Flashcards in Proximal Tubular Dysfunctions and Disorders of Water Balance - Gosmanova Deck (24):
Which segments of the PT secrete organic compounds?
S2 and S3
What are the types of transport mechanisms present in the PT?
What substances are reabsorbed via Na cotransport in the PT?
What substances are reabsorbed via Na antiport in the PT?
What does angiotensin II promote in the PT?
Na / H antiporter (luminal)
HCO3 / Na cotransport (basolateral)
What can cause a defect in glucose reabsorption?
Mutation of SGLT2 glucose transporter (Hereditary Renal Glucosuria)
What can cause a defect in amino acid reabsorption?
Mutation of brush border transporter for cystine, ornithine, lysine, and arginine
What can cause a defect in phosphate reabsorption?
Mutation in PHEX gene (X-linked hypophosphatemia - most common)
Mutation in FGF-23 (Hypophosphatemic rickets)
Increased FGF-23 production (Oncogenic hypophosphatemic osteomalacia)
What is Fanconi syndrome?
Collection of symptoms (different underlying causes)
Hyperchloremic metabolic acidosis
What is an inherited cause of Fanconi syndrome?
What are acquired causes of Fanconi syndrome?
Dysproteinemias (Multiple myeloma)
Acute tubular necrosis
What is the normal osmotic threshold for ADH and thirst?
What is osmolar clearance?
Amount of water needed to excrete solutes at the concentration of solutes in plasma
What is the most common electrolyte disorder?
What is hyperosmolar hyponatremia?
Dilutional hyponatremia due to presense of osmotically active substances (glucose, mannitol, glycine)
What is psudohyponatremia?
This occurs with increased solid phase of plasma and is an artifact of Na assays
What is true hyponatremia and what is the underlying mechanism?
Impaired urinary dilution mechanisms
What are causes of hypovolemic hyponatremia?
Third spacing (Pancreatitis, bowel obstruction, burns)
What causes euvolemic hyponatremia?
What causes hypervolemic hyponatremia?
Acute / Chronic kidney failure
How can you differentiate psychogenic polydipsia and SIADH?
Polydipsia - Low
SIADH - high
What is the main defense against hypernatremia?
What is polyuria?
> 3 L urine / day