Infectious Disease Flashcards Preview

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Flashcards in Infectious Disease Deck (29):

What are the different types of meningitis?

Bacterial (most common), Viral, Fungal, Mycobacterial


What are the signs/symptoms of Bacterial Meningitis?

fever, HA, meningismus, photophobia, vomiting


What are the common organisms that cause bacterial meningitis?

newborns - group B strep
child-young adult - Neisseria, strep pneumo
elderly - strep pneumo, listeria
Neurosurgical pts - staph aureus (MRSA)


How does the bacteria invade in meningitis?

colonization of the nose into the veins across the BBB or CSF leak allows it in with head trauma. Invasion of CSF leads to exudate formation, increased ICP, and inflammed arteries (think stroke!)


Tx of bacterial meningitis

get antibiotics going empiracally - ceftriazone (crossses BBB), vancomycin and maybe ampilcillin for listeria
steroids to reduce swelling


CSF in bacterial meningitis

cloudy, pressure > 180, WBC (PMNs) > 1000, protein > 40, glucose < 40, gram stain shows bacteria!


What are the signs/symptoms of Viral Meningitis?

HA, fever, meningismus - but less severe than bacterial and no changes in level of consciousness


What characterized viral meningitis?

self-limiting. caused by enterovirus, herpes (HSV2), measles, mumps, arboviruses. Tx bedrest, fluids, analgesia. CSF shows WBC < 500 mostly lymphocytes.


What is fungal meningitis?

rare, but severe form of meningitis - usually seen in immunosuppressed (cancer or AIDS) - that may be subacute or chronic. Typical organisms of Cryptococcus (most common), Aspergillus, Candida. S/Sx: HA, low grade fever, malaise, fatigue, confusion and dementia may present


CSF in fungal meningitis

hazy, WBC , 200 lymphocytes, high protein, glucose low but > 20, eosinophilia


What is mycobacterial meningitis?

It is a rare form of meningitis seen in immunocompromised or malnourished pts caused by tuberculosis that has reactivated from a previous infection.


CSF in mycobacterial meningitis

hazy, yellowish, WBC < 200 lymphocytes, protein high >300, glucose very low


Viral encephalitis

encephalitis characterized by changes in LOC (seizures/focal deficits), HA, fever, meningismus - but pt looks sicker than viral meningitis. Most often caused by HSV1, but also can be caused by arboviruses. Tx: IV acyclovir ASAP & hydration.


CSF of viral encephalitis

mostly normal with slightly elevated WBCs, overtime WBC, RBC and protein will increase!


Rabies Virus

virus transmitted by infected saliva into a wound and then enters neurons and moves in a retrograde fashion to the brain. 2-12 days latent, causes viral prodrome, encephalitis, change LOC, painful spasms, can't swallow, death in 2-10 days. Tx: antibodies and vaccination prior to sx onset


Bacterial encephalitis (neurosyphilis)

caused by Treponema Pallidum, primary infection is a painless ulcer that becomes latent and then can cause encephalopathy. early sx: meningitis, cranial neuritis, cerebrovascular. late sx: sensory ataxia, dementia w/ psychosis, Charcot joints.


Bacterial encephalitis (lyme disease)

Caused by Borrellia burgdorferi. Sx: spreading rash (erythema migrans), arthritis, mild meningismus, HA, neck pain. Dx: blood cultures w/ western blot. tx: doxycycline or ceftriaxone


Herpes Zoster

Reactivation of varicella zoster cirus that is common in elderly or immunocompromised. Causes vesicular skin eruptions in dermatomal distributions and dysesthesia (tingling). Dx: rash, skin biopsy, PCR. Tx: acyclovir
Pain may persist after recovery - Postherpetic neuralgia


Bacterial Brain Abscess

Usually caused by a mix of anaerobic and aerobic organisms, it presents with HA and focal sx and will show up as ring enhancing lesions due to inflammed tissue w/ dark necrotic center. Tx with antibiotics



The parasite, Toxoplasma, can cause brain abscesses that look like many ring enhancing lesions on CT. It is very responsive to Tx. Major DDx is primary CNS lymphoma.



The parasite Pork Tapeworm can cause cysticercosis presenting as calcified lesions seen on unenhanced CT. Also invades the liver, muscle, brain and eye.



build up of pus in a body space


Epidural abscess

infx in the epidural space of the spine (usually Staph Aureus) that causes a low grade fever and back pain that can lead to spinal cord damage and sepsis.


Common opportunistic infections in HIV/AIDS

toxoplasmosis, tb, cyptococcus, syphilis, progressive multifocal encephalopathy, cytomegalovirus


Progressive multifocal encephalopathy

reactivation of JC virus resulting in white matter leasions that presents in the immunocompromised. Tx: immune support.


AIDS dementia

HIV is neurotropic and can damage the brain. With increased viral loads, AIDs pts can develop disorientation and confusion. Tx: decrease the viral load.


Creutzfeld-Jacob Disease

Prion disease that causes spongiform encephalopathy when spread from infected tissue. It remains latent for a while and then progresses rapidly and the CSF is clear unless tested for specific proteins. Can present with myoclonic jerks or muscle twitches that worsen to ataxia overtime.


Botulinum Toxin

blocks neurotransmission by cleaving synaptobrevin (vesicle docking protein) usually causing facial or eye muscle paralysis first, then flaccid paralysis throughout (top down)


Tetnus toxin

Toxin that cleaves synaptobrevin to inhibit GABA and glutamate release resulting in uncontrolled neuronal firign and stiffness (lockjaw). Early anti-toxin may be life saving.