High Prolactin Level ( Hyperprolactinemia)
Prolactin is one of several hormones, produced by the pituitary gland.
Prolactin secretion has a circadian rhythm: its level is highest during sleep at night and lowest around noon time.
Secretion of prolactin takes place in pulses, usually separated by about 90 minutes.
The main normal function of prolactin is during and after pregnancy. During pregnancy, It is produced in large amounts and is responsible for lactation after delivery.
Prolactin also causes lack of mense during pregnancy and for a number of months after delivery.
Symptoms of High Prolactin Level.
A high blood level of prolactin is called Hyperprolactinemia.
In women, a high prolactin level can cause menstrual irregularities, including cessation of menses, infertlity, discharge from breasts, decreased libido, and mood swings. If untreated, patients with high prolactin can also develop a decrease in the bone density and osteopenia or osteoporosis.
In men, the main symptom of hyperprolactinemia is a decrease in libido and erectile dysfunction.
In women and men, symptoms may also include those of the underlying cause of high prolactin level. For example, a pituitary tumor, in addition to raising your prolactin level may also cause headaches and visual problems.
Causes of High Prolactin Level
When someone is found to have a high prolactin level on a blood testing, usually physicians ( especially in the USA ) have a knee jerk reflex of ordering MRI sacn of the brain to rukle out pituitary tumor. Because they don't want to miss the diagnosis of a tumor for fear of litigation. This mind set often results in unnecessary MRI scans of the brain. This kind of practice may actually miss the real cause of elevated prolactin level such as drugs.
Here is a list of the common causes of a high prolactin level in the blood:
Hypothyroidism (underactive thyroid)
Drugs such as estrogen( oral contraceptives), metoclopramide ( brand name, Reglan ),domperidone, verapamil, methydopa, reserpine, cimetidine (as intravenous), narcotics and many anti-depressants and anti-psychotic drugs.
Chest wall pain
Spinal cord lesions
Other Pituitary/hypothalamic diseases such as acromegaly, Cushing's disease, sarcoidosis, metastases, tuberculosis,hemochromatosis, meningioma, head trauma, empty sella.
Radiation to skull
Common pitfalls in Blood Drawing for Prolactin:
On your annual examination, your physician gives you a thorough breast examination and then nurse comes in and draws your blood for prolactin. Breast stimulation from the breast examination can result in mild elevation in prolactin level.
Having sexual intercourse before the blood draw can also cause a mild elevation in your prolactin level.
Stress causes a mild elevation in prolactin level.
Slight elevation in prolactin level often takes place in the afternoon.
Therefore, prolactin level should be drawn in a fasting state.
Normal prolactin blood level is less than 20 ng/ml.
A mild elevation such 20-40 ng/ml may be due to a peak of a pulse or due to stress or breast stimulation. Therefore, in these cases of slight elevation in prolactin, three levels of prolactin should drawn on three separate days to confirm the diagnosis of a true elevation in prolactin level due to a pathological reason.
Once a firm diagnosis of high prolactin level has been made, next step is to find out its cause.
A step-by-step approach is important, with special emphaisis to rule out pregnancy, drugs and hypothyroidism. Then an MRI of the pituitary area should be obtained in appropriate cases to evaluate for the possible pituitary pathology.
You should see an endocrinologist for the proper diagnostic work-up of the high prolactin level.
Treatment of High Prolactin Level
Treatment obviously depend upon the cause.
For high prolactin level due to a pituitary tumor, three treament modalities are available:
Drugs are the treatment of choice In most cases, . These drugs are: Bromocriptine ( brand name, Parlodel) and Cabergoline ( brand name, Dostinex).
Side-effects of these drugs include:
Nausea, dizziness, weakness, low blood pressure upon standing, nasal congestion, abdominal pain, and constipation.Rarely hallucinations can also occur.
Surgery itself is often non-curative and often needs to be followed by drugs.
Radiation takes years to be effective and can cause serious irreversible damage tothe pituitary gland and other strucures in the brain.
Obviously, you need to discuss pros and cons each treament modality with your physician.
This article was written by Sarfraz Zaidi, MD, FACE. Dr. Zaidi specializes in Diabetes, Endocrinology and Metabolism.
Dr. Zaidi is a former assistant Clinical Professor of Medicine at UCLA and Director of the Jamila Diabetes and Endocrine Medical Center in Thousand Oaks, California.
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