LGS Flashcards
What is encephalitis?
Acute inflammation within the brain
Most common cause is viral infections.
What are the signs and symptoms of encephalitis?
Headache, Acute Fever, AMS, Confusion, Seizures, Motor Weakness
Complications include coma and death.
What is meningitis?
Inflammation of the meninges
Classic triad includes sudden fever, neck stiffness, and AMS.
What is the classic triad of meningitis?
Sudden Fever, Neck Stiffness, AMS
Additional symptoms include headache, nausea, vomiting, muscle soreness, photophobia, and seizures.
What is myelitis?
Inflammation of the spinal cord.
In cases of altered mental status, what conditions should be considered?
Encephalitis or meningoencephalitis, usually arising from viral infections.
What are the causative organisms of encephalitis?
- Arboviruses
- HSV-1
- HHVs
- Measles
- Etc.
What are the causative organisms of meningitis?
- S Pneumo
- GBS
- N Meningitidis
- H Influenzae
- Listeria
- E Coli
- Etc.
Capsules help bacteria cross BBB
What are risk factors for developing meningitis?
- High population living areas
What are risk factors for developing encephalitis?
- Exposure to viruses such as HSV and Measles
- Unvaccinated individuals
- Mosquitos
- Immunodeficiency
- Pregnancy
When is a lumbar puncture indicated?
If there is a possibility of meningitis
Empiric antibiotics should be given immediately.
What is the recommended antibiotic treatment for a patient over 50 with suspected meningitis?
- Third Gen. Cephalosporin
+ Ampicillin
+ Vancomycin
Ampicillin covers Listeria, Vanc covers gram (+)
When should dexamethasone be administered?
Before or at the same time as initiating antibiotics
It helps decrease ICP, cerebral edema, and neuronal injury.
What are the indications for a CT before a lumbar puncture?
- Focal neurologic deficit
- AMS or deteriorating level of consciousness
- New onset seizure
- Papilledema
- Immunocompromised state
- Hx of focal CNS lesion
- Age > 60
What characterizes N. Meningitidis?
- Gram Neg. Diplococci
- Chemoprophylaxis recommended
- Rapid progression
- Grown on Thayer-Martin Media
What types of vaccines are available for N. Meningitidis?
- Serogroup B Meningococcal Vaccine
- Conjugate Vaccine for Serotypes A, C, W, and Y
What is supportive therapy for encephalitis and meningitis?
- Airway protection
- Seizure control
- Analgesics
- Antipyretics
What is Naegleria Flowleri associated with?
Primary amoebic meningoencephalitis
Opportunistic in HIV and immunocompromised patients.
What is Acanthamoeba associated with?
Keratitis and granulomatous amoebic encephalitis
Contaminated contact lens solutions.
What are prevention strategies for encephalitis and bacterial meningitis?
- Practice good hygiene
- Vaccinations
- Avoid sharing utensils
- Protect against mosquitoes and ticks
- Eliminate standing water
What is the treatment for GAE and PAM?
- Amphotericin B
- Azoles
- Antibiotics
- Miltefosine
What is the GCS of a patient with significant altered mental status?
A GCS of 7 or lower indicates coma.
What distinguishes meningitis from encephalitis?
Encephalitis presents with a significantly altered mental status.
What is the structure of California Encephalitis Virus?
Segmented, 3 circular segments, (-)ssRNA
Spread by Aedes mosquitoes.
Should dexamethasone be given to neonates with meningitis?
No, there is no proven benefit in neonates.
Dexamethasone is not recommended for neonates due to lack of evidence supporting its effectiveness.
Is there a benefit to giving dexamethasone to infants and children?
Yes, there is a benefit in cases of H Influenzae.
Dexamethasone can be beneficial in treating infections caused by H Influenzae in infants and children.
What is the main serogroup targeted by the Serogroup B Meningococcal Vaccine?
Serotype B
Serotype B is the predominant cause of meningococcal disease in adolescents and young adults.
What key protein does the Serogroup B Meningococcal Vaccine contain?
Factor H Binding Protein
This protein is crucial for the vaccine’s mechanism of action.
What is the role of Factor H in the context of the immune response?
Degradation of C3
Factor H helps regulate the complement system, preventing excessive immune response.
How does Factor H protect cells from being tagged for phagocytosis?
By preventing C3b tagging
C3b is a protein that marks cells for destruction by phagocytes.
What pathway does C3B activate?
Alternate Complement Pathway
This pathway is a part of the immune system that enhances the ability to clear pathogens.
If Factor H is bound, what happens to its protective role?
It cannot protect the cells but can protect the bacteria
This highlights the dual role of Factor H in immune evasion.
What family do the Eastern Equine Encephalitis and Western Equine Encephalitis viruses belong to?
Togaviridae
What are the dead-end hosts for the Eastern and Western Equine Encephalitis viruses?
Horses and Humans
Which organisms serve as live reservoirs for the Eastern and Western Equine Encephalitis viruses?
Swamp Dwelling Birds
What types of mosquitoes are associated with the Western Equine Encephalitis virus?
Aedes and Culex
What type of vaccine is available for both Eastern and Western Equine Encephalitis viruses?
Inactivated/Killed Vaccine
What is the primary reservoir for the Venezuelan Equine Encephalitis virus?
Rodents
Where is the Venezuelan Equine Encephalitis virus primarily located?
South America
How is Venezuelan Equine Encephalitis virus controlled?
Live Vaccination of Animals
What family does the California Encephalitis virus belong to?
Bunyaviridae
What is the structure of the California LaCrosse Virus?
Segmented – 3 Circular Segments; (-)ssRNA
What type of mosquito is responsible for spreading the California Encephalitis virus?
Aedes
What is the reservoir for the California Encephalitis virus?
Small Mammals– Chipmunks, Squirrels, or Forest Rodents
Is there a vaccine available for the California Encephalitis virus?
No Vaccines– Mosquito Control
What family does the St. Louis Encephalitis virus belong to?
Flaviviridae
What is the primary reservoir for the St. Louis Encephalitis virus?
Wild Birds– Sparrows, Crows, Pigeons, Blue Jays
Is there a vaccine available for the St. Louis Encephalitis virus?
No Vaccines– Mosquito Control
What type of vaccine is used for the Japanese Encephalitis virus in endemic areas?
Inactivated/Killed
What type of Japanese Encephalitis vaccine is used by the Chinese Military?
Live Attenuated Version ONLY
Who is commonly affected by the Japanese Encephalitis virus?
People in Endemic Regions, Military, etc.
What imaging modalities should be considered if a brain tumor is suspected?
Non-Contrast CT or MRI
MRI is superior for visualizing different brain tissues, but CT is often performed first due to cost.
What are the risks associated with CT and MRI imaging?
CT - Ionizing Radiation; MRI - Pacemaker, Shrapnel, etc.
These risks must be considered when selecting imaging modalities.
What is the advantage of PET-CT in brain tumor follow-up?
Easier to differentiate scar from recurrent tumor
This is important for accurate assessment of treatment response.
What is the primary imaging modality used for initial brain tumor diagnosis?
CT due to its lower cost
MRI is preferred if there is a good clinical history.
What diagnosis is indicated by a large tumor causing compression of ventricles and midline shift?
Meningioma
This is characterized by mass effect.
What is the significance of intra-axial versus extra-axial tumors?
Intra-Axial - Arising from tissue inside the brain; Extra-Axial - From tissues outside the brain
This distinction influences treatment and prognosis.
What imaging findings are associated with hydrocephalus?
Enlarged ventricles; mass effect causing occlusion of ventricles
Hydrocephalus can occur due to various tumors.
What is the WHO grade of a medulloblastoma?
Grade 4
Medulloblastomas are classified as high-grade malignancies.
What histological features are characteristic of medulloblastomas?
Pseudo-Rosettes and small round blue cells
These features are indicative of embryonal tumors.
What is the prognosis for pilocytic astrocytoma?
Benign tumor; often does not recur
Surgical removal is typically curative.
What molecular mutation is commonly associated with pilocytic astrocytomas?
KIAA1549-BRAF Mutation
This mutation is part of the MAPK pathway alterations.
What distinguishes glioblastoma multiforme from anaplastic astrocytoma?
Presence of necrosis and a pseudo-palisading pattern
Necrosis is a hallmark of grade 4 tumors.
What are the two broad categories of glioblastoma based on their development?
Primary (De Novo) and Secondary
Secondary glioblastomas arise from low-grade gliomas and generally have a better prognosis.
What is the significance of IDH mutations in glioblastoma?
IDH mutations indicate a favorable prognosis
Mutant types are often associated with secondary glioblastomas.
What is the typical demographic for ependymomas?
Younger patients, commonly found in the 4th ventricle
In older patients, they are more likely to occur in the spine.
What histological feature is often observed in ependymomas?
Pseudo-Rosettes
This feature helps in identifying the tumor type.
What imaging characteristics suggest a meningioma?
Dural tails and extra-axial mass
Meningiomas are often associated with these features.
What are psammoma bodies?
Calcified structures often found in meningiomas
They are indicative of certain tumor types.
What is the clinical presentation of glioblastoma multiforme?
Headaches, seizures, and mental status changes
Symptoms can vary based on tumor location.
What is the histological appearance of oligodendrogliomas?
Bland round nuclei with perinuclear clearing
Often described as having a ‘fried egg’ appearance.
What genetic alterations are characteristic of anaplastic oligodendrogliomas?
Deletion of Chromosome 1p and 19q
These alterations are associated with better prognosis.
What is a common indication of a meningioma in imaging?
Dural Tails and Extra-Axial Mass
Dural tails are characteristic findings associated with meningiomas on MRI.
What type of bodies may be present in meningiomas?
Psammoma Bodies
Psammoma bodies are calcified structures often found in certain tumors, including meningiomas.
List the three broad categories of meningioma cytology.
- Mesothelial Variant
- Epithelioid Variant
- Transitional Variant
These categories reflect different cellular appearances and characteristics of meningiomas.
What is the sarcomatoid variant of meningioma characterized by?
Cells that are Long and Skinny Spindles
The sarcomatoid variant can exhibit spindle-shaped cells, which may resemble sarcomas.
How do meningiomas generally grow and behave?
Slow Growing, Behave Well
Meningiomas are typically slow-growing tumors that have a favorable prognosis.
What is the WHO Grade classification for most meningiomas?
Most are WHO Grade 1
WHO Grade 1 tumors are considered benign and have the best prognosis.
What is the impact of mutations in meningiomas?
Tend to allow them to recur, but still slow grade
While mutations can lead to recurrence, meningiomas generally remain slow-growing.
What is the prognosis for meningiomas if they are resectable?
Good as long as location is amenable to resection
The ability to surgically remove the tumor significantly improves the prognosis.
Describe the gross features of meningiomas.
Attached to the Meninges and pushing inward
Meningiomas typically arise from the meninges and can compress adjacent brain tissue.
What imaging technique is used to visualize the coronal dissection of the brain with meningioma?
Coronal Dissection of the Brain
This imaging technique helps visualize the anatomical relationship between the tumor and surrounding structures.
