Huntington’s Disease (HD) is an inherited neurodegenerative disorder that relentlessly progresses, causing the deterioration of nerve cells in the brain. This condition is characterized by uncontrolled movements, cognitive decline, and psychiatric disturbances. Individuals with HD typically do not die from neurodegeneration directly. Instead, death results from severe complications that arise as the body’s physical and mental systems fail in the later stages of the disease.
Respiratory Complications
Respiratory failure, primarily due to aspiration pneumonia, is the most common cause of death in advanced Huntington’s Disease. The progressive neurological damage impairs the coordination of muscles used for chewing and swallowing, a condition known as dysphagia. This means food, liquid, or saliva can be misdirected into the trachea and lungs. When foreign material enters the lungs, it introduces bacteria, leading to aspiration pneumonia. Studies have shown that aspiration pneumonia accounts for a majority of HD fatalities, sometimes reported in over 85% of cases. The involuntary, jerking movements of chorea also disrupt the precise timing required for safe swallowing and breathing.
Weight Loss and Nutritional Failure
Severe, unintended weight loss, or cachexia, hastens mortality in people with Huntington’s Disease. This physical wasting occurs due to a complex metabolic imbalance where the body burns calories at an abnormally high rate. The involuntary muscle movements of chorea require a constant, excessive expenditure of energy, leading to hypermetabolism. This increased caloric demand is compounded by the inability to safely consume food because of dysphagia. The resulting malnutrition and protein deficiency compromise the immune system, leaving the body frail and unable to fight off infections, including pneumonia.
Accidental Injury and Systemic Infections
The motor symptoms of HD introduce a heightened risk of injury and acute death from trauma. Uncontrolled movements and a progressive lack of coordination lead to gait instability, making falls a frequent and dangerous occurrence. These accidents can result in severe trauma, such as hip fractures or debilitating head injuries. Sudden acute death can also occur directly from choking, a complication of advanced dysphagia. Systemic infections, such as sepsis from pressure ulcers or urinary tract infections, are also recorded causes of death. The combination of physical frailty and a weakened immune system makes individuals susceptible to a range of infections.
Suicide and Mental Health Mortality
Mortality is directly linked to the psychiatric symptoms of the disease, with suicide being a recognized cause of death. Individuals with HD face a risk of completed suicide estimated to be between two and nine times higher than that of the general population. This elevated risk stems from the severe psychiatric symptoms that are part of the disease, including depression, anxiety, and increased impulsivity. The risk is concentrated during specific periods, often before a formal diagnosis is received or in the middle stages when cognitive function remains relatively intact but physical independence is rapidly diminishing. Suicidal ideation can affect up to a quarter of the HD population at any given time. For younger individuals under the age of 45, the risk of death by suicide is markedly higher than their peers.