Diseases of the Nervous System

These flashcards cover various diseases of the nervous system, including bacterial and viral meningitis, rabies, encephalitis, listeriosis, and Hansen's disease, based on the lecture material.

Alzheimer's Disease

A nervous system disorder characterized by neurofibrillary tangles, amyloid-plaque deposits, and brain cell damage.

Multiple Sclerosis

A condition characterized by damage to the myelin sheath.

Peripheral Neuropathy

A condition characterized by damage to nerve endings.

Gut-brain axis

The connection where resident microbes in the gastrointestinal tract exert influence on nervous system functions such as movement, behavior, cognition, and emotion.

Meninges

Three layers of tissue that surround the brain and spinal cord, consisting of the dura mater, arachnoid mater, and pia mater.

Bacterial Meningitis

An inflammation of the meninges membranes covering the brain and spinal cord, diagnosed by culturing cerebrospinal fluid.

Necrosis

The death of tissues in a given area, which can be caused by meningitis.

Acute Meningitis

Meningitis acquired from carriers or endogenous organisms that gain access to the meninges directly or spread through the blood from other infections like pneumonia.

Chronic Meningitis

Meningitis with an insidious onset over weeks, occurring as an extension of underlying slow-growing bacterial diseases like syphilis or tuberculosis.

Meningococcal Meningitis

Meningitis caused by the bacterium Neisseria meningitidis, which has a mortality rate of about $85\%$ when untreated.

Waterhouse-Friderichsen syndrome

A complication of meningococcal meningitis where meningococci invade all parts of the body (sepsis), leading to death within hours from endotoxin shock.

Petechial skin rash

A rash that does not fade when pressed, sometimes seen in meningitis patients due to hemorrhaging.

Haemophilus influenza type B (hib)

A bacterium that was the leading cause of bacterial meningitis in infants prior to vaccine development and remains the leading cause of mental retardation worldwide.

Pneumococcal Meningitis

The most common cause of meningitis among adults, caused by Streptococcus pneumoniae, often spreading from lung, sinus, or ear infections.

Listeriosis

A foodborne disease caused by the Gram-positive bacillus Listeria monocytogenes, which can cross the blood-brain barrier and the placenta.

L-forms

Listeria bacilli that have shed their cell walls and are surrounded only by a plasma membrane, allowing them to potentially survive longer after phagocytosis.

Brain Abscesses

Infections that grow in mass and compress the brain, often reaching the brain from head wounds or via blood from another site.

Viral Meningitis

A usually self-limiting and nonfatal inflammation of the meninges, with approximately $40\%$ of cases caused by enteroviruses.

Rabies virus

An RNA-containing rhabdovirus transmitted via animal bites that migrates from injured tissue through nerves to the spinal cord and brain.

Hydrophobia

A symptom of rabies where throat muscles undergo painful spasms, especially during swallowing.

Aerophobia

A fear of moving air that occurs in rabies patients because the skin is hypersensitive to any sensation.

Negri bodies

Structures seen in brain tissue used as a postmortem diagnosis method for rabies.

Encephalitis

An inflammation of the brain caused by togaviruses or flaviviruses, often introduced through the bites of infected mosquitoes.

Eastern Equine Encephalitis (EEE)

A serious necrotizing brain infection with a fatality rate of $50\%$ to $80\%$, where swamp birds are the major reservoir.

St. Louis Encephalitis (SLE)

A viral brain inflammation occurring in late summer epidemics that may cause malaise, myalgia (muscle pain), and altered states of consciousness.

Myalgia

A term for muscle pain, noted as a symptom of St. Louis Encephalitis.

Chagas Disease

A disease caused by Trypnosoma cruzi, characterized by the formation of pseudocytes in lymph nodes and the destruction of nerve ganglia.

Pseudocytes

Aggregates formed by Trypnosoma cruzi parasites as they divide within lymph nodes.

Hansen’s Disease (Leprosy)

An illness caused by the acid-fast bacillus Mycobacterium leprae, occurring in Tuberculoid and Lepromatous forms.