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Flashcards in Renal & Electrolytes Deck (51):
1

Treatment of patients with severe hypovolemic hypernatremia

1st correct the hypovolemia with 0.9% saline.

Then switch to 0.45% saline + 5% dextrose to correct the hypernatremia no faster than 1mEq/L/hour

2

Earliest renal abnormality in patients with diabetes? Earliest observable abnormality in these patients?

Earliest abnormality = glomerular hyperfiltration

Earliest observable abnormality = GBM thickening

3

Imaging modalities of choice for patients with suspected kidney stones

Non contrast helical CT and ultrasound (preferred if alternate dx is unlikely or pregnant)

4

Treatment of choice for uric acid stones

Alkalinization of the urine to a pH of 6 to 6.5 with potassium citrate.

5

Stones not observable on imaging

Calcium stones

6

Most common type of nephrotic syndrome where you see renal vein thrombosis?

Membranous glomerulopathy

7

Differentiating benign renal cysts from malignant renal cysts

Simple: smooth, homogenous, do not enhance with contrast, asymptomatic and unilocular.

Malignant: thick, irregular walls, loculated, heterogenous, enhance with contrast, cause pain/hematuria/HTN

8

Most common causes of anion gap metabolic acidosis

Methanol
Uremia
DKA
Propylene glycol
INH
Lactic acid
Ethylene glycol
Salicylates

9

Appropriate rate of correction of serum sodium for patients with hyponatremia

No more than 0.5mEq/dL/hr and not exceeding 12mEq in 24 hours.

10

How to calculate serum osmolarity

2Na + BUN/2.8 + Glc/18

11

Calculate serum osmolar gap

Measured Sosm - Calculated Sosm. This is typically done when you suspect ethanol, methanol or ethylene glycol toxicity.

12

Diagnostic criteria for SIADH

Sosm Sosm

Una > 20

Absence of hypovolemia

Normal renal, adrenal and thyroid function

No obvious stimulus to activate the neuroendocrine hormonal response that increases ADH secretion

Absence of other known causes of hyponatremia

13

Why is metabolic acidosis due to renal disease rarely seen in patients with an eGFR > 20?

The remaining nephrons compensate greatly for decreased H+ secretion by increasing NH3 production that gets secreted in the urine as NH4 to get rid of the H+.

14

Dietary recommendations for patients with renal calculi?

Increased fluid to >2L urine/day, decreased Na+ to

15

Definitive measures used to reduce serum K+

Cation exchange resins like sodium polystyrene sulfonate

16

How to confirm the diagnosis of cystinuria in a patient with stones?

Hexagonal crystals and urinary cyanide nitroprusside test showing elevated cystine levels.

17

Post-void residual volume that is significant for bladder outlet obstruction

> 50 mL

18

Complete vs. partial DI

Complete: urine osmolarity is > 600

Partial: urine osmolarity is 300-600

19

Common causes of nephrogenic DI

Hypercalcemia, hypokalemia, tubulointerstitial renal disease, Li, demeclocycline, foscarnet, cidofovir and amphotericin

20

Why do saline-resistant causes of metabolic alkalosis have a high urine Cl- concentration?

Excess mineralocorticoid stimulation results in excess serum Na+ and volume retention. The kidneys respond by secreting more Na+ and Cl-, resulting in increased Cl- concentration.

21

Treatment of UTIs and pyelonephritis in non-pregnant women?

Acute uncomplicated cystitis: nitrofurantoin x 5 days (avoid if GFR 20%). Fosfomycin x1. Culture urine only if treatment fails.

Complicated cystitis: fluoroquinolones 5-14 days. Amp-gent for more severe cases. Culture urine to confirm correct antibiotic choice.

Pyelo: fluoroquinolones as outpatient therapy. IV fluoroquinolones or aminoglycoside +/- ampicillin for inpatient therapy. Culture urine to confirm correct antibiotic choice.

22

What constitutes a case of complicated cystitis?

DM, CKD, pregnancy, immunocompromised, urinary tract obstruction, hospital-acquired infection, procedure-associated infection or catheter-associated infection.

23

Management of hypercalcemia?

Severe (sx or Ca > 14): NS at 200mL/hr with goal urine output of 100-150mL/hr + calcitonin immediately. Give bisphosphonates for long-term treatment.

Moderate (Ca 12-14): no treatment

Mild (Ca

24

Tests to get in patients with BPH

Urinalysis and PSA if life expectancy is > 10 years

25

Most common type of kidney stone

Ca-oxalate

26

Acid-base abnormality seen with chronic vomiting

Hypochloremic, hypokalemic metabolic alkalosis. This is because for each H+ lost in vomit, one HCO3- is formed. Additionally, hypovolemia leads to RAAS activation, H+/K+ wasting and HCO3- retention.

27

Common extrapulmonary manifestations of Tb

Liver disease, splenic infiltration, renal disease, Pott's disease and adrenal insufficiency (very common in endemic regions).

28

NSAID effects on kidneys

Prostaglandin inhibition prevents afferent arteriole dilation and can cause renal failure.

Also, it potentiates the action of ADH and can cause SIADH.

29

ECG characteristics in hyperkalemia

Peaked T-waves, short QT, long PR and wide QRS that can progress to sine wave morphology.

30

Kidney stones that will likely pass spontaneously

31

Most common histology seen in patients with diabetic nephropathy?

Diffuse glomerulosclerosis

32

Most common causes of nephrotic syndrome in adults with no evidence of systemic disease?

Membranous nephropathy and FSGS

33

How do you know a patient has FHH vs. primary hyperparathyroidism?

They have very low urine Ca ( 0.02 due to high urinary Ca levels.

34

Factors that may precipitate hepatorenal syndrome

Those that reduce renal perfusion or GFR

35

How to diagnose hepatorenal syndrome

Confirm renal hypoperfusion with FeNa

36

Nephrotic range proteinuria, hematuria and dense intramembranous deposits that stain positive for C3

Membranoproliferative GN. This is due to IgG antibodies against C3 convertase that constitutively activate C3 and the alternative complement pathway.

37

Muddy brown granular casts
RBC casts
WBC casts
Fatty casts
Broad and waxy casts

Muddy brown granular casts - ATN
RBC casts - GN
WBC casts - AIN, pyelo
Fatty casts - nephrotic syndrome
Broad and waxy casts - chronic renal failure

38

Cardinal features of nephrotic syndrome

Proteinuria (glomerular injury), hypoproteinemia, hyperlipidemia (increased liver synthesis of albumin and lipids), edema (decreased oncotic pressure), hypercoaguability (loss of AT III and increased protein C/S) and hypovolemia

39

Drugs that commonly cause interstitial nephritis?

Cephalosporins, PCN, sulfonamides, sulfa diuretics, NSAIDs, rifampin, phenytoin and allopurinol.

40

Antibiotic that can cause hyperkalemia by blocking the eNaC and decreases creatinine secretion?

Trimethoprim

41

Characteristics of interstitial cystitis? Treatment?

Bladder pain with filling that is relieved by voiding with no other attributable cause for > 6 weeks. Treat by avoiding triggers + amitriptylene and analgesics during flares.

42

Why are loop diuretics associated with metabolic alkalosis?

They increase Na delivery to the DCT. This leads to increased Na resorption and K/H secretion -> metabolic alkalosis.

43

How to prevent at-risk patients from getting contrast-induced nephropathy if they really need imaging done.

Adequate IV hydration with isotonic NaHCO3 or 0.9% NS + acetylcysteine.

44

Extra-renal manifestations of ADPKD

Berry aneurysms
MVP/AR
Colonic diverticula
Abdominal wall/inguinal hernia

45

Aspects of patients on dialysis that increase their risk of dying from heart disease?

Elevated homocysteine levels

Hyperphosphatemia w/elevated PTH levels

Anemia

ESRD

Accelerated atherogenesis from enhanced oxidant stress

Enhanced Ca intake

NO inhibition

46

Patient has gross hematuria, low serum C3 and subepithelial humps consisting of C3 complement on renal biopsy

Post-strep GN

47

AA amyloidosis vs. AL amyloidosis

AA = chronic inflammatory conditions, beta-2 microglobulin, apolipoprotein or transthyretin gets abnormally folded and deposited.

AL = MM, Waldenstroms. Lambda light chains get deposited.

48

Nephritic syndromes with associated low C3 levels

Post-strep GN, lupus, MPGN, mixed cryoglobulinemia

49

Immune complexes that form in mixed cryoglobulinemia

IgM complexes with anti-HCV IgG, HCV RNA and complement.

50

Drugs that can cause crystal-induced nephropathy

Acyclovir, sulfonamides, MTX, ethylene glycol and protease inhibitors

51

What do +LE and nitrites on UA mean?

+LE = pyuria. Nitrites = enterobacter is present.