Posterior Pituitary Hormones Flashcards
What is Diabetes Insipidus (DI)?
Having too little or ineffective ADH
What is Central DI?
When the CNS is affected and produces too little ADH
What organ is affected in central DI?
Posterior pituitary gland
What are two signs/symptoms of central DI?
Polyuria and Polydipsia
How can we treat central DI?
Synthetic ADH
What is nephrogenic DI?
When the kidneys are affected and do not recognize/respond to ADH
What can cause nephrogenic DI?
Disease or drugs
What is gestational DI?
When the placenta releases an enzyme that destroys the mother’s ADH
What is Syndrome of Inappropriate ADH (SIADH)?
When there is too much ADH which causes CNS swelling (euvolemic hyponatremia) and can alter CNS function
What is euvolemic hyponatremia?
Swelling of the CNS organs (cerebral in particular) due to fluid shifts that can cause altered function of the CNS
What can caused SIADH?
Diabetes Mellitus
Head trauma or meningitis
Medications
Bronchogenic tumors
What does hyponatremia mean?
Decreased sodium levels
How do bronchogenic tumors cause SIADH?
Bronchogenic tumors are typically made up of neuroendocrine cells which release hormones. Since the cancerous cells in this case are neuroendocrine cells they produce ADH in excess (without proper regulation) which causes SIADH
How can SIADH cause euvolemic hyponatremia?
Too much ADH means increased blood volume
ADH signals the kidneys to retain/reuptake water back into circulation BUT NOT SODIUM
The result is very low osmolarity/osmolality
The high water content in the body stimulates the kidneys to get rid of the excess water
This causes total body water (TBW) to return to normal but hyponatremia worsens
What class of hormone is oxytocin?
Hydrophilic peptide hormone
