Influenza, sinusitis, and group A streptococcal pharyngitis Flashcards
Symptoms of flu
Abrupt onset of fever, headache, myalgia, and malaise
Symptoms generally resolve in 3-7 days
Transmission and shedding:
_ During incubation period, 1st 24-48hrs
_ Close contact: Sneezing and coughing
Cold vs Flu in table in ppt
Two major surface glycoprotein antigens
Principal antigen, hemagglutinin (HA or H)
responsible for cell attachment
Enzymatically active neuraminidase (NA or N)
assists virus maturation and release
Influenza
Three main types Type A (major outbreaks and severe disease) and Type B
Type C (sporadic upper respiratory infections)
Usually more severe than common cold
Serious illness and death are highest in at risk populations: elderly, Children < 2 years, those with chronic conditions
M2 inhibitor drugs
Amantidine, rimantidine
M2 inhibitor MOA
Prevent viral replication by blocking M2 protein ion channel - prevents uncoating of virus
“M2 channel blockers”- inexpensive, long history of use.
Blocks M2 channel in viral membrane once it has entered the host cell. (Influenza B has NB channels)
M2 Channel allows H+ to enter. Acid required for viral uncoating.
Inhibits uncoating of virus once inside host cells.
Not dependent on replication– Only inhibits ability to spread.
Side effect of M2 inhibitor
CNS toxicity (reversible)
Insomnia, dizziness, nervousness, difficulty concentrating
Rimantidine less CNS ADRs
What’s special about Amantadine?
Amantadine also has anti-tremor properties: Weakly increase dopamine in brain. Also used for Parkinson-like or drug-induced tremors, etc.
Neuraminidase Inhibitors (NAIS) drugs
Zanamivir
Oseltamivir
Peramivir
NAIS MOA
FDA indications: Prophylaxis and Tx of influenza A & B.
MOA: Prevent the release of new virions from the cell surface
Binds the surface antigen neuraminidase, on influenza A & B viruses preventing release of new viruses.
Neuraminidase releases virus from cell surface
Peramivir
Rapivab
Single IV dose - strong, prolonged affinity
Renal adjust CrCl <50 (90% unchanged in urine)
SEs:
diarrhea
reports of delirium/ abnormal behavior
primarily children, abrupt onset, rapid resolution
Zanamivir
Relenza
Administered via oral inhalation with Diskhaler 2 inhalations (10 mg) BID x 5 days
Begin within 48 hrs of symptom onset
Adverse Reaction = Bronchospasm
Advantages:
Less resistance seen than with oseltamivir
Disadvantages:
Administration may be difficult (5-6 steps per dose)
Oseltamivir
Tamiflu
Oral prodrug neuraminidase inhibitor
75 mg po BID x 5 days
Renally adjusted, no use in hemodialysis
Begin within 48 hrs of symptom onset
Adverse Reaction = Nausea/Vomiting
Advantages:
Oral formulation, capsule or suspension
Disadvantages:
Cochrane Review and efficacy controversy
Publication bias
Tamiflu is preferred for which population?
Elderly, children < 2 years, those with chronic conditions
The other population are not recommended
Acute Rhinosinusitis and Viral Rhinosinusitis
Mostly caused by virus 97%
Cant be cured by ABx
Acute Bacterial Rhinosinusitis (ABRS)
Acute rhinosinusitis that is caused by bacterial infection when:
_ Symptoms or signs of acute rhinosinusitis fail to improve within 10 days or more beyond the onset of upper respiratory symptoms
OR
_ Symptoms or signs of acute rhinosinusitis worsen within 10 days after an initial improvement (double worsening)
Treatment for children’s ABRS
Kids ABRS = Amoxicillin-clavulanate 10-14 days
45 mg/kg amoxicillin component per day; 2-divided doses
What criteria and treatment for resistance of Strep Pneumo for ABRS in children?
T >39C; Age <2yrs; daycare; Abx within 30d; Hospitalization within 5d
90 mg/kg amoxicillin component per day; 2-divided doses
Signs of resistance of Strep Pneumo for children and adult
T >39C; Age <2yrs; daycare; Abx within 30d; Hospitalization within 5d
> 65yo; hospitalized in last 5days; Abx <30d, or immunocompromised
What treatment for resistance of Strep Pneumo for ABRS in adults?
> 65yo; hospitalized in last 5days; Abx <30d, or immunocompromised
2 g (XR) po BID
What option for PCN-allergy for ABRS?
Pcn-allergic: either doxycycline or fluoroquinolone (levofloxacin / moxifloxacin)
Treatment for adult ABRS
Adults ABRS = Amoxicillin-clavulanate 5-7 days
500 mg/125 mg po TID or 875 mg/125 mg po BID
Which ABx should not be used for ABRS for resistance issue?
azithromycin, clarithromycin, or tmp-smx
Signs for viral pharyngitis or viral throat infection
cough
runny nose
hoarseness
mouth sores
Signs for bacterial pharyngitis or bacterial throat infection
IF 3 or more of these symptoms (Centor criteria):
sudden onset pain
tonsillar exudates
fever
cough and significant rhinorrhea are usually absent
THEN confirm with RADT strep before ABx is prescribed
Mostly caused by group A streptococcal (GAS)
Treatment for GAS pharyngitis for children
Children <27kg: PCN VK 250mg PO BID-TID x10d
OR
Children: Amoxicillin 25mg/kg PO BID x10d
Treatment for GAS pharyngitis if PCN allergy
3rd gen cephalosporins (cefdinir); Clindamycin
Treatment for GAS pharyngitis for adult
Adolescents/Adults: PCN VK 500mg PO TID x10d
