Lecture 20 - Neurological Problems Flashcards
What is the second most frequent cause of death worldwide?
Stroke
What is the likelihood of having a stroke after age 45?
The chances of having a stroke double each decade after age 45 and reach 1 to 2% per year by age 75.
What is atherosclerosis?
A condition where arteries develop a layer of plaque (cholesterol, fats, calcium, and cellular waste), leading to narrowed arteries and increased risk of strokes and heart attacks.
What are the risk factors for atherosclerosis?
Age, high blood pressure, smoking, diabetes, high cholesterol, obesity, poor diet, and lack of exercise.
Where do atherosclerotic plaques typically form?
In the internal carotid artery, which supplies blood to the cerebral hemispheres.
What is ischemic stroke?
A type of stroke caused by a blood clot (thrombus) or a piece of tissue (embolus) blocking a cerebral blood vessel, reducing blood flow to the brain.
What is the difference between a thrombus and an embolus?
A thrombus is a blood clot that forms within a blood vessel, while an embolus is a clot or tissue that travels from another part of the body and blocks a blood vessel.
What percentage of strokes are ischemic?
87% of strokes are ischemic.
What is a hemorrhagic stroke?
A stroke caused by the rupture of a cerebral blood vessel, often involving small arteries and leading to brain hemorrhage.
How can the size of a stroke’s affected blood vessel impact brain damage?
The amount of brain damage can vary greatly depending on the size of the affected blood vessel, from negligible to massive damage.
What are “clot-busting” drugs used for ischemic strokes?
Thrombolytics, such as tissue plasminogen activator (tPA), which dissolve blood clots to restore circulation, especially effective within 3-4 hours of a stroke.
What treatments are commonly used after a stroke?
Drugs to reduce swelling and inflammation, physical therapy, speech therapy, occupational therapy, and exercises like constraint-induced movement therapy.
What is a tumor?
A mass of cells that grow uncontrollably and serve no useful function.
What is the difference between malignant and non-malignant tumors?
Malignant tumors are cancerous, lack a distinct border, and can spread (metastasize), while non-malignant tumors are benign, have distinct borders, and cannot metastasize.
What does “metastasis” mean?
The process by which cancer cells break off from a tumor and travel through the bloodstream to grow in other parts of the body.
How can tumors damage the brain?
Tumors can damage brain tissue through compression, which can block cerebrospinal fluid flow and cause hydrocephalus, or through infiltration, where cancerous cells invade surrounding tissue.
What are gliomas?
Malignant brain tumors originating from glial cells, known for rapid growth and resistance to chemotherapy and radiation.
What is a meningioma?
A non-malignant brain tumor that forms from cells of the meninges (the protective membranes around the brain) and is often located between the cerebral hemispheres.
What is encephalitis?
Inflammation of the brain caused by infections, toxic chemicals, or allergic reactions, with symptoms including headache, fever, and nausea.
What is meningitis?
Inflammation of the meninges, usually caused by viral or bacterial infections, with symptoms like headache and stiff neck.
What is polio?
A viral disease that destroys motor neurons in the brain and spinal cord, leading to paralysis.
How is rabies transmitted?
Rabies is a viral disease transmitted through the bite of an infected animal, causing brain damage and death.
What does herpes simplex virus cause in rare cases?
Encephalitis and brain damage.
What is a closed-head injury (concussion)?
A brain injury caused by a blow to the head, causing the brain to strike the inside of the skull (coup) and then rebound (contrecoup).
What is an open head injury?
A brain injury caused by a penetrating object that damages blood vessels and increases pressure within the brain.
What is traumatic brain injury (TBI)?
A serious injury to the brain that can cause long-term neurological issues, including scarring, seizures, and increased risk of Alzheimer’s disease later in life.
How common is traumatic brain injury (TBI) in the United States?
Approximately 1.4 million people visit the ER for TBI, 270,000 are hospitalized, and 52,000 die from it annually.
What is the most common cause of seizures?
The most common cause of seizures is scarring, which often relates to an injury, a stroke, a growing tumor, or a developmental brain abnormality.
What are other causes of seizures besides scarring?
Other causes include high fevers (especially in young children) and withdrawal from GABA agonists, such as alcohol and barbiturates.
What does “idiopathic” mean in relation to seizures?
Idiopathic means that the cause of the seizure is unknown. Some contributing gene mutations have been identified.
How do gene mutations contribute to seizure disorders?
Gene mutations affect the amount or function of ion channels in the brain, the wiring of excitatory and inhibitory neurons, and the rules that govern synaptic plasticity, causing neural network instability.
What is the preferred term for epilepsy?
The preferred term for epilepsy is seizure disorder.
Do most seizures involve convulsions?
No, most seizures do not involve convulsions of the body. The seizures that do involve convulsions activate neurons in the motor system.
What is a convulsion?
A convulsion is a violent sequence of uncontrollable muscle movements caused by a seizure.
What is a partial (focal) seizure?
A partial (focal) seizure begins at a specific focus in the brain and remains localized. It does not generalize to the rest of the brain.
What is the difference between a simple and a complex partial seizure?
A simple partial seizure does not involve loss of consciousness, while a complex partial seizure causes loss of consciousness.
What is a generalized seizure?
A generalized seizure involves most of the brain, including tonic-clonic seizures, atonic seizures, and absence seizures.
How can seizures spread across the brain?
Seizures can spread across neighboring areas of the brain within and across episodes.
What is an aura in the context of seizures?
An aura is a sensation that precedes a seizure, and its exact nature depends on the location of the seizure focus.
What happens during a tonic-clonic seizure?
A tonic-clonic seizure typically starts with an aura, followed by a tonic phase (muscle contraction) and then a clonic phase (rhythmic jerking movements).
What is the tonic phase of a tonic-clonic seizure?
The tonic phase is the first phase, where all of the patient’s skeletal muscles are contracted.
What is the clonic phase of a tonic-clonic seizure?
The clonic phase is the second phase, characterized by rhythmic jerking movements.
Are children more susceptible to seizure disorders?
Yes, children are especially susceptible to seizure disorders, often experiencing absence seizures instead of tonic-clonic episodes.
What are absence seizures (petite mal seizures)?
Absence seizures are generalized complex seizures where a person stops what they’re doing, stares off into the distance, and blinks repeatedly. They usually last less than 15 seconds.
What drugs are used to treat seizure disorders?
Seizure disorders are treated with anticonvulsant drugs, such as benzodiazepines, which increase the effectiveness of inhibitory synapses.
How do anticonvulsant drugs help in treating seizure disorders?
They increase the effectiveness of inhibitory synapses, helping to prevent seizures.
What happens if anticonvulsant drugs don’t work for seizure disorders?
If drugs don’t help, the seizure foci may remain irritable, and brain surgery might be required.
What types of toxins and viruses can impair fetal brain development?
Toxins like organophosphates (from insecticides) and heavy metals (e.g., lead and mercury), as well as viruses like rubella and Zika, can impair fetal brain development.
How does alcohol affect fetal brain development?
Alcohol consumption during pregnancy can cause babies to be smaller and develop more slowly. Fetal alcohol syndrome can occur, leading to facial anomalies and severe intellectual disabilities.
What is phenylketonuria (PKU)?
PKU is a hereditary disorder caused by the absence of an enzyme that converts phenylalanine to tyrosine. This leads to brain damage unless treated with a special diet.
What is Tay-Sachs disease?
Tay-Sachs disease is a fatal, inherited metabolic storage disorder where a lack of an enzyme causes accumulation of waste products in the brain, leading to cell swelling and damage.
What causes Down syndrome?
Down syndrome is caused by having an extra twenty-first chromosome. It leads to moderate to severe intellectual disability and physical abnormalities.
How does Down syndrome affect the brain after age 30?
After age 30, the brains of people with Down syndrome begin to degenerate in a way similar to Alzheimer’s disease.
What is multiple sclerosis (MS)?
MS is an autoimmune disease that damages the myelin sheaths in the central nervous system, causing neurological disorders due to demyelination.
What happens to axons in multiple sclerosis?
In MS, the myelin sheaths are attacked by the person’s immune system, leading to demyelination. This prevents successful action potential propagation along axons.
Where does damage occur in multiple sclerosis?
Damage occurs in the white matter of the brain and spinal cord, resulting in a wide variety of neurological disorders.
What is the typical progression of symptoms in Multiple Sclerosis (MS)?
MS symptoms go through cycles of flare-ups (relapsing) followed by periods of remission. Over time, this is usually followed by progressive MS, which involves a continuous increase in symptoms.
What are two medications used to help manage Multiple Sclerosis?
- Interferon β – A protein that modulates immune system activity.
- Glatiramer acetate – Peptides that mimic myelin (acts as a decoy).
What environmental factor is associated with a higher likelihood of developing Multiple Sclerosis?
People who grew up far from the equator are more likely to develop MS. One theory is that a childhood disease disrupts the immune system, causing it to attack healthy myelin later in life.
What is Transmissible Spongiform Encephalopathy?
A contagious disease causing widespread brain degeneration, making the brain look like a sponge. It includes diseases like mad cow and Creutzfeldt-Jacob disease. It’s caused by the accumulation of misfolded prion proteins.
What is a prion protein?
A prion is a misfolded protein that causes other copies of the same protein to misfold. This spreads the issue throughout the brain and can lead to neurodegeneration.
How do prion diseases spread?
Prion diseases spread from cell to cell and from animal to animal through contact with misfolded prion proteins. The misfolded proteins cause other proteins to misfold as well.
What is unique about prion proteins as infectious agents?
Prion proteins are the only infectious agents made solely of protein. All other infectious agents (viruses, bacteria, fungi, parasites) contain nucleic acids (DNA or RNA).
What causes Huntington’s disease?
Huntington’s disease is caused by a mutation in the Huntingtin gene, leading to the misfolding of the huntingtin protein. It is a dominant mutation, so one bad copy of the gene is enough to cause the disease.
Where does the huntingtin protein accumulate in Huntington’s disease?
The huntingtin protein accumulates in the basal ganglia, causing degeneration of this area.
When do symptoms of Huntington’s disease usually begin?
Symptoms of Huntington’s disease typically begin between ages 30 and 50, and death occurs 15-20 years later.
What are the primary symptoms of Huntington’s disease?
Symptoms include lack of coordination, jerky involuntary limb movements, dementia, and eventually death. The movements appear as fragments of purposeful movements but happen involuntarily.
What is antisense therapy in the context of Huntington’s disease?
Antisense therapy involves introducing antisense DNA (or RNA) to bind with mRNA, preventing it from being translated into protein. This approach aims to alter gene expression in living patients.
Is there a cure for Huntington’s disease?
There is no cure for Huntington’s disease. Although antisense gene therapy shows potential, recent clinical trials have not been successful.
What causes Parkinson’s disease?
Parkinson’s disease is caused by the degeneration of dopamine-producing neurons in the substantia nigra, located in the midbrain, often accompanied by aggregates of misfolded alpha-synuclein proteins.
What are the symptoms of Parkinson’s disease?
Symptoms include muscle rigidity, slowness of movement, shaking, difficulty walking, and, eventually, dementia. People with Parkinson’s have increasing difficulty initiating purposeful movement.
What percentage of the population is affected by Parkinson’s disease?
Parkinson’s disease affects approximately 1% of the population, typically appearing after the age of 60.
Is there a cure for Parkinson’s disease?
There is no cure for Parkinson’s disease, but there are treatments that can alleviate motor symptoms.
What other symptoms develop as Parkinson’s disease progresses?
As Parkinson’s progresses, cognitive, emotional, and sleep disturbances can occur, but there are currently no effective treatments for these symptoms.
