URTI Flashcards
types of URTIs
- common cold
- influenza
- pharyngitis
- rhinosinusitis
- laryngitis
- otitis media
clinical presentation of pharyngitis
- acute onset of sore throat
- pain with swallowing
- fever
- erythema and inflammation of pharynx and tonsils (may have patchy exudates)
- tender and swollen lymph nodes
microbiology of pharyngitis
> 80% viral:
- rhinovirus
- coronavirus
- influenza
- parainfluenza
- epstein-barr
<20% bacterial:
- beta-hemolytic streptococcus pyogenes
pathogenesis of pharyngitis
- direct contact with droplets of infected saliva or nasal secretion
- short incubation of 24-48h
complications of S.pyogenes in pharyngitis
- acute rheumatic fever (prevented w early initiation of Abx)
- acute glomerulonephritis (not prevented by Abx)
benefit of Abx in bacterial pharyngitis
- prevent acute rheumatic fever
- shorten duration of symptoms by 1-2d
- reduce transmission (no longer infectious after 24h of antibiotics)
diagnostic test for S.pyogenes pharyngitis
- throat culture (24-48h)
- gold standard
- 90-95% sensitive - rapid antigen detection test RADT (minutes)
- 70-90% sensitive
modified centor criteria for S.pyogenes pharyngitis
- fever >38 (1)
- swollen, tender anterior cervical lymph nodes (1)
- tonsillar exudate (1)
- absence of cough (1)
- 3-14yo (1)
- > = 45yo (-1)
point evaluation for centor criteria
0-1: no additional testing indicated; low risk; presumed viral
2-3: test for S.pyogenes pharyngnitis or initiate empiric tx
4-5: high risk for s.pyogenes, initiate empiric
tx for s.pyogenes pharyngitis`
first line: Penicillin VK alternative: - amoxi - cephalexin - clinda - clarithro duration: 10d clinical response within 24-48h
rhinosinusitis major symptoms
- purulent anterior nasal discharge
- purulent/ discolored posterior nasal discharge
- nasal congestion/ obstruction
- facial congestion/ fullness
- facial pain/pressure
- hyposmia/ anosmia
- fever
minor symptoms of rhinosinusitis
- headache
- ear pain, pressure, fullness
- halitosis
- dental pain
- cough
- fatigue
clinical determination of sinusitis
> = 2 major symptoms or 1 major + >=2 minor symptoms
microbiology of sinusitis
viral (>90%):
- rhinovirus
- adenovirus
- influenza
- parainfluenza
bacterial (<10%):
- strepto pneumoniae
- haemophilus influenzae
- also moraxella catarrhalis
- also strepto pyogenes
pathogenesis of sinusitis
- direct contact w droplets of infected saliva or nasal secretions
- bacterial cases usually preceded by viral URTI (common cold, pharyngitis)
- inflammation results in sinus obstruction
limitation in diagnostic test for sinusitis
- viral and bacterial symptoms very similar
- imaging studies: non-specific, non-discriminatory
- sinus aspirate (gold standard test): invasive, painful, time consuming
clinical diagnosis of bacterial sinusitis
presence of any one:
- persistent symptoms >10d and not improving
- viral tend to be self limiting and resolved ~7-10d - severe symptoms at onset
- purulent nasal discharge x 3-4d
- high fever >=39 degree - double sickening:
- worsening symptoms after 5-6d after initial improvement
tx for bacterial sinusitis
first line:
- amoxi
- amoxi clav
alternative:
- respi FQ (levo/moxi)
- cotrimoxazole
- 2nd gen cephalo (cefixime, cefuroxime)
duration: adults 5-10d, peds: 10-14d
why are macrolides and tetracyclines not suitable for sinusitis
s. pneumoniae highly res to them (clarithro, azithro, doxy)
why is ciprofloxacin not used?
poor respi FQ, poor activity against strep pneumoniae
tx consideration for sinusitis
Strepro pneumoniae res
- multi step penicillin-binding protein mutation
- increase penicillin MIC
- prefer high amoxi>pen (pk better)
haemophilus influenzae res:
- beta lactamase production
- inhibited by beta-lactams inhibitor
consideration for amoxi dosing for strepto pneumoniae res
- amoxi preferred over pen (better pk)
- high dose amoxi preferred
normal amoxi: 45mg/kg OD (peds); 250-500mg (Adults)
high dose amoxi: 80-90mg/kg OD (peds), 1g (adults)
when to use amoxi clav in sinusitis
if haemophilus res use amoxi/clav when either:
- recent course of antibiotics
- recent hospitalisation
- failure to imrpove after 72h of amoxi
acute otitis media signs and symptoms
- ear pain (otalgia)
- ear discharge (otorrhea)
- ear popping
- ear fullness
- hearing impairment
- dizziness
- fever
- non-specific in young infants: ear rubbing, excessive crying, changes in sleep pattern
risk factors of AOM
- sibling
- attending day care
- supine position during feeding
- exposure to tobacco
- pacifier use
- winter
prevention of AOM
- avoid exposure to tobacco
- exclusive breast feeding 1-6mth
- minimize use of pacifier
- vaccinations (influenza, pneumococcal, haemophilus)
pathogenesis of AOM
- viral URTI (common cold)
2a. nose sniffing: leading to reflux of secretions into middle ear
2b. secretions and inflammation
3. eustachian tube obstruction
4. negative eustachian tube pressure: leading to reflux of secretions into middle ear
providing a medium for bacteria accumulation and growth
microbiology of AOM
bacterial (55-60%):
- strepto pneumoniae
- haemophillus influenzae
- moraxella catarrhalis
viral (40-45%):
- respiratory syncytial virus
- rhinovirus
- adenovirus
- parainfluenza virus
AOM diagnosis
- pneumatic otoscope (standard tool)
- acute onset (<48h)
- otalgia (holding, tugging, rubbing in non-verbal child) / erythema of tympanic membrane)
- bulging of tympanic membrane
challenges in management of AOM
- unable to distinguish bacterial vs viral etiologies
when to consider observation period instead of starting tx
- pt >= 6mth old
- non severe illness (no mod-severe otalgia, no otalgia >=48h, no fever >39 degree in last 48h)
- no otorrhea
- possible for close follow up
AOM tx timeline
- <6mth old: immediate abx
- 6mth-12yo: immediate abx, (if only unilateral AOM w/o otorrhea can consider observation first)
- > 2yo:
- immediate abx for AOM with otorrhea/severe symptoms
- uni/bi lateral AOM w/o otorrhea can consider observation first
what is observation period
observation period: supportive care 48-72h
- if improve: no Abx
- if worsens of fail to improve: start Abx
AOM tx
first line: amoxicillin if:
- no amoxicillin last 30d &
- no concurrent purulent conjunctivitis &
- no pen allergy
alternative first line : amoxi/clav if:
- amoxi taken in last 30d or
- concurrent purulent conjunctivitis or
- Hx of AOM non-responsive to amoxi
alternative:
1. cefuroxime/ ceftriazone IM (mild pen allergy)
2. Clindamycin (only good against s.pneumoniae)
criteria for improvement of AOM
improvement expected in 28-72h
duration of tx
<2 yo or severe symptoms (mod-severe symptoms): 10d duration
2-5yo + severe symptoms : 7d duration
>=6yo + non severe symptoms: 5-7d duration
