Nephrology Flashcards
(46 cards)
When to start sodium bicarb in a patient with CKD? how does it help outcomes?
when bicarb chronically < 22
slow progression of CKD
Treatment of minimal change dz (glomerulonephropathy)
1st line - Glucocorticoids a
+
standard treatment of the nephrotic syndrome (ACEi or ARB, diuretics for edema, and cholesterol-lowering medication if total cholesterol >200
Which drugs to use in CKD + T2DM to reduce risk of CKD progression/CV events (or both) ?
- SGLT2 inhibitor (empagliflozin)
- GLP1 receptor agonist (liraglutide).
What are the causes of euvolemic hyponatremia with Ur Na >20 and Uosm >300 ? what if Uosm 50-100?
- SIADH, Hypothyroidism, adrenal insufficiency (addison disease), cerebral salt wasting
- compulsive water drinking
whats a normal plasma osm? what is the equation? what is osmolar gap?
285-295
serum osm = 2{Na+] + gluc/18 + BUN/28
osm gap is measured - calculated osm, normal is <10, if elevated think of methanol, ethylene glycol, propylene glycol, and isopropyl alcohol poisoning
How to calculate free water deficit?
[(Na - 140)/140] x TBW
TBW = 0.5 x weight (kg)
in SIADH what is urine sodium? what is urine osm? what else do you have to rule out?
UNa >20 mEq/L
UOsm >300 mOsm/L
r/o hypothyroidsm, adrenal insufficiency (low cortisol), and cerebral salt wasting
How to differentiate renal vs. extra renal phosphate wasting?
24-hr phos collection or calculate FEPO4
If 24hr Phos >100mg/d OR FEPO4 >5% = renal phos wasting
FEPO4 = (Ur PO4 x Serum Cr x 100)/(Serum PO4 x Ur Cr)
How much should PCO2 correct for metabolic acidosis? (acute vs chronic)
Should decrease by…
ACUTE = (1.5 x HCO3) + 8 +/- 2
CHRONIC = HCO3 + 15
How much should HCO3 correct for respiratory acidosis? (acute vs chronic)
Should increase by …
ACUTE = 1 mEq/L for every 10mmHg of PaCO2
CHRONIC = 3.5 mEq/L for each 10mmHg of PaCO2
How much should PCO2 correct for metabolic alkalosis?
should increase by …
ACUTE = 0.7 mmHg for each 1 mEq/L
How much should HCO3 correct for respiratory alkalosis? (acute vs chronic)
should decrease by…
ACUTE = 2mEq/L for each 10mmHg of PaCO2
CHRONIC = 4mEq/L for each 10mmHg PaCO2
Anion gap equation?
Na - (Cl + HCO3) = 8-12
IF AG is reduced <4, what does that suggest?
Multiple myeloma or Hypoalbuminemia
Urine anion gap equation? what should it be with normal AG metabolic acidosis? what is it with impaired urine acidification (ie. type 1 RTA)?
(Ur Na + Ur K) - Ur Cl
- negative, -20 - -25
- positive, 20 - 40
What is Delta-delta equation? what does it tell you?
- (norm AG - measured AG) / (normal HCO3 - measured HCO3) – basically change in AG over change in HCO3, should be 1-2
- Used in METABOLIC ACIDOSIS –
- – If delta delta is <1 = concurrent normal AG acidosis
- – If delta delta is >2 = concurrent metab alkalosis
What is Balkan Endemic Nephropathy (BEN)?
- gross hematuria (non glomerular)
- CKD 2/2 tubulointerstitial injury
- slowly progressive tubulointerstitial disease linked to aristolochic acid (nephrotoxic alkaloid from the plant Aristolochia clematitis)
- high prevalence rate in southeastern Europe (Serbia, Bulgaria, Romania, Bosnia and Herzegovina, and Croatia) and is the cause of kidney disease in up to 70% of patients receiving dialysis in some of the most heavily affected regions
When/how does HCTZ help with recurrent nephrolithiasis?
Ca-oxylate or Ca-phosphate stones who have HYPERCALCIRUIA as urine Ca can be decreased by HCTZ by inducing mild hypovolemia, triggering increased proximal sodium reabsorption and passive calcium reabsorption. Can augment this affect by low sodium diet.
Other tx - potassium citrate or bicarb (but if urine citrate is normal this won’t make a difference)
Treatment of primary (75%) Membranous Glomerulonephropathy.
- observe for 6-12 months on conservative therapy - ACEi, statin, diuretic (edema management) 30% have spontaneous remission in 1-2yrs
- If remain nephrotic –> immunosupression
- - (1) Glucocorticoids + alkylating agents (75-85% remission in 1 yr)
- - (2) Calcineurin inhib (cyclosporine or tacrolimus)
- - (3) Rituximab (noninferior in inducing remission but superior in maintaining remission than cyclosporine)
What are causes of secondary (25%) membranous glomerulonephropathy
malignancy (solid tumors, lymphoma), infection (Hep B, Hep C, malaria, syphillis), SLE, drugs (NSAIDS)
**high propensity for renal vein thrombosis
What antibody is found in primary membranous glomerulonephropathy
Anti-PLA2R in 75% of primary cases (rarely in secondary) – podocyte antigen that elicits immune complex formation with circulating autoantibodies
Name 4-5 main nephrotic syndromes
- MCD (young)
- FSGS (black, HIV, APOL1 gene, common, obesity, premature birth, solitary kidney – all leads to adaptive podocyte injury)
- Membranous Glomerulonephropathy (white, malignancy, Hep C, Hep B, associated renal artery thrombosis)
- Diabetic Nephropathy
- Membranoproliferative GN (also nephritic, assoc Hep C)
Others… amyloidosis, monoclonal immunoglobulin deposition disease
Name nephritic syndromes
- Anti GBM (goodpastures)
- Pauciimmune (norm complement, necrotizing GN)
- - GPA - c-ANCA/PR-3
- - MPA - p-ANCA/MPO
- - EGPA
- - renal limited ANCA (anca positive but no other involvement)
3A. Immune deposition (low complement)
– post infectious (strep, staph, *IE) - 1-6 weeks post illness
– Lupus nephritis
– membranoproliferative GN
– cryoglobulinemia (HCV, Low C4)
3B. Immune deposition (normal complement)
– IgA nephropathy
– IgA vasculitis - can be 2 days post flu illness
pathophys of hypercoag in nephrotic syndrome?
- hypoalbuminemia (esp<2.8) –> hepatic overproduction of proteins –> inc levels of procoagulants (factor V, factor VIII, fibrinogen)
- Urinary loss of albumin in high volume + urinary losses of LMW anticoagulants (AT III, protein S) + fibrinolytics (plasminogen).