Pituitary-
Ant pit Physiology- Pituitary hormones ( ACTH, TSH, FSH, LH, GH and Prolactin ) these trophic hormones. They act on specific target organs to release target hormones.
Adrenal - cortisol Thyroid- T4 and T3 Gonads- estradiol / testosterone.
Pathology- Some rules to remember
1) in primary pathology of pituitary trophic hormone should not be looked first as they will be in normal reference range. 2) so look for target hormone level to make the diagnosis. 3) prolactin and ACTH are only two hormones which can be suppressed by medicine. 4) so medical Rx should be tried first in case of prolactinoma and adenoma secreting ACTH.
1- Hyperprolactinemia - >; 10
Clinical- Macroadenoma -pressure symptoms-headache, visual field defects(patient hit by a car coming from side which he could not see). Macro and micro adenoma both- galactorrhea(uni or bilateral) amenorrhea, loss of libido and impotence(is like amenorrhea in female)in male.
D/D -
1) rule out pregnancy. 2) Drugs affecting dopamine level. ( dopamine secreted from hypothalamus and inhibit prolactin; So drugs inhibiting dopamine increase prolactin like antipsychotic and antiemetic.) 3) primary hypothyroidism - high TRH increases prolactin. 4) Prolactinoma - prolactin secreting adenoma. 5) non functional adenoma compressing the stalk of pituitary so decrease dopamine to reach pituitary. So leads to high prolactin. So never make diagnosis prolactinoma Just seeing high prolactin. Rule out other more common causes first.
So what is next step - urine beta hcG
Next - TSH If normal. Then think of prolactinoma.
Next - MRI brain.
Now what if it is non functional adenoma compressing stalk. How to differentiate?
Prolactin will still be high because of block of dopamine pathway in stalk. But other ant pituitary hormone will also be low. So MRI can tell whether tumor is from pituitary or stalk. Now you have diagnosis.
What to do next? Other tests or treatment?
Go for treatment. But if asked about any other test then do visual field charting if not done before.
Treatment- what is best initial Rx ?
Always Dopamine agonist. Bromocritine. Other newer drugs like (CPR) cabergolin, premipixol, ropenirol.
Why not surgery? Two reasons 1) recurrence is very high after surgery.2) only two pituitary hormone can be blocked by medical Rx; Prolectin and ACTH. None other.
So now patient is on bromocryptine. 1) Patient is responding. First symptoms to go is clinical problems like amenorrhea, impotence and visual field defects. MRI should be done to check the decrease in size at 5-6 week after Rx.
2) if patient is not responding to Rx .then think of surgery. If after surgery patient has recurrence then put him on bromocryptine.
3) if patient reproductive age female is responding. What else to do? Contraception.
4) patient is old then?
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