Disorders of the Appetite Flashcards
What is the word for excessive thirst?
polydipsia
What is the word for lack of thirst?
adipsia
What is the word for lack of appetite?
anorexia
What is the name of the hormone responsible for the regulation of Osmolality?
ADH/ arginine vasopressin
How does ADH work and where is it stored?
acts on receptors in collecting duct resulting in more aquaporin 2 on apical side
*collecting duct is normally impermeable- aquaporin channels make it permeable
stored within neurones in hypothalamus
If the plasma concentration of ADH is low will there be a water diuresis or an anti-diuresis?
water diuresis
Which regions are sensory osmoreceptors found in the hypothalamus (2 answers)?
organum vasculosum and the subfornical organ of the lamina terminalis
What is the difference between primary and secondary polydipsia?
primary is a problem in the brain e.g., no ADH
secondary is everywhere else
What are causes of primary polydipsia?
Pituitary tumour (hypopituitarism in posterior)/ AVP deficiency
Hypothalamus tumour
Osmoreceptor problem in brain
Cancer and stoke can affect release of AVP
Psychogenic e.g., schizophrenia (and other mental disorders) leads to excessive thirst, also can lead to secondary because the medication given can induce polydipsia
Describe secondary polydipsia.
Medical issues that disrupt any step in osmoregulation or alter ADH can cause secondary polydipsia.
What are some conditions that lead to secondary polydipsia?
- AVP resistance
- Medication
- Diabetes mellitus
- Chronic kidney disease
- Heart failure
- Diuretics (meds)
- Laxatives (meds)
What should you use if you are allergic to ACE inhibitors?
aldosteron receptor blockers
Mr Smith is 48 year old gentleman who works as an accountant. He recently noticed a wound on his shin that does not seem to be healing very well and he has also lost some weight. He has to interrupt his meetings frequently as he must go to the toilet to pass urine. His relationship with his wife at home is not what it used to be.
What do you think is wrong with Mr Smith?
Diabetes
Poor wound healing because of high blood sugar content they are promoting risk of infection
- Also poor blood supply to wounds
- Immune dysfunction due to hyperglycaemia
Diabetics lose weight because they are not absorbing sugar
Mrs Smith is an 84 year old lady who retired following multiple coronary angioplasties. She used to enjoy a walk in the park but now gets severe shortness of breath walking around her house. The Doctor has prescribed some medication for this. She is a little forgetful and finds it difficult to answer her granddaughters text messages. Her daughter has noticed that lately, despite drinking a large amount of water, her lips are always dry.
Why does Mrs Smith drink so much water and why are her lips dry?
Diuretics (usually given after heart surgeries)
How is obesity classififed?
