Infections Flashcards
A 34 year-old man from Mexico presented with a long history of seizures.
Neurocysticercosis
Background
- Infection with Taenia solium = pork tapeworm
- Most common parasitic infection in CNS
- Commin in India, Mexico, South America, Asia, Africa
Clinical features
- Mass effect and edema = focal neuro deficits, headache
- Seizures
Imaging
- Ring-enhancing
- “Dot in a hole” sign
Treatment
- Albendazole
- Glucocorticoids
HIV patient with left-sided weakness.
Toxoplasmosis
Background
- Toxoplasma gondii parasite
- CD4 < 200
Clinical features
- Fever, decreased mental status, focal neuro deficits, headache, seizure
- Toxoplasma IgG positive
Imaging
- Ring-enhancing
- “Target” sign
-
On CT, hypodense
- Primary CNS lymphoma is hyperdense!
- Usually in basal ganglia or gray-white junction
Treatment
- Trimethoprim-sulfamethoxazole (Bactrim)
A 54 year-old man with HIV presented with dementia and personality changes.
Progressive multifocal leukoencephalopathy (PML)
Background
- JC virus
- CD4 < 200
Clinical features
- Focal neuro deficit, weakness, sensory deficit, visual problems, aphasia, cognitive decline
- Death within a year
Diagnosis
- JC virus via PCR in CSF
Imaging
- Asymmetric white matter lesion
- Bright on T2WI
- Dark on T1WI
Treatment
- HAART
45 year-old HIV patient with confusion and lethargy after starting HAART.
PML with IRIS (immune reconstitution inflammatory syndrome)
- Massive inflammatory response after HIV patient has reconstitution of immune system
- Patients with low CD4 counts not on HAART are at highest risk
A 45 year-old man with untreated HIV infection presented with 4 months of cognitive slowing.
HIV dementia
Background
- Late stage of HIV infection
- Low CD4, patients not on HAART
Clinical features
-
Personality changes, psychomotor retardation, subcortical dementia
- Attention, executive function, slow processing speed
- Langauage and memory intact
Imaging
- Symmetric white matter hyperintensities
- Looks like CMV, PML, lymphoma!
Treatment
- HAART
An otherwise healthy 23-year-old man presented with confusion and trouble speaking for 3 days. There was no prior trauma.
Herpes encephalitis
Background
- Most common cause of viral encephalitis (HSV-1)
Clinical features
- Rapid encephalitis, seizure, headache, changes in cognition and personality
- Fever
- CSF is bloody, high WBC, HSV PCR positive
Imaging
- Asymmetric
- Hemorrhagic necrosis of inferior frontal and temporal lobes
Treatment
- IV acyclovir
A 56 year-old immunocompromised man presented with seizures.
Aspergillosis
Background
- Aspergillus fungus
- Necrotizing vasculitis - hemorrhagic abscesses in ependymal region
- Infarction is common
Diagnosis
- Aspergillus PCR
Imaging
- Looks like metastasis, but calcification and ring-enhancing
- Infarctions on DWI
A 65 year-old man with dementia.
Creutzfeldt-Jakob Disease (CJD)
Background
- Prion protein leads to toxic gain of function
- Familial, infectious, and iatrogenic forms
Clinical features
- Rapid onset of dementia, personality changes, (3-4 months)
- Myoclonus, ataxia, weakness, sensory deficit
- Fatal within a year
- CSF = 14-3-3 protein
MRI
- “Double hockey stick” sign
- Cortical ribboning
- Abnormal T2WI and DWI of basal ganglia, thalamus
A 65 year-old man presented with the rapid-onset rapid progression of dementia and myoclonus.
Creutzfeldt-Jakob Disease (CJD) with cortical ribboning
A 54 year-old man presented with headaches and weakness on his left side.
Abscess
Background
- Commonly from infection of middle ear, mastoiditis, or hematogenous spread
- Pulmonary or endocarditis
- Usually multiple organisms
- Strep, Bacteroides, Enterobacter, Staph
- Biopsy needed to make diagnosis
Clinical features
- Headache, seizure, nausea/vomiting, focal neuro deficits
- Unlike meningitis, no fever or neck pain!
Imaging
- Hard to distinguish from neoplasm
- Restricted diffusion on DWI
Treatment
- Empiric antibiotics - vancomycin, metronidazole, 3rd gen. cephalosporin
- Surgical drainage
Encephalopathy and seizures in a patient with endocarditis from intravenous drug abuse.
Cerebral abscesses (early formation)
- In early stage abscesses, there is edema
- In late stage abscesses, there is capsule formation (image below)
Febrile, lethargic newborn.
Group B streptococcal meningitis
Background
- Most commonly from hematogenous spread from URI to choroid plexus
- Blood culture is diagnostic
Clinical features
- Stiff neck, fever, headache, altered mental status
- Focal neuro deficits (usually hearing loss)
- Seizure
- Lethargy, poor feeding, hypothermia in infants
Diagnosis
-
CSF shows:
- High WBC
- Low glucose
- High protein
- High opening pressure
Imaging
- Not important to do imaging unless there is suspicion of mass lesions that precludes LP
- Meningeal enhancement
- Hydrocephalus, subdural empyema, infarction
Treatment
- Empirical antibiotics - 3rd gen. cephalosporin
- Corticosteroids
28 year-old developed cranial nerve deficits and soon became encephalopathic and died.
Tuberculosis meningitis
Background
- Hematogenous spread from lungs
Clinical features
- Cranial nerve deficits (CN VI)
- Altered mental status, seizures, hydrocephalus
- CSF
- High protein
- Low glucose
- Lymphocytic pleocytosis
- Acid fast bacilli + PCR positive
Imaging
- Numerous ring-enhancing lesions = tuberculomas
