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PR3124 PT3 > URTIs > Flashcards

URTIs Flashcards

1
Q

Briefly describe the microbiology of pharyngitis.

A

Causative microorganims:
Viruses (> 80%)&raquo_space; Bacteria (< 20%)

Viruses: Rhinovirus, coronavirus, influenza, parainfluenza, Epstein-Barr
Bacteria: Group A beta-hemolytic Streptococcus pyogenes
-> “strep’ throat but less common in SG (no winter; lack of seasons)

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2
Q

What are some clinical presentations of pharyngitis?

A 
Acute onset of sore throat
Pain on swallowing
Fever
Erythema & inflammation of pharynx & tonsils
- w/ or w/o patchy exudates
Tender & swollen lymph nodes
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3
Q

Describe the pathogenesis of pharyngitis.

A

Direct contact with droplets of infected saliva or nasal secretions
Short incubation time of 24-48h

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4
Q

What are some complications that may emerge from patients with pharyngitis?

A

Viral: Self-limiting
Bacterial: Self-limiting but complications are possible
- Complications occur 1-3 weeks later
- Acute rheumatic fever (resulting in damage to heart muscle, joint and brain)
- Acute glomerulonephritis

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5
Q

Which complication(s) of pharyngitis can be prevented with early initiation of effective Abx?

A

Acute rheumatic fever

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6
Q

What are some challenges faced in the management of pharyngitis?

A

Differentiation between viral or bacterial causes is difficult due to similar clinical presentation.

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7
Q

What are some benefits behind the use of Abx for pharyngitis, despite its more common viral etiology?

A

Prevent acute rheumatic fever
Shorten duration of symptoms by 1-2 days
Reduce transmission (no longer infectious after 24h of Abx)

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8
Q

What are the tests available to diagnose a patient with bacterial pharyngitis?

A

Testing for S. pyogenes pharygnitis:

1) Throat culture (24-48 h) -> gold standard
- High sensitivity 90-95% but too long of a turnover
2) Rapid antigen detection test (RADT) (in min)
- Sensitivity 70-90%, but too expensive for day-to-day use

However, clinical testing of S. pyogenes is not commonly used.

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9
Q

How is pharyngitis clinically diagnosed?

A 
Modified Centor Criteria:
\+1 Fever > 38 deg C
\+1 Swollen, tender anterior cervical lymph nodes
\+1 Tonsillar exudate
\+1 Absence of cough
\+1 3-14 y/o
\+0 15-44 y/o
-1 > 45 y/o

Start empiric Abx Tx for S. pyogenes pharyngitis when 2 or more points is obtained.

  • Above are clinical presentations of likely S. pyogenes infection
  • S. pyogenes pharyngitis is rare among children < 3 y/o; presume viral etiology
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10
Q

List some recommended supportive care in the treatment of pharyngitis.

A

Analgesics / antipyretics (paracetamol, NSAIDs)
Analgesic sprays / lozenges (Difflam -> benzydamine)
Saltwater gargles
Adequate fluid & rest

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11
Q

List all recommended empiric Abx for the treatment of pharyngitis (with dosing regimen and Tx duration).

A

1st-line: Penicillin VK

  • A: 250 mg PO QDS or 500 mg PO BD
  • C: 250 mg PO BD-TDS

Alternatives:

1) Amoxicillin
- A: 500 mg PO BD or 1 g PO OD
- C: 50 mg/kg/day PO OD or divided BD
2) Clindamycin (for penicillin allergies)
- A: 300 mg PO TDS
- C: 7mg/kg PO TDS
3) Cephalexin
4) Clarithromycin

Tx Duration = 10 days
Expected clinical improvement in 24-48h.
Counsel on completing course of Abx to minimise sub-therapeutic dosing & increase curative potential.

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12
Q

Why is amoxicillin/clavulanate not a suitable recommendation as an Abx for the Tx of pharyngitis?

A

Antibacterial coverage is too broad against S. pyogenes.
Clavulanate allows additional gram-negative & anaerobic coverage due to beta-lactamase inhibitor activity but is unnecessary.

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13
Q

What are some clinical presentations of sinusitis?

A

Major Smx: purulent anterior nasal discharge, purulent or discoloured posterior nasal discharge, nasal congestion/obstruction, facial congestion/”fullness”, facial pain/pressure, hyposmia (reduced sense of smell) / anosmia (lack of smell), fever

Minor Smx: headache, ear pain / pressure / fullness, halitosis (bad breath), dental pain, cough, fatigue

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14
Q

How is sinusitis clinically diagnosed?

A

> = 2 major symptoms OR

1 major symptom + >= 2 minor symptoms

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15
Q

Briefly describe the microbiology of sinusitis.

A

Causative microorganims:
Viruses (> 90%)&raquo_space; Bacteria (< 10%)

Viruses: Rhinovirus, adenovirus, influenza, parainfluenza
Bacteria: (+) Streptococcus pneumoniae or (-) Haemophilus influenzae (most common), (-) Moraxella catarrhalis, (+) Streptococcus pyogenes

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16
Q

Describe the pathogenesis of sinusitis.

A

Direct contact with droplets of infected saliva or nasal secretions
Bacterial cases are usually preceded by viral URTIs (e.g. common cold, pharyngitis).
Inflammation results in sinus obstruction -> nasal mucosal secretions are trapped -> becomes a medium for bacteria trapping & multiplication

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17
Q

What are some diagnostic challenges faced in the management of sinusitis?

A

Bacterial & viral sinusitis have similar symptoms, thus there is limited use of diagnostic tests (i.e not clinically used).

  • Imaging studies: non-specific, non-discriminatory
  • Sinus aspirate (gold standard): invasive, painful & time-consuming
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18
Q

How is bacterial sinusitis clinically diagnosed?

A

Presence of sinusitis (>= 2 major smx or 1 major + >= 1 minor smx) AND either one of the following:

1) Persistent smx > 10 days & NOT improving
- Viral sinusitis should be self-limiting (resolve in 7-10 days)
2) Severe smx on onset
- Purulent nasal discharge x 3-4 days or high fever of >= 39 deg C
3) Double sickening
- Worsening of smx 5-6 days after initial improvement

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19
Q

Pt is a 25 y/o university student with no past medical Hx. He returned to Singapore 8 days ago after his vacation in South Korea. He developed a cold since he returned which initially improved with a 7-day course of amoxicillin. However, in the last 2 days, he reported having purulent discharge, nasal congestion and cough. Recommend an appropriate Abx dosing regimen to this pt.

A

Amoxicillin-clavulanate PO 625 mg TDS or 1g BD x 5-10 days

Cefuroxime, cotrimoxazole are also possible alternatives.

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20
Q

Pt is a 24 y/o university student with no past medical Hx. He returned to Singapore 8 days ago after his vacation in South Korea. He developed a cold since he returned which initially improved naturally. However, in the last 2 days, he reported having purulent discharge, nasal congestion and cough. Recommend an appropriate Abx dosing regimen to this pt.

A

Amoxicillin PO 1g TDS x 5-10 days

Cefuroxime, cotrimoxazole are also possible alternatives.

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21
Q

Pt is a 4 y/o child with no past medical Hx. She developed a cold with a reported fever of 39.1 deg C by her mother. Recommend an appropriate Abx dosing regimen to this pt.

A

Amoxicillin PO 80-90 mg/kg/day divided BD x 10-14 days

Cefuroxime 30 mg/kg/day divided BD or cotrimoxazole are also possible alternatives.

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22
Q

Pt is a 19 y/o young adult with a past medical Hx of reported penicillin allergy. He developed a cold with a reported fever of 39.0 deg C. Recommend an appropriate Abx dosing regimen to this pt.

A

Levofloxacin PO 500 mg OD x 5-10 days

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23
Q

Pt is a 5 y/o child with no past medical Hx. He returned to Singapore 12 days ago after his vacation in South Korea with his family. He developed a cold since he returned which failed to improve after taking amoxicillin for the past 11 days. Recommend an appropriate Abx dosing regimen to this pt.

A

Amoxicillin/clavulanate PO 80-90 mg/kg/day divided BD x 10-14 days

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24
Q

Why is clarithromycin, azithromycin & doxycycline NOT an appropriate recommendation for Tx of sinusitis?

A

Increased local resistance of S. pneumoniae against macrolides & tetracyclines in Singapore -> not recommended despite appropriate activity

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25
Q

Why is ciprofloxacin NOT an appropriate recommendation for Tx of sinusitis?

A

Lack of activity against S. pneumoniae & S. pyogenes, thus it is not considered as a respiratory FQ.

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26
Q

Under what conditions should amoxicillin-clavulanate be recommended over amoxicillin in the Tx of sinusitis?

A

Recent (<=30 days) course of Abx
Recent (<=30 days) hospitalisation
Failure to respond after 72h of amoxicillin

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27
Q

What are some Tx considerations when treating pt with sinusitis?

A

Development of Abx resistance:

1) S. pneumoniae
- Multi-step penicillin-binding proteins (PBPs) mutation of S. pneumoniae result in an increase in MIC of penicillin
- Thus, “high-dose” amoxicillin is preferred over normal dose amoxicillin & penicillin due to more effective Tx (to overcome resistance) & more favourable PK (better F) respectively
- Observed with doubling of dose for adults & paeds.

2) H. influenzae
- Beta-lactamase production inhibited by clavulanate to improve efficacy of Tx

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28
Q

Define “pharyngitis”.

A

Acute inflammation of the oropharynx or nasopharynx.

29
Q

Define “rhinosinusitis”.

A

Acute (w/in 4 weeks) inflammation & infection of the paranasal & nasal mucosa.
Also known as sinusitis in short.

30
Q

Define “acute otitis media”.

A

AOM: Infection of the middle ear space resulting in inflammation & fluid accumulation.
Usually in paediatric pt < 5 y/o & happens after viral URTI.

31
Q

What are some clinical presentations of AOM?

A 
Ear pain / Otalgia
Ear discharge / Otorrhea
Ear popping 
Ear fullness
Hearing impairment
Dizziness
Fever
Non-specific smx in infants: ear rubbing, excessive crying, changes in sleep & behavioural patterns
32
Q

Postulate a reason why the epidemiology of acute otitis media is usually children under the age of 5.

A

Younger children < 5 y/o have straighter Eustachian tube, thus allowing easier bacterial entry from nasal cavity to middle ear, as compared to adults.
- Eustachian tube connects the middle ear & nasopharynx & regulates middle ear pressure.

33
Q

What are some risk factors that increase the risk of paediatric patients to AOM?

A 
< 5 y/o
Siblings
Attending daycare
Supine position during feeding
Exposure to tobacco smoke
Pacifier use
Winter season
34
Q

What are some preventive measures that can be practised to minimise the risk of AOM in children?

A

Avoid exposure to tobacco smoke
Exclusive breastfeeding for the 1st 6 months
- Passive immunity acquired via mother’s Ab
Minimise pacifier use
Vaccinations (influenza, pneumococcal, H. influenzae type B)

35
Q

Briefly describe the pathogenesis of AOM.

A

Generally preceded by viral URTIs (e.g. common cold)
- causing secretions & inflammation to block the Eustachian tube & result in negative Eustachian tube pressure
- coupled with nose sniffing
Both lead to backflow/reflux of secretions into middle ear, thus allowing the accumulation of secretions for bacterial growth.

36
Q

Briefly describe the microbiology of AOM.

A

Causative microorganims:
Bacterial (55-60%) ~ Viral (40-45%)

Viruses: Rhinovirus, adenovirus, parainfluenza & respiratory syncytial virus (RSV)
Bacteria: (+) Streptococcus pneumoniae or (-) Haemophilus influenzae (most common), (-) Moraxella catarrhalis

37
Q

How is AOM clinically diagnosed?

A

Pneumatic otoscope as standard tool
Diagnostic criteria in children:
- Acute onset (< 48h)
- Otalgia (holding, tugging, rubbing in non-verbal children) or erythema of tympanic membrane
- Bulging of tympanic membrane due to fluid accumulation

38
Q

What are some challenges faced in the management of AOM?

A

Differentiation between viral or bacterial causes is difficult due to similar clinical presentation.
Prompt Abx initiation only decreases duration of smx of bacterial AOM by ~1 day
- ~80% of cases resolve in 3-4 days w/o Abx
Overprescribing Abx allows development of resistance.

39
Q

Briefly describe the general Tx approach of paediatric pt with AOM.

A

Immediate Initiation vs Observational Period

  • Observational period approach refers to supportive care for 48-72h & only initiate Abx if smx worsens / fail to improve.
  • Supportive care includes analgesic/antipyretics & rehydration
40
Q

Under what conditions can the observational period Tx approach be considered in pt with AOM?

A

ALL must be fulfilled!

Age >= 6 months
- For paeds aged 6 mths - 2y/o (exclusive), AOM must be unilateral.
Non-severe illness (otherwise, considered severe)
- Absence of moderate to severe otalgia
- Otalgia < 48h
- Fever < 39 deg C in last 48h
No otorrhea
Possible for close follow-up
Shared decision-making w/ parent/caregiver

41
Q

AB is a 1 y/o boy who presents to the clinic today with AOM of both his ears and no otorrhea. According to AB’s mom, AB has no fever at home, there’s mild ear pain x 1 day & AB is still able to go to his nursery. Mom is hesitant to use Abx for her son. Is AB suitable for observation period therapy for his AOM?

A

No.

Consider observational Tx if pt. fulfils (1) + (2) OR (1) + (3):
(1) No otorrhea
(2) Children >=2 y/o
(3) Unilateral AOM
as differentials in addition to conditions to consider observational period for AOM Tx

42
Q

TM is an 8-month-old boy who presents to the clinic today with AOM of his left ear and no otorrhea. According to TM’s mom, there was a fever of 39.2 deg C at home last night, irritable and rubbing of ears x 2 days. Mom is hesitant to use Abx for her son. TM has never taken Abx before and does not have any allergies. What will be your recommendation to TM’s mother?

A

Start immediately amoxicillin PO 80-90 mg/kg/day divided BD x 10 days.

Pt. fulfilled ALL 3 criteria:

1) No amoxicillin in the past 30 days
2) No concurrent purulent conjunctivitis
3) Not allergic to penicillin

43
Q

TM is an 8-month-old boy who presents to the clinic today with AOM of his left ear and no otorrhea. According to TM’s mom, there was a fever of 39.2 deg C at home last night, irritable and rubbing of ears x 2 days and there is concurrent purulent conjunctivits. Mom is hesitant to use Abx for her son. TM has never taken Abx before and does not have any allergies. What will be your recommendation to TM’s mother?

A

Start immediately amoxicillin/clavulanate PO 80-90 mg/kg/day divided BD x 10 days.

Pt. fulfilled either one of three criteria:

1) Amoxicillin in the past 30 days
2) Concurrent purulent conjunctivitis -> indicative of S. aureus; thus Augmentin is recommended
3) Hx of AOM not responsive to amoxicillin

44
Q

In the event of a penicillin allergy in pt. with AOM, what are the alternative Tx options available?

A

Mild: Cefuroxime 30 mg/kg/day divided BD or IM ceftriaxone
- Ceftazidime is NOT viable due to lack of activity against S. pneumoniae!!

Severe: Clindamycin 7 mg/kg TDS

  • Effective against S. pneumoniae ONLY
  • NOT active against gram-negative H. influenzae & M. catarrhalis
  • No other alternatives available for paediatrics -> FQ is C/I for pt. < 18 y/o!!
45
Q

How long should pt with AOM be treated with systemic Abx?

A

Clinical improvement expected in 48-72h.

Severe smx (i.e. moderate to severe otalgia, otalgia >= 48h or fever >= 39 deg C in last 48h) = 10 days
< 2 y/o = 10 days
>= 2 & < 5 y/o w/ non-severe smx = 7 days
>= 6 y/o w/ non-severe smx = 5-7 days
46
Q

Define “influenza”.

A

Viral respiratory tract infection

47
Q

What are some differences in clinical presentation between influenza & common cold?

A

Onset of flu is abrupt & flu often have more severe smx (higher fevers, more severe body aches & generalised chills) than common cold.
However, both influenza & common cold has a similar incubation period of 24-72h.

48
Q

What are some signs and symptoms that point towards a likely COVID-19 infection?

A

Change in or loss of taste or smell
N/V/D
- Both are more likely to happen in COVID-19 pt.
Longer incubation period (2-14 days; avg 5 days) than influenza (1-4 days).

49
Q

Briefly describe the epidemiology of influenza.

A

Broadly tracked by the number of people visiting polyclinics for acute respiratory tract infections.
Follows a bimodal distribution in SG
- Dec to Feb -> winter season in Northern Hemisphere
- May to Jul -> winter season in Southern Hemisphere

50
Q

Which of the following subtype is responsible for a more severe clinical presentation in a 30 y/o pt with influenza?

A

Influenza A

51
Q

Which of the following subtype of influenza is only transmissible between humans?

A

Influenza B

52
Q

Influenza B is responsible for causing massive flu pandemics in human populations. True or false?

A

False. Influenza A is responsible for causing severe epidemics & pandemics.

53
Q

Influenza A is responsible for causing significant mortality in young people. True or false?

A

True. Influenza B cause severe illness in older adults or high-risk pt in comparison.

54
Q

List some complications of influenza.

A

Viral pneumonia
Post-influenza bacterial pneumonia (esp. by S. aureus) -> mortality > 30%
Respiratory failure
Exacerbate underlying pulmonary/cardiac comorbidities
Febrile seizures
Myocarditis / Pericarditis

55
Q

Which populations are at high risk for influenza-related complications?

A

Children < 5 y/o
Elderly >= 65 y/o
Pregnant women or w/in 2 weeks post-partum
Residents of nursing homes or long-term care facilities
Obese individuals w/ BMI >= 40 kg/m2
Individuals w/ specific chronic medical conditions
- Asthma, COPD, heart failure, diabetes, CKD, immunocompromised

56
Q

What are some preventive measures we can adopt to minimise the risk of an influenza infection?

A

1) Good personal hygiene
- Wash hands regularly, minimise touching of eye/nose/mouth, cover nose & mouth when coughing or sneezing, use serving spoons
2) Healthy lifestyles
- eat balanced diet, regular exercise, sleep hygiene, no smoking
3) Vaccinations
- best prevention w/ inactivated trivalent/quadrivalent IM vaccine yearly
- indicated for ALL individual >= 6 months

57
Q

Why is chemoprophylaxis not a recommended preventive measure against influenza?

A

To avoid sub-therapeutic dosing that increases the risk for resistance; thus, it is not routinely recommended.

58
Q

What are some diagnostic tests available for pt with influenza?

A

Viral cultures are not recommended.
- Harder to perform & require longer turnover time

Molecular tests are available but primarily used in the inpatient settings with RT-PCR
- Limited use in outpatient; treated empirically

59
Q

What are some Tx considerations when treating a pt with influenza?

A

For documented / suspected influenza, initiate ASAP w/in 48h of smx onset when any ONE of the following is fulfilled:

  • Hospitalised
  • High-risk for complications
  • Severe, complicated or progressive illness

For outpatients w/in 48h of smx onset, Tx can be considered.

  • Do NOT recommend PO oseltamivir post 48h of smx onset!!
  • Greatest benefit in preventing complications when starting w/in 48h of smx onset
  • Upon -ve PCR to rule out flu, stop oseltamivir.
60
Q

Which strains of influenza are clinically significant?

A

Influenza A & B. C is not clinically relevant.

61
Q

What is the recommended Tx option for pt diagnosed with influenza within 24h of symptom onset?

A

Oseltamivir PO 75mg BD x 5 days

62
Q

What is the mechanism of action of oseltamivir?

A

Neuraminidase inhibitor

  • interferes with protein cleavage
  • inhibits release of new virus
63
Q

What are some common side effects of oseltamivir?

A

Well-tolerated. SE includes headache and mild GI effects.

64
Q

Oseltamivir is hepatically cleared. True or false?

A

False, primarily renal clearance.

65
Q

Testing is not required to differentiate a pt suffering from influenza from COVID-19. True or false?

A

False

66
Q

Influenza is more contagious than COVID-19. True or false?

A

False.

Pt w/ influenza remain contagious for about 7 days; longer for immunocompromised pt.

Pt with COVID-19 remains contagious for at least 10 days after signs & smx first appeared or after testing positive for COVID-19 despite being asymptomatic.

  • Immunocompromised pt can be contagious for >= 20 days
  • More easily spread & transmissible than influenza.
67
Q

COVID-19 is transmissible via close contact w/ infected individuals, via fomites, or via inhalation of infected droplets. True or false?

A

True. Similar to influenza.

68
Q

Which populations are at higher risk for severe illness of COVID-19 infection?

A 
Children & infants
Elderly >= 65 y/o
Underlying medical conditions
Pregnant women
Unvaccinated individuals
69
Q

List some of the complications resulting from COVID-19 infections.

A

Similar to influenza.
Additional complications include:
- Blood clots in veins & arteries of lungs, heart, legs or brain
- Multisystem Inflammatory Syndrome in Children (MIS-C) and in Adults (MIS-A)

PR3124 PT3 (12 decks)

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