Neuro System Pathology 1 Flashcards
What is the most common cause of infant meningitis?
Escherichia coli. Bacterial causes of meningitis are usually more common (and also more life threatening) than other causative agents.
Infection with Clostridium botulinum is associated with what kind of paralysis?
Flaccid paralysis
What microbe causes Lyme disease?
Borrelia burgdorferi (in the Americas) and Borrelia afzeli and Borrelia garinii (in Asia and Europe)
A patient comes in with fever, nausea and vomiting, stiff neck and petechiae. What is a likely diagnosis?
Neisseria meningitidis infection
Clostridium tetani causes what kind of paralysis?
Spastic paralysis
In what tissue can hsv-1 become latent?
The sensory ganglion cells of the dorsal root (trigeminal) ganglion, in sensory neurones
How does polio cause paralysis?
By destroying motor neurons in anterior horn and medulla
Which polio vaccine is alive attenuated and given orally?
Sabin
Which polio vaccine is inactivated multivalent and injectable?
Salk
What are the two types of leprosy?
Lepromatous and tuberculoid leprosy
Which type of leprosy is less infectious and has less bacteria?
Tuberculoid leprosy
Which type of leprosy is more infectious and has lots of bacteria present?
Lepromatous leprosy
Which type of leprosy is associated with defective cellular immunity?
Lepromatous leprosy. Specifically the dysfunctional expression of IL-2 receptors.
What happens when a neuron in the central nervous system (cns) is damaged?
The neuron and target cell and cells targeting that neuron atrophy and die. It is not replaced and damage is permanent
What happens when a neuron in the peripheral nervous system is damaged?
The neuron will try to repair itself and restore function through a process called the axon reaction, which involves:
(1) Sealing the severed ends to prevent loss of axoplasm
(2) Phagocytosis of the axon and synapse distal to the damaged area by the Schwann cells
(3) Filling in of the synaptic spaces by the Schwann cells
(4) Sending out sprouts from the axon proximal to the cut ends which enter connective tissue and form a synapse with the target cell
What are two examples of intraneuronal bodies?
(1) Pick bodies, which are dense spherical masses seen in Pick’s disease
(2) Lewy bodies, which are densely packed fine filaments found in the brains of patients with Parkinson’s disease
Neurofibrillary tangles are a type of intraneuronal body seen in the brains of what types of patients?
Patients with Alzheimer’s disease, supranuclear palsy, and post-encephalitic Parkinsonism
What are the effects of glial cell reactions on the body?
(1) They protect neurons and facilitate rebuilding
(2) They are destructive and cytotoxic when out of physiological control
What causes increased intracranial pressure?
(1) Space-occupying lesions, tumors
(2) Hemorrhage
(3) Tumors
(4) Cerebral edema
(5) Hydrocephalus
What are the types of cerebral edema?
(1) Vasogenic edema - caused by increased vascular permeability
(2) Cytotoxic edema - increase in intracellular water after cell injury, such as ischemia
(3) Interstitial edema - fluid accumulation in white matter with hydrocephalus
What causes hydrocephalus?
Decreased absorption or overproduction of csf
What is the major constituent of the white matter in the cns?
Myelin (which contains fat that gives white matter its distinct hue).
What are the two categories into which diseases of myelin may be grouped?
(1) Acquired diseases of myelin-previously normal myelin degenerates
(2) Hereditary myelin diseases, leukodystrophies - abnormal myelin from hereditary metabolic defects
Where are inclusion bodies found that are diagnostic features of viral infection in the brain?
(1) Herpes simplex, herpes zoster, and papovavirus - found in the nucleus
(2) Rabies - found in the cytoplasm
(3) Cytomegalovirus - found in nucleus and cytoplasm
What organisms cause bacterial meningitis?
Escherichia coli, main cause in newborns
Haemophilus influenzae B
Streptococcus pneumoniae, main cause in adults
Neisseria meningitidis, epidemic meningitis
What are the symptoms of encephalitis, a condition in which bacteria infect the brain?
Fever
Nausea and vomiting with neck pain
Focal neurological abnormalities
Seizures
Cognitive changes
What are Argyll-Robertson pupils?
A small, irregular pupil occurring in neurosyphilis in which the pupil accommodates normally with convergence but does not react to light.
What occurs with a brain abscess?
Acute inflammatory reaction and edema, followed by liquefaction necrosis, and increased intracranial pressure.
What are the subtypes of viral encephalitis?
Eastern equine
Western equine
St. Louis encephalitis
What is the vector for all subtypes of viral encephalitis?
Mosquitoes and birds
What viruses are known to cause viral meningitis?
Varicella zoster, Herpes simplex, HIV, influenza, and mumps
What symptoms are associated with rabies?
(1) Depression
(2) Malaise
(3) Fever
(4) Restlessness followed by uncontrollable excitement
(5) Excessive salivation
(6) Painful spasms of laryngeal and pharyngeal muscles
(7) Exhaustion, asphyxia, general paralysis and death if not treated within 3-10 days of onset of symptoms
What structures are affected by poliovirus infection?
Motor neurons of the anterior horn of the spinal cord, medulla, cerebellum, and motor cortex.
What is a potential neurological sequelae of natural measles infection?
Subacute sclerosing panencephalitis (sspe)
What neurological infection occurs in immunocompromised and late-stage AIDS patients?
Progressive multifocal leukoencephalopathy (pml)
What are the symptoms of Creutzfeldt-Jakob disease?
Severe, rapidly developing dementia, myoclonus, and death.
What is the most common site of cerebral infarction?
Middle cerebral artery, causing contralateral paralysis, motor and sensory defects, and aphasia. This is because it has direct blood flow from the internal carotid artery.
What is the most frequent cause of intracranial hemorrhage?
Hypertension
What is a hemorrhagic stroke?
Acute bleeding into the brain tissue
What is the most common cause of subdural hematoma?
Head trauma, frequently affecting the elderly, hemophiliacs, and alcoholics.
What is an epidural hematoma?
Hemorrhage from skull fracture or blunt trauma that causes bleeding between the skull and dissected dura.
What are the symptoms of hypertension encephalopathy?
Headache and vomiting that develop into lethargy, coma and death.
What is an acute subdural hematoma?
Bleeding from bridging veins accumulating between the dura mater and arachnoid
What is the definition of a concussion?
Transient posttraumatic loss of awareness or memory that lasts seconds to minutes without causing major damage to the brain.
What are the symptoms of postconcussion syndrome?
Dizziness, depression, apathy, variable amnesia, and headaches.
What types of damage occurs to the spinal cord as a result of trauma?
(1) Hemorrhage confined to cervical gray matter - lower motor neuron damage
(2) Laceration or transaction - loss of sensation and reflexes below level of injury, flaccid paralysis becoming spastic paraplegia
(3) Incomplete laceration - loss of function that depends on tract affected
(4) Spinothalamic tract damage - loss of temperature, pain, light or deep touch
(5) Posterior column damage - loss of vibration, posture, light touch
Where do tumors of the brain and brainstem occur in adults and children?
(1) Adults - above the tentorium cerebelli
(2) Children - below the tentorium cerebelli
What are the clinical effects of neoplasms?
(1) Destruction of functional neural tissue causes motor, sensory, cognitive or combination neurological deficits.
(2) Irritation of an area causes involuntary loss of activity, such as a seizure.
(3) As the neoplasm grows, its mass increases intracranial pressure and causes headaches and vomiting.
Medulloblastomas occur most frequently in what patient population?
Children
What are the three types of tumors of peripheral nerves?
(1) Schwannomas - arising from Schwann cells
(2) Neurofibromatosis - arising from Schwann cells
(3) Von Recklinghausen’s neurofibromatosis - commonly associated with cafe-au-lait spots
What are the symptoms of multiple sclerosis?
A variable clinical course with exacerbations and remissions, weakness of the lower extremities, visual and sensory disturbances, loss of bladder control, and mental deterioration.
What is perivenous encephalomyelitis?
An acute demyelinating disorder occurring 7-14 days after an infection or vaccination.
What often precedes Guillain-Barre syndrome?
Viral infection, immunization, or allergic reaction
What are the symptoms and characteristics of Alzheimer’s disease?
(1) Loss of short-term memory, progressing to loss of long-term memory
(2) Neuritic plaques
(3) Neurofibrillary tangles
(4) Granulovacuolar degeneration
(5) Atrophy of the cerebral cortex
What is the most common type of spinocerebellar degeneration?
Friedreich’s ataxia, usually seen in people of European descent.
What structures are affected in Huntington’s chorea?
Degeneration and atrophy of the basal ganglia and frontal cortex
What are the symptoms of Parkinson’s disease?
(1) Resting, pill-rolling tremor
(2) Masked, expressionless face
(3) Slow movements
(4) Muscular rigidity
(5) Shuffling gait
What occurs in amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease)?
Degeneration of upper and lower motor neurons, with atrophy of skeletal muscle
What is Wernicke-Korsakoff’s syndrome?
A disease, also known as alcoholic encephalopathy, that results in confusion, ataxia, and paralysis from thiamine deficiency.
What is the most common cause of vitamin B12 deficiency?
Malabsorption, particularly malabsorption caused by pernicious anemia.
What is Wilson’s disease?
An autosomal recessive disease of copper metabolism causing a decrease in serum ceruloplasmin and an increase in copper in the liver, kidney, brain, and cornea.
What do storage diseases have in common?
They are all caused by autosomal recessive inborn errors of metabolism
Tay-Sachs disease most commonly affects what group of people?
Jewish families of Eastern European origin
What are the symptoms of Hurler’s disease?
(1) Progressive mental retardation, deterioration
(2) Dwarfism
(3) Stubby fingers
(4) Corneal clouding
(5) Early death
What are some of the causes of peripheral neuropathy?
(1) Diabetes mellitus
(2) Uremia
(3) aids
(4) Nutritional deficiencies
(5) Mechanical compression or entrapment
(6) Direct trauma
(7) Fracture, dislocations, and penetrating injuries
What is a common example of entrapment neuropathy?
Carpal tunnel syndrome
What are the genetic characteristics of Trisomy 21 (Down’s syndrome)?
Trisomy 21 is an autosomal disorder in which an additional chromosome 21 is present from abnormal egg cell meiosis
Phenylketonuria is a genetic inability (because of the lack of phenylalanine hydroxylase) to convert phenylalanine into what amino acid?
Tyrosine
