Renal, USMLE Flashcards
Embryologic kidney in week 4 AOG
Pronephros
Functions as interim kidney for first trimester
Mesonephros
Mesonephros also contributes to which organ system
Male genital system
Embryologic kidney which is PERMANENT and first appears at 5th week AOG
Metanephros
Derived from the caudal end of the metanephros
Ureteric bud
Ureteric bud gives rise to (4)
1) Ureters
2) Pelvises
3) Calyces
4) Collecting tubules
Ureteric bud is fully canalized at
10th week AOG
Aberrant interaction of ureteric bud with this tissue may result in several congenital malformations of the kidney
Metanephric mesenchyme
Portion of the ureter that is the last to canalize and is the most common site of obstruction (hydronephrosis in fetus)
Ureteropelvic junction
Syndrome of oligohydramnios > fetal compression > limb and facial deformities + pulmonary hypoplasia
Potter’s syndrome
Cause of death in Potter’s syndrome
Pulmonary hypoplasia
To which structure is the horeshoe kidney trapped
IMA
T/F: Horseshoe kidney is dysfunctional
F
Syndrome with which horseshoe kidney is associated
Turner syndrome
Condition due to abnormal interaction between ureteric bud and metanephric mesenchyme leading to a nonfunctional kidney
Multicystic dysplastic kidney
Most common form of multicystic dysplastic kidney
Unilateral (asymptomatic)
Which kidney is taken during living donor transplantation
Left
Why is the left kidney preferred in living donor transplantation
Longer renal vein
Parietal layer of glomerulus
Bowman’s capsule
Visceral layer of glomerulus
Podocytes
JG cells are found ___
At the wall of afferent arteriole
Macula densa is found
At the wall of the DCT
Ureters in relation to the uterine artery and ductus deferens (retroperitoneal)
Under
Vessels and ureter at the renal hilum
Vein, artery, ureter
The glomerular filtration barrier is composed of
1) Fenestrated capillary endothelium (size barrier)
2) Fused basement membrane with heparan sulfate (negative charge barrier)
3) Epithelial layer consisting of podocyte foot processes
Hydrostatic pressure in glomerular capillaries
60 mmHg
Effect of afferent arteriole constriction on RPF
Decreases RPF
Effect of efferent arteriole constriction on RPF
Decreases RPF
Effect of ureteral constriction on GFR
Decrease GFR
Transporter at the PCT responsible for complete reabsorption of glucose
Na-glucose cotransport (SGLT-2)
Increase vs Decrease: Effect of pregnancy on reabsorption of glucose and aa at the PCT
Decrease
Transporter responsible for reabsorption of aa from PCT
Na-dependent transporters
Deficiency of neutral amino acid transporter at the PCT
Hartnup’s disease
AA wasted in Hartnup’s disease
Tryptophan
Hartnup’s disease is associated with this nutrient deficiency state
Pellagra
Hormone acting on PCT to increase phosphate excretion by inhibiting Na/phosphate cotransport
PTH
Hormone acting on PCT to increase Na, H2O, and HCO3 reabsorption by stimulating Na/H exchanger
ATII
Transport mechanism by which water is reabsorbed from the thin descending LOH
Passive diffusion via medullary hypertonicity
Transport mechanism by which Mg and Ca are reabsorbed in the thick ascending LOH
Paracellular transport via (+) lumen potential generated by K backleak
Means by which PTH increases Calcium reabsorption in the kidneys
Increases activity of Na/Ca exchanger in the early DCT
How aldosterone exerts its mineralocorticoid effect on kidneys
Insertion of Na channel in luminal side of principal cell
How ADH exerts its effect on kidneys (receptor; action)
Acts at V2 receptor>insertion of aquaporin H2O channels on luminal side of principal cell
Effects of ATII
1) Vascular smooth muscle constriction via AT1 receptors
2) Efferent arteriole constriction
3) Increase absorption of Na, HCO3 and water from PCT
4) Production of aldosterone by adrenals
5) Stimulates thirst via hypothalamus
Tubuloglomerular feedback fails once SBP falls below
80mmHg
Stimulus for release of ANP
Increased atrial pressure
Shift K out of cells causing hyperkalemia (6)
DO Insulin LAb
1) Digitalis
2) Hyperosmolarity
3) Insulin deficiency
4) Lysis of cells
5) Acidosis
6) b-adrenergic antagonist
How insulin and b-adrenergic agonists cause K shift into cells
Stimulation of Na-K ATPase pump
ECG changes in hypokalemia
1) U waves
2) Flattened T waves
Shift K into cells causing hypokalemia (4)
1) Hypoosmolarity
2) Insulin
3) Alkalosis
4) b-adrenergic agonist
Hypocalcemia vs hypercalcemia: Tetany
Hypocalcemia
Hypocalcemia vs hypercalcemia: Seizures
Hypocalcemia
Symptoms of hypercalcemia (4)
1) Stones
2) Bones
3) Groans
4) Psychiatric overtones
Hypomagnesemia vs hypermagnesemia: Tetany
Hypomagnesemia
Hypomagnesemia vs hypermagnesemia: Decrease DTR
Hypomagnesemia
Hypomagnesemia vs hypermagnesemia: Bradycardia
Hypomagnesemia
Hypomagnesemia vs hypermagnesemia: Hypotension
Hypomagnesemia
Predicted respiratory compensation can be calculated using
Winter’s formula
Winter’s formula
PCO2 = 1.5 (HCO3) + 8 +/-2
Normal anion gap
8-12 mEq/L
Type 1 vs Type 2 RTA: Distal
Type 1
Type 1 vs Type 2 RTA: Defect in COLLECTING TUBULE’s ability to EXCRETE H+
Type 1
Type 1 vs Type 2 RTA: Defect in PCT’s ability to REABSORB HCO3
Type 2
Type 1 vs Type 2 RTA: Risk for calcium phosphate formation in kidney
Type 1
Type 1 vs Type 2 RTA: Rickets
Type 2
Type 1 vs Type 2 RTA: Urine pH >5.5
Type 1
Type 1 vs Type 2 RTA: Urine pH less than 5.5
Type 2
Pathophy of Type 4 RTA
Lack of collecting tubule response to aldosterone resulting in hyperkalemia
Hyperkalemia in Type 4 RTA results in impaired
Ammoniagenesis in PT, decreasing buffering capacity, decreasing urine pH
RBC casts are seen in (3)
1) GN
2) Ischemia
3) Malignant HTN
WBC casts are seen in
1) Tubulointerstitial inflamm
2) Acute pyelonephritis
3) Transplant rejection
Casts seen in ATN
Granular/muddy casts
Casts seen in advanced renal disease/chronic renal failure
Waxy casts
Glomerular disorders with hypercellular glomeruli
Proliferative
Glomerular disorders with thickening of GBM
Membranous
Nephritic syndromes (4)
1) APGN
2) RPGN
3) Berger’s IgA glomerulonephropathy
4) Alport syndrome
Both nephritic and nephrotic (2)
1) Diffuse proliferative GN
2) MPGN
In nephrotic syndrome, risk of infection is increased due to
Loss of Igs in urine
Segmental sclerosis and hyalinosis on LM
FSGS
Effacement of foot processes similar to MCD on EM
FSGS
Normal glomeruli on LM
MCD
Type of proteins lost in MCD
Albumin, not globulins
Congo red stain shows apple-green birefringence under polarized light
Amyloidosis
MPGN type with tram-track appearance
I
MPGN type with dense deposits
II
Type I MPGN is associated with what infections (2)
1) HBV
2) HCV
Type II MPGN is associated with what factor
C3 nephritic factor
Pathophysiology of DM nephropathy
Non-enzymatic glycosylation of GBM increasing permeability and thickening
Kimmelsteil-Wilson lesion can be seen on LM as
Eosinophilic nodular glomerulosclerosis
Lumpy-bumpy appearance of APGN is seen under
LM
Subepithelial humps of APGN is seen under
EM