Acid, Base, electrolytes Flashcards
Causes of low anion gap
- low albumin
- normal AG acidosis can have low AG
- increased cations( Ca++, Mg++, Lithium intoxication, IgG paraproteinemia
Cause of elevated anion gap
- severe volume depletion ( hyperalbuminemia)
- Respiratory and metabolic alkalosis
- Increased anionic paraproteniemia( IgA)
- Severe hyperphosphatemia( ingesting fleet enemas)
Medications that cause type B lactic acidosis
-INH, Nucleoside RTI, Linezolid, Propofol, Metformin
Encephalopathy, ataxia, acidosis following CHO rich meals?
D Lactic acidosis, can cause high AG and normal AG acidosis
How do kidneys handle L lactate and D lactate?
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
What is the cause of hyperkalemia in DKA?
Hypertonicity and Insulin deficiency
NOT intracellular shift
Why do patients develop non gap acidosis in recovery phase of DKA?
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
Name three uricosuric agents.
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
What causes increase in Na absorption and decrease in Na absorption in kidneys?
Increase: RAAS and Sympathetic system
Decrease: ANP, Dopamine and Prostaglandins
Name the condition due to mutation of claudin 16 and 19.
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis
What is the major determinant of urinary Mg excretion?
Plasma Mg, hence slow and sustained release tablets is way to go. Consider Amiloride for chronic
What does hypermagnesemia do to calcium and K?
Hypocalcemia due to decreased PTH secretion.
impair K excretion> hyperkalemia
What happens if you drown in dead sea?
Hypermagnesemia and Hypercalcemia
Ethylene glycol poisoning; Fomepizole and dialysis?
Fomepizole is removed by dialysis, dosing interval q 4hrly
Look for - and - in Salicylate toxicity?
Hypokalemia and hypoglycemia
Osmolal gap acidosis and cranial nerve palsies?
Diethyelene glycol poisoning ( brake fluid)
What specific prescription for dialysis would you prefer in Metformin toxicity?
Large volume of distribution> practical way is to do iHD ~4-6 hrs and then put on CRRT with high clearance
What are the tests to look for urine acidifation defect?
- urine ph
- urine AG
- urine osmolal gap( probably best) <150 suggests acidification defect
Propylene glycol toxicity like manifestations in burn patient?
-Topical Silver sulfadiazine has propylene glycol as driver
Severe AG acidosis with relatively unimpressive lactate level?
- D lactate acidosis
- Pyroglutamic acidosis
Conditions of Pseudohypokalemia: K falls in test tube
mainly in Myeloproliferative disorders
can be associated with pseudohypophosphatemia, pseudohypoglycemia
Inherited hypokalemia periodic paralysis, where is the defect?
-majority have mutated gene coding alpha 1 subunit of dihydropyridine sensitive voltage gated calcium channel
Conditions where you should not agressively replace K?
Cellular shift
- Thyrotoxic periodic paralysis
- Barium sulfide poisoning( magic shave, rat poison)
5 Types of Bartter syndrome
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
Ogilvie Sydnrome and K pathophysiology
Increased expression of BK channel in Colon> increased secrtion of K> up to 100 meq/l in intestinal fluid
What can you do as a nephrologist for a patient of CKD who is planning pregnancy?
- 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
What other antihypertensive agents can you consider in breasfeeding lady other than pregnancy safe agents?
low milk/ plasma ratio of drugs like Captopril, Enalapril and Quinapril
What is the risk of CKD IV patient goes to pregnancy?
Everything else is very high. Risk of progression to ESRD is 20%. Pregnancy generally will increase your previous stage CKD by 1
General formula for predicting rise in Na based on water loss?
- 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
What do you monitor for in an alcoholic patient who is admitted with electrolyte disorders?
-Refeeding syndrome, Rhabdomyolysis and Hemolysis
Recognize anabolism as cause of hypokalemia
B12 treatment in pernicious anemia, rapidly growing Leukemia, lymphoma
Hypokalemia with metabolic alkalosis in diarrhea
Congenital chloridorrhea( SLC mutation) and villous adenoma and chronic laxative abuse( acting on colon)
Hyperkalemia in CKD usually occurs below <15-20 eGFR. What should you think if early?
hyporeninemic hypoaldosteronism, decreased distal Na delivery( CHF, hepatorenal), abnormal collecting duct (drugs, TI nephritis, obstruction)
What are the three mechanisms of acidosis?
-addition of acid, loss of bicarbonate( GI or renal) and impaired excretion of acid from kidney
Limitation of using urine AG in interpretation of normal AG acidosis
lots of anions in urine like ketoacids, Nahippurate> urine osmolal gap is better way
What toxin is in brake fluid?
Diethylene glycol ( osmolal gap and cranial nerve palsies)
Tell me one cause of pseudohypocalcemia.
post gadolinium ( interferes with colorimetry assay)
