Infections & HIV Flashcards
Meningitis is usually caused by
Spread of an infectious agent via bloodstream from an infective focus elsewhere in the body
Clinical manifestations of meningitis
Rapid onset over several days; generalized HA, fever, vomiting, lethargy, stiff neck, confusion
Neurologic complications of meningitis
Seizures, focal cerebral signs, acute cerebral edema, CN dysfx (3, 4, 6, 7), hearing loss, HP, dysphagia, hemianopsia
Brain abscess can be caused by
Infection spread from middle ear or sinus
In assoc. w/ congenital heart disease
Spread of infection from distant site
Direct intro of bacteria following PHI
Cardinal symptom of brain abscess
Relentless & progressive HA, usually followed by focal neurological signs
Pott’s disease
TB in spinal column
Early symptoms of neurosyphilis
Fatigue, irritability, personality changes, forgetfulness, tremor
Symptoms of late stage neurosyphilis
Impaired memory & judgment, confusion, disorientation, seizures, dysarthria, myoclonus, poor motor control
General paresis
Accumulation of neurosyphilis lesions causes dementia, behavioral changes, delusions of grandeur, psychosis, & diffuse UMN-type weakness
Tabes dorsalis
In neurosyphilis, there is involvement of the spinal cord dorsal roots resulting in degeneration of dorsal columns
Lyme disease
Neuro manifestations after a delay of several weeks; untreated cases eventually show WM abnormalities; may involve memory impairment & difficulty with complex cognitive fx, irritability, depressed mood
Tetanus
Affects the motor unit of the PNS
Tonic contractions eventually appear secondary to continuous activity of multiple muscle groups
Also see nuchal rigidity, lockjaw, risus sardonicus, dysphagia
Herpes simplex affects which area of the brain most?
Limbic cortex/temporal lobe
Presentation of CNS involvement of herpes simplex
Bizarre psychotic behavior, confusion, lethargy, HA, fever, meningeal signs, seizures, focal signs
Subacute sclerosing panencephalitis is caused by
persistent infection of genetically mutated forms of the measles virus that escape immune clearance; latent period of 6-8 yrs
Initial symptoms of subacute sclerosing panencephalitis
mild mental deterioration followed by myoclonic jerks, seizures, vision loss
Advanced state of subacute sclerosing panencephalitis
muscle spasms/rigidity, progressive deterioration to comatose & then persistent vegetative state
Progressive multifocal leukoencephalopathy
Demyelination of CNS due to destruction of oligodendrocytes by the JC polyoma virus (JCV)
Mostly seen in immunocompromised individuals
How does toxoplasmosis present on neuroimaging?
Ring-enhancing lesions
Common presenting features of toxoplasmosis
seizures, HA, fever, lymphocytic predominant meningitis, focal signs; general subacute encephalopathy & language impairment
Varicella-zoster
Herpes virus that causes chickenpox, becomes latent in CN & dorsal-root ganglia, & frequently reactivates decades later to produce shingles & postherpetic neuralgia
Varicella-zoster affects which cranial nerves?
5, 7, 3
Neurological complications of rabies
Delirium, seizures, nuchal rigidity, paralysis, excitabilty
Cysticercosis
Caused by ingestion of eggs of pork tapeworm, forms multiple cysts in muscles, eyes, & CNS
Seizures, HA, nausea, vomiting, lymphocytic meningitis, focal deficits
Kuru
Chronic, rapidly progressing, fatal nervous system disease caused by prions & characterized by prominent ataxia, dysarthria, tremulousness, dementia in late stages
Shows severe cerebellar loss, spongiform changes, & prion-amyloid plaques
Guillain-Barre syndrome
Post-infectious disease of peripheral myelin assoc. w/ paresthesias in the distal extremities & leg weakness
How does sarcoidosis affect the CNS?
takes form of a granulomatous infiltration of the meninges & underlying parenchyma, most frequent at base of brain
Lesions - focal collections of epithelioid cells surrounded by rim of lymphocytes
Retrovirus
Stores genetic info as RNA, releases RNA & an enzyme, making DNA using the viral RNA as a pattern; viral DNA is incorporated into host cell DNA
CDC classification of HIV/AIDS
Category A: pts who have remained medically asymptomatic or have had only a transient illness
Category B: pts w/ more serious HIV-related conditions
Category C: pts who have more serious AIDS-defining illnesses
AIDS is diagnosed in those w/ CD4<200 and/or a category C complication
What is the most common cause of CNS mass lesions in AIDS patients?
Toxoplasmosis
Common opportunistic infections in HIV/AIDS patients
Yeast infections, crytococcal meningitis, mycobacterium avium complex, cryptosporidium, PML, cytomegalovirus encephalitis, Kaposi’s sarcoma, lymphomas, toxoplasmosis
What percentage of AIDS patients may develop some form of CNS disease?
50-66%
HIV-related mild neurocognitive disorder/minor cognitive motor disorder
- Difficulty in concentrating, unusual fatigability, subjectively slowed down, mild memory
- May be seen as anxiety, depression, or hypochondriasis
- Difficulties w/ info processing speed, divided attention, sustained effortful processing, deficiencies in learning & recalling new info
- Verbal skills less affected
Diagnostic criteria for HIV-Associated dementia (HAD)
- Acquired impairment in 2 domains of cognitive fx, w/ focus in learning, slowed info processing, distractibility/inattention
- Verified by neurological, NP, or clinical eval
- Marked interference w/ daily fx
- Present for 1 mo or more
- No alteration in consciousness
- Ruling out other causative etiology
AIDS dementia complex staging scheme (Sidtis & Price)
- Stage 0 (normal)
- Stage 0.5 (equivocal/subclinical): no impairment of work or ADL performance
- Stage 1 (mild): able to perform all but more demanding asepcts of work or ADLs, can walk w/o assistance
- Stage 2 (moderate): cannot work or maintain more demanding aspects of daily life, can perform basic self-care
- Stage 3 (severe): major intellectual incapacity or motor disability
- Stage 4 (end stage): nearly vegetative
What are some psychosocial factors that should be considered with HIV/AIDS patients?
Stigmatism, may affect immediate social support, adjustment d/o, anxiety d/o, mood disorders, psychosis, substance use disorders (may/may not be pre-existing)
Asceptic meningitis
Nonbacterial meningitis, can be inflammatory, idiopathic, or viral infection
Cryptococcal meningitis
Meningitis caused by cryptococcus (yeast) infection; often result of opportunistic infection
Often presents with headache, CN involvement, & CSF obstruction
Mollaret meningitis
Recurrent asceptic meningitis of unclear origin
Mental status changes are more often associated with bacterial or viral meningitis?
Bacterial
Meningismus
Meningeal irritation often caused by meningitis or SAH, carcinomatous meningitis, or chemical sensitivity
6 common signs of meningismus
HA, lethargy, photo & phonophobia, fever, nuchal rigidity
Common symptoms of brain abscess
HA, lethargy, fever, nuchal rigidity, nausea, vomiting, seizures, focal signs
Where do epidural abcesses most often occur?
Spinal canal
Neurological symptoms of Lyme disease
Often delayed by weeks; meningeal signs, emotional changes, impaired memory & cognition
What is the most common cause of viral encephalitis?
HIV-1
Cerebritis
Focal bacterial invasion of the brain parenchyma with no associated capsule or pus
Granuloma
Focal, more or less encapsulated, chronic inflammatory lesion (e.g., sarcoidosis, syphilis, TB, fungi, larvae of intestinal parasites)
Progressive multifocal leukoencephalopathy
Demyelinating viral infection of the brain
Kaposi’s sarcoma
Tumor that appears as painless, red to purple, raised patches on skin
Lymphomas
Tumors of the immune system which may 1st appear in brain or other internal organs; pts typically present with slowly progressive neuro deterioration & may die within 3 months
The most common neurologic manifestation of HIV is
Emotional lability & delirium associated with HIV-associated dementia
