Causes of High Prolactin Level and How It May Affect You

What is high prolactin level?

When the prolactin level in the blood increases and the production of this hormone is in excess, this condition is called hyperprolactinemia. This hormone is responsible for milk production in women. However, elevated prolactin levels can cause problems in men and women.

Prolactin is a peptide hormone. It is responsible for breast enlargement in women during pregnancy and milk production. This hormone is a protein made from amino acid chains. If the prolactin level increases, then it gives rise to the condition called hyperprolactinemia.

The normal values of prolactin in the blood are:

• Men: Up to 18 ng/mL

• Women: Up to 29 ng/mL

• Pregnant Women: 10-209 ng/mL

Causes of High Prolactin Levels

The following conditions can cause an elevated prolactin level:

• Compressed pituitary stalk
• Low dopamine levels
• Prolactinoma (a tumor or adenoma of the pituitary gland)

High levels of prolactin are produced by the tumor. Usually, these tumors are benign and can be large or small. They are also noncancerous. If the tumors are large, then they may cause vision problems, headache, and in some cases, both of the symptoms. This condition is more common in women than in men and rarely occurs in children. Prolactin levels may also increase due to certain prescription medicines. The following medications may cause the prolactin level to increase:

• Medications for high blood pressure such as calcium channel blockers
• Medications for depression such as SSRI antidepressants and tricyclic antidepressants
• Medications for gastroesophageal reflux disease and heartburn
• Medications for vomiting and nausea
• Opiates that are derived from opium
• Medications for mental health disorders such as antipsychotics, which include haloperidol and risperidone

Drugs can cause an elevated prolactin level, especially those drugs that can inhibit the function of dopamine, cause a low production of dopamine, or deplete the stores of dopamine in the brain. These drugs include antipsychotics, drugs used to treat hypertension, and tranquilizers.

Other causes of elevated prolactin levels are hypothyroidism and polycystic ovary syndrome or PCOS. They might cause the prolactin level to slightly rise. Many other diseases can also cause a rise in prolactin levels. The symptoms of menopause may also cause high prolactin levels.

Other causes of high prolactin levels:

• An underactive thyroid gland or hypothyroidism, wherein not enough thyroid hormone is produced by the thyroid gland.
• Chest wall injuries or any other condition that can affect the chest wall.
• Any disease that affects the pituitary gland such as tumors
• Pituitary radiation treatment for tumors 

Sometimes, the cause of high prolactin levels cannot be determined. When an individual has an elevated prolactin level in the blood, doctors may order for an MRI scan of the brain to rule out pituitary tumors.

Below are other conditions that can also cause high prolactin levels:

• Breast stimulation
• Orgasm
• Stress
• Pregnancy
• Kidney failure
• Liver disease
• Lesions in the spinal cord
• Other medical conditions such as sarcoidosis, metastases, hemochromatosis, Cushing syndrome, hypothalamic disease, tuberculosis, head trauma, empty sella syndrome, and meningioma
• Radiation therapy for the skull
• An eating disorder called anorexia
• A tight bra leading to chest irritation or scars

Some other causes are:

• Nursing - A lot of prolactin is produced when women breastfeed. More prolactin is produced when there is increased breast stimulation. 

• Stress - Elevated prolactin levels may occur due to a lot of mental stress. The reason is that when the body is under stress, the hypothalamus is also affected. This directly affects the production of prolactin.

• Acromegaly - Acromegaly is a growth hormone disorder. In this condition, the neurotransmitter called dopamine is suppressed, so the levels of prolactin rise.

• Epileptic Seizures - Prolactin levels drastically rise after epileptic seizures. This is also a kind of diagnostic method through which the doctors are able to distinguish between epileptic and nonepileptic seizures. Thus, the prolactin level rises.

In the differential for female patients presenting with amenorrhea, oligomenorrhea, infertility, galactorrhea, or in the differential for male patients presenting with sexual dysfunction, the diagnosis of an elevated prolactin level should be included. 

Many normal physiologic conditions are included in it. Unless the patient is postmenopausal or had a hysterectomy, pregnancy should always be excluded. In addition to the postpartum period, an elevated prolactin level is a normal finding. Some other conditions that should be excluded are excessive exercise, a nonfasting sample, renal failure, surgery, trauma, cirrhosis, and a history of chest wall surgery.

This condition is also developed by postictal patients. Usually, the condition develops 1-2 hours after their seizure. A prolactin level of less than 500 ug/mL is produced by such condition.

A similar prolactin level can be produced when an individual has hypothyroidism, which is a disorder that can be easily treated. Many common conditions can cause an elevated prolactin level. A drug history should be obtained when the prolactin level is less than 100 ug/mL. Certain conditions can be caused by the following drugs:

• Dopamine receptor antagonists
• Dopamine-depleting agents
• Some other medications such as H2 blockers, cocaine, verapamil, isoniazid, tricyclic antidepressants

If a tumor is suspected without an obvious cause, then there may be a need to perform an MRI. Although the etiology of an elevated prolactin level cannot be determined by a single test, if the prolactin level is more than 250 ug/mL then most likely, it is prolactinoma and there is less likelihood of having a level of less than 100 ug/mL. Although a significant elevation of prolactin can occur due to medications, a diagnosis of a macroprolactinoma is having levels of 500 ug/mL or greater.

The evaluating physician must decide whether there is a need for a radiographic study if the level of prolactin is greater than 100 ng/mL or less than 250. In many cases, imaging is performed earlier if MRI scanners are available.

Another potential cause of an elevated prolactin level is macroprolactinemia. In the bloodstream, the majority of prolactin is monomeric. However, there are also dimeric and polymeric forms. Without typical symptoms, the serum production increases in macroprolactinemia. Polymerization can happen by serum prolactin molecules and then they bind to immunoglobulin G.

The prolactin of this form is unable to bind to the receptors of prolactin. Thus, no systemic response is exhibited. This condition should be considered in patients with elevated prolactin levels and without any symptoms. The patient can be saved from inconvenience and cost by the discovery of this condition. For any special collection requirement, consult the laboratory personnel. Women with this condition can conceive and no treatment is required.

It does not automatically mean that you have a problem if the value falls within the normal range. When you were doing a blood test that time, if you had eaten, or were under stress, then the levels of prolactin can be higher. Also, depending on which laboratory you get the diagnosis, the results will differ since what is considered as normal range may be different elsewhere.

How do elevated levels of prolactin affect us?

For men and women, the symptoms of an elevated prolactin level are not the same. The different symptoms exhibited are as follows:

Symptoms in Women

• Irregular Menstruation - A decrease in menstrual flow is experienced by those who are suffering from this condition. Sometimes, menstruation may stop altogether. This condition is known as amenorrhea. In some cases, menstruation may become irregular due to hypoestrogenism. In this condition, the estrogen production is decreased due to elevated prolactin levels.

• Infertility - In some women, elevated prolactin levels cause infertility. This may be due to hypoestrogenism, which happens due to a high prolactin level. 

• Lactation - In some women who are neither pregnant nor nursing, they may produce breast milk due to elevated prolactin levels. Some may even have pain in their breasts. This may happen when for the first time the prolactin level is high.

• Decreased Libido - Another symptom is a decreased interest in sex. Some may even experience pain during coitus since vaginal secretions are reduced making the vagina dry.

Symptoms in Men

• Erectile Dysfunction - Erectile dysfunction or impotence is one of the symptoms in men. During sexual intercourse, the body is unable to maintain an erection.

• Infertility - Due to a low sperm count, infertility may occur.

• Breast Enlargement - This condition is known as gynecomastia. In this condition, male breasts are enlarged.

• Eye Problems - Some men may show symptoms of an elevated prolactin level, but they do not consult the doctor. They only get to know their condition when they get headaches and eye problems due to pituitary pressure on the optic chiasma. 

• Decreased Libido - Men also experience this symptom. Usually, this symptom is unnoticed. In people suffering from elevated prolactin levels, osteoporosis may occur due to hypoestrogenism and hypoandrogenism.

How to diagnose high prolactin levels?

A preliminary diagnosis of an elevated prolactin level can be done by observing the patient's symptoms. The doctor may recommend a test to assess the prolactin level of the patient. The doctor will test for the level of thyroid hormones if the prolactin level is quite high.

The doctor will ask the patient a few questions before prescribing medications to find out if there are medications that can affect the prolactin level. An X-ray is performed if a tumor is suspected. With the help of an X-ray, the tumor can be detected if it is large enough.

If the tumor caused by an elevated level of prolactin is large, then it can be detected through an MRI. It can detect a very small tumor and can also determine its size. Moreover, through an MRI, the growth of a tumor that causes the elevated prolactin level can be monitored.

Treatment

• Medications - By using medications, which contain compounds that activate dopamine receptors or dopamine agonists, this condition can be treated. Some of these medications include bromocriptine, cabergoline, and lisuride.

• Surgery - Surgery can be done if the tumor has progressed quite far. Surgery is mainly done to remove the tumor. If in treating this condition the medicines prove to be ineffective, then surgery can be done. If the vision of the person is severely affected due to the tumor, then surgery can also be done.

The condition can also be treated using synthetic thyroid hormones. Generally, the prolactin level should return back to normal. Other types of medications can be explored if high prolactin levels are caused by certain prescribed medications.