisoning
(formic acid - blindness)

23

Pt to ER depressed/somnolent - friend says was initially excited - injgested unknown substance - smells acetone/ acetone urine +, likely ingested?

Isopropyl etoh

24

18yo brought to ER with confusion, seizure and ataxia dec'd DTR, fruity odor on breath - dx?

Toluene toxicity (glue sniffing)

25

Pt with tinnitus, lethargy, tachycardia - pH7.48, Na+140, Cl 100, HCO3 16 - pt has?

ASA tox
Resp alkalosis -> Met acidosis

26

76yo pt needs to inc' TV to hear better - c/o ringing in ear mild dizziness - pt with HTN taknig ASA x 10 years - VSS dx?

ASA tox (confusion, fever, hyperventilation, acidosis)

27

Non AG

Chronic renal failure

28

HyperK

peaked T wave
Renin problem
Aldo problem - not enough aldo (blocked by ACEi, spironolactone), hyperK, acidosis
Pre-renal state, no distal Na+, can't dump K into urine (needs K for pump to work)
Insulin def (cellular shifting)
Impaired renin (NSAIDS, BB, cyclosporin, tacrolimus, DM, age)
ACEi
ARB
Impaired aldo metabolism
Aldo rct blockers (spironolactone, epleronone)
Na+ channel blockers (need Na+ into cell to get K out of cell)

Acidosis - Type IV RTA (hypoaldo, hyporenin), CKD

29

Hypo K

Hyperaldo prim or sec
GI losses - diarrhea/vomiting
Conn's primary hyperaldo - tumor producing too much aldo - suppresses renin

Acidosis - RTA I/II, diarrhea, toleune
Alkalosis - hyperaldo, loop/thiazinde diuretics, genetic d/o, vomiting

30

Type IV RTA

no aldo
hyperkalemic
no renin