What is Huntington’s disease?
Huntington’s disease (HD) is an incurable, genetic illness affecting the nerve centers of the brain. Symptoms range from physical to psychological disabilities and differ in severity. Often, these symptoms leave the patient emaciated and immobile. There are a number of diagnostic tools available to aid physicians in diagnosing Huntington’s disease. Juvenile HD has separate symptoms and affects a different group of people. Treatment for HD is strictly symptomatic, as there is no cure. Unfortunately, the prognosis for those diagnosed is extremely bleak.
Huntington’s disease symptoms do not usually manifest until a person reaches middle age (30 to 50 years old). There are a wide variety of symptoms, and not all of them are found in every patient. Commonly, the first to appear are the physical symptoms.
The initial symptoms to be noticed are the symptoms that have physical characteristics–widely known as chorea. All of the physical symptoms include unusual bodily movement; sudden twitching and uncontrollable movements of the limbs or trunk are among them. This progresses into an inability to walk stably on one’s own. The repeated need to turn one’s head or shift their gaze is a compulsive physical symptom amid an extensive list of manifestations. Along with the broad list of physical symptoms is the gradual loss of intellectual abilities (Lukas, 2013).
An HD patient will experience a gradual deterioration of intellectual abilities. Originally, this manifests with a difficulty eating and swallowing. As expected, this will result in extreme weight loss. The patient will also experience difficulties dressing or caring for themselves at all. Speaking becomes difficult and leads to poor enunciation of speech. The aforementioned gradual loss of intellectual abilities will progress into severe intellectual disabilities, and ultimately death (Lukas, 2013).
After time, as the symptoms worsen, patients may experience a nearly complete loss of psychological capabilities. The most common behavioral problems are depression, anxiety, and obsessive-compulsive behavior. It appears as if everything is out of their control, so they attempt to control everything that they can. HD sufferers eventually undergo the loss of memory, judgment, and ability to think rationally. The more severe psychiatric manifestations consist of psychosis, paranoia, and hallucinations. Ultimately, Huntington’s disease can cause the inability to care for oneself physically or mentally and induce severe disability (Lukas, 2013).
Juvenile Huntington’s disease
As stated, Huntington’s disease symptoms usually manifest between the third and fifth decade of life. Uncommonly, HD will become symptomatic in children and young adults; when it does, it is called Juvenile Huntington’s Disease. Statistically, there is a very low possibility, even with HD diagnosed parents, that a juvenile will display symptoms of the disease (Lewis, 2013).
Juvenile Huntington’s disease is, quite literally, an anomaly. Roughly 5-7% of reported cases of HD are in juvenile form. The average age of a Juvenile HD patient is 14 years old, but the youngest ever diagnosed was 2 years of age. Though the disease is the same, it is discovered differently than in adult onset HD (Lewis, 2013).
Juvenile Huntington’s disease initially presents with behavioral disturbances. The patient will be failing in school due to short-term memory loss, suffer from seizures and dystonia, along with abnormal eye movements. The later stages of the disease are marked by loss of speaking ability and bladder/bowel control and emaciation. As with adult onset HD, Juvenile HD ends in death (Lewis, 2013).
Often, Juvenile HD causes severe anxiety and depression, leading the patient to commit suicide. When faced with this terrible, fatal disease that takes control of their entire body, the patient will find that it is too much for them to handle. When death is not caused by suicide, it is often caused by pneumonia or a serious fall.
There are several diagnostic tools used to assist doctors in making a definitive diagnosis of HD. These include genetic testing, physical examinations, psychological evaluations, and brain scans. Due to the genetic markers for HD, the genetic test is most significant.
In the genetic testing, doctors-whose patients have one or both parents diagnosed with HD-look for the HD gene on chromosome #4 in their patient (Lukas, 2014). There is a 50% chance that a child of a person with HD will test positive for the disease (Caple 2013). Possibly due to a noted reluctance of such offspring to be tested, the physical examination is also used and can be quite productive.
The physical examination is a simple neurological examination to evaluate the patient’s reflexes, vision, hearing, sense of touch, and coordination. The doctor will be able to perform this examination in his office, as it is not extensive. Persons with HD will most likely show poor reflexes and coordination and evidence of vision and hearing impairment during the physical exam. Even if they don’t, however, the psychological examination is likely to reveal Huntington’s disease (Mayo, 2011).
The psychological examination consists of an observation of the patient’s mental state. The doctor will evaluate the patient’s behavioral patterns, coping skills, and the quality of the patient’s judgment. The results of these examinations may confirm the Huntington’s diagnosis, but it is not conclusive (Mayo, 2011). To further support the diagnosis, the doctor will order brain imaging.
A series of brain scans will confirm a diagnosis of Huntington’s disease. Those with Huntington’s disease may show shrinkage of some parts of the brain-in two areas called the caudate nuclei and putamen-and an enlargement of the ventricles. The three tests that can examine the brain are a Computed Tomography (CT) scan, a Magnetic Resonance Imaging (MRI) test, and a Positron Emission Tomography (PET) scan (Lewis, 2013). Unfortunately, finding a diagnosis at any stage in the disease is not an advantageous event, because a diagnosis is a death sentence.
Because there is no cure for Huntington’s disease, treatment is strictly symptomatic; meaning that the disease cannot be treated, so the symptoms are treated. There are a great variety of medications that can be prescribed for HD patients, because there are a wide variety of symptoms that need to be treated. Among those medications, Tetrabenazine is almost always prescribed.
Tetrabenazine is a medication used to treat hyperkinetic disorders (such as Huntington’s chorea). Although the drug is not a cure for any disease or disorder, it infinitely increases the quality of life. Tetrabenazine works in the central nervous system to prevent the absorption of certain chemicals (such as dopamine and serotonin). This medication is used for the physical symptoms, but antidepressants aid the less severe behavioral disorders (Wikipedia, 2014).
Antidepressants are often helpful with the most common behavioral afflictions. Antidepressants are used to help with depression, anxiety, and obsessive-compulsive behaviors. Antidepressants are often used alongside selective serotonin reuptake inhibitors (SSRIs), which are also remarkably effective drugs to treat depression. For the more severe intellectual disabilities, antipsychotics are exceedingly advantageous (Caple, 2013).
Antipsychotics are used to treat the more extreme symptoms of Huntington’s disease; such as psychosis, hallucinations, and paranoia. Without antipsychotics, patients will experience extreme delusions and may be very difficult to treat or socialize with. As stated, since there is no cure for Huntington’s disease, treatment is solely concerned with increasing the patient’s quality of life (Caple, 2013).
Unfortunately, the prognosis for a diagnosed Huntington’s patient is quite bleak. As there is no way to cure HD, the only possible end-result is death. Since late-stage HD patients have trouble caring for themselves, assisted living is necessary.
Assisted living is a requirement for mid-to-late-stage Huntington’s disease. One may choose to remain at home and have a live-in caretaker attending to their needs, or to go live in a nursing home and have an entire staff of nurses taking care of them. After diagnosis, the patient does not have a long life expectancy (Schub, 2007).
The life expectancy for those with Huntington’s disease is roughly 15-20 years after diagnosis. The average life span after HD diagnosis is 16 years. Though death is certain, the immediate cause of death is indefinite and varies (Caple, 2013).
There are various causes of death for Huntington’s disease. The disease itself is not fatal, but the symptoms associated with it can be. The suicide rate for individuals with HD is 5 times higher than those among the general population (Caple, 2013). It is unknown whether the suicide is due to depression from being faced with a fatal disease, or if it is an HD-related psychiatric disturbance. Commonly, cause of death will be from illnesses such as pneumonia or infections. Choking is another common cause of death; as is falling-resulting in a broken neck or fatal brain injury (Schub, 2007).
To conclude, Huntington’s disease is a rare, incurable, genetic neurodegenerative disorder that affects the brain. It causes progressive degeneration of the nerve cells in numerous areas of the brain. Huntington’s disease cannot be transmitted in anyway other than genetic inheritance. HD symptoms usually start between 30 and 50 years of age (and differ in severity), but in rare cases symptoms can start around 20 years of age (Juvenile HD). The lamentable, but definite, result of a Huntington’s diagnosis is death.
Caple, C. (2014, JANUARY 3). Huntington’s disease: Psychiatric manifestations and treatment. Retrieved from http://web.b.ebscohost.com/nrc/detail?sid=f01c02ae-6aeb-4c48-8be4-d97a99a6170a@sessionmgr115&vid=1&hid=122&bdata=JnNpdGU9bnJjLWxpdmU =
Lewis, R. (2013, OCTOBER 11). Huntington disease, juvenile . Retrieved from http://web.b.ebscohost.com/nrc/detail?sid=b2cb4da3-360e-4833-a006-df1733a4c01d@sessionmgr113&vid=1&hid=122&bdata=JnNpdGU9bnJjLWxpdmU =
Lukas, R., & Randall, B. (2013). Huntington’s disease. Retrieved from http://web.b.ebscohost.com/nrc/detail?vid=4&sid=5200809e-58f5-47e5-9337-def7ce2f8ec0@sessionmgr198&hid=126&bdata=JnNpdGU9bnJjLWxpdmU =
Mayo, C. S. (2011, MAY 05). Huntington’s disease: Tests and diagnosis. Retrieved from http://www.mayoclinic.org/diseases-conditions/huntingtons-disease/basics/tests-diagnosis/con-20030685
Schub, T. (2007, OCTOBER 05). Huntington disease. Retrieved from http://web.b.ebscohost.com/nrc/detail?vid=4&sid=5200809e-58f5-47e5-9337-def7ce2f8ec0@sessionmgr198&hid=126&bdata=JnNpdGU9bnJjLWxpdmU=
Wikipedia. (2014). Tetrabenazine. Retrieved from http://en.wikipedia.org/wiki/Tetrabenazine