More imaging yay yatta desu ne Flashcards
Whats CNS Imaging for? and NOT for?
NOT for diagnosis; Neither for excluding Meningitis
- Meningitis diagnosis is by LP
FOR:
- Cx which needs surgical stuff
- eg abscess; Raised ICP
General principles of
- Bacterial
- Viral
- Fungal
Bacterial - think abscesses, meningitis
Viral - encephalitis
Fungal - think Immunocompromised
Whats needed to determine safety of LP?
Why LP need check safety?
Ask
- History of CNS infection
- Immunocompromised
- Papilloedema (optic disc swelling)
- Do CT scan for raised ICP
Cx
Coning: cerebellar tonsils move downward through the foramen magnum possibly causing compression of the lower brainstem and upper cervical spinal cord as they pass through the foramen magnum.
If got history of stuffies then how to proceed?
Blood Culture
AB, Dexamethasone,
CT scan
then LP
How does abscess and infraction present as on MRI?
and whats the diff between abscess and infraction presentation?
Both have restricted diffusion
- hence DWI is BRIGHT; and ADC is dark
Abscess has REL
infract no REL
REL need think what
- and also think more of what
Abscess - nocardia; toxoplasmosis; fungus for IC
Tumor - lymphoma, glioblastoma multiforme
- differentiate by onset of disease
- HIV px w REL need split btw toxoplasmosis and lymphoma
Herpes Simplex
- MRI properties?
Bilateral, Symmetrical
Medial frontal lobes
(from lecture notes)
In the immunocompetent adult patient, the pattern is quite typical and manifests as a bilateral asymmetrical involvement of the limbic system, medial temporal lobes, insular cortices and inferolateral frontal lobes. The basal ganglia are typically spared, helping to distinguish it from a middle cerebral artery infarct.
(from google)
Strep Pneumonia
- MRI properties?
Micro abscesses
REL
no encephalitis
TB
- MRI properties?
- then how?
- Nodular leptomeningeal enhancement in basal systems – typical of TB;
- Check CXR
What are the TORCHes
which is the most LITTY
Toxoplasmosis Others (Zika, Hep B) Rubella CMV (most common) HSV
CMV effects
- MRI presentation like 5???
- abit of pathogenesis; others like 5 also
Periventricular ICC Microcephaly Cerebral/Cerebellum atrophy - Gyri v broad, Sulci v shallow White matter disease (too bright, fluid) - predominantly in posterior parietal
Anterior Temporal Cyst;
Ventriculomegaly - CMV is neurotropic and replicates in the ependyma, germinal matrix and capillary endothelium
Hearing loss
Chorioretinitis
HSmegaly
How to diagnose congenital CMV infection and why need
PCR
- to give ganciclovir to decrease hearing loss;
What TORCH infections give ICC on CT and their differing locations
CMV - Periventricular
Zika - periphery
Toxoplasmosis - Basal Ganglia
How to differentiate time of CMV infection
- isit better or worse at the start?
- what the diffs
Worse at start
- SEVERE microcephaly
- lissencephaly - smooth brain - form of neuronal migration
2nd trimester:
- polymicrogyria - many small gyri
- schizencephaly - slits/cleft in brain filled w CSF
Otherwise all 3 trimesters have
- ICC
- ventriculomegaly
- WM disease // leukoencephalopathy (leuko means white)
Zika presentations
Cortical/Periventricular calcifications - more of near periphery cos Zika to grey white matter junction while CMV is to ependymal lining Ventriculomegaly Cerebral Atrophy micropthalmia
and others
Craniofacial disproportion
Redundant scalp skin (in occipital region)
Microcephaly + Prominent external occipital protuberance
