Week 28 Diabetes Insipidus PDF

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Week 28 Diabetes Insipidus Anatomy & Physiology...

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Week 28 Diabetes Insipidus Inability to resorb water from the distal part of the nephron 2 conditions known as: •central diabetes insipidus •nephrogenic diabetes insipidus symptoms: •polyuria (lots urine) •polydipsia (drink lots) •low urine osmolarity (dilute urine) central diabetes insipidus •failure of formation or secretion of ADH (hypothalamus/pituitary) –tumours, trauma, inflammation nephrogenic diabetes insipidus •failure of action of ADH on kidney –congenital or new condition after infection or obstruction –lack ADH receptor or can’t form/translocate aquaporins; interference in aquaporin translocation occurs if intracellular signalling pathways (cAMP etc) affected eg. hypokalaemia, hypercalcaemia, lithium therapy The Renin - Angiotensin -Aldosterone System • Multiple effects on the cardiovascular system and kidney to preserve blood pressure • Reduces sodium excretion Increases peripheral arterial resistance Aldosterone targets the DCT and collecting ducts:- sodium channels opened more sodium transporters synthesized more potassium channels synthesized •Aldosterone induces expression and activity of SGK (serum & glucocorticoid regulated kinase) in the collecting duct. •which causes translocation of ENaC to membrane and expression •driving force is Na+/K+ATPase (activity also increased by aldosterone...