Upper Respiratory Tract Infections

Question 1

What is part of the Upper respiratory tract?

Answer 1

Nasal Cavity
Pharynx
Larynx

Question 2

What is part of the Lower Respiratory tract?

Answer 2

Trachea
Primary Bronchi
Lungs

Question 3

What are the Upper tract Respiratory infections (URTIs)?

Answer 3

 Common cold
 Influenza
 Pharyngitis
 Rhinosinusitis
 Laryngitis
 Otitis media

Question 4

What are the Lower Respiratory Tract Infections (LRTIs)?

Answer 4

 Pneumonia
 Bronchitis
 Tracheitis

Question 5

What is pharyngitis?

Answer 5

Acute inflammation of the oropharynx or nasopharynx

*Sore throat

Question 6

What is the clinical presentation of pharyngitis?

Answer 6

 Acute onset of sore throat
 Pain with swallowing
 Fever (low grade)
 Erythema and inflammation of the pharynx and tonsils (With or without patchy exudates)
 Tender and swollen lymph nodes*

*checked using tongue depressors (ice cream sticks) to look for erythema at back of throat to confirm pharyngitis

Question 7

What is the microbiology of pharyngitis?

Answer 7

 Viruses* (> 80%)&raquo_space; bacteria (< 20%)

– Group A β‐hemolytic Streptococcus** (i.e. Streptococcus Pyrogenes)
• # 1 cause of bacterial pharyngitis
• US prevalence: 5‐15% (adults); 20‐30% (pediatrics)
• Less common in Singapore

*Rhinovirus, coronavirus, influenza, parainfluenza, Epstein‐Barr (common cold viruses)

Question 8

What is the pathogenesis of pharyngitis?

Answer 8

 Direct contact* with droplets of infected saliva or nasal secretions
 Short incubation of 24 – 48 hours

*requires close proximity for transmission to occur

Question 9

What are the complications of pharyngitis?

Answer 9

 Viral: self‐limiting
 S. pyogenes pharyngitis: self‐limiting or complications possible (occur 1‐3 weeks later)
– Acute rheumatic fever (Prevented with early initiation of effective abx)
– Acute glomerulonephritis (Not prevented by abx)

Question 10

What are the challenges in pharyngitis management?

Answer 10

1. Antibiotics have proven benefits in bacterial pharyngitis
   – Prevent acute rheumatic fever
   – Shorten duration of symptoms by 1‐2 days
   – Reduce transmission (no longer infectious after 24 hours of antibiotics)
2. Viral and bacterial pharyngitis have similar clinical presentation (hard to DDX)

Question 11

How is the lab/test diagnosis done for Pharyngitis?

Answer 11

Testing for S. pyogenes pharyngitis
1. Throat culture (24‐48 hours)
• Gold standard
(+) High sensitivity 90‐95%
(-) long delay*, not very useful clinically

2. Rapid antigen detection test (RADT) (minutes)
   (-) Sensitivity 70‐90%
   (-) expensive, not available in all GPs
   (+) used for local infection tracking

*starting abx too late for strep throat

Question 12

What is the challenge in diagnosing pharyngitis?

Answer 12

It is challenging to find diagnosis of strep throat, no good, inexpensive and fast test + similar sx between viral and bacterial

Question 13

What is the framework used to clinically* diagnose pharyngitis?

*Using patient sx and severity instead of labs

Answer 13

Modified Centor criteria

Question 14

What should be the follow up when a patient is evaluated to have a modified Centor criteria of 0 or 1 point?

Answer 14

• No additional testing indicated
• Low risk of S. pyogenes pharyngitis
• Presumed viral

Question 15

What should be the follow up when a patient is evaluated to have a modified Centor criteria of 2 or 3 points?

Answer 15

• Test for S. pyogenes pharyngitis; treat if positive

- Or initiate empiric antibiotics for S. pyogenes pharyngitis

Question 16

What should be the follow up when a patient is evaluated to have a modified Centor criteria of 4 or 5 points?

Answer 16

• High risk for S. pyogenes pharyngitis

- Initiate empiric antibiotics

Question 17

Why is there is no age category <3 years old under the age criteria of the modified Centor criteria?

Answer 17

• no age category <3 as strep throat is extremely uncommon in children < 3 years (presumed to be viral)

Question 18

What is a characteristic clinical symptom of bacterial pharyngitis?

Answer 18

Absence of cough

Question 19

What are the supportive care we can provide for a patient with viral pharyngitis?

Answer 19

 Analgesic/antipyretic: paracetamol, NSAIDs
 Topical analgesic lozenges/sprays (e.g. benzydamine)
 Saltwater gargle
 Adequate fluid and rest

Question 20

How can we treat a patient with bacterial pharyngitis?

Answer 20

Supportive care (as per viral pharyngitis) AND
PO abx for 10days (mild disease tx OP)

Question 21

What is the Empiric abx tx selection for Bacterial pharyngitis?

Organism to cover is Streptococcus pyrogenes (gram pos)

Answer 21

 1st line antibiotic – Penicillin VK
 Alternative antibiotics
– Amoxicillin
– Cephalexin*
– Clindamycin**
– Clarithromycin**

• Mild Penicillin allergy alternative (mild rash)
• *Severe Penicillin allergy alternative

Question 22

Why is Augmentin (Amoxicillin/Clavulanate) not used for Bacterial pharyngitis?

Answer 22

Overkill (no need broad coverage for gram negs/anaerobes -> not found in strep throat)

Question 23

Comment on the use of corticosteroids in Pharyngitis

Answer 23

 Use of corticosteroids is controversial
– Reduce duration and severity of symptoms
– Associated with adverse effects*
– Not recommended in clinical practice guidelines

*Increased BP, Blood glucose, harder to sleep at night etc..

Question 24

What is the expected clinical response for abx tx of bacterial pharyngitis?

Answer 24

 Clinical response expected within 24‐48 hours
– Counsel on completing antibiotic course

• fast response (adherence may drop as a result)
• counseling is key to prevent resurgence of infection

Question 25

What is Rhinosinusitis? (sinusitis)

Answer 25

Acute (within 4 weeks) inflammation and infection of the paranasal and nasal mucosa * Unlike chronic sinusitis (always inflammed) - usually due to allergies or structural issues in sinus - need to manage allergy or structural issues

Question 26

What are the 7 Major* clinical symptoms for Sinusitis? *more common and classic sx

Answer 26

```  Purulent anterior nasal discharge  Purulent or discolored posterior nasal discharge  Nasal congestion/obstruction  Facial congestion/ fullness  Facial pain/pressure  Hyposmia/anosmia*  Fever ``` *loss/reduced sense of smell Note: anterior nasal (nostrils) and posterior nasal (throat)

Question 27

What are 6 Minor* clinical symptoms for Sinusitis? *non-specific sx

Answer 27

```  Headache  Ear pain, pressure, fullness*  Halitosis*  Dental pain  Cough  Fatigue ``` * Due to connection of sinus with ears * *Bad breath

Question 28

How can we clinically decide on presence of Sinusitis?

Answer 28

> 2 major symptoms; OR | 1 major + > 2 minor symptoms

Question 29

How can we distinguish between Sinusitis and Pharyngitis based on clinical symptoms?

Answer 29

- Use location: sinusitis tend to have more nasal/facial sx (nasal blockage/pain) vs pharyngitis more throat sx - There is some overlap in sx i.e. non-specific ones such as fever that occurs for any infection

Question 30

What is the microbiology of Sinusitis?

Answer 30

Virus* (> 90%) >> bacteria (< 10%)  Bacterial – Streptococcus pneumoniae** and Haemophilus influenza) most common – Moraxella catarrhalis – Streptococcus pyogenes * Rhinovirus, adenovirus, influenza, parainfluenza (common cold viruses) * *very different from strep pyrogenes with tx implications

Question 31

What is the pathogenesis of Sinusitis?

Answer 31

1. Direct contact with droplets of infected saliva or nasal secretions 2. Bacterial cases usually preceded by viral URTIs (e.g. common cold, pharyngitis) 3. Inflammation results in sinus obstruction – Nasal mucosal secretions are trapped – Medium of bacterial trapping and multiplication *Similar mode of transmission as other URTIs

Question 32

What are the 2 Diagnostic challenges in Sinusitis?

Answer 32

1. Bacterial and viral sinusitis have similar symptoms 2. Limited use of diagnostic tests – Imaging studies: non‐specific, non‐discriminatory – Sinus aspirate* (gold standard): invasive, painful, time‐consuming * Take fluid clogged up in sinus -> send for culture - very telling (growth of bacteria vs no bacterial growth (viral)

Question 33

When will sinus aspirate be collected for diagnosis?

Answer 33

- For infection control purposes (i.e. tracking strep throat in envt) -> ID perspective to get sense of prevalence of infections - Identify causative organisms in possible fungal/other bacterial causes for sinusitis (in immunocompromised pts)

Question 34

How is the clinical diagnosis of bacterial sinusitis done?

Answer 34

1. Presence of Sinusitis* 2. Presence of any ONE of the following: I) Persistent of symptoms > 10 days AND not improving - Viral sinusitis: self‐limiting, resolves in 7‐10 days II) Severe symptoms at onset - Purulent nasal discharge x 3‐4 days or high fever > 39C III) “Double sickening” - Worsening symptoms after 5‐6 days after initial improvement * > 2 major symptoms; OR 1 major + > 2 minor symptoms

Question 35

When clinical diagnosis of bacterial sinusitis is established*, what should we do? *Presence of sinusitis + Presence of bacterial sinusitis

Answer 35

Start empiric abx to cover for strep pneumoniae and H flu | - no need to wait for cultures

Question 36

What is the supportive care for Viral Sinusitis?

Answer 36

 Analgesic/antipyretic*: paracetamol, NSAIDs  Nasal steroid spray  Saline irrigation  Expectorant: guaifenesin  Nasal/systemic decongestants/anti‐histamines (not guideline recommended) *Aspirin is not recommended for children due to risk of Reye syndrome

Question 37

What is the treatment plan for Bacterial Sinusitis?

Answer 37

``` Supportive care (as per viral Sinusitis) AND PO abx (usually empiric) ```

Question 38

What is the empiric abx (including alternatives) tx selection for Bacterial Sinusitis? Common organisms to cover: Streptococcus pneumoniae and Haemophilus influenzae

Answer 38

1st line antibiotic: Amoxicillin OR Augmentin Alternative antibiotics (i.e. penicillin allergy) – Respiratory fluoroquinolone (Levofloxacin OR moxifloxacin) – Trimethoprim/sulfamethoxazole – Cefuroxime PO* *Mild rash penicillin allergy alternative

Question 39

Can Ciprofloxacin be used in the tx of bacterial Sinusitis?

Answer 39

• Cipro is NOT respiratory FQ (due to poor activity against Streptococcus pneumoniae*) - Despite penetration to lungs and good Haemophilus influenzae cover *one of the more common pathogens causing sinusitis and many respiratory tract infections

Question 40

US IDSA guidelines recommend the use of Macrolides and Tetracyclines for the cover of Streptococcus Pneumoniae (gram pos). Can we do the same in SG?

Answer 40

Local: S. pneumoniae ↑ resistance to macrolides and tetracycline - Clarithromycin, azithromycin, doxycycline are NOT appropriate *Local guidelines are therefore different from IDSA

Question 41

What are the Bacterial Sinusitis treatment considerations for Streptococcus Pneumoniae?

Answer 41

Resistance – Streptococcus pneumoniae • Multi‐step penicillin‐binding proteins (PBPs) mutation • ↑ penicillin MIC • Penicillin‐resistant isolates uncommon locally (< 5‐10%)

Question 42

What is the solution to combat Streptococcus pneumoniae resistance?

Answer 42

- Prefer amoxicillin over penicillin: favorable pharmacokinetics* - Prefer ”high‐dose” amoxicillin for effective treatment ‐ Standard‐dose: 45mg/kg/day (pediatrics); 250‐500mg (adults) ‐ High‐dose: 80‐90mg/kg/day (pediatrics); 1g (adults) *Better oral bioavailability when using amoxicillin compared to penicillin = higher systemic conc

Question 43

What are the Bacterial Sinusitis treatment considerations for Haemophilus influenzae?

Answer 43

``` Resistance – Haemophilus influenzae • Beta‐lactamase production • Inhibited by beta‐lactamase inhibitor • Beta‐lactamase positive: ~ 18% locally ```

Question 44

What are the indications for Haemophilus influenzae resistance coverage in empiric treatment?

Answer 44

Use amoxicillin/clavulanate only if any ONE of the following:  Recent** course(s) of antibiotic(s)  Recent hospitalization  Failure to improve after 72 hours of amoxicillin Note: BL expression drives choice of augmentin vs amox in 1st line tx of bacterial sinusitis * these factors point towards higher likelihood of bacterial resistance * *recent duration is not really defined --> about last 30days (clinically)

Question 45

What is the treatment duration of Bacterial Sinusitis?

Answer 45

``` – Adults: 5 – 10 days • Improves compliance • Reduces antibiotic‐related adverse effects • Similar clinical cure – Pediatrics: 10 – 14 days* ``` *longer duration as evidence that supports shorter duration only done for adults, no pediatric data

Question 46

What is Acute Otitis media (AOM)?

Answer 46

Infection of middle ear space* resulting in inflammation and fluid accumulation *behind tympanic membrane/ear drum (separates middle ear space and external ear canal)

Question 47

What are the clinical presentations of AOM?

Answer 47

```  Ear pain (i.e. otalgia)  Ear discharge (i.e. otorrhea)  Ear popping  Ear fullness  Hearing impairment  Dizziness  Fever  Non‐specific in young infants*: ear rubbing, excessive crying, changes in sleep or behavioral pattern ``` *AOM is an infection in pediatric patients (usually < 5 years old)

Question 48

What are some risk factors for AOM?

Answer 48

```  Siblings/Attending day care*  Supine position during feeding**  Exposure to tobacco smoke at home  Pacifier use  Winter season*** ``` * AOM is a common complication of common cold/ viral URTI and siblings/day care are risk factors for transmission of viral URTIs/common cold * *if baby is flat, it is easier for fluid from nose to backflow into ear * **not applicable in SG

Question 49

Why do younger children get AOM more frequently than older children/adults?

Answer 49

- Angle is key (flatter for child) vs adult eustachian tube more angled - More angled --> discharge from nose more unlikely to backflow into eustachian tube compared to a more horizontal eustachian tube

Question 50

What are some strategies to prevent AOM?

Answer 50

```  Avoid exposure to tobacco smoke  Exclusive breastfeeding for 1st 6 months (passive immunity)  Minimize pacifier use  Vaccinations* – Influenza – Pneumococcal – Haemophilus influenzae type B vaccine ``` *as early as 6 months and older, protects against sinusitis (other than protecting against AOM)

Question 51

What is the pathogenesis of AOM?

Answer 51

1. Viral URTIs (e.g. common cold) 2. Secretions and inflammation 3. Eustachian tube obstruction 4. Negative eustachian tube pressure 5. Nose sniffing 6. Reflux of secretions into the middle ear (Medium for bacterial accumulation and growth) Route A: 1 - 2 - 3 - 4 - 6 Route B: 1 - 5 - 6

Question 52

What is the microbiology of AOM?

Answer 52

 Bacterial (55‐60%) ~ viral (40‐45%)  Viruses*  Bacteria – Streptococcus pneumoniae**, Haemophilus influenzae, Moraxella catarrhalis Note: microbiologically, sinusitis is quite similar to AOM * Also cause Viral Respiratory tract infections: Respiratory syncytial virus (RSV), rhinovirus, adenovirus, parainfluenza * *most common

Question 53

How is AOM diagnosed (tool and criteria)?

Answer 53

```  Pneumatic otoscope* as standard tool  Diagnostic criteria in children – Acute onset (< 48 hours) – Otalgia (holding, tugging, rubbing in a non‐verbal child) or erythema of tympanic membrane – Bulging of tympanic membrane** ``` * pointed area enters child's ear canal to look for bulging tempanic membrane, for s/sx of inflammation * *due to fluid buildup behind membrane space (in middle ear space) + more erythema

Question 54

What are the challenges in AOM management?

Answer 54

1. Unable to distinguish bacterial versus viral etiologies* Bacterial AOM – Prompt antibiotic initiation decreases duration of symptoms by ~1 day – ~80% of cases resolve in 3‐4 days without antibiotics 2. Overprescribing antibiotics = resistance Note: Kids just cry, dont report severity well and there is hesitancy in giving children abx *Sx exactly the same

Question 55

What is the supportive care tx for AOM?

Answer 55

– Analgesic/antipyretic*: paracetamol, NSAIDs – Decongestants and anti‐histamines have NOT shown to be beneficial *for all AOM pts (regardless bacterial/viral etiology)

Question 56

Are ear drop abx recommended for AOM?

Answer 56

No, AOM is a systemic infection, need PO abx for tx

Question 57

What are the 3 approaches to AOM abx tx initiation?

Answer 57

1. Immediate Initiation 2. Observation period 3. Watch and Wait Prescription

Question 58

What is the Immediate initiation method in AOM tx?

Answer 58

Start antibiotics at the initial doctor’s visit where AOM is diagnosed (-) many AOM due to viral (50-50) (-) 80% bacterial AOM self limiting (-) causes abx overuse in young pt (more side effects + hard to get young pt to take meds) Easy strategy but should be avoided

Question 59

What is the Observation method in AOM tx?

Answer 59

 No antibiotics given at the initial doctor’s visit  Supportive care* x 48‐72 hours Depending on pt:  Improves = no antibiotics  Worsens or fails to improve = antibiotics (-) Requires reliable follow‐up (may be inconvenient) (-) May require 2nd trip to the doctor (+) cautious and mindful usage of abx *paracetamol for fever and pain

Question 60

What is the Watch and Wait Prescription (WAWP) method in AOM tx?

Answer 60

 Prescription given at the initial doctor’s visit  Fill in 48 hours only if pt worsens or fails to improve (+) 2/3 prescriptions not filled (reduced abx use) (+) ↑ convenience and parent satisfaction Note: meant to address inconvenience factor - not used alot locally in SG as it is convenient to see a doctor - popular in western countries (big countries with a few hours drive to see paediatrician) --> convenience is a big factor

Question 61

What are the criteria to fulfil in order to warrant Observation period for AOM tx?

Answer 61

ALL of the following criteria must be fulfilled – ≥ 6 months* – Non‐severe** illness • Severe: moderate‐severe otalgia***, or otalgia > 48 hours, or fever > 39C in the last 48 hours – No otorrhea – Possible for close follow‐up – Shared decision‐making with the parent/caregiver * Younger = more likely to have complications = more unlikely to self-resolve * *Absence of all 3 'severe' criteria above * **Assessment is subjective i.e. otalgia (kids cant report severity) --> usually pediatrician err on side of caution and provide abx tx when child presents with AOM

Question 62

What should we consider for a pt who is: - < 6 months of age - Has unilateral AOM w/o Otorrhea

Answer 62

Observation period not recommended for all children < 6 months; immediate antibiotic therapy

Question 63

What should we consider for a pt who is: - ≥ 6 months to < 2 years of age - Has unilateral AOM w/o Otorrhea *non-severe

Answer 63

Immediate antibiotic therapy OR Observation* period *ALL of the following criteria must be fulfilled – Possible for close follow‐up – Shared decision‐making with the parent/caregiver

Question 64

What should we consider for a pt who is: - 2 years of age or older - Has unilateral AOM w/o Otorrhea

Answer 64

Immediate antibiotic therapy OR Observation* period *ALL of the following criteria must be fulfilled – Possible for close follow‐up – Shared decision‐making with the parent/caregiver

Question 65

What should we consider for a pt who is: - 2 years of age or older - Has Bilateral AOM w/o Otorrhea

Answer 65

Immediate antibiotic therapy OR Observation* period *ALL of the following criteria must be fulfilled – Possible for close follow‐up – Shared decision‐making with the parent/caregiver

Question 66

What should we consider for a pt who is: - 2 years of age or older - Has Bilateral AOM with Severe sx

Answer 66

Immediate antibiotic therapy

Question 67

What should we consider for a pt who is: - 2 years of age or older - Has Bilateral AOM with Otorrhea

Answer 67

Immediate antibiotic therapy Regardless of age - if Otorrhea/severe sx -> start abx

Question 68

What is the empiric 1st line abx selection and criteria for AOM? Recall - Bacteria in AOM: S. pneumoniae, H. influenzae, M. catarrhalis - “High‐dose” amoxicillin for effective treatment, especially S. pneumoniae (think sinusitis dosing)

Answer 68

``` 1st line antibiotic: Amoxicillin – MUST fulfill ALL 3 criteria • No amoxicillin in the last 30 days* • No concurrent purulent conjunctivitis • Not allergic to penicillin ``` Alternative 1st line antibiotic: Augmentin – ANY 1 of the following: • Amoxicillin in the last 30 days* • Concurrent purulent conjunctivitis** • History of AOM non‐responsive to amoxicillin * amoxicillin use in last 30 days = higher likelihood of amox resistance, worried about BL producing H flu * *AOM commonly presents as a complication post viral URTI (can be post purulent conjunctivitis caused by SA) - need to have MSSA cover

Question 69

What is the empiric abx selection and criteria for AOM if the patient has penicillin allergies? Recall - Bacteria in AOM: S. pneumoniae, H. influenzae, M. catarrhalis

Answer 69

– Cefuroxime PO, ceftriaxone (IM) • Possible option for mild penicillin allergies – Clindamycin* • Effective against S. pneumoniae only • Option for patients with severe penicillin allergies * No H flu cover - but ok as there are few alternatives to cover H flu if pt has severe penicillin allergy in kids (can use FQs for adult, not for kids) - Note 80% AOM self recover + cover S pneumo (most common) --> most kids do fine

Question 70

Can we use ceftazidime for the tx of AOM? Recall - Bacteria in AOM: S. pneumoniae, H. influenzae, M. catarrhalis

Answer 70

No, Ceftazidime is a 3rd gen cephalosporin (poor gram pos cover despite having pseudomonal cover)

Question 71

Is Clarithromycin used in the tx of AOM or Sinusitis in SG? Recall - Bacteria in AOM: S. pneumoniae, H. influenzae, M. catarrhalis

Answer 71

- High rate of local resistance of strep pneumoniae for macrolides and tetracyclines --> not appropriate - This applies to sinusitis as well (same pathogens)

Question 72

What are some things to note for AOM monitoring, counselling and subsequent response?

Answer 72

 Symptoms may worsen in the first 24 hours  Improvement expected in 48‐72 hours – Worsens or fails to improve*: re‐evaluate – If amoxicillin --> amoxicillin/clavulanate – If amoxicillin/clavulanate --> cefuroxime, ceftriaxone Note: impt to counsel caretakers that the abx take time for effect and the transient worsening of sx prior to improvement *uncommon as amox/augmentin are usually effective

Question 73

What is the tx duration for AOM?

Answer 73

1. < 2 years: 10 days 2. Severe symptoms* : 10 days 3. > 2 to 5 years AND non- severe symptoms: 7 days 4. > 6 years AND non‐severe symptoms: 5‐7 days *i.e. moderate‐severe otalgia, or otalgia > 48 hours, or fever > 39C in the last 48 hours Note: - Younger kids = longer tx duration (due to immature immune system or less data for younger kids <2years) - More severe initial sx = longer duration

Question 74

What are the adult and pediatric dose of Penicillin VK used in the tx of pharyngitis? *Bacterial (Streptococcus pyogenes)

Answer 74

Adult: 250mg PO QDS* or 500mg PO BD* Pediatric: 250mg PO BD – TDS*

Question 75

What are the adult and pediatric dose of Amoxicillin used in the tx of pharyngitis? *Bacterial (Streptococcus pyogenes)

Answer 75

Adult: 1g PO OD* or 500mg PO BD* Pediatric: 50mg/kg/day PO OD or divided BD* Larger OD dosing may have more GI side effects

Question 76

What are the adult and pediatric dose of Clindamycin used in the tx of pharyngitis? *Bacterial (Streptococcus pyogenes)

Answer 76

Adult: 300mg PO TDS Pediatric: 7mg/kg PO TDS

Question 77

What are the adult and pediatric dose of Amoxicillin used in the tx of Sinusitis? *Bacterial (mainly S. pneumoniae, H. influenzae)

Answer 77

Adult: 1g PO TDS Pediatric: 80 – 90 mg/kg/day PO divided BD* Here, we are using high dose Amoxicillin

Question 78

What are the adult and pediatric dose of Augmentin used in the tx of Sinusitis? *Bacterial (mainly S. pneumoniae, H. influenzae)

Answer 78

Adult: 625mg PO TDS; or 1g PO BD Pediatric: 80 – 90 mg/kg/day PO divided BD* True high dose: 1g PO BD Convenient high dose option: 625mg TDS

Question 79

What are the adult and pediatric dose of Levofloxacin used in the tx of Sinusitis? *Bacterial (mainly S. pneumoniae, H. influenzae)

Answer 79

Adult only: 500mg PO OD *not for pediatric pts

Question 80

What are the pediatric dose of Amoxicillin and Augmentin used in the tx of AOM? *Bacterial (mainly S. pneumoniae, H. influenzae, M. catarrhalis)

Answer 80

80 – 90 mg/kg/day PO divided BD* *Similar to Bacterial Sinusitis pediatric dosing

Question 81

What are the pediatric dose of Cefuroxime used in the tx of AOM? *Bacterial (mainly S. pneumoniae, H. influenzae, M. catarrhalis)

Answer 81

30 mg/kg/day PO divided BD

Question 82

What is the next step in care for this pt? 1) 3yo boy with AOM (left) and no otorrhea; per mom: no fever at home, mild ear pain and still able to go to kindergarten as usual, mom is hesitant to use antibiotics PMH: AOM x 1 (18mo) (treated with amoxicillin x 10 days – diarrhea) Allergy: none Weight: 16.8kg

Answer 82

Observational period reasonable esp if recurrent AOM, parents have some comparison of sx to tell if 'mild/severe' - Unilateral - 'non-severe' presentation - pt experienced side effects from previous amoxicillin use

Question 83

What is the next step in care for this pt? 2) 8mo boy with AOM (left) and no otorrhea; per mom: fever 39.2C at home last night, irritable and rubbing on his ears x 2 days, mom is hesitant to use antibiotics her baby PMH: none; never taken antibiotics Allergy: none Weight: 8.6kg

Answer 83

Amoxicillin 90mg/kg/day Unilateral - 'severe' presentation (objective due to fever) -> need to tx w abx - no PMH/Allergies/purulent conjunctivitis/past amox use

Question 84

What are some differences between influenza and the common cold in terms of s/sx?

Answer 84

Influenza tends to have a more severe presentation with a greater amount of systemic symptoms (fever, body aches, chills, malaise, chest discomfort, headache) Common cold symptoms are more restricted to local symptoms (stuffy nose, sore throat, sneezing)

Question 85

What is a hallmark sx of influenza?

Answer 85

Abrupt onset

Question 86

How does Covid-19 differ from influenza?

Answer 86

 Change in or loss of taste or smell (hallmark)  Nausea, vomiting, diarrhea - Both causes similar systemic symptoms

Question 87

What is the type of influenza infection distribution in SG and reason for it?

Answer 87

SG has a bimodal distribution December – February (winter in northern hemisphere) May – July (winter in southern hemisphere) Travelers bring the influenza with them when trying to escape winter

Question 88

What is the microbiology, epidemic potential and severity of clinical presentation of influenza?

Answer 88

Influenza A: Humans and animals, severe illness, mostly in younger pts Influenza B: Humans only, severe illness in older/high risk pt, less severe epidemics Influenza C: Humans and swine, mild disease with no epidemics

Question 89

What are some complications of influenza?

Answer 89

 Viral pneumonia  Post‐influenza bacterial pneumonia (particularly those caused by S. aureus) – Mortality > 30%  Respiratory failure  Exacerbate underlying pulmonary or cardiac comorbidities  Febrile seizures  Myocarditis or pericarditis

Question 90

Which individuals are high risk for influenza related complications?

Answer 90

– Children < 5 years – Elderly ≥ 65 years – Women who are pregnant or within 2 weeks post‐partum – Residents of nursing homes or long‐term care facilities – Obese individuals with BMI ≥ 40 kg/m2 – Individuals with chronic medical conditions (e.g. asthma, COPD, HF, DM, CKD, immunocompromised, etc.)

Question 91

What are some prevention strategies for influenza?

Answer 91

1) Good Personal Hygiene 2) Healthy Lifestyle 3) Vaccination (annual) 4) Chemoprophylaxis

Question 92

Is there a delay between vaccine administration and its protective effects?

Answer 92

- delay is about 2weeks from administration of vaccine to full protection - if exposure to influenza within 2 weeks --> tx as a unvax individual

Question 93

Who/when pre-exposure chemoprophylaxis indicated? | How do we initiate in this case?

Answer 93

 Institutional outbreaks; OR  High‐risk individuals ≥ 3 months of age who CANNOT receive vaccination  Initiate as soon as outbreak or influenza activity is identified

Question 94

Who/when is POST-exposure chemoprophylaxis indicated? | How do we initiate in this case?

Answer 94

 ALL* high‐risk individuals ≥ 3 months of age; OR  Unvaccinated individuals ≥ 3 months of age who are household contacts of high‐risk individuals  Initiate as soon as possible (within 48 hours) of exposure *regardless of vax status

Question 95

What are the available diagnostics for influenza? Comment on their place in therapy

Answer 95

 Viral cultures are not recommended  Molecular tests are available for use in practice – Limited use in outpatient (Mostly treated empirically) – Used inpatient; Reverse‐transcriptase polymerase chain reaction (RT‐PCR)

Question 96

What is the treatment criteria for influenza?

Answer 96

 For documented or suspected influenza – Initiate as soon as possible (within 48h) of symptom onset for individuals who fulfill any ONE of the following • Hospitalized • High‐risk for complications • Severe, complicated or progressive illness – May be considered for others (e.g. outpatients) presenting within 48 hours of symptom onset

Question 97

If a patient discovers they have influenza >48h post symptom onset?

Answer 97

* for inpatient setting ONLY --> sometimes can still give tx after 48h (anti-virals) for IP pts - may still have some benefit (reducing sx duration and complication incidence)

Question 98

What is the main drug used in the treatment of Influenza and its side effects?

Answer 98

Oseltamivir (Tamiflu) for both tx and chemoprophylaxis - Neuraminidase inhibitor Side effects: Headache, Mild gastrointestinal effects

Question 99

What is the tx regimen for chemoprophylaxis of influenza?

Answer 99

75mg PO daily x 7days Renal adjustment necessary - Tx duration may be longer to cover at risk period - can be 7 days after exposure (post exposure prophylaxis) - pre-exposure prophylaxis (7 days from resolution of influenza activity/outbreak) i.e. duration of outbreak + 7days

Question 100

What is the tx regimen for treatment of influenza?

Answer 100

75mg PO BD x 5days | Renal adjustment necessary

Question 101

Suggest clinical response for this patient: 20yo NUS student who is suspected of influenza in his GP's office. Symptoms started 4 days ago. He is otherwise healthy

Answer 101

can consider antiviral for OP within 48h of presentation NO NEED TX - if healthy, stable OPs might not need anything -> rest is enough 2 reasons why no tx: - pt low risk - > 48h since onset (the giving of tx >48h is for IP who are presenting w severe illness)

Question 102

Suggest clinical response for this patient: 7yo boy whose mother is diagnosed with influenza. He last received influenza vaccine 2 months ago. – What if this is a 2yo boy?

Answer 102

vaccine is preventive and effective (2mo ago) - considering post-exposure prophylaxis (presumably exposed to the mom) - only high risk pts 3mo or older will receive tx - 7yo not high risk (5yo is high risk) - does not meet post exposure indication --> NO TX - if 2yo --> high risk category --> then we can give post exposure prophylaxis

Question 103

Suggest clinical response for this patient: 63yo M with hyperlipidemia who is exposed to influenza. He lives at home with family members who are healthy.

Answer 103

hyperlipidemia = obese (no mention + needs to be morbid obesity, BMI 40 and above) --> number is impt - no indication for tx - family members are generally healthy

Question 104

Suggest clinical response for this patient: 70yo M with heart failure who is exposed to influenza. He last received influenza vaccine 2 months ago.

Answer 104

most appropriate for tx - post exposure prophylaxis - age + HF puts him in high risk - HF -> underlying co-morbidity increases risk for complication - indicated for post exposure prophylaxis (regardless of vaccination status)

Question 105

Suggest clinical response for this patient: 40yo F with no PMH is exposed to influenza. She last received influenza vaccine 2 months ago and lives with her 86yo mother.

Answer 105

lady not high risk - mom is high risk (age) - lady does not need post exposure prophylaxis as she is vaccinated - tx is for unvax individuals with vulnerable household contacts only