Disorders of appetite Flashcards
(50 cards)
What is polydipsia?
Excessive sensation of thirst or abnormal behaviour of increased drinking
What is adipsia?
Adipsia is a decreased sensation or absent feeling of thirst – involves an increase in urine osmolarity which stimulates the secretion of ADH from the posterior pituitary gland to increase water reabsorption.
• Increased water retention
• Sensation of thirst decreased
What is anorexia?
Lack or loss of appetite for food
What is obesity?
Abnormal or excessive fat accumulation that presents a risk to health.
What is secondary polydipsia?
The most common pathological manifestation of secondary polydipsia that arises due to a disruption in osmoregulation or alterations in ADH release.
What happens to urine osmolarity when there is elevated plasma ADH?
Hyperosmolar and small volume of urine is excreted (anti-diuresis effect).
What type of effect is exhibited by low plasma ADH?
Hyposmolar and large volume of urine is excreted (water diuresis effect).
What are the chronic causes of secondary polydipsia?
Diabetes insipidus & mellitus Kidney failure Conn’s Syndrome- hypokalaemia Addison’s disease – low BP. Sickle cell anaemia
What types of medications can induce secondary polydipsia?
Diuretics
Laxatives
Antidepressants
What are the main symptoms of diabetes mellitus?
• Osmotic symptoms: Polyuria, nocturia and polydipsia
• Blurred vision
• Fatigue
• Paraesthesia – extremities as a result of neuropathy in those with prolonged undiagnosed diabetes
• Infections: Candidal, UTI, and skin infections.
• Unintentional weight loss
• Acanthosis nigricans
Impaired clotting
How does Conn’s syndrome lead to polydipsia?
• Conn’s syndrome: Hypokalaemia can induce tubular damage and renal tubule ADH resistance – manifesting as polydipsia.
What are the main causes of primary polydipsia?
- Mental illness – psychogenic polydipsia (or acquired)
- Schizophrenia
- Mood disorders- depression and anxiety
- Anorexia
- Drug use – Diuretics (For congestive heart failure or fluid overload).
- Brain injuries and organic brain damage.
What problems are associated with polydipsia?
- Kidney and bone damage
- Headache
- Nausea
- Cramps
- Slow reflexes
- Slurred speech
- Low energy
- Confusion
- Seizures
What are four main types of polydipsia?
Type A-D
What is Type A polydipsia?
Increased level in which solutes pass through cell membranes for vasopressin release and the activation of thirst
Change in AVP osmotic threshold - lower
What is type B polydipsia?
• Occurs when vasopressin responses are at a decreased level in the presence of osmotic stimuli – there is reduced secretion of AVP due to osmoreceptor deficits.
Which type of polydipsia is concerned with cranial diabetes inspidus?
Type C
What is Type C polydipsia?
• A complete elimination of osmoreceptors – no AVP release. This is found in patients with cranial diabetes insipidus.
What are the examples of eating disorders?
A mental disorder defined by abnormal eating habits includes:
• Binge eating disorder
• Anorexia nervosa
• Bulimia nervosa
• Pica
• Rumination syndrome
• Avoidant/restrictive food intake disorder
What are the signs of anorexia nervosa?
- Low BMI
- Continuous weight loss
- Amenorrhoea
- Halitosis
- Mood swings
- Dry hair, skin and hair thinning.
Which hormone is deficient in anorexia nervosa?
Serotonin
Which amino acid is the precursor to serotonin?
Tryptophan
Why does serotonin decrease in anorexia nervosa?
Tryptophan is the precursor molecule of serotonin – available in diet. Therefore, excessive diet restriction and malnutrition decreases the store of serotonin, as the precursor is less available to the rate liming enzyme of 5-HT synthesis.
Mild anorexia is defined as a BMI of?
• Mild >17
