Renal 1 - Acid Base Disorders

Question 1

Met Acidosis + High Anion Gap

Answer 1

MUD PILERS
-Methanol/Metformin
- Uremia
- DKA, Alcoholic ketosis
- Paraldehyde/phenformin
- Iron, Isopropyl etoh, Isoniazid
- Lactic Acidosis
- Ethyelene Glycol, Ethyl Etoh
- Rhabdo
- Salicylates
MC: Lactic acidosis, ARF,  DKAa

Question 2

Met Acidosis + normal AG

Answer 2

- Hypokalemia (diarrhea, diversion, RTA, mineralocorticoid def, CAH inhibitor, post hypocapnia, NS)
, sulfur.
USED CARP
-ureteral diversion
- SB fistural
- Extra chloride
-Diarrhea
-CAH (acetazolamide, mefenamic)
- Adrenal insuff
-RTA
- Pancreatic fistula

Question 3

Met acidosis + high osmolal gap

Answer 3

• Toxic etoh ingestion (ethylene glycol, methanol)

- Ketosis (etoh or dka)

Question 4

Anion Gap

Answer 4

AG= Na- Cl - HCO3

normal 10-14

Question 5

Labs in Met Acidosis

Answer 5

• ABG: dec pH, bicarb, PaCO2
• UA: pH>6 renal cause, <6 GI cause
• U AG +10 renal non AG

Question 6

FE-HCO3

Answer 6

<5% : distal RTA

>15% Proximal RTA (assumes serum HCOE >20meq/L)

Question 7

Type I RTA - Causes

Answer 7

• Distal RTA, fails to excrete ammonium
• Auto dominant or
• Acquired: SLE, sickle cell, nephrocalcinosis, meds (amphotericin B, lithium, toluene)

Question 8

Type I RTA signs/labs/tx

Answer 8

• Sx: msk weakness, recurrent nephrolithiasis
• Labs: Non AG met acidosis, urine pH >5.5 despite acidosis, Low to nl K, FE-HCOR <5%
• Tx: bicarb supplementation 1-2mEq/day with goal serum >22, corrects hypo K

Question 9

Type 2 RTA - Causes

Answer 9

• children
• Proximal tubule defect of HCO3 reabsorption -> HCO3 wasting
• Acetazolamide, Fanconi’s synd, medullary cystic disease, mltp myeloma, nephrotic synd, renal tx

Question 10

Type 2 RTA - Presentation

Answer 10

• Failure to thrive, growth retard, emesis, dehydration, lethargy, rickets vs osteopenia
• ABG mild to mod Non AG met acidosis
• dec serum HCO3, >5.5 urine pH
• FE-HCO3 >15 % if serum >20meq/L

Question 11

Type 2 RTA - Management

Answer 11

• High dose HCO3 supp (10-25 meq/kg/day
• watch for low K
• Tx osteomalacia: vit D, calcium
• Tx Rickets: vit D, NaPO4 1.6g/day

Question 12

Type 3 RTA

Answer 12

-Variant of type 1, distal RTA, affects children
- Severe HCO3 wasting, can be down to lethal levels <3 meq/L
- Acute hypoK paralysis
-Coma, shock
-

Question 13

Type 4 RTA - Causes

Answer 13

• Aldosterone deficiencyL syndrom hyporeninemic hypoaldosteronism, Addison’s dz, heparin, K sparing diuretics
• Collecting duct malfx from renal insufficiency: diabetic nephropathy, intersitial nephritis, obstructive uropathy, renal tx

Question 14

Type 4 RTA - labs/tx

Answer 14

• Met acidosis, hyperK, urine ph <5.5 with severe met acidosis, dec Cr clearance
• Tx: Fludrocortisone (if aldosterone def)
• if chronic renal insuff: restrict K, loops diuretics, low dose po HCO3 102 meq/kg/day