(gastro) disorders of appetite Flashcards
define polydipsia
excessive thirst or excess drinking
define adipsia
inappropriate lack of thirst |(even in severe dehydration)
= with consequent failure to drink in order to correct hyperosmolality
define anorexia
lack or loss of appetite for food
define obesity
abnormal or excessive fat accumulation that presents a risk to health
what types of polydipsic disorders are there?
primary polydipsia = psychogenic and dipsogenic polydipsia
secondary polydipsia
what types of adipsic disorders are there?
four types (A-D)
what are the types of primary polydipsia?
psychogenic = seen in patients with psychiatric disorders
dipsogenic = seen in patients w hypothalamic conditions
differentiate between primary and secondary polydipsia?
primary = a condition where there is excess consumption of fluids leading to polyuria with diluted urine and, ultimately, hyponatremia
secondary = drinking excess water due to disease-induced or medication-induced thirst prompted by an actual need for water
which is the more common type of polydipsia?
secondary polydipsia = more common
(diseases can disrupt the steps of osmoregulation or alter ADH secretion)
what are the causes of secondary polydipsia?
pic
which chronic medical conditions can cause secondary polydipsia?
diabetes insipidus & mellitus
kidney failure
Conn’s syndrome
Addison’s disease
sickle cell anaemia
which medications can cause secondary polydipsia?
diuretics
laxatives
antidepressants
(top two result in dehydration)
which forms of dehydration lead to secondary polydipsia?
acute illness
sweating
fevers
vomiting
diarrhoea
underhydration
what are the most common causes of secondary polydipsia?
diabetes and kidney failure
differentiate between diabetes insipidus and diabetes mellitus
diabete insipidus
- relatively uncommon
- related to pituitary problems
- impaired ADH production
diabetes mellitus
- very common
- related to high blood sugar
compare the treatment for diabetes mellitus to diabetes insipidus
diabetes mellitus = treat the high blood sugar
diabetes insipidus = treat with desmopressin
what causes the large volume of urine in diabetes mellitus?
high sugar levels
= filtered in the kidney and the hypertonic tubular fluid draws more water into the renal filtrate
= forms a higher volume of sugary urine (diuresis)
(higher blood sugar causes diuresis)
why does diabetes mellitus cause polydipsia?
high blood sugar induces diuresis
= higher urine output, more dehydrated and thirstier so you drink more
why does diabetes insipidus cause polydipsia?
pituitary problems (cranial diabetes insipidus, not nephrogenic)
= lack of ADH
= kidney cannot concentrate the urine
= larger amounts of dilute urine are produced
what are the common symptoms of diabetes?
what is Conn’s syndrome alternatively known as?
primary aldosteronism
what is Addison’s disease alternatively known as?
hypoadrenocorticism
how does Conn’s syndrome lead to polydipisia?
dunno whoops
how does Addison’s disease lead to polydipsia?
adrenocortical insufficiency
= less aldosterone produced
= less H2O retention due to less Na+ and Cl- reabsorption
= larger volumes of more dilute urine produced
= increased water loss from the body
= dehydration
= triggers polydipsia
