CNS Infections and Diabetic Neuropathy (Exam 2) Flashcards
What is meningitis?
-inflammation of the meninges surrounding the brain and/ or spinal cord
-meningoencephalitis refers to inflammation of only the meninges surrounding the brain
-most commonly caused by bacterial or viral infection
What are the 3 meningitis pathogenic classifications?
1) acute pyogenic (bacteria causes pus formation)
2) acute aseptic (viral)
3) chronic (bacterial)
Which bacteria most commonly infects newborns with acute pyogenic meningitis?
E. coli and group B strep
Which bacteria most commonly infects older adults with acute pyogenic meningitis?
steptococcus pneumoniae and listeria monocytogenes
Which bacteria most commonly infects adolescents with acute pyogenic meningitis?
neisseria meningitidis
How is acute pyogenic meningitis diagnosed?
spinal tab and blood culture
What are the clinical features of acute pyogenic meningitis and acute aseptic meningitis?
-fever
-headache
-eyes sensitive to light
-neck stiffness
-irritability
note: the symptoms are the same for both types but acute pyogenic is more severe
Most cases of acute aseptic meningitis is caused by enteroviruses. The other 20% of cases are caused by what bacteria?
borrelia burgdorgeri (spirochete bacteria that causes lyme disease)
What is chronic meningitis caused by?
-TB (mycobacterium TB)
-lyme disease (spirochetal)
-neurosyphilis (spirochetal)
-fungus (cryptococcal)
-malaria protozoan (parasite)
-toxoplasmosis (parasite)
Who is most commonly infected with meningitis?
anyone who lives in close quarters
-children in daycare centers
-dorm rooms
-military barracks
What is neurosyphilis?
bacteria infection caused by treponema pallidum (STD, spirochete bacteria)
What are the tertiary stages of syphilis that affect the CNS?
1) meningovascular neurosyphilis (chronic meningitis)
2) paretic neurosyphilis (kills cortical neurons= dementia)
3) tabes dorsalis (loss of joint proprioception, pain sensation and discriminative touch)
What is tabes dorsalis?
-stage 3 of neurosyphilis
-damage to sensory axons in dorsal spinal nerve roots, dorsal horn, and dorsal white columns (medial lemniscus tract)
-damaged fasciculus gracilis will result in loss of discriminative touch and vibration
-damaged fasciculus cuneatus will result in loss of joint proprioception
What is lyme disease?
-bacterial infection caused by borrelia burgdorferi (spirochete bacteria)
-transmitted through the deer tick
-erythema migrans (bulls eye rash) occurs at tick bite site
-flu like symptoms
-knee pain
What is neuroborreliosis?
-lyme disease that spreads to CNS
-chronic meningitis
-facial nerve palsy unilateral or bilateral
-polyneuropathies
-encephalopathy
What is herpes simplex encephalitis?
-viral infection
-encephalitis of the temporal and frontal lobes
-frontotemporal lobar degeneration
-major cause of fatal sporadic encephalitis in US
-loss of cortical neurons
-fatal to newborns and immunocompromised
What is varicella zoster virus (herpes zoster)?
-viral infection
-initially chicken pox (cutaneous only)
-latent phase in adults is shingles (neurological manifestations)
-chicken pox is highly contagious contact virus that causes infection of keratinocytes
-shingles virus is dormant in dorsal root or trigeminal ganglia
-chicken pox is random vesicular blisters
-shingles is vesicular blisters that follow a dermatome
What is rabies?
-severe viral encephalitis
-transmitted to humans by the bite of a rabid animal (its in the saliva)
-carried to the CNS via retrograde axoplasmic transport!!!!!
-encephalitis
-negri bodies within CNS neurons
-widespread neuronal degradation
-foaming at the mouth and aversion to swallowing and water hydrophobia (due to contracture of the pharyngeal musculature)
What is progressive multifocal leukoencephalopathy?
-fancy word for common wart
-viral infection caused by JC polyomavirus
-demyelination of oligodendrocytes causes encephalitis (typically only effects immunocompromised, MS most as risk)
-enlarged oligodendrocyte nuclei containing glassy amphophilic viral inclusions
-lesions show an area of demyelination and reduced number of axons
What is wernicke’s encephalopathy?
-thiamine (vit B1) deficiency long term will damage mammillary bodies
-inability to absorb thiamine from intestines due to chronic alcoholism, gastric disorders, including carcinoma, chronic gastritis, or persistent vomiting
-hemorrhage and necrosis in the mammillary bodies and the walls of the 3rd and 4th ventricles
-lesions in the dorsomedial nucleus of the thalamus
-psychotic symptoms
-nystagmus
-untreated can lead to korsakoff syndrome (create memories that never happened and short term memory is distorted)
What is diabetic neuropathy?
-distal peripheral nerve damage (finger tips, toes, hands, feet)
-leaky microvessels caused by chronic DM type 1/2
-degeneration of axons and or myelin sheath
-distal symmetric polyneuropathy (numbness, paresthesia (pins and needles), and pain)
-skin ulcers which can lead to amputation
-uncontrolled hyperglycemia damages microvessels supplying axons which leads to degeneration due to decreased oxygen and NGF
-diabetic neuropathy can also affect autonomic neurons
