myopathy, neuropathy, cns infections rachel garvin, md assistant professor, neurocritical care...
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Myopathy, Neuropathy, CNS InfectionsRachel Garvin, MDAssistant Professor, Neurocritical CareDepartment of Neurosurgery
ObjectivesDescribe critical care myopathy
and neuropathy, causes, diagnosis and management
Describe CNS infections, diagnosis and management
Critical Illness Polyneuropathy (CIP) and Myopathy (CIM)Seen in conjunction with severe
sepsis and prolonged use of neuromuscular blockade +/- steroids
Seen in up to 40% of ICU patients
CIM/CIPFirst sign is often inability to
wean from ventilatorNot usually noted until patient at
least 2 weeks on ventilatorSevere diffuse weakness and
muscle wasting
CIPDiagnosis by EMGAxonal degeneration of motor
and sensory fibersCK is normalMuscle biopsy shows denervation
atrohpy
MeningitisBacterial (septic) vs Other infectious or
inflammatory (aseptic)Most often caused by bacteremia that
seeds meninges by crossing BBB and multiplying in CSF
Ventriculitis more common in those with ventricular drains/shunts
Cerebral edema can occur d/t inflammatory effects of infection leading to vasogenic and cytotoxic edema
MeningitisClassic signs of fever, HA and
meningismus may not always be present (esp. elderly)
Also seen with photophobia, N/V, altered consciousness
Pathogens dependent on:◦Adult in community: strep pneumo,
neisseria, listeria◦Hospitalized patient: gram negatives
Meningitis Dx: LPElevated opening pressure
(>20cmH2O)Increased protein (>100mg/dl)Decreased glucose (<40% serum
level)Elevated nucleated cell count
(usually >100)
TreatmentAbx appropriate to pathogenEnsure appropriate CNS dosingDuration from 14-21 days
depending on pathogen
EncephalitisInfection of brain parenchymaMultiple modes of infectionMost are hematogenous spread
except for HSV and rabies which spread via neurons
Most are viral
Encephalitis: PresentationVaries as certain infections have
certain locations they affect:HSV: inf/medial temporal lobes
and orbito-frontal cortexArboviruses (West Nile, equine):
cortical gray matter, brainstem and thalamic nuclei
Japanese B virus: brainstem nuclei and basal ganglia
Encephalitis: DiagnosisHistory and physicalNeuroimaging: CT and MRILP: many present as
meningoencephalitisHSV PCR may be falsely negative
in first 48 hours and then again 10 days after infection
Other viruses: IgM in CSF, viral culture from blood, tissue or CSF
Encephalitis: Treatment and OutcomesOnly treatment for HSV with
Acyclovir for 14 daysOther viruses are supportive care
only
Brain AbscessEncapsulated collection of pus
within brain parenchymaRisk factors include: head and
neck infections, penetrating head injury, immunocompromised state
Presentation often non-specific but can have symptoms related to location of abscess
Brain Abscess: PathophysiologyBegins as a cerebritis, day 1-3
with surrounding inflammation and edema
1 week into infection, central necrosis develops
By 14 days, fibrous capsule apparent which becomes more established
Braun Abscess: ComplicationsSeizures are most common
morbidity (up to 70%)Abscess rupture leading to
meningitis/ventriculitisFormation of subdural empyema,
epidural abscess, septic thrombophlebitis
Brain Abscess: TreatmentIV abx based on pathogen or
presumed source (otitis, odontogenic)
Surgical drainage