HD refers to the resolution of display devices, such as television and computer monitors. Higher resolutions feature more pixels for greater detail and clarity in images displayed.
Although it’s commonly believed that HD symptoms appear once an activated gene mutation has taken effect, reports of high rates of psychiatric disorders among those who do not carry the mutation have raised concerns that such changes may reflect other risk factors or early family histories.
Symptoms
HD is a condition affecting movement, thoughts and behaviors that impacts part of the brain called the striatum. People living with HD can have difficulties walking, balancing and speaking; difficulty swallowing or choking may result in weight loss; they can become very irritable; some experience depression, apathy or paranoia while others exhibit hallucinations and periods of increased agitation (mania). Furthermore, people living with HD often struggle with dual tasking, such as eating while talking or driving and using computers simultaneously; forgetting how to do simple tasks and being negligent about maintaining personal hygiene or housework duties – they often forget how do simple tasks as well.
Early-onset HD typically begins during middle adulthood; however, symptoms can arise in children or young adults in rare instances. Early-onset symptoms tend to be milder than adult-onset HD and tend to focus more on motor functions than their counterparts.
At this stage, symptoms become increasingly severe, with involuntary movements becoming the primary focus. People also struggle with balance and speech difficulties; appetite loss may occur as well as suicidal thoughts being generated from this disease. Sleep issues arise and forgetfulness becomes prevalent; their family, friends and carers may require support during these changes.
Researchers around the world are actively searching for ways to delay or prevent symptoms of HD. One approach involves limiting formation of toxic substances in the brain. Another strategy entails searching for biological changes that can predict or diagnose HD prior to symptoms appearing, a practice known as biomarkers. Studies such as PREDICT-HD sponsored by NINDS as well as international ones have focused on biomarkers such as changes in brain scans, chemical changes in urine or cerebrospinal fluid, behavioral indicators or behavioral symptoms as indicators of impending disease before symptoms appear.
Understanding the mechanisms underlying mental illnesses is essential to designing effective treatments. Based on data collected from one of the largest samples of individuals living with HD, this analysis details typical progression of motor, emotional/behavioral, cognitive symptoms (including chorea) through six onset periods: initial, early-middle, middle-late and late onset.
Diagnosis
Diagnosing HD typically begins during middle age; however, juvenile Huntington’s disease (JHD) has been known to appear earlier. Symptoms may include uncontrollable jerking movements (chorea), problems with balance and movement, muscle weakness, memory loss, difficulty swallowing, depression and other mental changes that become increasingly severe over time. Ultimately these symptoms become irreparable.
To diagnose HD, a neurologist (a doctor who specializes in brain and nerve health) will perform a physical exam that looks for signs such as twitches and jerking. They’ll also ask about your family history; if someone in your family already has HD, chances are 50/50 of inheriting its gene mutation that causes it. A neurologist may order imaging tests like magnetic resonance imaging (MRI) or computerized tomography (CT) scans in order to assess how your brain is working – these tests may help rule out other conditions that cause similar symptoms.
Genetic testing can identify whether you carry the HD gene mutation. The most reliable test counts the number of CAG repeats in your DNA; an increased count indicates having the mutation and developing symptoms, while lower numbers mean it doesn’t exist and will never manifest symptoms of HD. A genetic counselor (who specialize in genetic testing) will then discuss your results with you.
Many studies, such as the NINDS-funded PREDICT-HD study, are exploring biomarkers as potential indicators of HD in those carrying the faulty gene. Biomarkers could include changes in brain scan images or chemical markers found in blood or cerebrospinal fluid as well as any measurable differences in personality or mood that indicate HD is present.
A multidisciplinary team can help manage and treat your symptoms and other health concerns effectively. This team may include neurologists, psychologists, social workers or genetic counselors; while some patients may benefit from physical or speech therapy. Others find psychiatric medications, like antidepressants or mood stabilizers (Lithium (Eskalith(r)), can reduce anxiety or hallucinations.
Treatment
HD symptoms progress gradually and can interfere with an individual’s ability to think clearly, engage in activities, or care for themselves. Sleep disturbances, eating difficulties and breathing issues are also often symptoms. They usually begin in early adulthood and persist over a lifetime period.
Doctors can diagnose HD by analyzing urine and blood samples. Furthermore, they may order brain imaging via computed tomography (CT) or magnetic resonance imaging (MRI), which shows shrinkage in certain parts of the brain and an increase in fluid-filled cavities called ventricles; however these changes could be indicative of other disorders as well.
A neurologist will perform a neurological exam and gather your medical history, including any family histories related to HD. A genetic counselor or clinical neuropsychologist may then review your family tree to detect mutations that cause HD.
Medication may provide temporary relief of some HD symptoms, but they do not slow or stop its progression. One antipsychotic, Zyprexa (olanzapine), was the first drug that showed promise for relieving chorea’s involuntary movements; other antipsychotics have shown promise by decreasing depression and irritability for those living with HD; however these medications may cause side effects like tremors or tardive dyskinesia.
Researchers worldwide are in pursuit of an HD cure, yet many promising strategies exist to limit or delay its progression and to prevent its onset. Stem cells offer one promising approach for replacing dying neurons; another strategy targets stopping huntingtin release from cells to block its toxic effect.
Research is exploring new technologies that could identify biomarkers – biological changes used to detect or diagnose disease – such as NINDS-funded PREDICT-HD study and other international ones that investigate whether HD progression relates to changes in brain scan images, or chemical alterations found in blood, urine or cerebrospinal fluid.
Prevention
Many people with HD have a genetic mutation which causes repeats in cytosine, adenine and guanine building blocks to repeat more often than normal – this causes HD. If one parent carries this mutation then their children have a 50/50 chance of inheriting it; otherwise they won’t experience HD symptoms themselves or pass them down to future generations.
Infection is the leading cause of hospitalization and death among dialysis patients, and its risk varies depending on the method used to access bloodstream; central venous catheters (CVC) have been associated with an eightfold higher infection risk compared to arteriovenous fistulae (AVF). Preventative strategies include proper access site care (including using chlorhexidine gluconate skin antisepsis and disinfecting hubs before access), along with regular readministration of antibiotics.