ICL 1.1: Tubular Disorders Flashcards
which tubular disorders are associated with the PCT?
- pRTA
- Fanconi
- Dent/Lowe
which tubular disorders are associated with the loop of henle?
- Bartter
2. familial hypomagnesemia with hypercalcuiuria
which tubular disorders are associated with the DCT?
- Gitelman
2. Gordon
which tubular disorders are associated with the collecting duct?
- Liddle
- PHA1
- NDI
- hereditary SIADH
- dRTA
what is fractional excretion?
(clearance of X/GFR)*100
clearance = UV/P
GFR is approximately equal to creatine clearance
what are the types of renal tubular acidosis?
type I = distal RTA
type II = proximal RTA
type IV = collecting duct
type III is combination of proximal and distal RTA and isn’t common
what is the job of the PCT when it comes to HCO3?
reabsorption of HCO3 via both active and paracellular transport
HCO3 goes into the interstitum via Na/HCO3 NBC1 cotransporter on the basolateral surface of PCT
what are the causes of primary isolated proximal RTA?
- hereditary (AD and AR forms)
2. sporadic
what are the causes of secondary isolated proximal RTA?
- Fanconi syndrome (multiple myeloma)
- drugs and toxins
- other conditions = Alport syndrome, amyloidosis, vitamin D deficiency, hyperparathyroidism, chronic hypocapnia, etc.
what is primary distal RTA?
- persistent
- classic form is sporadic or inherited as AD or AR
- has neurosensorial deafness (AR)
- bicarbonate wasting
what is the formula for urine AG?
UAG = Na + K - Cl
urinate anion gap is usually negative and is the major measure of NH4+
distal tubular renal acidosis if the UGA isn’t negative
what is Fanconi syndrome?
- proximal RTA invovlement
- glycosuria
- AA in urine
- phosphaturia
- low molecular weight proteinuria
- hypercalcuria
which conditions are associated with inherited Fanconi syndrome?
- cystinosis (AR)
- idiopathic
- Wilson’s disease
- hereditary fructose intolerance
- mitochondrial disease
what is dent disease?
Recessive X-linked defect in intracellular Cl transporter or in intracellular phosphatase enzyme
Nephrocalcinosis, nephrolisthiasis
what are some of the causes of acquired Fanconi syndrome?
- malignancy
- MM
- renal transplant
- nephrotic syndrome
- heavy metals
- medications = adenovirus, tenor, ahminoglycosides, cisplatin, valproate, tetracyclines
what is Bartter syndrome?
failure of Na Cl reabsorption in TAL due to defect in Na/K/2Cl cotransporter on luminal surface
loss of K+ via ROMK transporter
failure to concentrate the urine
hypotension and volume depletion may be present which leads to RAAS being activated
Bartter syndrome is similar to loop diuretic excess
what is Gitelman syndrome?
prevalence 1/40,000 and it’s diagnosed adolescence early adulthood
milder renal salt losses than Barter but Ca+2 loss won’t be that bad so it’s kind of like a thiazide overdose
you’ll have hypokalemia, metabolic alkalosis, hypomagnesemia
what is Gordon syndrome??
overactivity of NCC transporter in the DCT so you have a lot of Na and Cl reabsorption
so you’ll have HTN, metabolic acidosis, hypercalcuria, hyperkalemia
it’s sensitive to treatment with thiazide diuretics
what is Liddle syndrome?
mutation in ENaC that prevents its removal so it’s always on and Na is always being reabsorbed
people get metabolic alkalosis, hypokalemia and HTN
response to amiloride which blocks ENaC channels but NOT spironolactone
what is diabetes insipidus
central or nephrotgenic problems with ADH
nephrogenic DI has elevated ADH but the body isn’t responding
patients will have polyuria, polydipsia, nocturne, and urinary concentration is low
