Renal Flashcards

1
Q

What is the cause of mucosal bleeding in CKD?

A

Increased urea –> inhibits arginine conversion to urea and shunts it towards GSA –> nitric oxide –> decreased vWF secretion, decreased ADP and thromboxane A2, and decreased GP IIb/IIIA receptor activation –> decreased platelet adhesion, activation and aggregation

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2
Q

Membranous nephropathy - what kind? Associated secondary causes?

A

Nephrotic syndrome, subepithelial deposits, gradual podocyte damage, subacute presentation (vs acute for minimal change disease)

Malignancy
Infection (Hep B/C, syphilis)
Autoimmune (eg lupus, thyroiditis)
Drugs (NSAIDs)

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3
Q

Amyloidosis - what kind? Risks?

A

Nephrotic syndrome - glomerular amyloid deposition

Risk of restrictive cardiomyopathy

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4
Q

What does low urine chloride in metabolic alkalosis suggest?

A

Body depletion of chloride (e.g. vomiting, diuretic overuse) –> should replete with normal saline

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5
Q

Acute papillary necrosis - most causes, signs

A
  1. Analgesic overuse
  2. Sickle cell anemia

Signs:
AKI, hematuria, flank pain, fever

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6
Q

Desmopressin indications and adverse effects

A
  1. Diabetes insipidus
  2. Mild-moderate heavy menstrual bleeding associated with vWD

Adverse: Induces effects of ADH –> hypotonic hyponatremia with euvolemia (due to increased natriuretic peptide secretion)

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7
Q

Hypercalcemia symptoms

A
  1. Nausea
  2. Polyuria
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8
Q

When does hypercalcemia of immobilization occur?

A

After 4 weeks

May be as soon as 3 days in those with chronic renal insufficiency

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9
Q

How does acute rhabdomyolysis affect calcium?

A

Precipitation of calcium and phosphorus in damaged muscles –> hypocalcemia

During diuretic/recovery phase, hypercalcemia and hyperphosphatemia

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10
Q

What are paraneoplastic syndromes of renal cell carcinoma?

A
  1. EPO production
  2. Hypercalcemia
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11
Q

What should be used to relieve urine in acute bacterial prostatitis?

A

Suprapubic catheter - don’t want to spread bacteria from prostate upward or rupture prostate

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12
Q

Ureteral stone - medication?

A

Alpha blocker (e.g. tamsulosin) for stones >5 and <=10 mm to facilitate passage

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13
Q

How do kidneys respond to metabolic acidosis from non-renal etiology?

A
  1. Increased bicarbonate reabsorption (Cl excretion increases via beta-intercalated cells in collecting duct)
  2. Increased excretion of ammonium and dihydrogen phosphate
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14
Q

Oliguria definition

A

<500 mL of urine/24 hours

Often present in prerenal AKI

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15
Q

Hypocalcemia signs

A
  1. Paresthesia
  2. Hyperreflexia
  3. Trousseau sign (BP cuff inflated >SBP 3 min causes carpopedal spasm)
  4. Chvostek sign (tapping facial nerve causes ipsilateral facial muscle contraction)

Tetany, seizure, others

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16
Q

When is bicarb indicated in metabolic acidosis?

A

When pH<7.2

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17
Q

Why does DKA have hyperkalemia but total potassium deficit?

A

Osmotic diuresis, elimination of ketoacid anions as potassium salts, and secondary hyperaldosteronism from volume contraction lead to potassium deficit

Hyperkalemia due to hyperosmolarity and diminished insulin

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18
Q

Fibroblast growth factor 23

A

Lowers phosphate by decreasing intestinal absorption and increasing renal excretion

Increased in phosphate retention and secondary hyperPTH due to CKD

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19
Q

What is suggested by hypercalcemia with renal injury?

A

Malignancy (eg multiple myeloma)

Normally kidney injury results in hypocalcemia due to decreased phosphate excretion

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20
Q

How do loop and thiazides affect calcium and sodium in kidney

A

Loop: promote Ca wasting
Thiazide: decreases urinary excretion

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21
Q

Adrenal vein sampling - purpose

A

Differentiate between adrenal hyperplasia and adenoma

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22
Q

Tumor lysis syndrome prophylaxis for AKI

A

Normal saline
Allopurinol or rasburicase

Hyperuricemia and hyperphosphatemia lead to uric acid and calcium phosphate stones, respectively

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23
Q

How to avoid contrast-induced AKI?

A

0.9% saline increases intravascular volume first

Do not give if already volume overloaded

Would expect to see creatinine rise 24-48h after administration

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24
Q

What electrolyte disturbance in alcohol use causes refractory hypokalemia?

A

Hypomagnesemia - intracellular magnesium normally inhibits renal outer medullary potassium (ROMK) pump, preventing excessive K+ loss

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25
Diabetic nephropathy - injury to what part?
Basement membrane and adjacent structures -Albuminuria (albumin-creatinine ratio 30-300 mg/g Random urine test should be done at diagnosis (type 2) or 5 years after type 1
26
Diabetic nephropathy - treatment
BP control: ACEi/ARB Glycemic control: SGLT2 inhibitor or GLP-1 agonist
27
Opioid meds to avoid in kidney disease
Morphine Tramadol Codeine Meperidine
28
How to alkalinize urine for uric acid stones?
Potassium citrate
29
Diabetes predisposes to which stones?
Uric acid stones
30
How does CKD affect phosphate and calcium?
Hyperphosphatemia Hypocalcemia Secondary hyperPTH
31
Calcium in which direction causes seizures?
Severe hypocalcemia -> neuronal hyperexcitability
32
When is serum osmolality possible helpful in evaluating hyponatremia?
When suspected hypertonicity (e.g. hyperglycemia causing translocational hyponatremia) or isotonicity (e.g. hyperlipidemia causing lab artifact pseudohyponatremia) Otherwise, most likely hypotonic
33
How does PTH affect alk phos?
Increased
34
Nephrotic syndrome infection risk
Loss of IgG -> decreased humoral immunity, particularly to encapsulated organisms
35
Nephrotic syndrome effect on anemia
Via loss of transferrin, erythropoietin
36
Nephrotic syndrome effect on vitamin D
Deficiency due to loss of vit D-binding protein
37
ADPKD effects from cyst development
Hypertension - cysts cause ischemia, resulting in RAAS Polyuria/nocturia - mild, neprhogenic diabetes insipidus from cyst damage to distal tubules and receipt of vasopressin signals
38
Milk-alkali pathogenesis
Calcium carbonate antacids: Hypercalcemia causes renal vasoconstriction, decreased GFR Calcium inhibits NaK2Cl cotransporter due to activation of calcium-sensing receptors in thick ascending tubule Ca impairs ADH activity These cause hypovolemia and increased bicarb reabsorption, compounding alkali intake
39
Milk-alkali risk factors
CKD Thiazide use (increased Ca retention) ACEi, NSAIDs (decreased GFR)
40
How do loop diuretics affect calcium and magnesium levels?
Hypocalcemia and hypomagnesemia - blocking NaK2Cl prevents K reabsorption, leading to Ca and Mg loss
41
Why does metabolic alkalosis (hypochloremic hypokalemic from vomiting, NG, diuretics) benefit from normal saline?
Replenishes Cl to help bicarb excretion by kidneys Restored volume to decrease RAAS signaling, reducing loss of K and H from kidneys
42
What protein is proteinuria?
>3.5 g/day
43
“Spike-and-dome”: Diffuse BM thickening with subepithelial granular deposits (light) and IgG/C3 (IF)
Membranous nephropathy Primary: anti-PLA2R Ab serology or antigen on tissue stain Secondary: Solid tumors, infections, SLE, NSAIDs
44
Describe typical urinalysis for myeloma at diagnosis
Bland with granular casts and protein detecting albumin moreso than Ig; elevated creatinine
45
Severe hypercalcemia treatment
Aggressive hydration Calcitonin Bisphosphanates are more for long-term management
46
Why do patients with hypercalcemia have polyuria?
Calcium-induced nephrogenic diabetes insipidus Poor oral intake (hypercalcemia causes confusion, stupor)
47
What is one of the most common causes of humoral hypercalcemia of malignancy?
Renal cell carcinoma
48
Euvolemic hyponatremia occurs with...
SIADH Treat with salt tablets and oral fluid restriction
49
Loop diuretic-induced metabolic alkalosis - treatment
Acetazolamide Do not use if volume-depleted
50
What is the Cl/HCO3 exchanger?
Pendrin Cl depletion (from vomiting) impairs renal HCO3 excretion
51
When is ammonium chloride used?
Metabolic alkalosis when volume overloaded and cannot receive normal saline
52
Most common causes of death in ESRD
1. Cardiovascular - Metabolic (hyperphosphatemia) + increased calcium load (vitamin D supplementation) lead to arterial calcification, uremia and renal replacement therapy cause oxidative stress, anemia 2. Infection
53
Muscle cramps and weakness after thiazide for high blood pressure
Consider hyperaldosteronism, with hypokalemia causing symptoms
54
What causes the acidosis in DKA?
Lipolysis and fatty acid breakdown to ketones in the liver; vomiting, abdominal pain, and Kussmaul respirations result to get rid of acidity
55
Membranoproliferative GN vs membranous nephropathy vs diffuse proliferative
Membranoproliferative: Hep C/cryoglobulinemia, monoclonal gammopathy; nephritic Membranous: primary PLA2R Ab or secondary solid tumors, NSAIDs, Hep B, lupus nephritis Diffuse proliferative: lupus nephritis only
56
IgA vasculitis requires what follow-up?
Serial urinalyses
57
Nonblanching, palpable purpura of buttocks and lower extremities and arthralgia of lower extremities
IgA vasculitis
58
Low Mg can lead to low what electrolytes?
K and Ca - due to impaired mobility out of cells
59
Mg toxicity due to renal impairment - treatment
Ca gluconate IV - stabilizes myocardium similar to why it's used with hyperkalemia Dialysis for severe
60
Mg toxicity - signs
Nausea, flishing, headache, hyporeflexia Somnolence, areflexia, hypocalcemia Cardiac or respiratory paralysis
61
When to give sodium bicarb for acidosis?
Only when pH <7.1 Sodium bicarb can cause myocardial depression and increase lactic acid production
62
What is normal osmolality, and what is formula?
2xNa + glu + BUN/2.8 Normal range 275-295
63
How do urine findings help differentiate in setting of hypotonic, hypovolemic hyponatremia?
Urine Na <40: nonrenal salt loss (e.g. vomiting, diarrhea) Urine Na >40: renal salt loss (e.g. diuretics, primary adrenal insufficiency)
64
How do urine findings help differentiate in setting of hypotonic, euvolemic hyponatremia?
Urine osmol <100: Primary polydipsia; malnutrition (e.g. beer potomania) Urine osmol >100 and urine Na >40: SIADH (after ruling out hypothyroidism and secondary adrenal insufficiency)
65
Difference between emphysema and chronic bronchitis DLCO
Emphysema: decreased DLCO Chronic bronchitis: normal DLCO
66
Why is glomerular hematuria darker?
More time in nephrons results in hemoglobin oxidization to methemoglobin
67
High osmolal gap in metabolic acidosis
Measured osmolality - calculated osmolality High osmolal gap suggests active metabolites in serum, such as toxic alcohols Normal osmolal gap indicates other causes, including lactic acidosis or salicylates
68
69
Hypernatremia algorithm: urine osmolality <300 vs >600, urine Na <1% vs >2%
<300: Diabetes insipidus >600: <1% Na: extrarenal fluid loss >2% Na: sodium gain
70
Isotonic (serum osmolality 275-295) hyponatremia vs hypertonic (>295) hyponatremia
Isotonic: Lipids, proteins Hypertonic: Glucose, contrast agents Mannitol can contribute to both
71
How do urine findings help differentiate in setting of hypervolemic hyponatremia?
Urine Na <40: CHF, cirrhosis, nephrotic syndrome Urine Na >40: AKI, chronic kidney failure
72
Envelope-shaped crystals in urine - cause
Urine calcium oxalate = ethylene glycol
73
Saline-resistant metabolic alkalosis
Urine Cl >20, Cl wasting - caused by hyperaldosteronism, Bartter or Gitelman syndrome
74
Negative vs positive urine anion gap
UAG = Na + K - Cl; increased Cl in urine means increased ammonium NH4 excretion Negative suggests proximal/type 2 RTA or GI bicarb loss Positive suggests distal/type 1 RTA (impaired NH4 excretion)
75
Fatty casts are seen in…
Nephrotic syndrome
76
“Tram track” double-layered basement membrane; subendothelial and mesangial deposits
Membranoproliferative GN - can be immune complex-mediated (primary in children, secondary to HBV/HCV/SLE/cryoglobulinemia) or complement-mediated (low C3)
77
Which nephritic syndrome may require plasma exchange therapy?
Goodpasture syndrome Also pulsed steroids and cyclophosphamide
78
Minimal change disease - treatment
Steroids
79
Nodular glomerulosclerosis (Kimmelstein-Wilson nodules)
Diabetic nephropathy or renal amyloidosis
80
Low pH stones
Uric acid Calcium oxalate Cystine Note: calcium phosphate and struvite stones are high pH
81
Stone shapes
Envelope/dumbbell: calcium oxalate Wedge-shaped prism: calcium phosphate Staghorn: struvite Rhomboid: uric acid Hexagonal: Cystine
82
Thiazides may be used to treat what stones?
Calcium oxalate, NOT calcium phosphate that is 2/2 hyperPTH
83
Positive urinary cyanide nitroprusside test for stone
Cystine stone
84
Chronic pyelonephritis due to infected kidney stone obstruction can cause…
Xanthogranulomatous pyelonephritis - observe multiple, dark round areas on CT (Bear Paw sign)
85
Nephrogenic DI - treatment
Salt restriction, HCTZ, amiloride, low-protein diet
86
SIADH - treatment
Fluid restriction, IV hypertonic saline if necessary Severe: ADH antagonists (e.g. tolvaptan) Chronic: Demeclocycline