CNS Infections & Pathology Flashcards
Asplenic or complement-deficient individuals are at higher risk for infection caused by what bacteria?
N. meningitidis
What organisms are most likely to cause viral meningitis in infants, children, and adults?
Enteroviruses, Arboviruses
What is the most common arbovirus in the US?
West Nile Virus
Tabes dorsalis is a potential complication of what type of meningitis?
Neurosyphilis meningitis
What are common causes of granulomatous amebic encephalitis?
Acanthamoeba & Balamuthia mandrillaris
What is the cause of neurocysticercosis?
Ingestion of Taenia solium eggs
What is Waterhouse-Friderichsen Syndrome?
Meningitis-associated septicemia that causes hemorrhagic infarction of the adrenal glands
A 70yo woman comes to the clinic. She has developed progressive muscle weakness over the past several months. All tests are normal. The patient reports polio infection as a child and believes her symptoms are related. Is this possible?
Yes - Post-Polio Syndrome potentially due to neuronal wear and tear
This type of poliovirus disease has no CNS dissemination.
Abortive poliomyelitis
What bacterial organisms are most likely to cause acute meningitis in immunocompromised persons?
Cryptococcus neoformans, Listeria monocytogens, Toxoplasma gondii
How is the rabies virus transmitted?
Via saliva - a bite closer to the head is more likely to develop into rabies
HSV is the most common cause of acute viral meningitis in what population?
Newborns
What unusual CSF finding may be seen in an immunocompromised patient with meningitis due to Listeria?
Presence of lymphocytes. Generally, only neutrophils are present with bacterial meningitis.
A well-circumcised intraparenchymal mass due to chronic tuberculosis infection is called…?
Tuberculoma
Why is N. meningitidis known to cause skin lesions, such as papules and petechiae?
Outer membrane has lipo-oligosaccharide that triggers immune response and vascular damage
H. influenzae is most common among what populations?
Unvaccinated children, people with other medical conditions
A patient comes to the ER complaining of rapid onset, asymmetric limb weakness. CN abnormalities are present, but seizures, LOC, altered mental status, and nuchal rigidity are not. What is a potential diagnosis?
Acture Flaccid Myelitis
What enteroviruses are most associated with meningitis?
Echovirus, Coxsackievirus
What is the classic presentation of neuroborreliosis (Lyme disease meningitis)?
Aseptic meningitis, facial nerve palsy, radiculoneuritis
What is the empiric treatment for bacterial meningitis?
Ceftriaxone
True/False. Photophobia and nuchal rigidity are present in both meningitis and encephalitis, making it difficult to differentiate between the two diseases.
False. Nuchal rigidity and photophobia are NOT present in encephalitis, but may be present in meningitis and meningoencephalitis.
This is the paralyzing type of polio disease.
Paralytic poliomyelitis
What is the leading cause of viral encephalitis?
HSV-1
Where does poliovirus first target upon entering the CNS?
Motor neurons in the anterior horn of the spinal cord
What CNS cell serves as a reservoir for HIV?
Microglial cells
Arthropod viruses generally target what CNS structures?
Cortex, cerebellum, spinal cord
What will CSF analysis during viral meningitis show?
Normal/increased opening pressure, Lymphocytes, normal/decreased glucose, moderately elevated protein
The bacteria is a gram-positive diplocci and number one cause of meningitis in adults.
S. pneumoniae
Subdural empyemas (pockets of pus) are most often due to what etiology?
Bacterial infection - rarely occur in arachnoid or subarachnoid spaces
What is the morphology of the second-leading cause of meningitis in adults?
N. meningitidis - Gram negative diplocci
What is a classic finding on imaging due to toxoplasma gondii infection?
Ring-enhancing lesions
What is the inactivated form of the polio vaccine used in the US?
Salk vaccine
Brain abscesses may present with focal neurologic deficits and/or increased intracranial pressure. What are potential complications of these abscesses?
Fatal brain herniation, abscess rupture, venous sinus thrombosis
What are the most common causes of neonatal meningitis?
S. agalactiae (GBS), E. coli, Listeria monocytogenes, HSV
What is the recommended treatment for potential rabies infection?
Wound treatment, local administration of rabies immune globin, vaccination
What is the effect of the JC virus on the white matter of the brain?
Demyelination
What virus is more likely to cause severe neuroinvasive disease in children under 16yo?
La Crosse Virus
What is the morphologic composition of a brain abscess?
Necrotic purulent core, layer of granulation tissue, layer of fibrosis, surrounding gliosis
What is the normal appearance/composition of CSF?
Few cells, with a clear appearance. CSF may appear opaque with bacterial meningitis infection
What is the active form of toxoplasma gondii that causes infection?
Tachyzoites
A woman undergoes natural vaginal birth at home and arrives at the hospital shortly thereafter. While examining the mother, the physician notes active lesions from HSV infection. What medication should be used to treat the newborn given HSV exposure?
Acyclovir - C-sections are recommended for women with active HSV lesions
The temporal lobe is primarily targeted by what virus in viral encephalitis?
HSV
What is the most common cause of acquired epilepsy and intracranial masses worldwide?
Neurocysticercosis - caused by taenia solium
What is the treatment for toxoplasma gonddi retinochoroiditis and encephalitis?
Sulfadiazine & Pyrimethamine
A pediatrician is conducting an examination of a newborn several days after birth. The physician notes fluid-filled vesicles around the mouth and eyes that are beginning to ulcerate. Acyclovir treatment is immediately initiated. What is the diagnosis?
Neonatal herpes - untreated, may progress to include hepatitis, CV issues, meningoencelopalitis, cognitive issues, death
Lymphocytes are predominantly present in meningitis due to this etiology.
Viral & Fungal etiology. Neutrophils are primarily present with bacterial meningitis.
What are the most common organisms responsible for brain abscesses?
Streptococci & Staphylococci
Where does the JC virus remain dormant?
Kidney, B Cells, Monocytes
Rash, petechiae, or purpuric lesions may indicate meningitis caused by what organism?
Neissiera meningitidis
When symptoms of meningitis and encephalitis are present, patients are diagnosed with what condition?
Meningoencephalitis
What virulence factors are carried by bacteria causing meningitis?
Capsules, IgA protease, Pili, Endotoxin
What is the most important arbovirus worldwide?
Japanese Encephalitis Virus
Cytomegalovirus may occur in fetuses. What pathological findings are present?
Brain destruction followed by microcephaly and periventricular calcification
This fungus is associated with transmission via pigeon droppings or bird guano.
Cryptococcus neoformans
Biphasic fever is characteristic of what tick-transmitted disease?
Colorado Tick Fever - Arbovirus
What CNS disease is associated with measles infection?
Subacute sclerosing panencephalitis (SSPE)
This disease is inflammation of the brain parenchyma.
Encephalitis
Pili serve what bacterial function?
Attachment
Effective ART in an HIV patient may cause this disease due to an overwhelming response by the immune system.
Immune Reconstitution Inflammatory Syndrome (IRIS)
N. meningitidis is known to bind Factor H. What is the effect on immune response?
Binding to Factor H downregulates the alternative complement pathway and promotes infection
What bacterial organisms are most likely to cause acute meningitis in healthy children and adults?
S. pneumoniae, N. meningitidis, H. influenzae
What histologic findings are seen in HSV infection?
Perivascular lymphocytic inflammation & Cowdry A inclusions (viral inclusion within nucleus)
Epidural abscesses are most associated with what pathology?
Osteomyelitis
What non-laboratory, physical exam tests may be conducted to assess for meningitis?
Kernig’s Sign & Brudinski’s Sign
Symmetric myelin pallor and multinucleated giant cells may be present due to what viral disease?
HIV encephalitis
What is the appearance of the CSF due to amebic infection?
Yellow/white to gray appearance that becomes bloody
What viruses are associated with chronic CNS disease?
Measles, HIV, JC Polyomavirus
This type of poliovirus disease causes aseptic meningitis.
Nonparalytic poliomyelitis
How do viruses enter the CNS to cause encephalitis?
Cross BBB in macrophages due to increased vascular permeability, infect cells of the choroid plexus, travel via anterograde axonal transport
What is the cause of tuberculosis meningitis?
Rupture of a tuberculoma in the CNS
What will CSF analysis during fungal meningitis show?
Increased opening pressure, lymphocytes, decreased glucose, moderately elevated protein
What is the morphology of N. meningitidis?
Gram-negative coccobacillus
This disease is the inflammatory process of the leptomeninges and CSF within the subarachnoid space.
Meningitis
What is the empiric treatment for neuroborreliosis?
Doxycycline
What is the function of IgA proteases in bacteria?
Cleaves IgA at mucous membranes to facilitate entry into the body
Negri bodies are a histologic finding specific to what disease?
Rabies virus - located within cytoplasm of a neuron
This bacteria is a common cause of meningitis in the military and college campuses due to close living proximity.
N. meningitidis
What medications may be used for prophylaxis of meningitis in close contact?
Rifampin, Ciprofloxacin, & Ceftriaxone
Fungal meningitis may cause what pathology seen in the brain during autopsy?
Microbial capsules with a glistening clear appearance (“soap bubbles”)
What will CSF analysis during bacterial meningitis show?
Very increased opening pressure, neutrophils, decreased glucose, elevated protein
Naegleria fowleri is the most common amebic cause of meningoencephalitis. How does the organism enter and spread through the body?
Enters via nasal passages and migrates to the brain via the olfactory nerve. It is not transmitted via contaminated water
True/False. Rabies virus disseminates via neurons to salivary glands and tissues.
True. This is unlike most pathogens that disseminate via blood.
Brain abscesses exhibit what type of necrosis?
Liquefactive necrosis
Aseptic meningitis is generally due to what etiology?
Viral infection
What is the oral, live-attenuated form of the polio vaccine used in vaccination programs across the globe?
Sabin vaccine
Empiric treatment for fungal meningitis includes what medications?
Amphotericin B & Flucytosine
What are gitter cells?
Seen in viral encephalitis, they are microglial phagocytes with myelin debris
Immunocompromised patients with meningitis require greater antibiotic coverage. What is the empiric treatment for this population?
Cefepime (4th Generation Cephalosporin)
Where are viral inclusions of the cytomegalovirus found?
Within the nucleus, with a clear surrounding ring
What bacterial organisms are most likely to cause chronic meningitis?
M. tuberculosis, Borrelia burgdorferi, Treponema pallidum
The rabies virus generally targets what CNS structures?
Brainstem and cerebellum
Vaccines exist for S. pneumoniae, H. influenzae, and N. meningitidis. What is the only vaccine not currently considered a routine vaccine and is only recommended for at-risk populations?
Serogroup B Vacines against N. meningitidis. A conjugated vaccine also exists and is recommended regularly
These conditions may predispose an individual to the development of a brain abscess.
Acute bacterial endocarditis, congenital heart disease, chronic pulmonary sepsis
