Pituitary gland Flashcards
Name hormones of pituitary gland
Anterior pituitary: Adenohypophysis (80%)
1. ACTH
2. TSH
3. FSH
4. LH
5. GH
6. Prolactin
Posterior pituitary: Neurohypophysis
1. Oxytocin
2. ADH
3. Stored oxytocin
4. Stored diuretic
Hormones released by hypothalamus
- TRH
- GRH
- GHRH (Growth hormone)
- CRH (Corticotropin)
- Dopamine
- Somatostatin
- Vasopressin
- Oxytocin
Melatonin is released by which gland
Pineal gland
Melanocyte stimulating hormone is released by
Intermediate pituitary gland
Causes of Hyper-prolatinaemia
BPP* MAA MOO (most drugs inhibit dopamine)
B- Breast feeding
P- Pregnancy
*P- Pituitary gland adenoma
Drugs
M- Marijuana
A- Antidepressants (SSRI)
A- Antipsychotics
M- Metaclopromide (antiemetic)
O- Oestrogen
O- Opiates
Symptoms of Hyper-prolatinaemia
Females:
Galactorrhoea
Amenorrhoea
Osteopenia
Osteoporosis
Males:
Gynecomastia
Hypogonadism
Erectile dysfunction
Decreased libido
Mechanism of amenorrhoea due to Hyper-prolatinaemia
Prolactin inhibits:
1. GnRH … Decreased LH and FSH
2. LH surge … no ovulation
Effect of dopamine on prolactin production
Dopamine has inhibitory effect on prolactin production
Drugs decreasing dopamine … Increase prolactin
1. Antipsychotics
2. Metoclopramide
3. Phenothiazine
4. Alpha methyl dopa
5. Reserpine
6. Tricyclic antidepressants
7. Narcotics
8. Cocaine
9. Risperidone
Thyroid effect on prolactin
HYPOthyroid … increased TRH production … HYPERprolactineamia
Check TSH levels always
Manage a case with complaints of galactorrhoea and amenorrhoea > 2 months
- Check prolactin levels <100ng/ml is normal
- Check TSH, pregnancy, lactation, drugs causing prolactin increase
- MRI - ?Pituitary adenoma (mc - micro in women, macro in male)
Initial Rx is medication in pituitary adenoma
4. Cabergoline»_space; Bromocriptine (increase dopamine)
5. Surgery if neurological symptoms occur
6. Radiotherapy if drugs and Sx not effective
When is surgery required in pituitary adenoma. Is it more effective for micro/macro adenoma
When neurological symptoms occur
More effective for micro adenomas
Macro tend to recur
C/F of Acromegaly
- Increase in size of hands, feet, jaw, lips, nose
- Sleep apnoea
- CVS - hypertension, Hypertonic cardiomyopathy, arrhythmias, atherosclerosis
- Impaired GTT, Diabetes in 20%
Diagnosis of Acromegaly
- Initial -
IGH measurement (Insulin like growth hormone) - Confirmatory -
100mg glucose given and GH levels
checked. If GH not decreased, confirm
acromegaly - MRI - Macroadenoma
Management of Acromegaly
- Primary - Surgery
- Octreotide > Lanriotide (Somatostatin analogues)
- Cabergoline > Bromocriptine (Dopamine agonists)
*Drugs if Sx not enough
Pegvisomant
GH analogue
Antagonizes endogenic GH by blocking peripheral GH
By binding to its receptor in the liver
Second-line agent.
Diabetes insipidus is dysfunction of which hormone
Decreased ADH/Vasopressin of posterior pituitary
In DI, what happens to urine osmolarity, serum sodium
Diuresis (Urine osm - decreases)
Hypernatraemia
Types of DI
Central - ADH decreased production
Nephrogenic - ADH cannot work on kidneys (ADH levels increased)
Causes of nephrogenic DI
- Idiopathic
- *Lithium, colchicine, demeclocycline
- Pyelonephritis
- Hypercalcemia, Hypokalemia
- Sjogrens
- Sarcoidosis
- Amyloidosis
- Sickle cell disease
Diagnosis of DI
Water deprivation test
Urine volume remains high in ID
Central ID - Low ADH
Nephrogenic ID - High ADH
Mx of DI
Hormonal replacement
Vasopressin sc
Desmopressin sc, intranasally, oral
ADH releasing
1. Chlorpropamide
2. Chlorfibrate
3. Carbamazepine
Nephrogenic - HCTZ, Amiodarone, Chlorthalidone
SIADH water and sodium levels?
Euvolemic Hyponatremia
Inc ADH … Water retention … Heart releases ANP, BNP
… Inc GFR … Water and Na lost
Hence euvolemic but hyponatremia
Drugs causing SIADH
1*Carbamazepine
2. Chlorpropamide
3. Clofibrate
4. Cyclophosphamide
5. Vincristine
6. Vinblastin
Causes of SIADH other than drugs
- Small cell CA
- Pancreatic CA
- Lung - TB, Abscess, Pneumonia
- CVA
- Encephalitis
- Head injury
