URTI - Pharyngitis, Sinusitis, AOM & Influenza Flashcards
What is pharyngitis?
Acute inflammation of oropharynx/ nasopharynx
Clinical presentation of Pharyngitis
- Acute onset of sore throat
- Pain when swallowing
- Erythema & inflmm of pharynx & tonsils (May have patchy exudates)
- Tender & swollen lymph nodes
- Fever
Microbiology of Pharyngitis
1) Viruses (80%)
- rhinovirus, coronavirus, influenza, parainfluenza, epstein-barr
2) Bacteria
- Strep pyrogens (Group A Beta-hemolytic Streptococcus)
- #1 cause
Pathogenesis of Pharyngitis
Direct contact with droplets of infected saliva/ nasal secretions (Short incubation: 24-48hrs)
Complications of Pharyngitis
S. pyrogens Pharyngitis (Self-limiting/ Complications)
- 1-3 weeks later
i) Acute rheumatic fever - Can cause damage to joints, heart tissue fever
- Prevented with early initiation of effective antibiotics
ii) Acute glomerulonephritis
- Kidney damage
- NOT preventable by antibiotics
(Viral: Self-limiting)
Challenges in managing Pharyngitis
Viral & bacterial have similar clinical presentations!
Antibiotics use in Bacterial Pharyngitis:
1) Prevent Acute rheumatic fever
2) Shorten duration of symptoms by 1-2days
3) Reduce transmission (no longer infectious after 24hrs of antibiotics)
Diagnosis of Pharyngitis
1) Clinical diagnosis with criteria (higher score, > likely)
- Criteria: Fever > 38C, Swollen tender anterior cervical lymph nodes, tonsillar exudate, no cough, 3-14yo
0-1 points: Viral; self-limiting
2-3 points: Optional, but usually will just start
4-5 points: Start antibiotics
2) Throat culture (24-48hrs)
- gold standard but not practical
3) Rapid antigen detection test (mins)
- expensive, not usually done
Treatment of Pharyngitis
1) Penicillin VK (1st line): 250mg PO QDS/ 500mg BD
[P: 250MG PO BD-TDS]
2) Amoxicillin: 1g PO OD/ 500mg PO BD
[P: 50mg/kg/day* or divided BD*]
3) Cephalexin
4) Clindamycin: 300mg PO TDS
[P: 7mg/kg TDS]
5) Clarithromycin
Duration: 10 days
(though clinical response expected within 24-48hrs)
What is rhinosinusitis (sinusitis)?
Acute (within 4 weeks) inflammation & infection of the paranasal & nasal mucosa
Clinical presentation of Sinusitis
> = 2 major/ 1 major + 2 (or more) minor symptoms
Major:
- Purulent anterior nasal discharge
- Purulent/ discoloured posterior nasal discharge
- Nasal congestion/ obstruction
- facial congestion/fullness
- facial pain/ pressure
- hyposmia (decreased sense of smell) / anosmia
- fever
Minor:
- HA, ear pain/pressure/fullness, halitosis (bad breath), dental pain, cough, fatigue
Microbiology of Sinusitis
1) Virus (>90%)
- rhinovirus, adenovirus, influenza, parainfluenza
2) Bacteria (<10%)
- Streptococcus pneumoniae & Haemophilus influenzae (most common)
- Moraxella catarrhalis
- Streptococcus pyrogens
Pathogenesis of Sinusitis
Direct contact with droplets of infected saliva/ nasal secretions, usually preceded by viral URTIs
- > Inflammation results in sinus obstruction
- > Nasal mucosal secretions are trapped
- > Medium of bacterial trapping & multiplication
Diagnostic challenges of Sinusitis
Bacterial & Viral have similar symptoms!!!
Limited use of diagnostic tests:
1) Clinical diagnosis (USE THIS)
Presence of sinusitis + 1 of these criteria:
- Symptoms persist > 10 days & doesn’t improve
(vs Viral Sinusitis: self-limiting)
- Severe symptoms at onset
(Purulent nasal discharge x 3-4 days/ high fever >= 39C)
- “Double sickening”
(Symptoms worsen 5-6days after initial improvement)
2) Imaging tests: non-specific, non-discriminatory
3) Sinus aspirate (gold standard):
invasive, painful, time-consuming
Treatment of Sinusitis
1st line:
i) Amoxicillin: 1g PO TDS*
[P: 80-90mg/kg/day* or divided BD]
ii) Augmentin: 625mg PO TDS/ 1g PO BD*
[P: 80-90mg/kg/day* or divided BD*]
Alternatives:
i) Levofloxacin (500mg PO OD*)/ Moxifloxacin
ii) Trimethoprim/ Sulfamethoxazole
iii) Cefuroxime
Duration: Adults (5-10 days), Pediatrics (10-14 days)
Why is Amoxicillin preferred over Penicillin for treatment of S. pneumoniae?
Favourable PK, amoxicillin can get higher bioavailability
- S. pneumoniae -> Multi-step PBPs mutation -> Increases penicillin MIC
- “High-dose” Amoxicillin [80-90mg/kg/day (pediatrics); 1g (adults)] for effective treatment
Considerations of H. influenzae?
- Beta-lactamase production
- Inhibited by beta-lactamase inhibitor
When to use Augmentin > High-dose Amoxicillin for Sinusitis?
1) Recent course of antibiotics (~30days)
2) Recent hospitalization
3) Failure to improve after 72hrs of amoxicillin
What is Acute Otitis Media?
Infection of the middle ear space resulting in inflamm & fluid accumulation
Clinical presentation of AOM
- Ear pain (eg. otalgia) / discharge (eg. otorrhea) / popping/ fullness, hearing impairment, dizziness, fever
(Non-specific in young infants)
Risk factors for AOM
- Siblings/ Daycare (Increase chance for interactions to pick up infection) - Supine position during feeding - Exposure to tobacco smoke @ home - Pacifier use - Winter season
An infection in pediatric patients (usually < 5yo)
- Eustachian tube is more straight, easier backflow of fluid to ears
Prevention of AOM
- Avoid exposure to tobacco smoke
- Exclusive breastfeeding for 1st 6 mths
- Minimise pacifier use
- Vaccinations (Influenza/ Pneumococcal/ H. influenzae type B vaccine)
Pathogenesis of AOM
Viral URTIs (ie. common cold) -> Secretions & inflammation -> Eustachian tube obstruction -> -ve Eustachian tube pressure -> Reflux of secretions into middle ear [Medium for bacterial accumulation & growth]
Viral URTIs (ie. common cold) -> Nose sniffing -> Reflux of secretions into middle ear
Microbiology of AOM
1) Bacterial (55-60%)
2) Viral (40-45%)
- S. pneumoniae, H.influenzae, Moxarella catarrhalis
Diagnosis of AOM
Pneumatic otoscope (standard tool)
Diagnostic criteria:
- Acute onset (<48hrs)
- Otalgia (holding, tugging or rubbing of ear) OR erythema of tympanic membrane
- Bulging of tympanic membrane (Fluid buildup that creates increased pressure)
Challenges in management of AOM
Difficult to distinguish between bacterial/ viral!!!
- Prompt antibiotic initiation decreases duration of symptoms by ~1 day
- ~80% of cases resolve in 3-4days without antibiotics
- Overprescribing antibiotics -> Resistance ):
Type of approaches towards AOM
1) Immediate initiation
2) Observation period (Supportive care for 48-72 hrs first, assess again afterwards)
- Criteria: >= 6 months of age, non-severe illness (minor otalgia not more than 48hrs, no fever >39C), no ottorhea, possible for close follow-up, shared decision making
Eligibility:
i) 6mths-2yo: Unilateral AOM without otorrhea
ii) 2yo & above: Unilateral/Bilateral AOM without otorrhea
Treatment of AOM
1st line: Amoxicillin: 80-90mg/kg/day* or divided BD*
- Needs to: Not have taken amoxicillin in past 30days + No concurrent purulent conjunctivitis + No penicillin allergy
Alternative:
i) Augmentin: 80-90mg/kg/day* or divided BD*
Penicllin-allergy:
ii) Cefuroxime: 30mg/kg/day* or divided BD
iii) IM Ceftriaxone
If really no choice, severe penicillin allergy:
iv) Clindamycin
- Effective against S. pneumoniae only (Gram +)
Treatment duration of AOM
Improvement expected in 48-72hrs
Below 2yo: 10 days
2-5yo, non-severe: 7 days
Above 6yo, non-severe: 5-7 days
Severe illness (mod-severe otalgia/ otalgia >= 48hrs, Fever > 39C in the last 48hrs): 10 days
Symptoms of Influenza
Fever, body aches, chills, fatigue/weakness, stuffy/runny nose, sore throat, chest discomfort, HA
Microbiology of Influenza & its clinical presentation
A: Humans/swine/equine/avian/multiple other species
- More severe illness; significant mortality in young
persons
- Epidemics & pandemics
B: Human only
- Severe illness in older/ higher risk persons
- Less severe epidemics
C: Humans, swine
- Mild respiratory illness w/o seasonality
- No epidemics
Complications of Influenza
- Viral pneumonia
- Post-influenza bacterial pneumonia (particularly those caused by S.aureus; Mortality > 30%)
- Resp failure
- Exacerbate pulmonary/ cardiac comorbidities
- Febrile seizures
- Myocarditis/ Pericarditis
Groups that are at “high risk” for influenza-related complications
Child < 5yo/ Elderly >= 65yo
Pregnant women/ within 2 weeks post-partum
Residents of nursing homes/ long term facilities
Obese indvs (BMI >= 40)
Indvs with chronic medical conditions (Asthma/ COPD/ HF/ Diabetes/ CKD/ Immunocompromised)
How to prevent Influenza?
1) Good personal hygiene
2) Healthy lifestyle
3) Vaccinations
- Inactivated trivalent/ quadrivalent vaccine
- Adm IM 1x/year
- Recommended for all individuals > 6months
Note: Chemoprophylaxis NOT recommended
- To avoid sub-therapeutic dosing which can increase resistance
Diagnostic tests for influenza
1) Viral cultures (hard to perform; not recommended)
2) Molecular tests
- Outpatient: Mostly treated empirically based on clinical presentation
- Inpatient: RT-PCR test to identify pts with Influenza
Treatment of influenza
For documented/suspected influenza: Initiate asap within 48hrs of symptom onset (> 48h contradicting info) for indvs with ANY of these: - Hospitalised - High risk for complications - Severe/complicated/progressive illness
Antiviral choice:
1) Oseltamivir (75mg PO BD* x 5d)
- Neuraminidase inhibitor (interfere with protein cleavage, inhibiting virus release)
- Active for Influenza A/b
- ADE: HA, mild GI effects (well tolerated)
