Traumatic Brain Injury




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Editors
Jens Bollerslev, MD
Anne Klibanski, MD
Nicholas Tritos, MD



Additional Resources
Mayo Clinic
National Institutes of Health

What is traumatic brain injury?

Traumatic brain injury, also called TBI, is sudden damage to the brain. It happens when the head hits something violently or is hit again and again, or when an object goes through the skull and into the brain. Causes include:

  • Falls
  • Motor vehicle accidents
  • Violence, such as gunshot wounds, child abuse, or beatings
  • Injuries from sports or during combat (such as explosions)

What is the endocrine system?

Your endocrine system includes glands and organs that make and release hormones, which are chemicals that help your body work properly. They control growth, sexual development, how your body uses and stores energy (metabolism), how it deals with illness, and more. You need proper types and amounts of hormones to feel well.

How can TBI affect the endocrine system?

Two important parts of the endocrine system—the pituitary gland and the hypothalamus—are located in or near the brain. The hypothalamus and the pituitary gland are like orchestra conductors. Their job is to tell other endocrine glands throughout the body to make the hormones that affect and protect every aspect of your health. TBI can injure them, causing hormone problems. A person with TBI may have hormone problems right away or months or even years after the injury.

What hormone problems can happen with TBI?

Someone with TBI can have one or more problems, depending on the injury. Problems that often occur soon after TBI include

  • Adrenal insufficiency: when the adrenal glands don’t make enough hormones; results in fatigue, weight loss, low blood pressure, vomiting, and dehydration. Adrenal insufficiency can be life-threatening if not treated.
  • Diabetes insipidus: when the pituitary doesn't make enough ADH; results in frequent urination and extreme thirst.
  • Hyponatremia: when certain hormone problems upset the balance of salt and water in the body; can result in headache, fatigue, vomiting, confusion, and convulsions.

Problems that may occur later and their symptoms include

  • Hypothyroidism (not enough thyroid hormone): fatigue, constipation, weight gain, irregular menstrual periods, cold intolerance
  • Hypogonadism (not enough sex hormones): in women, a stop in menstruation and loss of body hair; in men, sexual dysfunction, breast enlargement, loss of body hair, and muscle loss
  • Growth hormone deficiency (not enough growth hormone): in adults, increased fat, loss of muscle and bone, and decreased energy; in kids, growth problems
  • Hyperprolactinemia (too much prolactin): irregular menstrual periods, nipple discharge, and erectile dysfunction

How are TBI-related hormone problems diagnosed?

Your doctor will ask about your medical history and do a physical exam. Blood tests are done to check your hormone levels. You may have an MRI to look at the pituitary gland and check for tumors, cysts, or other problems.

What is the treatment for TBI-related hormone problems?

Often, you will take hormones to replace what's missing (called hormone therapy). Other problems require various treatments, such as treating hyponatremia by cutting back on fluid intake, getting an IV (through a vein) salt solution, and taking medicines.

What's the long-term outlook for TBI-related hormone problems?

The outlook depends on the type of problem and how severe it is. Some endocrine problems may be temporary and disappear within a year after TBI. Hormone therapy is a very important part of treatment. It can restore your health, relieve symptoms, and improve your quality of life. In some cases, it can save your life.

Questions to ask your doctor

  • What specific hormones are affected by my injury and how can they be replaced?
  • Will treatment relieve my symptoms?
  • How long will I need treatment?
  • What are the risks and benefits of the treatment?
  • How will I know whether my hormone function is returning on its own?
  • How often will I need to be checked?
  • Will the dose of hormones change as I get older?