Thread by @MayoClinicINFD

35M DM with severe influenza B
CXR (photo). WBC 30. N80%

Required mechanical ventilation. VV ECMO.
Rx: peramivir —> oseltamivir

D+1 Blood / sputum culture: MRSA
TEE (-). Rx: vancomycin.
#MayoIDQ MCQ next

35M MRSA pneumonia / bacteremia during severe influenza.

D+5: vanco —> linezolid
D+6: T40C. Sweating. Loose stools.
PE: BP 150/100. PR 120. Agitated. Confused. Shivering. No focal deficits.
Blood / sputum culture: negative
WBC 12. AST 32. Cre 1.5

What is most likely cause?

1/
Case diagnosis:
Severe #Influenza B infection complicated by #MRSA pneumonia and bacteremia

#Linezolid associated #serotonin syndrome (interaction with fentanyl)

Let us discuss....

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#Influenza #Pearls
- Seasonal respiratory virus infection: 2020 data: 32M infections, 310K hospitalizations, 18K deaths to date
- #Vaccination: best protection
- Rx: oseltamivir, peramivir, zanamivir, baloxavir

CDC for up to date info

cdc.gov/flu/weekly/ind…

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#Influenza and #MRSA
- S aureus: common complication that increases morbidity and mortality of influenza
- Influenza increases susceptibility and impairs immune response to MRSA (see link)

rupress.org/jem/article/21…

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#MRSA pneumonia Rx with Linezolid

Linezolid may be better compared to vancomycin for treatment of nosocomial MRSA pneumonia

doi.org/10.1093/cid/ci…

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#Linezolid

Linezolid is a synthetic compound that acts a reversible MAO inhibitor

MAOI prevents breakdown of monoamine neurotransmitters thereby increasing their levels - serotonin, dopamine, epinephrine and norepinephrine.

ncbi.nlm.nih.gov/pmc/articles/P…

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#Fentanyl and Serotonin Syndrome

Fentanyl is a phenylpiperidine opioids with mild serotonin-reuptake inhibition (SRI) properties - thereby increasing serotonin levels

ncbi.nlm.nih.gov/pmc/articles/P…

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#Serotonin Syndrome due to Linezolid and Fentanyl interaction

Linezolid prevents its breakdown and fentanyl inhibits its reuptake —> serotonin excess!!!

ncbi.nlm.nih.gov/pmc/articles/P…

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#Serotonin Syndrome

Excessive serotonin:
1. Mental status (confusion, agitation)
2. Autonomic hyperreactivity (sweating, loose stools)
3. Neuromuscular (tremors, shivering, clonus)

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#Serotonin Syndrome

CNS effects:
1. Attention (confusion)
2. Behavior (agitation)
3. Thermoregulation (Fever)

Peripheral effects:
1. GI motility (“loose stools”)
2. Vasoconstriction (“high BP”)
3. Bronchoconstriction

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#Serotonin Syndrome

Hunter Criteria
1. Spontaneous clonus
2. Inducible clonus + agitation / diaphoresis
3. Ocular clonus + agitation/ diaphoresis
4. Tremor + hyperreflexia
5. Hypertonia + T38C + ocular/inducible clonus

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#Serotonin Syndrome

Treatment and case resolution
- Discontinue serotonergic drugs (switched back to vancomycin; fentanyl stopped) —> clinical cure
- Supportive care

C. difficile was top DDx
- Should be tested when loose stools in at risk patients. Negative in this case.

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#Influenza and #Aspergillosis

Association between risk of Aspergillus in patients with influenza has been described!

doi.org/10.1164/rccm.2…