Diseases of the CNS and Neurodegenerative Disorders

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Questions and Answers

What is the definition of a brain abscess?

A localized area of inflammation in the brain.

A localized area of suppuration of brain tissue. (correct)

A localized area of necrotic brain tissue.

A diffuse area of infection throughout the brain.

Which of the following is NOT a route of infection for brain abscesses?

Direct extension from adjacent infections.

Via cerebrospinal fluid.

Hematogenous spread.

Exposure to environmental toxins. (correct)

Which condition involves localized areas of inflammation in the heart?

Endarteritis obliterans.

Endocarditis. (correct)

Brain abscess.

Conjunctivitis.

What is a common symptom that might accompany conjunctivitis?

Discharge from the eye. Signup and view all the answers

Which term refers to the inflammation of blood vessels that can lead to insufficient blood flow?

Endarteritis obliterans. Signup and view all the answers

What condition can result from obstruction of cerebrospinal fluid (CSF)?

Hydrocephalus Signup and view all the answers

Which cranial nerves are commonly associated with arthritis-related palsies?

3rd and 5th Signup and view all the answers

What is a potential complication from thrombophlebitis?

Cranial nerve compression Signup and view all the answers

What is a common pathway for cerebrospinal fluid to the subdural and extradural spaces?

Hydrocephalus Signup and view all the answers

Which condition is least likely to cause cranial nerve compression?

Otitis Media Signup and view all the answers

What are the primary components that make up brain substance?

Neurons and supporting glial cells Signup and view all the answers

Which type of glial cell is primarily responsible for providing nutritional support in the brain?

Oligodendrocytes Signup and view all the answers

Astrocytes play which crucial role in the brain's functionality?

They provide structural support. Signup and view all the answers

Which of the following is NOT a component of brain substance?

Erythrocytes Signup and view all the answers

What is the role of neurons in brain substance?

To transmit electrical signals Signup and view all the answers

Study Notes

Diseases of the CNS

The nervous system is distinct from other systems as each part of the brain has specialized functions.
Brain tissue is composed of neurons (nerve cells and fibers) and supporting glial cells (astrocytes, oligodendrocytes, microglial cells).

Neurodegenerative Diseases

Characterized by progressive loss of neurons, particularly those with intricate functional connections.
Affect various brain regions, including the hippocampus and cortex (cognitive changes), basal ganglia (movement disorders), and cerebellum (ataxia).
Alzheimer's disease is a common form, often linked to protein aggregates (Aβ and tau).
Parkinson's disease is a neurodegenerative disorder resulting from dopaminergic neuron loss in the substantia nigra, leading to symptoms such as tremor, rigidity, bradykinesia, and instability.

Increased Intracranial Pressure

Defined as CSF pressure exceeding 15 mmHg (200 mm water) in the lateral decubitus position.
Potential causes include space-occupying lesions, cerebral edema, and obstructive hydrocephalus.
Common symptoms include projectile vomiting, headache, papilledema, and decreased level of consciousness.

Meningitis

Inflammation of the leptomeninges (membranes covering the brain and spinal cord) and the subarachnoid space.
Types include acute pyogenic (bacterial), acute lymphocytic (viral/tuberculosis), and chronic (bacterial/fungal).
Infection routes can be via the bloodstream (most common) or direct implantation.
Common causative organisms for acute pyogenic meningitis include E. coli (neonates), H. influenzae (infants and children), N. meningitides (adolescents and young adults), and pneumococcus (very young and old).

Clinical Picture of Meningitis

General signs of infection, including fever, malaise, and rigor, and petechial eruption.
Meningeal irritation signs, such as headache, neck stiffness, photophobia, and irritability are common findings.

Complications of Meningitis

Infection spread to the ventricles, extradural spaces, or thrombophlebitis.
Possible complications include arthritis, otitis media, endocarditis, and conjunctivitis.
Healing can lead to fibrosis, obstructive hydrocephalus, compression of cranial nerves, and brain infarcts.

Brain Abscess

Localized brain tissue suppuration.
Infection routes include direct implantation (trauma), local extension (e.g., mastoiditis), and hematogenous spread (e.g., from endocarditis).
Common causative organisms are Staphylococcus aureus, Streptococcus species, and pneumococci, and E. coli.

CNS Trauma

Includes epidural hematoma, subdural hematoma, and traumatic parenchymal injuries (concussion, diffuse axonal injury, contusion).

Concussion

Transient loss of consciousness following head trauma.
Associated symptoms like widespread paralysis, seizures and memory loss about the trauma are common.
Typically resolves within hours or days with complete recovery, with no lasting anatomical lesion.

Hydrocephalus

Abnormal dilatation of the ventricular system due to excessive cerebrospinal fluid with brain tissue atrophy.
Types include communicating and non-communicating hydrocephalus.

Brain Tumors (Primary)

Benign tumors can be fatal if located in critical positions.
Usually infiltrative, making complete resection impossible.
They rarely metastasize but can spread through the cerebrospinal fluid.
Symptoms arise from local effects and from increasing intracranial pressure.

Tumors of the Nervous System

Classification includes primary parenchymal, primary non-parenchymal, and metastatic tumors.
Primary parenchymal tumors originate from neuroglia (e.g., astrocytes, oligodendrocytes, ependymal cells).
Primary non-parenchymal tumors originate from meninges, nerve sheath cells (e.g., schwannomas, neurofibromas), pituitary gland, or craniopharyngioma, and epidermoid/dermoid cysts.
Common primary brain tumors include meningiomas.
Metastatic tumors are the spread of cancer to the brain from other sites (e.g., lung, breast, skin, kidney, gastrointestinal tract).

Meningioma

Often arises in the front half of the cranial cavity (hemispheric convexity).
Develops from meningothelial cells of the arachnoid.
Represents about 20% of primary brain tumors.
Usually occurs in middle to later life and more common in females.

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Description

Explore the intricate world of central nervous system diseases, focusing on neurodegenerative disorders such as Alzheimer's and Parkinson's disease. This quiz covers the anatomical and functional aspects of the brain along with the implications of increased intracranial pressure. Test your knowledge on the specialized functions of brain regions and the effects of neuron loss.