Kidneyss Flashcards
Pronephros
week 4 then degenerates
Mesonephros
functions as interim kidney for 1st trimester; later contributes to male genital system
metanephros
permanent, first appears in 5th week of gestation; nephrogenesis continues though 32-36 weeks of gestation
ureteric bud
derived from the caudal end of the mesonephric duct; gives rise to the ureter, pelvices, calyces and collecting ducts, fully canalized by the 10th week
The kidneys are derivitives of?
mesoderm
the urethra is a derivitive of?
endoderm
Metanephric mesenchyme and utereric bud interact
the interaction induces differentiation and formation of glomerulus through to distal convoluted tubule, if the interaction goes wrong –> congenital malformations
Ureteropelvic junction
last to canalize –> most common site of obstruction (hydronephrosis) in fetus
Potter sequence
oligohydramnios –> compression of developing fetus –> limb deformities, facial anomalies (low sets ears and retrognathia), compression of chest (pulmonary hyperplasia leads to death)
causes include: ARPKD, posterior urethral valves and bilateral renal angenesis
Potter mnemonic
Pulmonary hypoplasia oligohydramnios twisted face twisted skin extremity defects renal failure in utero
horse shoe kidney
- inferior poles of both kidneys fuse
- as the ascend from pelvis during fetal development they get trapped under the IMA and remain low in the abdomen.
- kidney function is normal
- increased risk for ureteropelvic junction obstruction, hydronephrosis, renal stones and rarely renal cancer (wilms tumor)
assoc with TURNERS
multicystic dysplastic kidney
-due to abnormal interaction of the ureteruc bud and the metanephric mesenchyme —> cysts and connective tissue issues and non functioning kindey, can be seen on US
What do we use to estimate the GFR? why?
Creatinine
GFR = clearance of creatinine = UV/P
it is freely filtered, not reasorbed and not secreted, well just a tiny bit of secretion
What do we use to measure RPF?
PAH, to measure the ERPF = UV/P = clearance of PAH
RBF= RPF (1-hct)
PAH is both filtered and actively secreted in the proximal tubule, nearly all PAH entering the kidney is excreted
Hartnup disease
autosomal recessive disorder
- deficiency of neutral amino acid transporters in the PT.
- lose tryptophan, need tryptophan to make niacin with the help of B6
- pellagra (diarrhea, dementia and dermatitis)
Fanconi syndrome
- reabsorption defect in PT
- assoc with increase excretion of nearly all amino acids, glucose, HCO3 and PO4
- may result in metabolic acidosis
- type II renal acidosis (cant reabsorm HCO3/make)
Bartter sydrome
- reabsorption defect in thick ascending loop
- Na/K/2Cl transporter, autosomal recessive
- lead to hypokalemia and metabolic alkalosis with hypercalciura (Mg and Ca will not be reabsorbed)
Gitelman syndrome
- autosomal recessive
- DCT
- Na/Cl channel defect
- like a thiazide so more calcium resorbed
- hypokalemia and metabolic alkalosis
Liddle syndrome
Autosomal dominant
- increased Na reabsorption in distal and collecting tubules (increased activity of the Na channel)
- result in HTN
- hypokalemia
- metabolic alkalosis
- decrease aldosterone
treat: amiloride
Where is EPO made?
interstitial cells in the peritubular capillary bends
Where does vitamin D get activated?
Proximal tubule
What affect does prostaglandins have on the kidney?
paracrene sections vasodilate the AFFERENT arterioles leading to increase RBF.
-so if we have NSAIDS this will block the renal protective prostaglandin and lead to decreased GFR which may result in renal failure
Anion gap metabolic acidosis
MUDPILES
methanol uremia diabetic ketoacidosis propylene glycol iron tablets or INH lactic acidosis ethylene gylcol salicylate toxicity late
normal anion gap metabolic acidosis
HARD-ASS
Hyperalimentation addison disease renal tubular acidosis diarrhea acetazolamide spirinolactone saline infusion
Type 1 distal renal tubular acidosis urine ph>5.5 (but the serum is metabolic acidosis)
defect in a-intercalated cells to secrete H+ via the H+ATPase, thus no new HCO is generated. Since the lumen remains “-ve” more K is secreted –> hypokalemia
-increase urine pH has increase risk for calcium phosphate kindey stones
causes? amphoteriblecinB, analgesics, MM and obstructions
Type 2 proximal renal tubular acidosis urine pH<5.5
defect in PT HCO3 reabsorption results in increase secretion of HCO3 in urine and subsequent metabolic acidosis, hypokalemia.
- the urine is acidified by a intercalated cells in the CT
- increased risk for hypophosphatemic rickets
- causes fanconi syndome, chemical toxins (lead, aminogylcosides), CA inhibitors
Type IV renal tubular acidosis “hyperkalemic”
- hypoaldosteronism, aldosterone resistance, or K+ sparring diuretics, ENAC issue
- result in hyperkalemia
Calcium kidney stones
- decrease pH calcium phosphate
- increase pH calcium oxalate
- radioopaque
crystal: envelope of dumbbell shaped
- promoted by hypercalciuria
- oxalate cyrsals can be from ethelene glycol, vitamin C or crohns disease
treat: citrate, thiazides
Ammonium magnesium phosphate (stuuvite) stone
- increased pH precipitation
- radioopaque
- coffin lid shaped cystals
- caused by infection with urease + bugs (proteus, staph, kleb) –> alkalization
- can form staghorn caliculi
treat: erradication of infection and surgical removal of stone
Uric acid stones
- decreased pH precipitates
- RADIOLUCENT but can be seen on ultrasound, CT
assoc. with hyperuricemia, leukemia treatments
treat: alkaline the urine
Cystine stones (cystine is cysteine -S-cysteine)
- cystinuria, Autosomal recessive, defect in PT amino acid transporter (cysteine, ornithine, arginine)
- sodium nitroprusside test
treat: alkalinize the urine and hydration
Wilms tumor (nephroblastoma)
-age 2-4 common child renal malignancy
-loss of function mutations
-WT1, WT2 on chromosome 11
-may be a part of Beckwith-Wiedemann syndome:
wilms tumor, aniridia, genitourinary malformations and mental retardation
common associations with transitional cell carcinoma
phenacetin (acetominophen is one)
smoking
aniline dyes
cyclophasohamide (hemmoragic cystitis)
Acute pyelonephritis histo
- affect cortex with relative sparing of glomeruili/vessels
- neutrophillic infiltration of renal interstitium
Chronic pyelonephritis histo
-course, asymmetric corticomedullary scarring, blunted calyx
tubules can contain eosinophilic casts resembling thyroid tissue (thyroidization of kidney)
What drugs are associated with drug-induced interstitial nephritis (tubulointerstitial nephritis)
nephritis 1-2 weeks after drug
diuretics, penicillin derivatives, sulfonamides, rifampic
-NSAIDS can occur months later!
What are the three stages of Acute tubular necrosis
- inciting event
- maintenance phase- oliguric; lasts 1-3 weeks; risk of hyperkalemia, metabolic acidosis
- recovery phase-polyuric; BUN and serum creatinine fall; risk of hypokalemia
What can cause ATN?
Ischemia secondary to
-decrease RBF
Nephrotoxicity secondary
-aminoglycosides, radio contrast, lead, cisplatin, crush injury/myglobinuria, hemoglobinuria
PT is especially susceptible
Renal papillary necrosis
sloughing of renal papillae -gross hematuria and proteinura -may be triggered by a recent infection of immune stimulus assoc with: DM Acute pylonephritis chronic phenacetin use sickle cell and trait
What is the mutation in ADPKD?
autosomal dominant
- mutation in PKD1 chromosome 16 85%
- mutation on PKD2 chromosome 4 15%
assoc with berry aneurisms, mitral valve prolapse, benign hepatic cysts
complex cysts
complex cysts including those that are septated, enhanced, or have solid components as seen on CT, require follow up or removal due to risk of renal cell carcinoma
