Renal Flashcards
Where does ADH act?
V2 receptors in the thick ascending loop of henle, DCT, cortical collecting duct and medullary collecting duct
What happens when ADH is released?
Release of aquaporin 2 which binds to the luminal surface leading to water resorption into the circulation.
What is Tolvaptan?
V2 receptor blocker, stopping the action of ADH - used in polycystic KD
What are the lab findings in SIADH?
Low serum Na, Low plasma osmolality, high usine osmolality (>100), high urine Na
Where / how do loop diuretics work?
Blockade of Na-K-2Cl transporter in the loop of henle.
What is the effect of loop diuretics on calcium?
Also block calcium reabsorption so there is increased calcium in the urine - risk of stones
Where and how do thiazides act?
Blockade of the Na-Cl cotransporter in distal convoluted tubule. (works synergistically with loop diurectic BC DCT comes later)
What is the effect of Thiazides on Calcium?
Increase Ca resorption in the DCT and PCT so can be good for hypercalciuria + recurrent stones
What is gittleman syndrome?
Defects the same as thizide - Defect in DCT in Na/Cl transporter
Low K+, metabolic alkalosis
What is Barters syndrome?
B for BABY
Defect in loop of Henle Na/K/2Cl transporter ( defect the same as therapy with loop). Hypokalaemia, metabolic alkalosis. Also low Ca, Mg
What is the effect od aldosterone in the kidney?
Increases the number of Na/K channels in principal cells both on the tubular and basolateral surfaces.
Promoting Na absorption and K+ excretion
What is type 1 renal tubular acidosis?
Defect in the distal hydrogen ion excretion
Low K
Metabolic acidosis
Hypercalciuria, hypocitraturia, nephrolithiasis
What is type 2 RTA?
Proximal type - reduced capacity to rectain filtered bicarbonate ( normal subjects do not have bicarb in urine). Bicarb excreted in urine
Low K
What is type 4 RTA?
Secondary to hypoaldosteronaemia - also have hyperkalaemia
how to treat RTA 1?
Bicarb tablets to bind retained hydrogen ions
What is used to treat PKD in high risk patients?
Tolvaptan is a vasopressin V2-receptor (V2R) antagonist with proven beneficial results in ADPKD
What are general treatment principles for PKD?
- Lower BP with ACEi/ARB - 110/70
- Drink >3L water / day to maintain hypoosmolar urine / supress ADH
What PKD patients are prescribed tolvaptan?
Age >18
eGFR >25, but declining either 5 in one year or 2.5 per year/5 years
Limited data for use in >55y/o
4 years of use delays dialysis by 1 year
What are contraindicators to Tolvaptan?
Liver disease ( 3xULN), use of CYP3a4 inhibitors, hypernatraemia at baseline, inability to respond to thirst, diuretic use
How do patients with PKD present clinically?
can present with hypertension, hematuria, proteinuria, or kidney function impairment. Flank pain, due to kidney hemorrhage, obstructive calculi, or urinary tract infection, is the most common symptom reported by patient
What neurologic condition is associated with PKD?
Intracranial aneurysms, hypertensive haemorrhage
What are the feautres of minimal change GN?
Loss of podocytes on EM, pure nephrotic syndrome, normal light microscopy,
Treatment for minimal change GN?
Steroids, if no / minimal response to steroids rituximab or cyclophosphamide
What is serum soluble urokinate type plasminogen activator receptor ( suPAR) a marker of?
Disease activity in FSGS
Renal disease occurs when sufficient circulating suPAR activates podocytes B3 integrin causing foot process effacement, proteinuria and FSGC like GN
