Nephrology Flashcards

1
Q

1st trimester interim kidney - later contributes to male genital system

A

Mesonephros

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2
Q

Structures originating from ureteric bud - derived from caudal end of mesonephric duct

A

Ureter
Pelvis
Calyces
Collecting ducts

Note - Fully canalized by 10th week

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3
Q

Structures originating from interaction of metanephric mesenchyme and ureteric bud

A

Glomerulus through DCT

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4
Q

Last embryologic structure to canalize and most common site of obstruction (hydronephrosis) in a fetus

A

Ureteropelvic junction

obstruction primarily occurs in males and results in hydronephrosis because the kidney produces urine at a greater rate than can drain into the ureter

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5
Q

Kidneys trapped low in the abdomen under the inferior mesenteric artery

Associated with…
Hydronephrosis
Chromosomal aneuploidy

A

HORSESHOE KIDNEY

Inferior poles of both kidneys fuse

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6
Q

Complete absence of kidney and ureter

A

UNILATERAL RENAL AGENESIS

Ureteric bud fails to develop

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7
Q

Nonfunctional kidney consisting of cysts and connective tissue

A

MULTICYSTIC DYSPLASTIC KIDNEY

Ureteric bud fails to induce differentiation of metanephric mesenchyme

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8
Q

Y-shaped bifid ureter

Leads to…
Vesicoureteral reflux/UTIs
Ureteral obstruction

A

DUPLEX COLLECTING SYSTEM

Bifurcation of ureteric bud as it enters metanephric blastema

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9
Q

Only one functioning kidney - compensatory hypertrophy

A

CONGENITAL SOLITARY FUNCTIONING KIDNEY

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10
Q

Order of renal arteries

A
Renal artery
Segmental artery
Interlobar artery
Arcuate artery
Interlobular artery
Afferent arteriole
Glomerulus
Efferent arteriole
Vasa recta/peritubular capillaries
Venous outflow
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11
Q

Components of glomerular filtration barrier…

Size barrier
Negative charge/Size barrier
Negative charge barrier

A
Fenestrated capillary endothelium
Fused basement membrane with Heparan sulfate
Epithelial podocytes (visceral layer of Bowman's capsule)
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12
Q

Location of Juxtaglomerular cells - modified smooth muscle cells

A

Between Macula Densa (early DCT) and afferent arteriole

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13
Q

Location of ureters relative to…
Gonadal arteries
Iliac bifurcation
Uterine arteries/Vas deferens

A

Under
Over
Under

Note - Medial to gonadal vessels

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14
Q

Fluid compartments…
Total body water
ICF
ECF

A

60%
40% (includes RBC volume)
20% (includes plasma volume, interstitial fluid)

Note - All of ECF can be measured with Inulin/Mannitol, just plasma can be measured with Albumin

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15
Q

Nephrotic syndrome due to loss of which part of filtration barrier

A

Charge barrier

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16
Q

Renal Clearance (Cx) - Volume of plasma from which the substance is cleared per unit time

A

(Ux*V)/Px

Ux = Urine concentration of X
V = Urine flow rate
Px = Plasma concentration of X
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17
Q

Relationship of Cx and GFR with…
Net tubular resorption
Net tubular secretion
No tubular resorption/secretion

A

Cx < GFR
Cx > GFR
Cx = GFR (e.g. Inulin)

Note - Inulin is all filtered but not secreted, Cr is mostly filtered and somewhat secreted

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18
Q

Calculation of RBF (renal blood flow)

A

RPF/Plasma = RPF/(1-Hct)

RPF = Cpah (para-aminohippuric acid)

Note - PAH is filtered but mostly secreted (PCT) until saturation, and almost none is reabsorbed (conc. lowest in Bowman’s capsule)

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19
Q

Calculation of FF (filtration fraction)

A

GFR/RPF (normally 20%)

Note - RPF = Cpah; GFR = Ccr or Cinu

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20
Q

Effect of the following on GFR/RPF/FF…

Afferent arteriole constriction
Efferent arteriole constriction
Increased plasma protein concentration
Decreased plasma protein concentration
Ureter constriction
Dehydration
A
Decreased/Decreased/No change
Increased/Decreased/Increased
Decreased/No change/Decreased
Increased/No change/Increased
Decreased/No change/Decreased
Decreased/Decreased/Increased
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21
Q

Equation for net filtration pressure

A

(Pgc + Obs) - (Pbs + Ogc)

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22
Q

Equation for FENA

A

(Pcr x Una) / (Ucr x Pna)

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23
Q

Proximal convoluted tubule (PCT) reabsorption via Na cotransport (3) and diffusion (4)

Note - 65-80% of Na is reabsorbed in PCT in this way

Note - Isotonic resorption

A

Na cotransport:
Glucose (SGLT2/1)
Amino acids
Phosphate

Diffusion:
K
Cl-
H2O
Urea

Note - Glucose resorption is independent of insulin

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24
Q

Mechanism of NH3 secretion in proximal convoluted tubule (PCT)

A

Glutamine forms NH3 and a-ketoglutarate
a-ketoglutarate turns into bicarbonate
Bicarbonate reabsorbed from basal membrane
NH3 secreted from apical membrane

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25
Q

Mechanism of HCO3- reabsorption in proximal convoluted tubule (PCT)

A

Carbonic anhydrase converts H2CO3 to CO2 and H2O
CO2 resorbed
Carbonic anhydrase converts CO2 and H2O to H2CO3
H2CO3 gives off H+ and resorbed from basal side as HCO3-

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26
Q

Mechanism of ATII on PCT

A

Stimulates Na/H+ antiporter - increases Na, H2O, and HCO3- resorption

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27
Q

Thin descending loop of Henle responsible for…

A

Passive reabsorbs H2O via medullary hypertonicity (impermeable to Na) - Concentrates urine (hypertonic)

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28
Q

Thick ascending loop of Henle responsible for…

Note - 10-20% of Na reabsorbed here

A

Na, K, Cl resorption - NaK2Cl symporter

Mg, Ca resorption - ROMK pumps out K to generate positive potential that drives Mg/Ca into cells

Dilutes urine (impermeable to H2O; responsible for medullary hypertonicity) but individual concentrations of non-reabsorbed solutes remain the same as the amount of water remains constant

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29
Q

Early distal convoluted tubule (DCT) responsible for…

Note - 5-10% of Na reabsorbed here

A

Na, Cl resorption - NaCl symporter

Ca resorption

Note - Urine most dilute here (even during water deprivation when ADH levels are high)

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30
Q

PTH action on renal tubules

A

Inhibits PCT apical Na/PO4- symporter decreasing PO4 resorption and thus preventing formation of insoluble calcium phosphate salts

Increased TRPV5 Ca channel activity and calbindin expression levels in the distal convoluted tubule and CT

Stimulates DCT basolateral Ca/Na antiporter increasing Ca resorption

In PCT increases conversion of 25 Vit D to 1,25 Vit D (calcitriol) via 1a-hydroxylase

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31
Q

Collecting duct responsible for…

Note - 3-5% of Na reabsorbed here

A

Na resorption - ENAC

K secretion - ROMK
H+ secretion - H+ ATPase, H/K antiporter

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32
Q

Aldosterone action on principal cells and a-intercalated cells - via mineralocorticoid receptor

A

Principal cells:
Increased ENaC (Na resorption)
Increased basolateral Na/K ATPase
Increased K conductance, lumen negativity (K secretion)

a-intercalated cells:
Increased apical H+ ATPase activity (H secretion)

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33
Q

ADH action (2) on collecting duct in response to increased plasma osmolarity

A

Acts on V2 receptor to increase apical H2O channels in cortical collecting duct

Increases cell surface urea transporters in medullary collecting duct to increase medullary hypertonicity and thus water resorption

Note - Also acts on V1 receptor to directly increase BP

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34
Q
Polyuria
Polydipsia
Glycosuria
Phosphaturia
Hyperuricosuria
Bicarb wasting
Proteinuria/aminoaciduria
Metabolic acidosis
Hypophosphatemia rickets (children)
Osteomalacia (adults)
A

FANCONI SYNDROME

Congenital or acquired - Generalized reabsorptive defect in PCT leading to decreased resorption of amino acids, glucose, PO4, and HCO3-

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35
Q
Reabsorptive defect resulting in...
Increased Renin
Increased Aldosterone
Hypokalemia
Hypercalciuria
Metabolic alkalosis
A

BARTTER SYNDROME

Autosomal recessive defect in NaK2Cl cotransporter (thick ascending loop of Henle)

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36
Q
Reabsorptive defect resulting in...
Increased Renin
Increased Aldosterone
Hypokalemia
Hypocalciuria
Hypomagnesemia
Metabolic alkalosis
A

GITELMAN SYNDROME

Autosomal recessive defect in NaCl cotransporter (DCT)

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37
Q
Gain of function mutation resulting in...
Hypertension
Decreased Renin
Decreased Aldosterone
Hypokalemia
Metabolic alkalosis
A

LIDDLE SYNDROME

Autosomal dominant gain of function mutation in collecting duct ENaC channel

Treat with…
Amiloride (blocks ENaC)

Note - Acquired HTN with decreased Renin/Aldosterone may be SIADH

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38
Q
Enzyme deficiency resulting in...
Hypertension
Hypokalemia
Metabolic alkalosis
Decreased aldosterone
A

SYNDROME OF APPARENT MINERALOCORTICOID EXCESS

Deficiency of 11B-hydroxysteroid dehydrogenase which converts cortisol (acts on mineralocorticoid receptor) to cortisone (inactive on mineralocorticoid receptor)

Treat with…
Corticosteroids to reduce endogenous cortisol production

Note - Same deficiency can occur with excessive licorice consumption

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39
Q

Increased Renin secretion from JGA in response to…

Note - Converts Angiotensinogen (liver) to Angiotensin I
Note - Angiotensin converted to Angiotensin II in pulmonary veins

A
Decreased afferent arteriole BP
Decreased Na delivery to macula densa (early DCT)
Increased b1 (sympathetic) tone
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40
Q

Mechanism for effects of Angiotensin II…

Increased BP
Increases FF with low RBF
Increased Na reabsorption
Increased H2O reabsorption
Thirst
Contraction alkalosis

Note - Prevents reflex bradycardia by acting on baroreceptors

A
AT1 receptors on vascular smooth muscle
Constricts efferent arteriole
Aldosterone from adrenal glands
ADH from posterior pituitary
Stimulates hypothalamus
Increased PCT Na/H antiporter increasing HCO3 resorption

Note - Preferential constriction of efferent arteriole because locally produced Prostaglandins/NO at afferent arteriole counteract Angiotensin II action there

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41
Q

Action of ANP/BNP on GFR/Na reabsorption

A
Afferent arteriole dilation
Efferent arteriole constriction
Increased GFR and Na filtration
Decreased Renin release
No compensatory Na resorption in distal nephron
Diuresis
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42
Q

Action of ATII on GFR/Na reabsorption

A

Efferent arteriole constriction
Increased GFR and FF
Compensatory Na reabsorption in proximal/distal nephron
Preserves renal function (FF) while maintaining circulating volume

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43
Q

NSAIDs effect on kidney function

A

Block renal prostaglandin (vasodilator) production leading to afferent arteriole constriction and decreased GFR

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44
Q

Dopamine effect on kidney function

A

Secreted by PCT cells - dilates interlobular, afferent, and efferent arterioles increasing RBF with no change in GFR

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45
Q
Mechanism behind hyperkalemia caused by...
Hyperosmolarity
Cell death
Acidosis
Digitalis
B-blocker
Hyperglycemia/insulin deficiency
A
Water drags K out with it
Lysis releases intracellular K
Increased cellular H/K antiporter
Blocks Na/K ATPase
Blocks Na/K ATPase
Decreases Na/K ATPase activity

Note - Insulin given for hyperkalemia to increase Na/K ATPase

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46
Q
Muscle cramps
Spasms
Weakness
Arrhythmias
EKG shows U waves with flattened T waves
A

Hypokalemia

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47
Q

Muscle weakness
Arrhythmias
EKG shows wide QRS with peaked T wave

A

Hyperkalemia

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48
Q
Chvostek sign (twitching)
Trousseau sign (spasm)
Tetany
Seizures
EKG shows QT prolongation
A

Hypocalcemia

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49
Q
Stones
Bones
Groans (constipation, pancreatitis)
Thrones (urinary frequency)
Psychiatric overtones
A

Hypercalcemia

Note - Do not always see hypercalciuria

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50
Q

Tetany
EKG shows Torsades
Associated with hypokalemia

A

Hypomagnesemia

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51
Q
Decreased DTR
Lethargy
Hypotension
EKG shows bradycardia
Cardiac arrest
Associated with hypocalcemia
A

Hypermagnesemia

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52
Q

Renal stones
Metastatic calcifications
Hypocalcemia

A

Hyperphosphatemia

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53
Q

Increased blood pressure
Decreased Renin
Increased Aldosterone

A

Primary Hyperaldosteronism (Conn Syndrome)

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54
Q

Winter’s formula - predicted respiratory compensation for a metabolic acidosis

A

CO2 = 1.5 [HCO3] + 8

If measured CO2 is higher than calculated then suspect concomitant respiratory acidosis secondary to respiratory fatigue (e.g. DKA)

If measured CO2 is lower than calculated CO2 there is a concomitant respiratory alkalosis (ASA poisoning) - Note that in this case the pH will be normal (compensation does not result in a completely normal pH)

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55
Q

MUDPILES

A
Methanol
Uremia
DKA
Propylene glycol
INH or Iron
Lactic acidosis
Ethylene glycol
Salicylates (late)

Note - Early salicylate toxicity results in a respiratory alkalosis

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56
Q

Causes of normal anion gap (hyperchloremic) metabolic acidosis

(“HARDASS”)

Note - Normal anion gap is 8-12 and is calculated by [Na]-([Cl]+[HCO3])

A
Hyperalimentation
Addison's disease
Renal tubular acidosis
Diarrhea
Acetazolamide
Spironolactone
Saline infusion
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57
Q

Hyperchloremic metabolic acidosis
Hypokalemia
Calcium phosphate stones
Urine pH > 5.5

Caused by…
Ampho B
Analgesic nephropathy
Congenital anomalies

A

DISTAL RENAL TUBULAR ACIDOSIS (TYPE 1)

Defect in a-intercalated H secretion

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58
Q

Hyperchloremic metabolic acidosis
Hypokalemia
Hypophosphatemic rickets
Urine pH < 5.5

Caused by…
Fanconi syndrome
Carbonic anhydrase inhibitors (Acetazolamide)

A

PROXIMAL RENAL TUBULAR ACIDOSIS (TYPE 2)

Defect in PCT HCO3- resorption

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59
Q

Hyperchloremic metabolic acidosis
Hyperkalemia
Urine pH < 5.5

Caused by…
Hypoaldosteronism
Aldosterone resistance

A

HYPERKALEMIC RENAL TUBULAR ACIDOSIS (TYPE 4)

Hyperkalemia results in decreased NH3 production, and thus decreased H+ excretion in the form of NH4

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60
Q

Presence of casts indicate

A

Glomerular or tubular origin of disease

61
Q

Causes of RBC casts

A

Glomerulonephritis

Malignant HTN

62
Q

Causes of WBC casts

A

Tubulointerstitial inflammation
Pyelonephritis
Transplant rejection

63
Q

Causes of fatty casts (oval fat bodies) - “Maltese Cross” under polarized light

A

Nephrotic syndrome

64
Q

Causes of granular (muddy brown) casts

A

Acute tubular necrosis

65
Q

Causes of waxy casts

A

ESRD

CKD (GFR < 30)

66
Q

Causes of hyaline casts

A

Normal finding - concentrated urine sample

67
Q
GBM disruption resulting in...
Hypertension
Elevated Cr
Elevated BUN (Azotemia)
Oliguria
Hematuria
RBC casts
Proteinuria < 3.5 g/d
A

NEPHRITIC SYNDROME

68
Q
Podocyte/charge barrier disruption resulting in...
Edema
Hyperlipidemia
Hypoalbuminemia
Frothy urine
Fatty casts
Proteinuria > 3.5 g/d
Hypercoagulability (ATIII loss)
Increased infections (Ig loss)
A

NEPHROTIC SYNDROME

Note - Aldosterone increased due to decreased effective intravascular volume (interstitial edema)

69
Q

Causes of nephritis-nephrotic syndrome - extensive GBM damage also damages charge barrier

A

Diffuse proliferative glomerulonephritis

Membranoproliferative glomerulonephritis

70
Q
Histology associated with...
Previous skin or throat infection
Hypertension
Cola-colored urine
Peripheral and periorbital edema
Low complement (C3)
High ASO/anti DNAse B titer
Cryoglobulins
A

ACUTE POSTSTREPTOCOCCAL GLOMERULONEPHRITIS

LM - Hypercellular inflamed glomeruli
IF - “Starry sky” granular IC deposition
EM - Subepithelial humps

Note - Antibiotics are to prevent Rheumatic Fever and do not treat PSGN

Note - Similar finding may be seen in acute nephritic syndrome from IE

71
Q
Renal histology associated with...
Goodpasture syndrome
Granulomatosis with polyangiitis (Wegener)
Microscopic polyangiitis
PSGN in adults

ESRD within months

A

RAPIDLY PROGRESSIVE (CRESCENTIC) GLOMERULONEPHRITIS

LM - Crescent moon shape
IF - Negative or linear pattern

Note - Crescent composed of fibrin and macrophages

72
Q

Hematuria
Hemoptysis
Histology showing RPGN
Linear IF pattern

A

GOODPASTURE’S SYNDROME

Type II hypersensitivity IgG against GBM type IV collagen - Cross-reaction with alveolar membranes.

Treat with...
Emergent plasmapheresis (poor prognosis)

Note - Granulomatosis with polyangiitis and Microscopic polyangiitis are pauci-immune under IF

73
Q

Histology associated with Diffuse Proliferative Glomerulonephritis (DPGN)

Most common renal disease in lupus

A

DIFFUSE PROLIFERATIVE GLOMERULONEPHRITIS (DPGN)

LM - “Wire-looping” capillaries
IF - Granular IC deposition
EM - Subendothelial IC deposition

74
Q

Histology associated with…
Episodic gross hematuria
2-3 days after a respiratory/GI infections

Associated with Henoch-Schonlein purpura

A

IGA NEPHROPATHY (BERGER DISEASE)

proliferation of mesangial cells, widening of the mesangium, and the glomerular endothelial proliferation

LM - Hypercellular inflamed glomeruli
IF - IgA-based IC deposits in mesangium
EM - Mesangial IC deposition

75
Q

Retinopathy
Lens dislocation
Sensorineural deafness
Isolated hematuria

A

ALPORT SYNDROME

X-linked dominant mutation in Type IV collagen

Thinning and splitting of basement membrane - Basket weave on EM

76
Q

Histology associated with Membranoproliferative Glomerulonephritis (MPGN)

Type 1: Subendothelial deposits (HBV, HCV)

Type 2: Deposits within basement membrane - C3 nephritic factor stabilizes C3 convertase

A

MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS (MPGN)

LM - Capillary membrane thickening with tram-tracking
IF - Granular IC deposit

77
Q

Histology associated with a child with preceding immune activation (anaphylaxis, infection) and nephrotic syndrome

Associated with Hodgkin’s

Note - Selective albuminuria (no hypogammaglobulinemia)

A

MINIMAL CHANGE DISEASE

LM - Normal (may see lipid)
IF - Negative
EM - Foot process effacement

Excellent response to corticosteroids

78
Q

Histology associated with African American or Hispanic with nephrotic syndrome

Idiopathic or associated with…
HIV
SCD
Heroin

A

FOCAL SEGMENTAL GLOMERULONEPHRITIS

LM - Segmental hyalinosis
IF - Negative
EM - Foot process effacement

May progress to CKD

Note - If no response to steroids in minimal change disease then progression to FSGS

79
Q

Histology associated with caucasian adult with nephrotic syndrome

Caused by...
SLE
HCV/HBV
Solid tumors
Drugs
A

MEMBRANOUS NEPHROPATHY

LM - GBM thickening
IF - Granular subepithelial IC deposition
EM - “Spike and dome”

May progress to CKD

80
Q

Nephrotic syndrome with LM showing congo red stain “apple-green” birefringence under polarized light

A

AMYLOIDOSIS

81
Q

Histology of diabetic nephrotic syndrome

Caused by nonenzymatic glycosylation of GBM and efferent arterioles (increased GFR)

A

DIABETIC GLOMERULONEPHROPATHY

Mesangial expansion, glomerular basement membrane thickening, and glomerular sclerosis

LM - Hyaline arteriosclerosis progressing to eosinophilic nodular glomerulosclerosis (Kimmelstiel-Wilson lesions)

Note - Hyaline arteriosclerosis also seen in HTN

Note - Most common cause of End Stage Renal Disease

82
Q

Cause and treatment of kidney stone…
Radiopaque on XR
Radiopaque on CT
Envelope/Dumbbell shaped

A

CALCIUM OXALATE

Can result from...
Malabsorption (increased free Oxalate)
Ethylene glycol
Hypocitraturia
Vit C abuse

Treat with…
Thiazides
Citrate
Low-sodium diet

83
Q

Cause and treatment of kidney stone…
Radiopaque on XR
Radiopaque on CT
Wedge-shaped prism

A

CALCIUM PHOSPHATE

Caused by…
Increased urine pH

Treat with…
Thiazides

84
Q
Cause and treatment of kidney stone...
Radiopaque on XR
Radiopaque on CT
Coffin-lid
Staghorn calculi
A

STRUVITE/AMMONIUM MAGNESIUM PHOSPHATE

Caused by…
Urease+ infection (Proteus, Klebsiella, S. saprophyticus)

Treat with…
Antibiotics
Surgical removal of stone

85
Q
Cause and treatment of kidney stone...
Radiolucent on XR
Minimally visible on CT
Visible on US
Rhomboid/Rosettes
Develops slowly in acidic urine
A

URIC ACID

Caused by…
Gouty nephropathy
Increased cell turnover/tumor lysis syndrome (e.g. Leukemia, hemolysis)
Decreased urine pH (e.g. CD compensation for metabolic acidosis)

Treat with…
Urinary alkalinization
Allopurinol

86
Q
Cause and treatment of kidney stone...
Radiopaque staghorn calculi on xray
Sometimes visible on CT
Sodium cyanide nitroprusside + (deep purple color)
Hexagonal
A

CYSTINURIA

Caused by…
Decreased urine pH
Autosomal recessive defect of renal PCT transporters (SLC3A1 gene) preventing reabsorption of Cystine, Ornithine, Lysine, and Arginine (“COLA”)

Treat with…
Urinary alkalization and aggressive hydration is mainstay of therapy
Chelating agents (e.g. Penicillamine)
Low-sodium diet

87
Q
Obese, smoker with...
Painless hematuria
Flank pain
Palpable abdominal mass
Fever
Weight loss
Polycythemia
Paraneoplastic syndromes
Complex cyst on US

Grossly golden-yellow mass
Abundant clear cytoplasm with branching vascular tissue

A

RENAL CELL CARCINOMA

Originates from PCT cells - spreads hematogenously via IVC to Lung/Bone

Caused by…
Autosomal dominant mutation in tumor suppressor gene VHL on Chromosome 3 - von Hippel-Lindau (hemangioblastomas, pheochromocytomas, RCC)

Treat with…
Resection if localized
Aldesleukin (IL-2) - resistant to chemotherapy/radiation

88
Q

Painless hematuria
Flank pain
Abdominal mass

Grossly circumscribed mass with central scar
Histologically large eosinophilic cells without perinuclear clearing

A

RENAL ONCOCYTOMA

Benign epithelial cell tumor

Treat with…
Resection to rule out RCC

89
Q

Toddler with…
Large, palpable unilateral flank mass
Painless hematuria

A

WILMS TUMOR (NEPHROBLASTOMA)

Loss of function mutation mutation…
WT1 mutation - Aniridia, genitourinary malformation
WT2 mutation - Beckwith-Wiedemann with macroglossia, organomegaly, hemihypertrophy

90
Q

Painless hematuria
No casts

Associated with...
Smoking
Aniline dyes
Cyclophosphamide
Phenacetin
A

TRANSITIONAL CELL CARCINOMA OF BLADDER

Note - On imaging may appear to be a kidney mass if located near renal calyces/pelvis

91
Q
Painless hematuria without casts associated with...
Schistosoma
Chronic cystitis
Smoking
Chronic nephrolithiasis
A

SQUAMOUS CELL CARCINOMA OF BLADDER

92
Q

Treatment of stress incontinence (urethral hypermobility)

A

Kegels
Pessaries
Weight loss

93
Q

Treatment of urge incontinence (detrusor instability)

A

Kegels
Bladder training
Antimuscarinic (Oxybutynin)

94
Q

Treatment of overflow incontinence (detrusor underactivity)

Note - In DM patients lose automatic afferents (inability to sense full bladder) then autonomic efferents (inability to void)

A

Catheterization

a-blockers for BPH

95
Q

Sterile pyuria and negative urine cultures

A

URETHRITIS

Neisseria gonorrhoeae or Chlamydia trachomatis

96
Q

Neutrophil infiltration of renal cortex with relative sparing of glomeruli and vessels

A

ACUTE PYELONEPHRITIS

Note - On CT shows as striated parenchymal enhancement

97
Q

Causes of…
Coarse, asymmetric corticomedullary scarring
Blunted calyx
Eosinophilic tubular casts resembling thyroid tissue

A

CHRONIC PYELONEPHRITIS

VUR due to perpendicular ureter insertion
Chronic ureteral obstruction
Posterior urethral valves in males (bilateral; malformation of Wolffian ducts results in persistent membrane)

Note - If granulomatous tissue with foamy macrophages then xanthogranulomatous pyelonephritis

98
Q

Mechanism of hypocalcemia in renal osteodystrophy - subperiosteal thinning of bones

A

Tubular failure means no PO4 secretion or response to PTH (hyperphosphatemia), and decreased Ca resorption

Decreased calcitriol decreases intestinal Ca (and PO4) absorption

Hyperphosphatemia decreases serum Ca by causing tissue calcification

99
Q

Urine osmolality, Na, FENa, and serum BUN/Cr in prerenal azotemia

A

Urine osmolality > 500
Urine Na < 20
FENa < 1%
BUN/Cr > 20

Note - BUN is resorbed increasing ratio

100
Q
Nausea and anorexia
Platelet dysfunction
Pericarditis
Asterixis
Encephalopathy
A

UREMIA

Result of consistent azotemia

101
Q
Iatrogenic causes (5 Ps) of...
Fever
Rash
CVA tenderness
Hematuria
Sterile pyuria with eosinophilia
Elevated BUN (Azotemia)
A

ACUTE INTERSTITIAL NEPHRITIS (TUBULOINTERSTITIAL NEPHRITIS)

Pee (Diuretics)
Pain-free (NSAIDs)
Penicillins and Cephalosporins
PPIs
rifamPin

Note - Chronically presents as interstitial fibrosis and tubular atrophy (CKD)

102
Q
ARF caused by...
Ischemia/decreased RBF
Aminoglycosides
Radiocontrast
Ethylene glycol
Cisplatin
Foscarnet
Ampho B
Crush injury (myoglobinuria)
Hemoglobinuria
A

ACUTE TUBULAR NECROSIS

Initial oliguria with recovery polyuria

On histology loss of epithelial surface, vacuolar degeneration, and tubular dilation/ballooning - Preferentially affects straight proximal tubule and TALH as the medulla has low blood supply

103
Q
Abrupt gross hematuria and flank pain caused by...
Sickle cell disease or trait
Acute pyelonephritis
Renal stones within the urinary pelvis
Chronic analgesic use (NSAIDs)
Diabetes
A

RENAL PAPILLARY NECROSIS

Note - Coagulation necrosis with preserved tubule outline

104
Q
Adult with...
Hypertension
Bilateral flank pain
Hematuria
Urinary infections
Progressive renal failure

Associated with…
Berry aneurysms
Benign hepatic cysts
MVP

Note - Cysts are non-enhancing on CT

A

AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE

Mutation in PKD1 on Chromosome 16 and PKD2 is on chromosome 4

105
Q
Child with...
Potter sequence
Oliguria
Hypertension
Portal hypertension
Progressive renal failure

Associated with…
Congenital hepatic fibrosis

A

AUTOSOMAL RECESSIVE POLYCYSTIC KIDNEY DISEASE

Cystic dilation of collecting ducts

106
Q

Effect of hydronephrosis on GFR and FF

A

Buildup of backpressure into Bowman’s space causes reduced GFR which decreases FF

107
Q

Region of nephron responsible for majority of water resorption

A

PCT (even in dehydrated state)

Note - While PCT reabsorbs the most water, the late DCT and Collecting Duct are responsible for increased reabsorption in dehydration

108
Q

Which rib can penetrate the kidneys

A

12th

Note - 9th - 11th may damage the spleen or liver instead

109
Q
Fever
Neurologic symptoms
Renal failure
Anemia with schistocytes
Thrombocytopenia

Prolonged bleeding time
Normal PT and aPTT

A

THROMBOCYTOPENIC THROMBOTIC PURPURA (TTP)

Platelet activation in arterioles and capillaries, diffuse microvascular thrombosis, and microangiopathic hemolytic anemia

Note - Other thrombotic microangiopathy (HUS) does not commonly present with neurologic symptoms

110
Q

Excretion Rate equation

A

Filtration rate - Reabsorption rate
(GFR x P) - Reabsorption rate

Note - Secretion rate = Excretion rate - Filtered rate

111
Q
Mechanism of ARF caused by...
Sulfonamides
Methotrexate
IV Acyclovir
Triameterene
A

Precipitation and tubular obstruction

Note - Amorphous hyaline tubular obstruction might be Tamm-Horsfall proteins from Multiple Myeloma

112
Q

Mechanism of cystitis

Note - No fever or flank pain

A

Suppression of endogenous flora allows for colonization by pathogenic GNRs

Note - Anatomic abnormalities (e.g. VUR due to repeated cystitis) required for pyelo

113
Q

Straw-colored discharge from umbilicus with surrounding erythema

A

PATENT URACHUS/ALLANTOIC DUCT (URACHAL FISTULA)

Normally obliteration forms the median umbilical ligament (medial is distal umbilical artery) which connects the upper end of the bladder to the umbilicus

Note - Only patent distal urachus forms sinus (purulent discharge), while only patent proximal urachus forms urachal cyst

114
Q

Management of patient with microalbuminuria (< 300 mg/d)

Note - Not detected by normal urine dipstick

A

ACEi

Note - Initially before microalbuminuria glomerular hypertrophy causes hyperfiltration and elevated GFR

115
Q

Mechanism of hyperkalemia in DKA

A

Osmotic diuresis from ketones
High serum osmolarity increases Aldosterone
Aldosterone increases K loss

Increased serum osmolarity and H
Drives K out and H in

ECF hyperkalemia with ICF hypokalemia

116
Q

Effect on ECF, ICF, and Osmolarity by…

DI, Sweating, Dehydration
Hemorrhage, Diarrhea
Adrenal insufficiency
Hypertonic saline
Polydipsia, SIADH
A

Hyperosmotic volume contraction (ECF, ICF)
Isosmotic volume contraction (ECF)
Hypoosmotic ECF contraction and ICF expansion
Hyperosmotic ECF expansion and ICF contraction
Hypoosmotic ECF euvolemia and ICF expansion

117
Q

Newborn with…
Absence of normal pelvicalyceal system
Ureteral atresia

A

MULTICYSTIC KIDNEY DYSPLASIA

118
Q

Metabolic alkalosis with…
Low urine chloride
High urine chloride

A

Low:
Vomiting (saline-responsive)
Prior diuretic use (saline-responsive)

High:
Current diuretic use (saline-responsive)
Bartter/Gitelman (saline-unresponsive)
Hyperaldosteronism/Cushing’s (saline-unresponsive)

119
Q

Most common cause of death in patients with CKD

A

CAD

120
Q

Mechanism of decreased BUN/Cr in intrinsic ARF

A

Debris obstructs tubules and prevents resorption of H2O, Na, and Urea - Decreased urinary osmolality, increased urinary Na/FENA, and decreased BUN/Cr

121
Q

High cell turnover treated with chemotherapy
prevent with urine alkalinization and hydration
DCT and collecting ducts

A

tumor lysis syndrome causing Na, K, uric acid release into serum

uric acid ppt in acidic environment of DCT and collecting ducts

122
Q

desmopressin administration effects on someone with DI

A

increase ADH
increased V2 receptor mediated increase in water reabs
activates urea transporters to increase urea reabs and thus also water reabs gradient

123
Q

How is renal blood flow maintained at a near constant level as SBP increases

A

Via RBF autoregulation through reflexive constriction of the afferent arterioles in response to rising arterial pressure

rapid component: myogenic mechanism ( vascular smooth mm cells contract reflexively in response to rising wall tension caused by increasing perfusion pressure)

follow by

Slower component: Tubuloglomerular feedback (TGF is when SBP rises the GFR rises also which increases NaCl delivery to macula densa. This causes MD to release ATP and adenosine which diffuse via mesangial cells to the afferent arteriole where they stimulate contraction)

NOTE: efferent arteriole does not contribute to autoregulation of renal blood flow

124
Q

What is the renal threshold for glucose?

What happens to the threshold with chronic hyperglycemia?

A

180-200 mg/dl

plasma glucose levels above this range cause glucosuria (glucose reabsorption is carrier mediated. There is saturation of renal Na-glucose cotransport capacity)

Chronic hyperglycemia (diabetes) can raise the renal threshold

125
Q

Glucose reabsorption pathway

A
  • glucose is freely filtered across the glomerular filtration barrier and normally 100% is reabsorbed in the proximal tubule
  • proximal tubule reabsorption is via SGLT2 (low affinity, high capacity) and SGLT1 (high affinity, low capacity) Na-glucose cotransporters
  • the transport maximum (Tm) is reached when all glucose carriers in all nephrons are saturated
126
Q

how does GFR affect the transport maximum

A

Increase GFR, lowers the threshold
decrease GFR, increases the threshold

why?

increasing GFR increases the glucose filtered load and renal transport capacity is rapidly overwhelmed causing glucosuria even though plasma concentration was not changed

127
Q

this diuretic increases the risk of hypercalcemia

what is the mechanism

A

Thiazides inhibit NaCl reabsorption but also enhance reabsorption of calcium via TRPV5 Ca channel “ca sparing diuretics” at the distal convoluted tubule

128
Q

HTN with increased plasma renin activity but normal aldosterone/renin ratio. What is causing the increased plasma renin

A

increased sympathetic nervous system activity is a contributing factor in many cases of essential hypertension. This increases renin secretion via B1 adrenergic receptors which then causes angiotensin II and aldosterone to rise.

129
Q

When is acetazolamide contraindicated and why

A

patients with hypokalemia, hyponatremia, metabolic acidotic states (non-anion gap), and severe hepatic/renal dysfunction

it causes acidosis because it inhibits CA which is associated with rapid increase in urinary HCO3 excretion –> alkaline urine –> metabolic acidosis

130
Q

Generalized aminoaciduria and more specific abnormalities of tryptophan metabolism

A

Hartnup disease

131
Q

Septic patient that develops purpura and ecchymoses over the trunk and legs. Develops anuria (unable to pass urine) and causes uremic death What do you expect to see on renal autopsy?

labs show low platelets, low fibrinogen, increased PT and PTT (due to consumption of clotting factors), and presence of fibrin degradation products.

A

Diffuse Cortical Necrosis

This pt has disseminated intravascular coagulation as a complication of gram negative sepsis. Widespread clotting and fibrinolysis occurs producing thrombosis in many renal vessels and causing diminished vascular perfusion, leading to diffuse cortical necrosis

132
Q

Cortical scarring or benign nephrosclerosis is a chronic change seen with

A

diabetes mellitus type 2 and hypertension

there is hyaline arteriolosclerosis, glomerulosclerosis, tubular atrophy, and interstitial fibrosis

133
Q

Wedge shaped necrosis

A

focal and seen in acute renal infarct

due to trauma, thrombus, or embolus

134
Q

Mechanism causing sickle cell nephropathy

A

sickling crisis occurs within areas of high osmolarity, hypoxia, and slow blood flow rates of the vasa recta of the renal medulla (renal medulla has very high osmolarity and is a hypoxic environment)

sickling within the vasa recta can lead to patchy papillary necrosis, hematuria, proteinuria, and sometimes renal scarring

135
Q

complications associated with rapid correction of sodium:

1) high to low
2) low to high

A

1) high to low. The brain will blow
2) low to high. The pons will die (osmotic demyelination syndrome affecting the corticospinal and corticobulbar areas in basis pontis) and can cause “locked in” syndrome (vertical eye movements and blinking remain intact)

136
Q

Calculating amount of sodium reabsorbed by the renal tubule each day

A

Na reabsorbed=filtered-excreted

filtered= GFR x plasma sodium concentration

Excreted=urinary Na concentration x urinary flow

note: GFR=inulin or creatinine clearance

137
Q

Increased BUN and creatinine suggests

A

decreased GFR

138
Q

virulence factor of proteus mirabilis causing staghorn calculi

tx with fluoroquinolones

A

urease

raises the pH of the urine by splitting urea and forming ammonia

in the presence of ammonia, the magnesium ammonium phosphate(struvite) is produced and causes the formation fo the staghorn renal calculi

139
Q

Patient presents with damage to base of the skull and now have low specific gravity in his urine

A

Central diabetes insipidus

This type of fracture is associated with damaged hypothalamus or pituitary gland resulting in an inability to make vasopressin in the hypothalamus and store in the pituitary gland

140
Q

ACE inhibitors are often used in patients with early stage chronic kidney disease because it has reno-protective effects (decreased glomerular load and protein filtration). In what situation would you NOT give ACE inhibitors

A

atherosclerotic renal artery stenosis (renal artery bruit and history of atherosclerotic cardiac disease)

Means there is baseline renal hypoperfusion. Adding ACE inhibitor decreases GFR durthere and patient can develop acute kidney injury with elevated creatinine

avoid in settings of hypoperfusion (shock etc.)

141
Q

Patient has a severe flank pain radiating to the groin with intermittent hematuria. You do a high resolution CT

A

Ureteral obstruction from renal stone

CT will show stone or ureteral dilation

142
Q

How does hyperglycemia cause ADH resistance

A

1) hyperglycemia increases glucose delivery to the proximal tubule and exceeds its re-absorptive capacity, causing osmotic diuresis
2) high volume flow through the renal tubule washes out the corticopapillary osmotic gradient established by the loop of henle
3) This gradient is required for reabsorption of water from the collecting duct, so hyperglycemia can cause ADH resistance

143
Q

Poorly managed type 2 DM is most likely to produce a

A

hyperglycemic, hyperosmotic, non-ketotic state (HHNS)

hypernatremia
high chloride
hypokalemia

144
Q

common complication of urinary tract stones

A

acute pyelonephritis due to microtraumatic injuries to the mucosa and urine stasis facilitating bacterial proliferation

145
Q

why does increasing hematocrit cause a increase in renal blood flow

A

Hematocrit represents the percentage of blood volume occupied by RBCs

increases hct will decrease plasma volume and increase glomerular capillary oncotic pressure

this opposes filtration, so RBF increase to ensure the glomerular filtration rate is maintained at an optimal level

146
Q

Diuretics lead to aldosterone excess and hypokalemia by the following mechanisms:

A

1) diuretic induced volume depletion causing increase in angiotensin II and stimulation of potassium excretion
2) saline diuresis increases sodium delivery to the distal segments
3) saline diuresis also causes rapid fluid flow in the distal segments which prevents potassium reabsorption

147
Q

Renal complication of aortic dissection

A

bilateral renal infarction

dissection progresses distally to involve the major arteries arising from the aorta. This can cause bilateral renal artery occlusion, leading to renal hypoperfusion and infarction with flank pain and hematuria.

148
Q

Produces a positive dipstick test for blood without hemoglobin/rbc in microscopic examination

A

myoglobinuria

dipstick test detects peroxidase activity rather than specifically reacting to blood.

hydration and alkalinization of the urine is essential to prevent renal damage due to precipitation of myoglobin in the tubules, which causes obstruction and generation of reactive oxygen species

149
Q

HSN reaction for lupus nephritis and IF pattern

A

granular lumpy bumpy pattern due to random deposition of immune complexes into the glomerular basement membrane

type III HSN)