Misc Renal

Question 1

Type 1 RTA

Answer 1

• distal RTA
• inability of alpha intercalated cells to secrete H+ –> no new HCO3 generated –> metabolic acidosis
• urine pH >5.5
• low serum K+

Causes: amphotericin B, analgesic nephropathy, SLE, RA, Sjogren

high risk for calcium phosphate kidney stones (bc high pH, and high bone turnover)

Question 2

Type 2 RTA

Answer 2

• PCT
• defect in PCT HCO3 reabsorption –> more HCO3 excretion –> metabolic acidosis
• urine can be acidified in CD, but not enough to overcome high HCO3 secretion
• urine pH <5.5
• low serum K+

Causes: Fanconi syn, multiple myeloma, carbonic anhydrase inhibitors

increased risk for Rickets (hypophosphatemia)

Question 3

Type 4 RTA

Answer 3

• hyperkalemic RTA
• hypoaldosteronism or aldo resistance –> hyperkalemia –> decreased NH3 synthesis in PCT –> decreased ammonium excretion
• urine pH <5.5
• HYPERkalemia (only RTA with high K+)

Causes: diabetic hyporeninism, ACE inhibitors, ARBs, NSAIDs, adrenal insufficiency, K+ sparing diuretics, obstructive nephropathy

Question 4

Cl dependent metabolic alkalosis

Answer 4

• decreased volume
• RAAS activation
• Angiotensin 2 increases PCT HCO3 reabsorption
• aldo increases H+ ATPase in CD, acidifies urine
• no pendrin activity bc no Cl-
• Cl <30

Question 5

Cl independent metabolic alkalosis

Answer 5

• low K+
• high volume or HTN
• aldo increases H+ ATPase in CD, acidifies urine
• low K+ causes increase in H+/K+ ATPase activity to conserve K+, acidifies urine

-pendrin cannot keep up

Caused by adrenal tumor, exogenous aldo, licorice

Cl > 30

Question 6

CKD (GFR) Stage 1

Answer 6

GFR >90

Diagnose and treat cause

Question 7

CKD (GFR) Stage 2

Answer 7

GFR <90 (60-90)

Estimate progression

Question 8

CKD (GFR) Stage 3

Answer 8

GFR <60 (30-60)
Adjust med doeses.
Evaluate/treat complications.

Question 9

CKD (GFR) Stage 4

Answer 9

GFR <30 (15-30)

Prepare for kidney replacement therapy (KRT)

Question 10

CKD (GFR) Stage 5

Answer 10

GFR <15

Assess need for kidney replacement therapy, start if indicated.

Question 11

CKD albumin stages

Answer 11

1: <30 mg/dL
2: <300 mg/dL (30-300)
3: >=300 mg/dL

Question 12

diagnosing pre vs intra vs post renal AKI

Answer 12

PRE: low FENa (low vol but working tubules)

INTRA: urine sediment
-high FENa

POST: ultrasound imaging

Question 13

causes of metabolic acidosis

Answer 13

MUDPILES

Methanol
Uremia
DKA
Paraldehyde
Ingestion/Iron
Lactic acidosis
Ethylene glycol
Salicylates

Question 14

markers of kidney damage

Answer 14

1) proteinuria
2) abnormal urine sediment (cells, casts, crystals)
3) abnormal imaging (hydronephrosis, kidney stones, horseshoe kidney)
4) tubular syndromes (SIADH, diabetes insipidus, RTAs, Bartter Syn, Gitelman syn)