Question

What are typical neurodegenerative diseases without overt neuropathology? a. Creutzfeldt-Jakob disease b. Schizophrenia c. Essential tremor d. Torsion dystonia e. All but a

Short answer

Choices: a. Creutzfeldt-Jakob disease b. Schizophrenia c. Essential tremor d. Torsion dystonia e. All but a Answer: e. All but a

Step-by-step solution

Definition of terms

First, let's define the terms in the exercise. Neurodegenerative diseases are disorders characterized by the progressive loss of neurons, often resulting in cognitive decline or physical dysfunction. Overt neuropathology refers to the presence of visible or easily detectable brain abnormalities.

Analyzing the alternatives

Now, let's analyze each option and determine which diseases are neurodegenerative and do not have overt neuropathology: a. Creutzfeldt-Jakob disease (CJD) is a rare and fatal neurodegenerative condition characterized by rapidly progressive dementia. It involves the accumulation of an abnormal protein in the brain called a prion, which leads to severe brain damage with overt neuropathology such as spongiform changes and neuronal cell death. b. Schizophrenia is a chronic psychiatric disorder that affects an individual's thoughts, perceptions, and behaviors. While the exact cause remains unknown, it is not considered a neurodegenerative disease. c. Essential tremor is one of the most common movement disorders, characteristically causing uncontrolled shaking in various parts of the body. It is considered a neurodegenerative disorder, and overt neuropathology is not typically observed in essential tremor. d. Torsion dystonia (also called primary dystonia) is another movement disorder that results from involuntary muscle contractions and abnormal twisting postures. The pathophysiology is not entirely understood, but it is not considered a classical neurodegenerative disease like Alzheimer's or Parkinson's.

Select the correct answer

Based on our analysis, the correct answer is: e. All but a That means essential tremor (c) and torsion dystonia (d) are considered neurodegenerative diseases without overt neuropathology, while Schizophrenia (b) is not classified as a neurodegenerative disease. Conversely, Creutzfeldt-Jakob (a) is a neurodegenerative disease but has overt neuropathology.

Key concepts

Essential Tremor

Essential Tremor (ET) is a common movement disorder that often manifests as uncontrollable shaking or trembling, mainly affecting the hands and arms. It can also impact the head, voice, and legs. It tends to worsen over time and can significantly interfere with daily activities.

• Symptoms: The primary symptom is a tremor that occurs during voluntary movements, such as holding a glass, tying shoelaces, or writing.
• Causes: While the exact cause is not fully understood, it is believed to involve an abnormality in the brain regions controlling movement, such as the thalamus.
• Inheritance: It is often hereditary, with a 50% chance of being passed from parent to child if one parent has the condition.

It’s important to highlight that essential tremor is not the same as Parkinson’s disease, which often presents with tremors when the body is at rest. In essential tremor, the shaking mainly occurs during movement.

Occupational therapy and medications, such as beta-blockers or anti-seizure drugs, can help manage the symptoms. However, as of now, there is no cure for essential tremor.

Torsion Dystonia

Torsion Dystonia, also known as primary dystonia, is a movement disorder characterized by sustained muscle contractions, causing twisting and repetitive movements or abnormal postures. It's quite different from neurodegenerative disorders like Alzheimer's or Parkinson's.

• Onset: It can occur at any age but is often seen in children and young adults, and the symptoms tend to worsen over time.
• Symptoms: Symptoms can vary widely, including spasms, tremors, and would be present intermittently or persistently.
• Genetics: A subset of torsion dystonia is hereditary and follows a pattern of autosomal dominant inheritance.

The cause of torsion dystonia is not entirely understood. Unlike many traditional neurodegenerative diseases, overt neuropathology (clear structural changes in the brain) is often absent. This makes it tricky to diagnose and treat effectively.

Currently, treatment focuses on relieving symptoms and may include medication, physical therapy, or surgical interventions like deep brain stimulation to help manage the symptoms.

Schizophrenia

Schizophrenia is a complex psychiatric disorder that mainly affects an individual's mental processes like perception, thought, and behavior. It is often confused with neurodegenerative diseases but follows a different path in terms of symptoms and causes.

• Symptoms: Schizophrenia is characterized by hallucinations, delusions, disorganized thinking, and impaired concentration and memory.
• Causes: While the precise cause isn't known, a mix of genetic, environmental, and brain chemistry factors are believed to contribute to its development.
• Diagnosis: It is typically diagnosed in late adolescence or early adulthood.

Unlike neurodegenerative diseases like Alzheimer's, which involve physical neuron loss over time, schizophrenia does not cause neuron destruction but alters how the brain functions.

Treatment typically involves a combination of antipsychotic medications and psychotherapies to help manage symptoms, reduce psychotic episodes, and improve functionality.