Nervous system Pathology Flashcards
Define gliosis
The scarring of the CNS after injury. Astrocytes and fibroblasts forms the scar after exposure to noxious agents or injury
- Astrocytes swell
- Usually there is neuronal loss
What are the signs of ischemic neuronal damage??
- Nissl substance disappears
- Cytoplasmic eosinophilia
- Nuclear condensation (pyknosis)
Define neurophagia
phagocytosis of neurons by microglia (microphages), often occurs with viral infections
What are the signs of neuronal atrophy??
- Cytoplasmic basophilia
- Nuclear pyknosis
- Increased lipofuscin and neurofibril pigment
Define central chromatolysis
Also called Axonal reaction, is the reaction of the soma to a lesion of the LMN axon
- There is swelling of the soma, with peripheral displacement of the nucleus
- Another cause is pellagra
Alzheimer is the most common form of ……. . The clinical features include ……….
Dementia
* impaired short term memory & thinking, irritability etc… . Later, aphasia & apraxia, ultimately the patient enters a vegetative state
What is the Alzheimer pathology?
- Grossly: cortical atrophy, with wide sulci and thin gyri (some primary neurons are spared)
- Microscopic: “Characterized” by neurofibrillary tangles (intracytoplasmic paired helical filaments), granules, senile plaques (enlarged presynaptic axon terminals surrounding extracellular amyloid), Hirano bodies (intracellular aggregate of actin)
Parkinson, also called ……, begins after the age of ……
paralysis agitans
40
What are the main symptoms of Parkinson disease?
Mask facies, bradykinesia, resting tremor, dementia, festinating gait
* Doesn’t affect cognitive functions
What is the cause of Parkinson disease?
Loss of dopaminergic neurons in the locus ceruleus & substantia nigra, which project to caudate nucleus and putamen
Parkinsonism is caused by …….
- Encephalitis
- Neuroleptics (anti psycosis meds, like phenothiazine)
- CO and Mn poisoning
- Strokes
- MPTP (methylphenyltetrahydropyridine), which is found in heroin
Atrophy with fasciculations indicated ……, while hyperreflexia & spastic paralysis indicate ………
LMN damage
UMN damage
* In Amyotrophic lateral sclerosis (ALS), there is degeneration of both UMN & LMN
Thrombosis in the brain usually occurs in ……
medium and large size vessels
Emboli in the brain could be sourced from ……
mural (from left ventricle), aortic or carotid plaques, septic or fat/air emboli
* Usually in medium sized vessels
Define Lacunar infarcts
Small cavities formed deep in the gray or white matter indicating occlusion of a deep artery
* Associated with hypertension
Emboli in the brain produce their deficit within ……
1 minute
* Symptoms depend on the area
Thrombotic infarcts are characterized by ….., and usually preceded by ……
permanent neural damage
transient ischemic attacks (TIAs, which resemble mini strokes)
Intraparenchymal bleeds usually are the result of ……
hypertension
* The most common cause of death from stroke
What are the clinical symptoms of stroke?
- Sudden headache with neurologic deficit
2. CSF is bloody, especially in hypertension
Berry (saccular) aneurysms are the most common cause of non traumatic …… . They are caused by …..
hemorrhage in the subarachnoid space
- caused by defect in the arterial media, atherosclerosis, or hypertension
- Usually at the bifurcation of the anterior circle of Willis
Arteriovenous fistulas are sometimes found in the CNS. T/F??
True
Define concussion, and what is the best index for its severity?
Transient paralysis of cerebral function immediately after head trauma with no structural damage.
* Measure by the severity of post traumatic amnesia
Define Contusion
is the bruising of the brain parenchyma involving the summit of the gyrus.
* There is wedge shaped necrosis (base to the meninges, apex towards white matter) with petechial hemorrhage
Epidural hemorrhage usually is the result of …….
What are the most common signs?
laceration of middle meningeal artery
- usually due to trauma to the lateral skull
- Headache, vomiting, change in vision, coma, and even death if pressure is not released sugically
- Bleeding occurs rapidly, with symptoms within the first 2 days
Subdural hemorrhage results from …….
trauma to the small bridging veins, so symptoms take some time to occur
* Hematomas lie between the dura and the arachnoid
Arachnoid hemorrhage occurs between …….
the arachnoid and pia (ie. sub arachnoid space)
* Patients describe having the worst headache of their lives
What are the signs of increased intracranial pressure?
- Headache
- Nausea, vomiting
- Papilledema (optic disk swelling)
- Autonomic changes (bradycardia, hypertension, respiratory changes)
Phakomatoses is …….
tumors of the skin, eye and nervous system
* also called neurocutaneous disorders
What are the clinical features of neurofibromatosis?
- Café au lait spots
- Neural tumors (neurofibromas)
- Lisch nodules (benign pigmented hamartomas of the iris)
Demyelination occurs primarily …… or secondarily ………
like MS
like wallerian degeneration (degeneration of the separated/crushed axon distal to the site of injury)
Guillain Barre is
an autoimmune, post infectious, peripheral demyelinating disorder
- Causes limb paralysis and autonomic failure
- Affects peripheral nerves, but facial and ocular muscles could also be affected
- Motor > sensory
Vitamin B12 deficiency is almost always due to …… . It causes …..
malabsorption rather than dietary deficiency (except for strict vegans)
* pernicious anemia (which results in CNS and PNS demyelination and axonal degeneration)
What are the effects of alcohol on the nervous system?
- Cerebellar degeneration
- Pontine demyelination
- Polyneuropathies (axonal degeneration of peripheral nerves)
- Fetal alcohol syndrome (mental retardation, microcephaly, hypotonia, irritability, characteristic facies)
Methanol intoxication is treated with …..
ethanol (because ethanol competed with methanol for alcohol dehydrogenase and prevents formation of formaldehyde)
Formaldehyde causes ……
metabolic acidosis, visual disturbances
What are the symptoms for acute meningitis?
fever, nuchal rigidity (neck stiffness), headache, photophobia, altered mental status
What are the causative agents for meningitis depending on the age group??
- Neonates: E.coli, group B streptococci, Listeria monocytogenes
- Infants and children: Streptococcus pneumoniae, H. influenzae
- Young adults: Neisseria menigitidis
- Middle age & elderly: Streptococcus pneumoniae
What are the causes for brain abscesses?
- Otitis, mastoiditis, or sinusitis extension
- Surgical wound contamination
- Trauma
- Hematogenous dissemination of infection
Cerebral abscesses are localized to the ……
parenchyma (walled of from the rest of the brain)
What are the causative agents of brain abscess?
anaerobic streptococci, staphylococci, Bacteroides, G-ve bacilli
What are the clinical features for brain abscess?
Death following herniation, or rarely, rupture with ensuing meningitis and ventriculitis
Candidiasis of the brain often results from ……
dissemination from distant sites
- It is the most common fungal infection
- There is a “mixture of yeast & pseudohyphae”
Aspergillosis, Mucormycosis & Cryptococcosis are all …..
Mycotic infections of immunocompromised patients (diabetes, steroid therapy, AIDS etc…)
* All caused by inhalation & blood dissemination of infection to the brain, resulting in meningitis
Toxoplasmosis is caused by …….., which is transferred via …… & …… .
Toxoplasma gondii
contact with infected cats feces & infected meat
* It can cross the placenta and cause congenital defects (convulsions, intracerebral calcifications, hydrocephalus, chorioretinitis of the choroid)
Mumps causes meningitis in …… of patients
25%
Rubella virus causes the congenital rubella syndrome, which is ……
chorioretinitis, low birth weight, cardiac defects, cataracts, neurologic abnormalities
What are the neurological effects of Rabies ?
Hyperactivity, abnormal behavior, autonomic dysfunction, laryngeal muscle spasm
Negri bodies are …..
eosinophilic, oval cytoplasmic inclusions, characteristic of rabies
Herpes encephalitis is caused by ……..
HSV-1
* Treated with acyclovir
CMV usually infects immunocompromised individuals causing
disseminated glial nodules (infiltrated by histiocytes)
Creutzfeldt-Jacob disease & Kuru are both caused by ……
prions
* They both cause neurological deficit
Post concussion syndrome is characterized by three of the following ……
headache, dizziness, lowered tolerance to light and noise, fatigue, irritability, amnesia, visual disturbance, confusion, cold perspiration
Seizures is defined as ……
It is of two types ….. & …..
change in the electrical activity of the brain
- partial and general
- Epilepsy is recurrent seizures
- Grand mal (tonic-clonic) seizure is tonic (loss of consciousness & muscle spasm, few seconds), followed by clonic (muscle twitching)
Lewy body is …..
protein aggregate inside the neurons of patients with Parkinson
Meningioma is …….
benign neoplasm of meninges
- F>M
- Associated with breast cancer, may be due to high estrogen
Wallerian degeneration is reversed only if ……..
the neurolemma (endoneurial sheath) is intact * Note that if the cell body is irreversibly injured, the entire neuron degenerates
