Hypothalamic obesity occurs when damage to the hypothalamus causes an imbalance between someone’s energy intake from food and the amount of energy their body has used.
The hypothalamus is a small region of the brain that helps with several bodily functions. One important role is the regulation of energy intake and use. “Intake” refers to the calories a person takes in through food and drink, while “use” refers to the energy the body consumes to perform functions that include movement and internal processes.
An imbalance between energy intake and use due to damage to the hypothalamus may lead to rapid weight gain that can be difficult to manage. A person with hypothalamic obesity may feel the need to eat more, or their body may not use the energy it intakes properly.
This article reviews the symptoms, causes, diagnosis, and treatment of hypothalamic obesity.
The hypothalamus controls different functions in the body, including energy regulation. As a result, it can affect people in different ways.
Some people living with hypothalamic obesity may feel the need to continually eat foods. This may be in combination with a feeling of never feeling satisfied following food intake.
For others, weight gain occurs or continues, even when they restrict their caloric intake, exercise regularly, and eat healthily. The reason for this is that the body’s resting metabolism decreases. The effects may worsen if a person lives a relatively sedentary lifestyle.
In both cases, a person can rapidly gain weight that is difficult to lose through traditional weight management techniques.
Some people living with hypothalamic obesity may also experience issues with hypopituitarism, which is when the pituitary gland does not make enough of certain types of hormones.
In people with damage to the hypothalamus or pituitary gland, there may be improper communication between the gland and the hypothalamus, leading to endocrine hormone deficiencies. Without treatment, some endocrine hormone deficiencies, such as growth hormone deficiency or hypothyroidism, can contribute to weight gain and obesity.
Other symptoms that a person may experience due to a damaged hypothalamus include:
In a 2022 study, researchers noted that imaging studies have shown that the extent of the damage to the hypothalamus directly correlates to the presentation of obesity.
Damage to the areas of the hypothalamus responsible for energy regulation is the main cause of hypothalamic obesity. This may occur due to brain tumors or head injury. In people with brain tumors, swelling of the optic nerve at the initial diagnosis indicates high pressure in the brain, which is a risk factor for future obesity.
Experts also suspect that environmental and genetic factors may play a role in the extent of obesity and the risk of future obesity in children. In addition to having obesity at the time of treatment, other factors that may increase the risk of future obesity include:
- decreased energy use, both when someone is resting and while they are active
- increased appetite
- decreased feeling of being full after meals
- chronically high circulating levels of insulin, a hormone that helps to manage blood sugar levels
- potential resistance to leptin, a hormone that helps regulate appetite
- disordered sleep and circadian rhythm regulation
- pituitary hormone deficiencies
- psychosocial factors that may negatively affect healthy behaviors, such as eating well-balanced meals or exercising
In a 2019 study, researchers identified possible causes of hypothalamic damage that included:
- brain tumors, such as craniopharyngioma
- cranial irradiation, a form of radiation therapy
- genetic conditions
- traumatic brain injury
They also noted that possible risk factors associated with the development of hypothalamic obesity following injury to the hypothalamus include:
- high level of damage to the hypothalamus
- presence of endocrine dysfunction at the time of diagnosis
- age at diagnosis — the researchers suggest that younger children tend to have more obesity
- being heavier at the time of diagnosis
- family history of obesity
- high amounts of radiation to the hypothalamic area
A person may first visit a doctor with concerns about weight gain and the inability to lose weight even with dietary modifications and exercise. A healthcare professional will most likely start diagnosis with a physical examination and review of a person’s medical history.
A doctor may ask about any recent head injury or trauma. They may order imaging tests to check for damage to the hypothalamus. If rapid weight gain coincides with the timing of the injury, a doctor may diagnose hypothalamic obesity.
Finally, they may order a blood test to check for hormone levels. Irregular levels of certain hormones could suggest that damage to the hypothalamus may be causing weight gain.
Following diagnosis, a healthcare professional may monitor a person and conduct diagnostic tests for complications or other conditions that could develop as a result of hypothalamic obesity, such as type 2 diabetes and fatty liver disease.
The Food and Drug Administration (FDA) has not yet approved any therapies for hypothalamic obesity.
Instead, doctors focus on treating any existing underlying conditions that caused the damage to the hypothalamus, which can vary. They may also try different strategies to manage obesity, although this is usually ineffective.
In a 2022 study, researchers suggested that therapies to manage the effects of hypothalamic obesity could involve:
- dietary interventions
- bariatric surgery, which refers to surgical procedures that may help a person lose weight
It is important to note that these therapies will not cure the condition.
Hypothalamic obesity refers to rapid weight gain following damage to the hypothalamus. The damage may occur due to a brain tumor or head injury.
When it occurs, a doctor may diagnose the condition by determining if a person has experienced damage to their hypothalamus using imaging tests. Currently, there is no specific treatment for hypothalamic obesity, but treating any underlying conditions and taking additional measures to manage weight gain may help manage it.