Overview of Huntingtons Disease - Coursework Example

Huntington Disease affiliation Huntington Disease Definition Huntington disease is a progressive and degenerativedisorder of the brain. It is a devastating that is hereditary and has no current cure. In Huntington disease, the nerve cells in specific parts of the brain degenerate are causing the problems with the functions of these parts. Being hereditary, the disorder runs in families (APA, 2013). The disease was first described by Dr. George Huntington in 1872 and hence named after him (Dunckley & Caviness, 2007). Etiology of Huntington disease The incident of Huntington disease is estimated to be 3-7 per 100,000 persons of European descent. It is less common in other populations. The condition is caused by genetic mutation that causes a defect on chromosome 4. The defect is manifested by an abnormal reoccurrence of the CAG repeat on the DNA. This reoccurrence occurs up to 120 times compared with the normal 10-28 repeats (Vargas, Carod-Artal, Bomfim, Vázquez-Cabrera, & Dantas-Barbosa, 2003). These repeats increase with heredity and the manifestations of the condition, therefore, worsen with generations. Similarly, the age of onset tends to reduce as the condition is passed along the family line. The heredity probability from a parent who has the condition is 50%, when both parents have the condition; the children will have the disease and will pass it to their children (Folstein, 1989). Huntington disease is inherited in an autosomal dominant fashion. This means that if a copy of the repetitive gene is present in each cell, the condition will appear. Although the disease is hereditary, rare cases of severe mutations leading to the development of the condition have been reported. Symptoms of Huntington Disease With the inheritance f the condition, the symptoms do not appear at birth. They appear between ages 30 and 50. The cardinal symptom of the condition is an abnormal and uncontrolled movement of the limbs, head, face and the upper trunk (Vargas et al., 2003). These are because of degeneration of the cells in the control centers in the brain that govern voluntary movements of these parts. The symptoms can therefore be categorized as movement disorders, cognitive disorders and psychiatric disorders. In movement disorders, Huntington’s disease manifest as involuntary movement of limbs (chorea), speech problems, muscular rigidity, abnormal ocular movement and impaired gait and posture. Cognitive symptoms include impaired reasoning, judgment, memory, concentration, and general human organization. Further, the symptoms include psychiatric manifestations such as depression, panic disorders, anxiety, irritability, obsessive-compulsive disorder symptoms and schizophrenia like-symptoms which include insomnia, irritability, malaise, and social withdrawal. The condition also manifest as obsessive compulsive disorder, mania or a bipolar disorder (mayoclinic.org). The course of Huntington disease In most cases, the disease has a late onset, appearing between the ages of 30 and 50 years. However, with increased heredity, the age of onset decreases and the condition has been reported in children as young as two years (Vargas et al., 2003). This early onset is related to the expansion of the CAG segment of the DNA. Early symptoms are the effects on the cognitive ability with progressive loss of memory, thought ability deterioration, and loss of control. Those symptoms that require care include the psychiatric symptoms of irritability, anxiety, depression and mood impairment (APA, 2013). Depression, forgetfulness clumsiness, involuntary motor activities and lack of coordination occur within a few weeks of symptoms onset (Homberg & Huttunen, 1994). With disease progression, loss of memory worsens, affecting general concentration. These cognitive symptoms precede the motor symptoms sometimes by up to 15 years. Involuntary movements of limbs, head and trunk increase and many activities such as walking, swallowing and talking are severely affected. Appearance of fidgeting of extremities, mild apraxia occurs first before major motor disturbances (Feigin et al., 1995). Eventually, self-care becomes a problem and complications such as heart failure, choking of severe infection follow. Diagnosis of Huntington’s disease Medical diagnosis of Huntington’s disease is based on the appearance of symptoms, age of onset and familial history of the disease. The familial history of the disease and the symptoms are used as predictive diagnosis especially in patients who are at risk of developing the disease. Genetic testing has been extensively used to confirm the diagnosis, and this is based on the presence of the protein huntingtins in the blood. Medical imaging, mainly computerized tomography and magnetic resonance imaging are used to confirm changes in the striatum and other parts of the midbrain (Frank & Jankovic, 2010). With improved technology, pre-implantation diagnosis is possible to identify the defective genes in the embryo before implantation. This is done in in-vitro fertilization and ensures that the child developing is free from the disease (Lemiere, & Katholieke, 2004). Prognosis of Huntington’s disease Children who develop the disease in their early years (Juvenile Huntington disease) do not live to adulthood. This is because the loss of function of the brain cells reaches a point that is irreparable causing increased degeneration and manifestation of the complications that are life threatening (APA, 2013). The impaired cognitive and motor abilities together with the complications of the disease are life threatening. The condition, therefore, leads to disability and death. There is currently no cure for the disease, and treatment is aimed at reducing the symptom and helping prevent complications. However, death occurs within less than 15 years in 70% of the patients. However, with conservative treatment, the patients can live longer (Feigin et al., 1995). Treatment options There is no known cure for Huntington disease. Further, there are no available drugs that can slow down the rate of neuro-degeneration as a result of Huntington disease. Medications focus on the major disabling symptoms. For involuntary movement (chorea), antipsychotics such as barbiturates are used. For irritability, atypical antipsychotics are used as first-line. When the irritability is less severe, antidepressants are recommended. The antidepressants are also used for obsessive-compulsive thoughts and activities. Tricyclic antidepressants such as amitriptyline and imipramine; selective serotonin re-uptake inhibitors such as fluoxetine; and antipsychotics are used in control of depression and other psychiatric disorders (netdoctor.co.uk). The movement disorders are controlled using tetrabenazine, haloperidol, fluphenazine and other antiparkinsonians drugs (Leuven University Press &Scott, 2011). Irritability and other antisocial behaviors associated with Huntington’s disease are treated using chlorpromazine, clozapine and risperidone, which control the behavioral problems (Frank & Jankovic, 2010). Alternative therapies are also used to control the progression of the symptoms and increase the cognitive control. These treatment options include behavioral therapy, which is aimed at controlling the behavioral manifestation (Scott, 2011). To increase control of actions and improve self-care, physical therapy, occupational therapy and speech therapy are used to ensure that the patient maintains a considerable level of activity. Psychotherapy is also done to help reduce depression and anxiety disorder. Current research indicates that there is a possibility that a better form of psychotherapy can be developed by a combination of behavioral and cognitive therapy to reduce the symptoms. Electrotherapy is also being considered as an option (Caine, Ebert, & Weingartner, 1977). Further, there are studies and clinical trials that are focusing on invention of a remedy to the disease. Some of these include the neuronal stem cell replacement, measures to improve brain cells survival hence reduce the rate of degeneration as well as reducing the rate of production of the protein huntingtin in the brain. Huntington’s disease And the Brain The disease symptoms are the results of the changes in the neurochemistry that causes the cognitive and motor disturbances. The increased repetition and segmentation of the CAG section of the DNA causes an increased production of huntingtin, a protein that is toxic to the brain neurons and result to disruption in the chemical excitation of brain cells by normal neurotransmitters. The effects of the damage are first noted in the striatum part of the brain, and as the disease progresses, other areas of the brainstem, cerebellum and the cerebral cortex are also affected. After the striatum, other parts of the midbrain, the hippocampus, basal ganglia, Purkinje cells, lateral tuberal nuclei, thalamus and hypothalamus are also affected. Since the striatum ant its cortical connections controls movement, mood, memory and higher cognitive functions, the initial symptoms are depression, mood disorders and loss of control of motor functions (Kremer, 2002). The disease, therefore, has a number of associated psychological symptoms, which include depression, panic disorders, anxiety, and disturbed cognitive functions. The patients also experience progressive loss of memory, learning disabilities, behavioral problems and lack of coordination. The disease has also been identified to be associated with obsessive-compulsive disorder and Sydenham Chorea (Klppel et al., 2009). These psychological symptoms mimic psychiatric symptoms and arise from the same neurotransmitters disturbances and brain cells degeneration that causes the symptoms. This, therefore, means that psychiatric drugs are used in conservative management of Huntington’s disease. These medications include antipsychotics such a barbiturates, antidepressants such as the selective serotonin reuptake inhibitors and the mood stabilizers (Knowles, 2007). These drugs are however used with caution to minimize the side effects, which can worsen the psychological status of the patient. References American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders: DSM-5. Washington, D.C: American Psychiatric Association. Read More