Acid, Base, electrolytes

Question 1

Causes of low anion gap

Answer 1

• low albumin
• normal AG acidosis can have low AG
• increased cations( Ca++, Mg++, Lithium intoxication, IgG paraproteinemia

Question 2

Cause of elevated anion gap

Answer 2

• severe volume depletion ( hyperalbuminemia)
• Respiratory and metabolic alkalosis
• Increased anionic paraproteniemia( IgA)
• Severe hyperphosphatemia( ingesting fleet enemas)

Question 3

Medications that cause type B lactic acidosis

Answer 3

-INH, Nucleoside RTI, Linezolid, Propofol, Metformin

Question 4

Encephalopathy, ataxia, acidosis following CHO rich meals?

Answer 4

D Lactic acidosis, can cause high AG and normal AG acidosis

Question 5

How do kidneys handle L lactate and D lactate?

Answer 5

L-Lactate is reabsorbed well and eventually converted to HCO3
D-lactate is not absorbed and is lost as Na-D lactate, so loss of HCO3

Question 6

What is the cause of hyperkalemia in DKA?

Answer 6

Hypertonicity and Insulin deficiency

NOT intracellular shift

Question 7

Why do patients develop non gap acidosis in recovery phase of DKA?

Answer 7

Due to loss of Na salts of ketoacid> which reflects indirect loss of HCO3
increased holding to NaCl by kidneys
receiving NaCl during treatment and KCL

Question 8

Name three uricosuric agents.

Answer 8

1)Probenecid
2)Losartan and
3) High dose Aspirin
Salicylate toxicity> check uric acid next time if you dont believe > very low
act on uric acid transporter in PCT luminal side

Question 9

What causes increase in Na absorption and decrease in Na absorption in kidneys?

Answer 9

Increase: RAAS and Sympathetic system
Decrease: ANP, Dopamine and Prostaglandins

Question 10

Name the condition due to mutation of claudin 16 and 19.

Answer 10

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis

Question 11

What is the major determinant of urinary Mg excretion?

Answer 11

Plasma Mg, hence slow and sustained release tablets is way to go. Consider Amiloride for chronic

Question 12

What does hypermagnesemia do to calcium and K?

Answer 12

Hypocalcemia due to decreased PTH secretion.

impair K excretion> hyperkalemia

Question 13

What happens if you drown in dead sea?

Answer 13

Hypermagnesemia and Hypercalcemia

Question 14

Ethylene glycol poisoning; Fomepizole and dialysis?

Answer 14

Fomepizole is removed by dialysis, dosing interval q 4hrly

Question 15

Look for - and - in Salicylate toxicity?

Answer 15

Hypokalemia and hypoglycemia

Question 16

Osmolal gap acidosis and cranial nerve palsies?

Answer 16

Diethyelene glycol poisoning ( brake fluid)

Question 17

What specific prescription for dialysis would you prefer in Metformin toxicity?

Answer 17

Large volume of distribution> practical way is to do iHD ~4-6 hrs and then put on CRRT with high clearance

Question 18

What are the tests to look for urine acidifation defect?

Answer 18

• urine ph
• urine AG
• urine osmolal gap( probably best) <150 suggests acidification defect

Question 19

Propylene glycol toxicity like manifestations in burn patient?

Answer 19

-Topical Silver sulfadiazine has propylene glycol as driver

Question 20

Severe AG acidosis with relatively unimpressive lactate level?

Answer 20

• D lactate acidosis

- Pyroglutamic acidosis

Question 21

Conditions of Pseudohypokalemia: K falls in test tube

Answer 21

mainly in Myeloproliferative disorders

can be associated with pseudohypophosphatemia, pseudohypoglycemia

Question 22

Inherited hypokalemia periodic paralysis, where is the defect?

Answer 22

-majority have mutated gene coding alpha 1 subunit of dihydropyridine sensitive voltage gated calcium channel

Question 23

Conditions where you should not agressively replace K?

Answer 23

Cellular shift

• Thyrotoxic periodic paralysis
• Barium sulfide poisoning( magic shave, rat poison)

Question 24

5 Types of Bartter syndrome

Answer 24

1) NKCC2
2) ROMK
3) Cl channel
4) Barttin subunit of Cl channel; Barttin subunit also present in cochlea> hearing loss
5) Ca sensing receptor

Question 25

Ogilvie Sydnrome and K pathophysiology

Answer 25

Increased expression of BK channel in Colon> increased secrtion of K> up to 100 meq/l in intestinal fluid

Question 26

What can you do as a nephrologist for a patient of CKD who is planning pregnancy?

Answer 26

• Make sure they are on Hydroxychloroquine if SLE
• Initiate Aspirin 81-150 mg prior to 16 weeks POG.
• and Calcium supplementation
• control HTN
• stop ACE/ ARB ( at conception ok, not necessarily preconception) eg in a patient of DM with proteinuria. You would rather have less proteinuria at the time of conception
• Proteinuria >0.3 gm/day greatly increases risk of preterm delivery, small for gestational age and preeclampsia

Question 27

What other antihypertensive agents can you consider in breasfeeding lady other than pregnancy safe agents?

Answer 27

low milk/ plasma ratio of drugs like Captopril, Enalapril and Quinapril

Question 28

What is the risk of CKD IV patient goes to pregnancy?

Answer 28

Everything else is very high. Risk of progression to ESRD is 20%. Pregnancy generally will increase your previous stage CKD by 1

Question 29

General formula for predicting rise in Na based on water loss?

Answer 29

• Loss of 3 ml/kg/ H2O will raise serum Na by 1 meq/L

- 1 ml/kg 3% NaCl will raise serum Na by 1 meq/L

Question 30

What do you monitor for in an alcoholic patient who is admitted with electrolyte disorders?

Answer 30

-Refeeding syndrome, Rhabdomyolysis and Hemolysis

Question 31

Recognize anabolism as cause of hypokalemia

Answer 31

B12 treatment in pernicious anemia, rapidly growing Leukemia, lymphoma

Question 32

Hypokalemia with metabolic alkalosis in diarrhea

Answer 32

Congenital chloridorrhea( SLC mutation) and villous adenoma and chronic laxative abuse( acting on colon)

Question 33

Hyperkalemia in CKD usually occurs below <15-20 eGFR. What should you think if early?

Answer 33

hyporeninemic hypoaldosteronism, decreased distal Na delivery( CHF, hepatorenal), abnormal collecting duct (drugs, TI nephritis, obstruction)

Question 34

What are the three mechanisms of acidosis?

Answer 34

-addition of acid, loss of bicarbonate( GI or renal) and impaired excretion of acid from kidney

Question 35

Limitation of using urine AG in interpretation of normal AG acidosis

Answer 35

lots of anions in urine like ketoacids, Nahippurate> urine osmolal gap is better way

Question 36

What toxin is in brake fluid?

Answer 36

Diethylene glycol ( osmolal gap and cranial nerve palsies)

Question 37

Tell me one cause of pseudohypocalcemia.

Answer 37

post gadolinium ( interferes with colorimetry assay)