Week 1: Sore Throat Flashcards

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1
Q

What is the most common cause of sore throat?

A

Viral more than bacterial. Fungal is rare

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2
Q

Viral Pharyngitis

A

Infection of pharynx by a virus

Most common cause: common cold

At least 25% of cases due to rhinoviruses and coronaviruses

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3
Q

Viral infections

A

Rhinovirus
Coronavirus
Adenovirus
Herpes simplex virus (HSV)
Influenza A and B
Parainfluenza virus
Epstein-Barr virus
Cytomegalovirus
Human herpesvirus (HHV) 6
HIV

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4
Q

Bacterial Pharyngitis

A

Infection of pharynx by bacteria
Most common cause: Group A beta-hemolytic streptococci (GABHS)
5-15% of sore throats in adults
20-30% sore throats in children (ages 5-15)

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5
Q

Bacterial infections

A

Group A beta-hemolytic streptococci (GABHS)
Fusobacterium necrophorum
Group C beta-hemolytic streptococci
Neisseria gonorrhoeae
Corynebacterium diphtheriae
Mycoplasma pneumoniae
Chlamydophila pneumoniae

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6
Q

Frequency of infections CHART

A
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7
Q

Distribution of causes of sore throat

A
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8
Q

Non-infectious Pharyngitis

A

Consider in patients:
With chronic sore throat
Without signs of infection
Who do not respond to treatment

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9
Q

Causes for non-infectious pharyngitis

A

Persistent cough
Upper airway cough syndrome (postnasal drip)
Gastroesophageal reflux disease
Acute thyroiditis
Neoplasm
Allergies
Smoking

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10
Q

General approach to acute pharyngitis

A

Rule out serious diagnoses and red flags/alarm symptoms that prompt emergent/urgent management
Most cases of acute pharyngitis are due to infectious cause – determine the specific infectious cause (i.e., viral or bacterial)
Identify acute sore throat caused by group A beta-hemolytic streptococcal (GABHS) pharyngitis
Antibiotic treatment may be indicated

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11
Q

What is a red flag or alarm symptom/sign?

A

Red flags are signs and symptoms found in the patient history and clinical examination that may indicate possible serious underlying pathology.

Red flags prompt further investigation and/or referral.

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12
Q

Serious diagnoses and alarm symptoms CHART

A
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13
Q

Acute epiglottitis: Where? Who? When? Emergency?

A

Rare but potentially fatal condition
Inflammation of epiglottis and adjacent tissues
Bacterial infection primarily caused by Haemophilus influenzae
In the past, most commonly seen in children aged 2-6
HiB vaccination in infants has decreased incidence
Most common in winter and spring
Positive thumb sign on lateral radiograph of the neck is diagnostic
Medical emergency  refer!
Airway management is key to prevent airway compromise
May require intubation
Requires antibiotic therapy

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14
Q

Acute epiglottitis: clinical presentation. What NOT to do?

A

Clinical Presentation
Acute onset fever, severe sore throat, toxic appearance
The 4 Ds:
Dysphagia (difficulty swallowing)
Drooling
Dysphonia (muffled, hoarse, abnormal voice)
Distress (inspiratory stridor, tripod position, severe dyspnea, irritability, restlessness)

Do NOT use a tongue depressor when examining the oropharynx as it can precipitate airway obstruction

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15
Q

Peritonsillar abscess: Where, who, common organisms?

A

Aka quinsy
Most common deep infection of head and neck (30% of abscesses of head and neck)
Most common in young adults (ages 20-40); increased risk in immunocompromised and diabetics
Usually begins as acute tonsillitis  cellulitis  abscess formation
Polymicrobial infection
Common organisms: Group A streptococci, Staphylococcus aureus, Haemophilus influenzae, Fusobacterium, Peptostreptococcus, Pigemented Prevotella species, Veillonella
Diagnosis can be made clinically without labwork/imaging in patients with typical presentation

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16
Q

Peritonsillar abscess: Clinical presentation?

A

Clinical Presentation
Severe unilateral sore throat
Dysphagia and odynophagia  pooling of saliva or drooling
Fever and malaise
Dysphonia: muffled “hot potato” voice
Rancid or fetor breath
Otalgia
Trismus (66% of patients)
Oropharyngeal exam: erythematous enlarged tonsil and bulging soft palate on affected side, uvular deviation to contralateral side
May have severely tender cervical lymphadenopathy

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17
Q

Peritonsillar abscess: Testing?

A

Culture of pus from abscess drainage confirms diagnosis

Imaging not necessary to confirm diagnosis
CT with IV contrast (LR+ 4, LR- 0)
Intraoral ultrasonography (sensitivity 89-95%, specificity 79-100%)

Treatment includes drainage, antibiotic therapy, supportive care

18
Q

Retropharyngeal abscess

A

Retropharyngeal edema due to cellulitis and suppurative adenitis of lymph nodes in retropharyngeal space

Preceded by upper respiratory infection, pharyngitis, otitis media, wound infection following penetrating injury to posterior pharynx

Peak incidence in 3-5 year olds
Observed as prevertebral soft-tissue thickening on lateral X-ray of neck

Treat as impending airway emergency
Requires antibiotic therapy, possible surgical consultation for needle aspiration or incision and drainage

19
Q

Retropharyngeal abscess: Clinical presentation?

A

Clinical Presentation
Sore throat and dysphagia
Fever
Drooling
Dysphonia (muffled voice)
Neck stiffness; limited neck ROM (especially hyperextension)
Stridor
May see bulging of the posterior wall of oropharynx on clinical examination

20
Q

Viral pharyngitis

A

Most pharyngitis cases are viral in origin
Associated symptoms that are more likely to present with viral illness: cough, nasal congestion, conjunctivitis, hoarseness, diarrhea, oropharyngeal lesions (ulcers or vesicles)

Viruses that are most likely to cause pharyngitis in children:
Common cold (50%) – caused by rhinovirus, coronavirus, adenovirus, parainfluenza virus, respiratory syncytial virus
Influenza (5%) – caused by Influenza virus (type A and B) most commonly
Mononucleosis (5%) – caused by Epstein-Barr Virus (EBV), cytomegalovirus (CMV)

Viral causes of pharyngitis do not require antibiotic therapy unless there is a secondary bacterial infection

21
Q

Streptococcal pharyngitis

A

aka “strep throat”, GABHS pharyngitis
Infection of pharynx caused by group A beta-hemolytic streptococci (GABHS)
Most common in children aged 5-15
Risk factors: exposure to sick contact with GABHS, winter or early spring

Typical Presentation
Acute onset fever and sore throat
Headache, nausea, vomiting, malaise, dysphagia, abdominal pain
Cough and rhinorrhea usually absent (presence suggests more viral cause)
Edema and erythema of tonsils and pharynx; non-adherent tonsillar and/or pharyngeal exudate
Enlarged and tender anterior cervical lymph nodes
1 in 10 cases of streptococcal pharyngitis may evolve into scarlet fever: scarlatiniform rash and strawberry tongue
May have palatine petechiae

22
Q

Complications of group A beta-hemolytic streptococci? NON-SUPPURATIVE?

A

Non-suppurative complications

Acute rheumatic fever (ARF) – rare in North America

More common in children than adolescents and adults

In Canada, 0.1 to 2 cases per 100,000
Higher in remote, Canadian Indigenous communities (Northern Ontario 8.33/100,000)
Risk may be higher in immigrants from endemic areas (e.g., Philippines, China)
In USA, 3000-4000 cases of GABHS pharyngitis need to be treated to prevent 1 case of ARF
Can develop 1-4 weeks after GABHS pharyngitis

Cross-reactive antibodies produced in reaction to GABHS infection leading to fever, arthralgia, erythema marginatum, subcutaneous nodules (Osler’s nodes), increased ESR and CRP, carditis, prolonged PR interval, Sydenham’s chorea

Poststreptococcal glomerulonephritis
Can develop 1-2 weeks after infection with GABHS
Injury to the glomerulus due to deposition of immune complexes and circulating autoantibodies
Pediatric autoimmune neuropsychiatric disorder associated with group A streptococcal (PANDAS) infection
Abrupt onset of severe exacerbations of obsessive-compulsive type behaviours or tics in children following GABHS infection
Thought to be due to antibodies cross-reacting with regions in the basal ganglia  behavioural and motor disturbances

23
Q

Complications of group A beta-hemolytic streptococci? SUPPURATIVE?

A

Peritonsillar abscess
Retropharyngeal abscess
Otitis media
Sinusitis
Mastoiditis
Cervical lymphadenitis
Meningitis
Bacteremia

24
Q

Likelihood ratios for GAS infection CHART

A
25
Q

Accuracy for History and Physical Examination Elements in the Diagnosis of Strep Throat
CHARTS (2)

A
26
Q

Clinical decision rules

A

A clinical decision rule (CDR) is a clinical tool that quantifies the individual contributions that various components of the history, physical examination, and basic laboratory results make toward the diagnosis, prognosis, or likely response to treatment in a patient.
Attempt to formally test, simplify, and increase the accuracy of clinicians’ diagnostic and prognostic assessments.
Existing CDRs guide clinicians, establish pretest probability, provide screening tests for common problems, and estimate risk.

27
Q

The modified centor score

A

Also know as the McIssac Score, the McIsaac Modification of the Centor Score, or the Adapted Centor Score
A validated score to help predict the probability of streptococcal pharyngitis and guide clinical decision making
Original Centor Score looked at 4 features: absence of cough (presence of cough suggest more viral illness), presence of fever, tonsillar exudates, and anterior cervical lymphadenopathy
McIssac modified the score to include age as a feature
Streptococcal pharyngitis is most common in ages 5-15 years
It is rare in infants (< 3 years) and in adults > 45 years

28
Q

The modified centor score:remember mnemonic m-centor

A

Must be older than 3 years oldCough — No cough (+1)Exudates or swelling — Tonsillar exudates/swelling (+1)Nodes — Anterior cervical adenopathy (+1)Temperature — Hx of fever or temperature >38 (+1)Only Young — Patients <15yo (+1)Rarely Elder — Patients >45yo (-1)

29
Q

Rapid strep test

A

aka rapid antigen detection test (RADT)
Rapid screen for streptococcal antigens  if positive the patient is treated without follow-up cultures; if negative a throat culture is obtained
Point-of-care test that can be done in office: rapid turnover time (minutes to 1 hour) compared to throat culture (about 48 hours)
Swab collected from tonsils and posterior pharyngeal wall of patient
Specificity 97%, Sensitivity 85%; LR+ 17.2, LR- 0.15
This video highlights how the test is performed: https://www.youtube.com/watch?v=-nOPDcAUOOc

Newer nucleic acid tests offer better sensitivity
Specificity 99%, Sensitivity 92%
LR+ 92, LR- 0.08
Disadvantages: Rapid point-of-care testing cannot distinguish between carriers of GABHS and active infection, nor does it indicate antibiotic susceptibility or strain virulence

30
Q

Throat culture

A

Gold standard for diagnosis of streptococcal pharyngitis (10% or lower false negative rate)

Swab collected from tonsils and posterior pharyngeal wall of patient
Sample from swab placed on a culture in the lab to observe for bacterial growth
Culture showing growth of streptococcal species confirms the diagnosis

31
Q

To treat or not to treat? (strep)

A

Benefits of antibiotic treatment of GABHS pharyngitis:
Prevents acute rheumatic fever (NNT=4000)
Decreases the transmission of GABHS
Shortens the illness by 1 to 2 days (NNT=8)
Reduces symptoms such as headache, sore throat and fever (NNT=6 to reduce symptoms after 3 days of treatment, NNT=21 after 1 week of treatment)
May reduce suppurative complications
Subsequent acute otitis media (NNT=29 in children, NNT=145 in adults)
Subsequent acute sinusitis (NNT=50)
Subsequent peritonsillar abscess (NNT=27)
Most cases are self-limiting in 7-10 days even without antibiotics

Harms of antibiotic treatment of GABHS pharyngitis:
Shortens the illness by 1 to 2 days but no difference in time off school or work
Has not shown to decrease risk of poststreptococcal glomerulonephritis or subsequent meningitis

Harms of antibiotic treatment in general:
Mild reactions: diarrhea, vomiting, abdominal pain, rash (NNH=10)
Severe reactions: Clostridium difficile-associated diarrhea
Life-threatening reactions: anaphylactic shock, sudden cardiac death

32
Q

antibiotic therapy – Some considerations

A

Many international guidelines consider GABHS pharyngitis self-limiting and do not recommend antibiotic treatment
Delayed prescriptions decrease antibiotic use with no significant effect on symptom duration or clinical outcomes
Populations with a higher incidence of GABHS complications, such as Indigenous people in Canada, might be more likely to benefit from antibiotic treatment
Children are at a greater risk of complications (e.g., otitis media, peritonsillar abscess, rheumatic fever), may initiate antibiotic therapy sooner
Carriers of GABHS do not require treatment
At least 30% of GABHS cultured in primary care are due to carriers who are not sick and are at very low risk of infecting other people

33
Q

Management of strep

A

Most cases are self-limiting in 7-10 days even without antibiotics, but Canadian guidelines suggest a full 10-day course of antibiotic therapy for confirmed GABHS infection
For those with high likelihood of strep throat (i.e., score of 4 or more) with no signs of complications, a reasonable approach is watchful waiting and delayed prescription for antibiotics while waiting for culture results
Advise patient to monitor symptoms and only fill the antibiotics prescription after confirmation of positive throat culture
Another approach: empirical antibiotic therapy while waiting for throat culture results (and stop antibiotics if the culture is negative)
Antibiotic therapy of choice: penicillin (unless patient has allergy)
5-day course of antibiotic therapy as clinically effective as 10-day course, although it might be less effective in eradicating GABHS infection
Antibiotic therapy started within 9 days of symptom onset in confirmed GABHS will prevent rheumatic fever

If the likelihood of streptococcal infection is low (i.e., Modified Centor score of 1 or less) or culture is negative, viral pharyngitis is likely.
Provide supportive therapies and symptomatic relief:
Analgesics (NSAIDs, acetaminophen, topical anesthetics)
Throat lozenges or sprays
Warm soothing drinks/liquids
Gargle/rinse

34
Q

Infectious mononucleosis

A

aka mono or “kissing disease”
Infection usually caused by Epstein-Barr virus (EBV) – more than 90% of cases
Most common in ages 5-25 years

Typical Presentation
Gradual onset, low-grade fever, sore throat
Malaise, fatigue
Tonsillar exudates
Palatine petechiae
Lymphadenopathy (especially posterior cervical lymph nodes)
Splenomegaly (50% of cases)  splenic rupture is an uncommon complication (0.1-0.5%) – highest risk in first 3 weeks of illness

35
Q
A
36
Q

Accuracy of Signs for the Diagnosis of Infectious Mononucleosis

A
37
Q

Accuracy of Signs for the Diagnosis of Infectious Mononucleosis

A
38
Q

Accuracy of White Blood Cell Count for the Diagnosis of Infectious Mononucleosis

A
39
Q

Monospot Test

A

Rapid screening test that detects heterophil antibody agglutination
Best initial test for diagnosis of EBV infection – fast, inexpensive, has high specificity
Can be conducted in-office

Sensitivity 82%, specificity 99%
LR+ 82, LR- 0.18

40
Q

Algorithm for the management of suspected infectious mononucleosis (IM)

A