Huntington's Disease
As a hereditary disease, Huntington’s disease has a population group on which it most frequently unloads its presence. Although statistics establish that about 5 out of every 100,000 people with European ancestry suffer from it, the numbers vary depending on the geographical region to which we refer.
The characteristic symptoms of the evolution of the clinical picture have to do with mobility and cognition. The nervous system is the site where the lesions that lead to signs of imbalance, lack of coordination, and even psychosis are located.
The process is often described as neuronal deterioration as, in these patients, genetics determines that both the brain and the peripheral nerves undergo a sort of aging process. The degeneration of the cells prevents them from carrying out the functions for which they’re intended.
Huntington’s disease symptoms
Although the genetic alteration of Huntington’s disease is inherited and is present from the patient’s birth, the symptoms usually begin when the person is an adult. Most of the diagnosed cases are concentrated between the ages of 30 and 40.
In any case, there’s also a clinical picture as a variant of early presentation, as there are children or adolescents who have compatible symptoms before the age of 30.
Generally speaking, the cardinal sign is a lack of motor coordination. Patients are unable to combine movements and often start having difficulty performing small actions that involve precision, such as picking up a cup of coffee with their fingers.
At a psychological level, there’s depression, partly due to neuronal deterioration and partly due to the despair associated with physical changes. The next step is psychosis with hallucinations, which is accompanied by cognitive failures. The person’s decision-making process slows down and they may even spend hours without making a decision regarding something that should be quickly resolved.
The progression of Huntington’s disease leads to a condition known as chorea. These are involuntary and stereotyped movements that are concentrated in a few muscles or involve large extensions of the body. The person can be still and suddenly raise their hands and legs without sending an order from their brain, for example.
Along with psychosis, there’s a change in personality that leads to confusional states and memory loss. The disintegration of the personality is severe as time goes by. At the same time, communication is difficult because the patient has obstacles in the articulation of words.
The early form of presentation
In early-onset Huntington’s disease, the symptoms are similar. In any case, there have been more cases of muscle contractures and stiffness in adolescents and children, as well as seizures.
In a more subtle way, there’s worse academic and intellectual performance due to slow thinking and the lack of correct verbal expression. This is a difficult indicator to relate to the diagnosis unless the child has parents with the disease or a family history of the disease.
The early onset of Huntington’s disease also involves slowness of movement as its most distinctive sign. Once the brain issues the order to a muscle, it takes time for it to receive and execute it.
Genetic inheritance in the disorder
The genetic cause of Huntington’s disease is hereditary. This means that it’s passed on in families that carry the defective gene. But unlike many other pathologies, its condition is dominant, meaning the patient only needs to carry one copy with defects for the syndrome to become visible.
In numerical and statistical terms, if one of the parents is a carrier of the gene with the defect, then the children have a 50% chance of having the disease. It will depend on genetic chance whether it’s transmitted or not.
Microscopy of the error in the gene indicates where there’s a replication or copy failure. Specifically, a genetic section is copied repeatedly when it’s transcribed, and this is amplified as it’s passed from generation to generation, so the error is increasingly greater.
Some scientific studies have associated the number of misreplications with the time of onset of symptoms. It’s assumed that the greater the number of errors, the earlier presentation will occur and the worse evolution will be.
The diagnosis of Huntington’s disease
The suspicion of Huntington’s disease, in addition to the symptoms, begins with the registration of the family history. At present, there’s a greater diagnosis and it’s possible to follow the traces of entire generations that have had the mutation.
In any case, the neurological clinic continues to be part of the disorder identification process. Neurologists run the usual office tests that include reflexes and motor coordination assessment. Small deviations in these parameters are enough to raise suspicion. At the same time, this makes it possible to detect those with early onset.
The use of the electroencephalogram usually comes from patients with the infantile form who suffer from seizures. Part of the approach protocol is the performance of this test to evaluate the electrical activity of the brain. This is likely to be followed by complementary imaging methods; the most used are nuclear magnetic resonance and computed tomography.
Psychiatric evaluation is helpful in characterization but isn’t diagnostic.
Genetic diagnosis
Genetic testing is currently required when the suspicion is reliable. There are precise methods to determine the existence of the defective gene and catalog it in complete families. In any case, this is confirmatory, although it doesn’t alter the approach plan, as the protocols aren’t modified based on this information.
If a person doesn’t have symptoms, but their relatives have Huntington’s disease, they can request a genetic test to find out if they carry the defect. Once again, there’s no therapeutic benefit from knowing about the diagnosis in advance, but preparations and psychological counseling can be done.
What treatments help Huntington’s disease?
The prognosis of the disease is serious. Its evolution is inexorable and progresses towards further degeneration of the central nervous system with each passing week and month. Approaches aim to alleviate symptoms and improve quality of life to the extent possible.
Pharmacology
The use of medications is divided into those that help calm involuntary movements and those that regulate mood. There’s also ongoing research on drugs that don’t yet have full marketing authorization. Because it’s a rare disease, it’s common for patients to receive invitations to participate in these experimental protocols.
Among the pure neurological drugs, we have the following:
- Tetrabenazine: Prescribed for symptoms of chorea. It’s not free of serious side effects, such as depression.
- Risperidone: This has very specific doses of use that must be respected.
- Levetiracetam: Many times prescribed for seizures, it’s also used as an adjuvant to combat involuntary movements. Its digestive side effects are milder and more tolerable.
On the other hand, the approach to depression and mood swings isn’t a minor issue. To this must be added the psychoses that lead to hallucinations. For this, the therapeutic arsenal is as follows:
- Antidepressants: Fluoxetine and sertraline are used. Also, escitalopram is an option.
- Antipsychotics: Risperidone, sometimes indicated for movements, is useful against psychosis. You can also opt for quetiapine or olanzapine.
- Mood stabilizers: In this group, we have valproic acid and lamotrigine.
Psychological therapy
Psychological support is key in the treatment of Huntington’s disease. Changes in mood, depression, and the presence of hallucinations are serious situations that alter the person and their environment.
The sensations derived from learning about the inexorable evolution of the disease shouldn’t be underestimated. The patient knows that their worsening is progressive and that the medications are only a patch in the global context.
Physiotherapy
Exercises to support posture and muscle strength help delay dependence on third parties. In the same way, the combination with occupational therapy techniques improves performance in daily life tasks, such as moving, cooking, or bathing.
Balance is addressed in kinesiotherapy sessions so that walking isn’t as affected. If this is supported by modifications to the home with adapted steps and ramps, the time of independence is prolonged, also improving the state of mind.
Without neglecting communication problems due to speech impairment, the physiotherapist can strengthen the muscles used for posture and those of the chest and neck so that a speech therapist can provide rehabilitation techniques. A multidisciplinary team can devise information transmission methodologies that are applicable and can be carried out at home.
A disease with a poor prognosis
The evolution of Huntington’s disease is known and there’s no treatment to stop it. It’s estimated that, on average, a patient lives a maximum of 20 years after the appearance of the first signs. The causes of death vary from neurological complications to suicides.
Medical science continues to investigate the disorder, seeking cures or palliative treatments that increase survival. In any case, so far, expectations aren’t good and only temporary relief is available.
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