Hypothalamic obesity is unusual weight gain and obesity that can happen after damage to the hypothalamus. The hypothalamus is a small but important part of the brain that helps control hunger, satiety (the feeling of being full), and energy balance (how your body uses and stores calories).

People living with hypothalamic obesity may feel hungry much of the time, even if they’ve just eaten. They may also have a difficult time losing weight, even with changes to eating habits and physical activity.

This article will discuss six facts about hypothalamic obesity, common causes, and potential treatment options.

1. Hypothalamic Obesity Comes From Damage to the Hypothalamus

Hypothalamic obesity is a type of obesity caused by damage to the hypothalamus, which is located at the base of your brain. To understand hypothalamic obesity, it helps to know what the hypothalamus does.

The main role of the hypothalamus is to maintain a stable and balanced state in your body, called homeostasis (your body’s “steady state,” like keeping temperature, fluids, and energy levels in a healthy range). The hypothalamus gathers information about your body from hormones (chemical messengers) and signals from the nervous system (your body’s communication network). After processing these signals, the hypothalamus responds by influencing the nervous system and the endocrine (hormone) system to help keep many body functions in balance.

The hypothalamus helps regulate several body functions, including:

• Hunger
• Satiety
• Thirst
• Metabolism (how your body uses and stores energy)
• Body temperature
• Mood
• Sleep

Damage or injury to the hypothalamus can lead to weight gain and other health problems by disrupting the brain’s ability to maintain this careful balance — including signals that affect hunger, fullness, and how the body uses energy.

2. Hypothalamic Obesity Has 3 Main Causes

The main cause of hypothalamic obesity is damage to the hypothalamus due to a brain tumor (or its treatment), a traumatic brain injury, or certain genetic conditions that affect how the hypothalamus works.

Brain Tumors

A brain tumor is an abnormal growth of brain cells. If a brain tumor develops in or near the hypothalamus, it can cause damage that affects the ability to regulate your appetite and metabolism. In some cases, the brain tumor itself can cause hypothalamic obesity. However, it’s often linked to treatment (such as surgery and/or radiation) for tumors near the hypothalamus, which can injure this area.

One type of brain tumor, called craniopharyngioma, is responsible for more than half of all cases of hypothalamic obesity. A craniopharyngioma is a rare and benign (noncancerous) type of brain tumor that develops near the pituitary gland, close to the hypothalamus. It’s usually diagnosed in children or older adults. Studies suggest that about 60 percent of people with a craniopharyngioma eventually develop hypothalamic obesity.

One type of brain tumor, called craniopharyngioma, is responsible for more than half of all cases of hypothalamic obesity.

Other types of brain tumors associated with hypothalamic obesity include:

• Gliomas — Malignant (cancerous) tumors caused by the abnormal growth of glial cells (cells that support brain tissue)
• Hamartomas — Benign tumors that develop in or near the hypothalamus
• Pituitary adenomas — Benign tumors that develop on the pituitary gland

Brain Injury

Weight gain is common in people who experience a traumatic brain injury. Trauma can cause bleeding, inflammation, and swelling in the brain that may damage the hypothalamus. Common causes of traumatic brain injury include car accidents, falls, assaults, and sports injuries.

Genetic Conditions

Some people are born with a genetic condition that causes hypothalamic dysfunction (when the hypothalamus doesn’t work as it should). For example, Prader-Willi syndrome is a rare genetic condition that is present from birth but often becomes more noticeable in early childhood, between the ages of 2 and 6. This condition can affect metabolism and lead to developmental delays.

3. Hypothalamic Obesity Symptoms Vary

The symptoms of hypothalamic obesity can differ from person to person. Rapid weight gain is the most common symptom and may happen even when someone hasn’t changed their usual eating or activity habits.

Symptoms that can lead to weight gain include:

• Hyperphagia (strong, hard-to-control hunger and increased eating)
• Trouble feeling “full,” even after eating enough food
• Exercise intolerance (feeling unusually tired or unwell with physical activity)

Symptoms of Related Conditions

Some people may have additional symptoms related to the underlying cause (like a brain tumor) or disruptions in hypothalamic regulation of other body functions, including:

• Trouble sleeping and daytime sleepiness
• Fatigue (extreme tiredness that doesn’t improve with rest)
• Temperature sensitivity (feeling too hot or too cold)
• Difficulty regulating heart rate and blood pressure
• Early or delayed puberty in children
• Electrolyte imbalance (minerals like sodium and potassium in the blood being too high or too low)
• Seizures
• Vision problems, including vision loss
• Headaches
• Confusion
• Trouble concentrating

4. Some People Are at a Higher Risk of Hypothalamic Obesity

The risk factors for developing hypothalamic obesity are related to the risk of developing a brain tumor, injury, or genetic condition. Children ages 5 to 14 years are the group most commonly diagnosed with hypothalamic obesity. The diagnosis is usually related to a brain tumor in this age group.

Children ages 5 to 14 years are the group most often diagnosed with hypothalamic obesity.

Craniopharyngioma, the most common condition associated with hypothalamic obesity, doesn’t have any known risk factors. Some older, traditional types of brain surgery to treat brain tumors may have a higher risk of causing hypothalamic obesity compared to newer techniques.

According to Mayo Clinic, the groups of people at the highest risk of traumatic brain injury include:

• Children younger than 4 years
• Young adults
• Older adults at risk of falling
• Males of any age

Additionally, you may be at risk of hypothalamic obesity if you have a family history of an associated genetic condition. Genetic testing may help you understand your risk.

5. Blood Tests and Imaging Tests Help Diagnose Hypothalamic Obesity

Your healthcare provider may suspect hypothalamic obesity if weight management interventions haven’t helped you lose weight or if you have rapid weight gain associated with a brain injury or brain tumor. Blood tests and imaging tests can help your healthcare provider make a diagnosis.

Blood Tests

Blood tests for hypothalamic obesity will check for health conditions caused by hormone deficiencies often related to hypothalamic dysfunction, such as:

• Arginine vasopressin deficiency — Low levels of vasopressin, also called antidiuretic hormone (ADH), leading to high urine production and increased thirst
• Adrenal insufficiency — Low levels of the hormone cortisol
• Hypothyroidism — Low levels of thyroid hormone
• Growth hormone deficiency — Low levels of growth hormone
• Hypogonadism — Low levels of sex hormones (estrogen and testosterone)

You may also need blood tests to check for complications of obesity, including:

• Type 2 diabetes
• Fatty liver disease
• High cholesterol

Imaging Tests

Imaging tests, such as a CT scan or an MRI, create an image of your brain. Your healthcare provider can use an imaging test to check for signs of a brain tumor or traumatic brain injury.

6. Hypothalamic Obesity Treatment Is Based on the Cause

There are currently no treatments specifically approved by the U.S. Food and Drug Administration (FDA) for hypothalamic obesity. Currently, treatment of hypothalamic obesity focuses on addressing the underlying cause and finding a weight loss strategy that works for you. However, you may have a difficult time losing weight with diet and exercise alone.

Managing Underlying Conditions

Appropriate management of underlying conditions related to hypothalamic obesity can help prevent further damage to the hypothalamus. Specific treatments depend on the underlying cause.

Managing underlying conditions related to hypothalamic obesity can help prevent further damage to the hypothalamus.

People with a brain tumor may need surgery to remove the tumor. After surgery, regular imaging tests are typically needed to check if the tumor has come back. Treatment after a brain injury may include medications, surgery, and rehabilitation programs. Hormone deficiencies related to a genetic condition or complications of brain tumors can be managed with hormone replacement therapies.

Appetite Suppressant Medications

Medications to suppress the appetite can help manage excessive hunger. Several glucagon-like peptide 1 (GLP-1) receptor agonists, commonly known as GLP-1 drugs, have been approved to treat general obesity. These medications help suppress the appetite by slowing how fast food leaves the stomach and increasing the feeling of fullness.

Although these medications are often successful in people with general obesity, the evidence is mixed yet promising for people with hypothalamic obesity based on the results of small adult trials. A clinical trial of GLP-1 drugs in children with hypothalamic obesity found no significant change in body mass index (BMI) after one year. While children taking GLP-1 drugs did have reduced food intake, their bodies used less energy. More research is needed to learn if newer GLP-1 drugs may be helpful.

It’s important to work closely with a specialist while taking medications for obesity.

Weight Loss Surgery

Bariatric (weight loss) surgery can lead to significant weight loss in people with hypothalamic obesity, but results vary. Gastric bypass appears to also be effective for people with hypothalamic obesity. This surgery involves creating a small pouch from the stomach and connecting it directly to the small intestine, bypassing most of the stomach and part of the small intestine.

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