Pituitary infarction

Endocrine glands release hormones (chemical messengers) into the bloodstream to be transported to various organs and tissues throughout the body. For instance, the pancreas secretes insulin, which allows the body to regulate levels of sugar in the blood. The thyroid gets instructions from the pituitary to secrete hormones which determine the pace of chemical activity in the body (the more hormone in the bloodstream, the faster the chemical activity; the less hormone, the slower the activity).

Also known as: Pituitary apoplexy

Definition

Pituitary infarction is the death of an area of tissue in the pituitary gland, a small gland joined to the hypothalamus (part of the brain). The pituitary produces many of the hormones that control essential body processes.

Causes, incidence, and risk factors

Pituitary infarction is most commonly caused by bleeding due to a noncancerous tumor of the pituitary. When this bleeding occurs in a woman during or right after childbirth, it is called Sheehan syndrome.

Risk factors for pituitary infarction include:

Bleeding disorders
Diabetes
Head injury
Radiation to the pituitary gland
Use of a breathing machine

However, in most cases, the cause is not clear.

Symptoms

Pituitary infarction usually has a short period of symptoms (acute), but it can be life-threatening.

Symptoms usually include:

Severe headache
Paralysis of the eye muscles, causing double vision (ophthalmoplegia)
Low blood pressure, nausea, and vomiting from acute adrenal insufficiency

Less commonly, pituitary dysfunction may appear more slowly. In Sheehan syndrome, for example, the first symptom may be a failure to produce milk caused by a lack of the hormone prolactin.

Over time, problems with other pituitary hormones may develop, causing symptoms of the following conditions:

Growth hormone deficiency
- Fatigue
- Increased fat in the abdomen
- Lack of energy
Hypoadrenalism (if not already present or treated)
- Inability to deal with physical stress
- Light-headedness
- Nausea
Hypogonadism
- Absent periods (amenorrhea) in women
- Sexual dysfunction and loss of muscle mass in men
Hypothyroidism
- Cold intolerance
- Constipation
- Depressed mood
- Dry skin
- Fatigue
- Hair or skin changes
- Hoarseness
- Menstrual changes
- Mental slowing
- Weight gain

When the posterior pituitary is involved (rare), symptoms may include:

Failure of the uterus to contract as needed to give birth to a baby (in women)
Failure to produce breast milk (in women)
Uncontrolled urination

Signs and tests

Signs of acute pituitary infarction may include:

Low blood pressure
Visual field defects

Signs of chronic pituitary insufficiency include:

Growth hormone deficiency
- Loss of muscle mass
- Problems with fat metabolism (dyslipidemia)
Hypoadrenalism
- Low blood pressure
- Poor response to stress and infection
Hypothyroidism
- Delayed reflexes

Tests may include:

Eye exams
MRI or CT scan

Blood tests will be done to check levels of:

ACTH
Cortisol
FSH
Growth hormone
LH
Prolactin
TSH
Somatomedin C (IGF-1)

Treatment

Treatment for acute infarction may require surgery to relieve pressure on the pituitary and improve vision symptoms. Severe cases need emergency surgery.

Immediate treatment with adrenal replacement hormones (glucocorticoids) is essential. Other hormones will be replaced, including:

Sex hormones (estrogen/testosterone)
Thyroid hormone

Evidence is also growing for the need to replace growth hormone.

Expectations (prognosis)

Acute pituitary infarction can be life-threatening. The outlook is good for people who have chronic deficiency that is diagnosed and treated.

Complications

Complications of untreated pituitary infarction can include:

Adrenal crisis
Vision loss

If other missing hormones are not replaced, you may develop problems related to hypothyroidism and hypogonadism.

Calling your health care provider

Call your health care provider if you have any symptoms of chronic pituitary insufficiency.

Go to the emergency room or call the local emergency number (such as 911) if you have symptoms of acute pituitary infarction, including:

Eye weakness
Headache
Low blood pressure (which can cause fainting)
Nausea
Vomiting

Be especially concerned if you develop these symptoms and you have already been diagnosed with a pituitary tumor.

References

Melmed S, Kleinberg D. Pituitary masses and tumors. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 9.

Review date:: November 12, 2011
Reviewed by:: Nancy J. Rennert, MD, Chief of Endocrinology & Diabetes, Norwalk Hospital, Associate Clinical Professor of Medicine, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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