Upper Respiratory Tract Infections Flashcards
(45 cards)
How is URTI transmitted?
- Droplets or aerosols when infected person cough, sneeze, talk
- Spread indirectly when person touches a surface, then touches nose or mouth
- Share food without serving spoon
=> Particles inhaled into respiratory tract and invade upper airway mucosa
What are the innate immunity against URTI?
- Nostril hair lining traps organisms
- Mucus traps organisms
- Angle between the pharynx and nose which prevents particles from falling into the airways
- Mucociliary system in lower airways that transport pathogens back up the pharynx
- Adenoids and tonsils (secondary lymphoid tissues) that contain immunological cells
What are the risk factors for URTI?
- Close contact
- Lack of personal/hand hygiene
- Medical disorders: people with chronic respiratory disease like asthma and allergic rhinitis
- Smoking
- Immunocompromised individuals including CF, HIV, use of corticosteroids, transplant, post-splenectomy
- Anatomical anomalies, including facial dysmorphic changes or nasal polyposis
What are some ways to prevent URTI?
- Hand/personal hygiene, mask wearing, stay away from crowds
- Vaccination - e.g., influenza, pneumococcal, Hemophilus influenzae (others: varicella, BCG, pertussis, diphtheria, MMR)
- Manage known risk factors - e.g., smoking cessation, control asthma and AR
Management of URTI includes symptom management, use of antibiotics, and prevention of future recurrence by managing/reducting risk factors.
In what cases should antibiotics be used in the management of URTI?
NEVER USED:
- Common cold
- Influenza
SOMETIMES USED:
- Pharyngitis
- Rhinosinusitis
- Otitis media
- Confirm presence of infection [COMMON COLD]
- Risk factors (as above)
- Clinical presentation
Describe the subjective and objective clinical presentation
Low grade temp <38 (gradual)
Rhinorrhea
Nasal blockage
Sneezing
Sore throat
Productive (wet) cough
Some headache, body ache
*There should be NO high fever of >=38, HR should be normal, lungs clear to auscultation bilaterally (no compromised breathing)
- Identification of pathogens [COMMON COLD]
- What microbiological diagnostics may be required?
- What are the common pathogens of common cold?
No microbiological diagnostics required, unless to rule out influenza or covid-19
Pathogen - rhinovirus, coronavirus
- Selection of antimicrobial and regimen [COMMON COLD]
What antibiotics should be considered?
NIL
- Monitor response [COMMON COLD]
Describe the monitoring parameters
- Recover in ____
- Feel better within _____
- See Dr if symptoms do not improve after _____
Self limiting, recover in 7-10 days
Cough lasts 2-3 weeks (due to postnasal drip)
Feel better within 3-4 days, but symptoms can linger for a few weeks
See doctor if symptoms does not improve after 10 days or if symptoms worsen
Normal for nasal discharge to change colour
- yellow/green may be due to inflammation, DOES NOT imply bacterial cause
- Confirm presence of infection [INFLUENZA]
What is the clinical presentation of influenza?
*more serious than common cold
Symptoms: fever (abrupt), chills, headache, malaise, myalgia, anorexia
Respi symptoms: sore throat, dry cough, nasal discharge
Elderly pt may present with confusion
- Confirm presence of infection [INFLUENZA]
What are some complications that may develop from influenza? (due to weakened respiratory tract)
Primary viral pneumonia
Secondary bacterial pneumonia
- often Staph Aureus and Strep Pneumoniae and Haemophilus Influenzae
Exacerbation of chronic respiratory disease
Myocarditis
- Confirm presence of infection [INFLUENZA]
What diagnostics may be used for influenza?
Nasopharyngeal swab or aspirate
- Rapid detection kits, POCT - immunofluorescence (IF), enzyme immunoassay (EIA), immunochromatographic method
- Reverse-transcriptase PCR
*More for hospitalized/LTC (to determine use of antivirals), not routine in outpatient setting (uncomplicated, hence symptomatic relief sufficient)
- Confirm presence of infection [INFLUENZA]
What groups of patients are at high risk for flu complications? (hence may need antivirals)
- Children <5yo
- Elderly >= 65yo
- Women who are pregnant or within 2 weeks post-partum
- Residents of nursing homes or long-term care facilities
- Obese individuals with BMI >=40kg/m2
- Individuals with chronic medical conditions (e.g., asthma, COPD, heart failure, diabetes, CKD, immunocompromised)
- Confirm presence of infection [INFLUENZA]
Describe the differences in symptoms of cold and flu
Symptom onset more gradual in cold, more abrupt in flu
Fever and aches and chills and fatigue more common in flu
Sore throat, rhinorrhea, nasal congestion, sneezing more common in cold
Cough occurs in both (wet in common cold, dry in flu)
- Confirm presence of infection [INFLUENZA]
Describe the similarities and differences in symptoms of flu and covid 19
Similar clinical presentation - need diagnostics tests to confirm
Similarities: wide spectrum of disease, treatment and vaccination available
Differences: covid 19 more contagious, covid 19 cause more severe illness in vulnerable population
- What is the pathogen [INFLUENZA]
What are the common influenza viruses in human
Influenza A - cause seasonal epidemics, can cause pandemics
- Two surface proteins: Hemagglutinin (H) and Neuraminidase (N)
- Usual circulating subtypes: H1N1, H3N2
Influenza B - cause seasonal epidemics
- Two lineages: B/Yamagata and B/Victoria
Influenza C - causes febrile mild upper respiratory illness, does not occur in endemics
*D occurs in cattles
- What is the pathogen [INFLUENZA]
When do influenza peaks occur?
Influenza A and B cause seasonal epidemics
- Middle (May to July): southern hemisphere winter
- End/beginning of year (Nov to Feb): northern hemisphere winter
*Could be spread due to travel, close contacts during these seasons
- Selection of antimicrobial treatment [INFLUENZA]
Discuss the treatment option and when it should be initiated
Initiate antiviral as soon as possible (best within 48h, up to 5 days) of symptom onset for indiv who fulfill any ONE of the following (SERIOUS ILLNESS):
- Hospitalized
- High-risk complications
- Severe, complicated or progressive illness
If started for oupatient setting, initiate within first 48h of symptom onset. If not, just offer symptomatic relief.
- Selection of antimicrobial treatment [INFLUENZA]
Discuss the MOA, dose, SE of the antiviral used.
Oseltamivir (PO) - Tamiflu
- Active against influenza A and B
- MOA: Neuraminidase inhibitor (interferes with protein cleavage and hence inhibit release of new virus)
- Dose: PO 75mg bid x5d, require dose adj in renal impairment CrCl <60ml/min
- SE: well tolerated, some headache and mild GI discomfort (N&V)
- Monitor response [INFLUENZA]
What are the monitoring parameters
*Most ppl with flu do not need medical or antiviral, only those with serious illness
Symptoms should improve within 10 days
If symptoms does not improve after 10 days => doctor
If symptoms improve then develop new fevers, worsening dypsnea or cough => doctor (possible secondary bacterial infection)
Discuss the influenza vaccines
Available type:
- Inactivated trivalent (2A1B)
- Inactivated Quadrivalent (2A2B)
=> Prepared from the prevailing strains of influenza A and B
Update:
- Vaccine is updated every year based on the predicted predominant strain for the season by WHO
Administration:
- IM, once a year
- However, since there are two peaks, may also take 2 times (although normal popln >= 6 months is only recommended to take once a year)
- Those at high risk of complications are recommended to take the vaccine
Vaccine property:
- Confer immunity within 2 weeks
- Efficacy: 75%
- Confirm presence of infection [PHARYNGITIS]
What are the clinical presentations?
Sore throat (worse with swallowing)
Fever
Erythema and inflammation of the pharynx and tonsils (with or w/o patchy exudates)
Tender and swollen lymph nodes (esp cervical lymph nodes)
- Confirm presence of infection [PHARYNGITIS]
Differentiate viral and bacterial pharyngitis
Viral Pharyngitis:
- S&S of viral infections such as low-grade fever <38dc, malaise, fatigue, rhinorrhea, cough, hoarseness, oropharyngeal lesions (ulcers, vesicles), conjunctivitis
- Self-limiting
Bacterial Pharyngitis:
- Sore throat with tonsillar exudates, fever (>38dc), cervical lymphadenopathy, w/o typical viral symptoms
- Modified centor criteria to guide GAS testing and/or antibiotic treatment
- May be self-limiting or have complications
- Confirm presence of infection [PHARYNGITIS]
What is the Modified Centor Criteria (to guide GAS testing and/or antibiotic treatment
- May be self-limiting or have complications
- Fever >38dc
- Swollen, tender anterior cervical lymph nodes
- Tonsillar exudate
- Absence of cough
- Age 3-14 years
*Each criteria is 1 point
*Unlikely in 15-44yo (0 points), does not occur in 45yo and older (-1 points)
*Rare amongst <3yo, hence no testing
0-1: no testing indicated, low risk of GAS pharyngitis, presumed viral
2-3: test for S. pyogenes pharyngitis, treat with Abx if positive (culture-directed)
4-5: high risk for S. pyogenes, intitate empiric Abx
*IDSA: fewer than 3 do not need to be tested
