Acquired hypothalamic obesity overview
Fact-checked by Acquired hypothalamic obesity, or aHO, is a rare obesity disorder that can develop after damage to a brain area called the hypothalamus. Certain types of brain tumors, treatments for those tumors, and other brain injuries can cause aHO.
The hypothalamus acts as a link between the nervous system and the endocrine system, a network of glands and organs that produce and release hormones to regulate processes throughout the body. It helps control appetite and metabolism, or how the body generates and uses energy. When disease or injury disrupts these functions, it can lead to rapid weight gain and other symptoms of hormonal imbalance, including mood changes and sleep problems.
aHO often requires specialized treatment beyond standard weight loss strategies used for obesity. A multidisciplinary approach to treatment and monitoring can help people with aHO manage symptoms and potential complications.
Causes and risk factors
Hypothalamic damage is a distinguishing feature and key cause of aHO. It can occur as a result of:
- brain tumors near the hypothalamus
- surgery or radiation therapy to treat brain tumors
- traumatic brain injuries
- bleeding in the brain
Craniopharyngioma, a type of noncancerous tumor that usually affects children and older adults, is a leading cause of aHO. Such tumors grow near the pituitary gland, a small gland sitting below the hypothalamus. Other types of tumors, including cancerous tumors, can also cause aHO if they develop near the hypothalamus and cause hypothalamic dysfunction.
Treating these brain tumors with surgery or radiation can also damage the hypothalamus, which may increase the risk of aHO.
Regardless of the cause, hypothalamic damage and dysfunction may cause people with aHO to feel excessively hungry and use less energy. The combination of these behavioral and metabolic effects often leads to weight gain following hypothalamic injury, a hallmark feature of aHO.
Symptoms
Symptoms of aHO can vary depending on the type and extent of damage to the hypothalamus, but may involve both physical and behavioral changes.
Rapid weight gain, often beginning within a year of the precipitating injury or disease, is a key physical sign of aHO. Other signs and symptoms can include:
- appetite changes, including excessive hunger (hyperphagia)
- using less energy and burning fewer calories at rest
- a limited ability to exercise and be physically active
- sleep problems, such as difficulty sleeping or excessive daytime sleepiness
- behavioral problems
- mood changes
Damage to the hypothalamus and pituitary gland can also lead to hormone deficiencies. In pediatric aHO, changes in pituitary hormone levels can affect development, leading to stunted growth and early or delayed puberty. Pituitary dysfunction in adult aHO may lead to sexual dysfunction or infertility.
People with known hypothalamic damage from a tumor, injury, or other cause may want to seek medical attention if they experience major weight gain within a short period of time. Monitoring for other symptoms can also support prompt diagnosis.
Diagnosis
Early aHO diagnosis is important for effective treatment and management. International diagnostic guidelines outline some features that can help support a diagnosis:
- a source of hypothalamic damage
- rapid, sustained, and clinically meaningful weight gain
- obesity exceeding a certain threshold
Physicians typically use body mass index, a ratio of weight and height that can help estimate body fat, to define clinically meaningful weight gain and obesity thresholds. These criteria differ for adults and children.
The diagnostic process in aHO can include:
- MRI scans or other imaging tests to identify damage to the hypothalamus
- blood tests to measure hormone levels
- tests to estimate energy expenditure at rest
- screening for other symptoms of hypothalamic damage
During diagnosis, healthcare professionals must also rule out other possible causes of obesity, such as lifestyle changes, use of certain medications, or genetic disorders.
Treatment and management
Treating aHO typically involves both lifestyle-based management strategies and medical interventions.
On their own, lifestyle changes like following a healthy diet and exercising aren’t usually effective at helping people with aHO lose weight. However, such changes may supplement other interventions and help people with aHO maintain good overall health and manage body weight.
Other treatment options for aHO may involve:
- Behavioral training and mental health support: Behavioral therapy can help some people with aHO manage eating habits, particularly if they experience hyperphagia. In addition to affecting weight, appetite changes can cause emotional distress, so mental health support may be important.
- Medications to promote weight loss and suppress appetite: To date, Imcivree (setmelanotide) is the only medication specifically approved in the U.S. for weight loss in people, ages 4 and older, with aHO. It targets a signaling pathway that regulates hunger and energy expenditure and is disrupted by hypothalamic damage. Other medications may also be used off-label, although evidence supporting their benefits is less clear.
- Hormone replacement therapy: Such treatments may help with symptoms associated with the lack of certain hormones, such as growth hormone that influences height, or sex hormones that affect sexual development and reproductive health.
- Weight loss (bariatric) surgery: These types of procedures may help some aHO patients lose weight, although research in this area is still limited.
It is important for people with aHO to have regular check-ups with their healthcare team and monitor changes in symptoms. This can help identify signs of complications, like diabetes and liver disease, so they can be treated appropriately. People with brain tumor-related obesity may also require regular monitoring for signs of tumor recurrence.
Living with aHO
Emotional and practical support resources can help people living with aHO and their caregivers navigate the experience of diagnosis, treatment, and everyday life. Various organizations, including the Raymond A. Wood Foundation, offer resources in these areas.
Specialists and rare obesity-focused groups may also help provide support for caregivers and patients in specific areas, like managing behavioral symptoms.
Rare Obesity News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
