Upper Respiratory Tract Infections

Question 1

Why is it important to learn about URTI?

Answer 1

Most common infections in humans and medical consultations. They are also most important reason for inappropriate antibiotics.

Question 2

What causes pharyngitis?

Answer 2

Rhinoviruses

Coronavirus

Parainfluenza and influenza virus

Adenovirus (Commonly associated with pharyngo-conjunctival fever which causes eyes to become more red and runny nose and sore throat)

RSV

EBV

Question 3

How are viral infections of the URT different to bacterial infections?

Answer 3

Bacterial infections are associated with pus

Question 4

Which bacteria are associated with pharyngitis?

Answer 4

Streptococcus pyogenes

Arcanobacterium haemolyticum

Mycoplasma pneumoniae

Vincents angina

Haemophilus influenzae

Corynebacterium diptheriae

Question 5

What is the most common bacterial cause of pharyngitis?

Answer 5

Streptococcal pharyngitis caused by streptococcus pyogenes (Group A beta haemolytic strep).

Question 6

Why is it difficult to distinguish strep from other viral infections?

Answer 6

Only 2/3rds of people have typical features.

Question 7

What are coryzal symptoms?

Answer 7

Unwell feeling associated with the flu/viral infections.

Question 8

What are symptoms associated with Group A strep (strep pyo)?

Answer 8

Constitutional symptoms

Abrupt onset sore throat and fever >38c

Mucosal erythema, exudate on tonsils.

Tender cervical/tonsillar lymph nodes +/- rash

Question 9

Examples of alpha haemolytic strep:

Answer 9

Strep. mitins

Strep. mutans

Strep. salivarius

Question 10

What type of bacteria are strep agalactae?

Answer 10

group B beta haemolytic

Question 11

What percentage of strep throat are associated with scarlet fever?

Answer 11

<10% strep throats

Question 12

What investigations can be done for an URTI?

Answer 12

Throat swab (cultured but organism can be missed in 5 - 10% of cases and it may identify carriage only.)

Serology (anti-streptolysin O titre which must be investigated later)

Blood test (atypical lymphocytosis suggests EBV)

Question 13

What can be done with a throat swab which helps arrive at a diagnosis?

Answer 13

Culture

Rapid antigen tests

Question 14

How good is a throat swab for diagnosis?

Answer 14

It has a sensitivity of 90 - 95%.

Question 15

When should blood tests be conducted for URTIs?

Answer 15

They should be deferred for the future and if there is no improvement they can be conducted

Question 16

What are the complications of Group A Strep (GAS)?

Answer 16

Peritonsillar abscess (Usually unilateral swelling and medial displacement of tonsilllar tissue) and often mixed with anaerobes. If this occurs there may be need for surgical drainage.

Question 17

Should antibiotics be given for GAS infections?

Answer 17

No unless they experience suppurative complications or if indigenous due to risk of RHD.

Question 18

What antibiotics should be given if someone must be given antibiotics for GAS infection? What precaution must be taken?

Answer 18

Macrolides (Erythromycin, azithromycin)

Do not give amoxycillin or ampicillin (if it is EBV it can cause a rash and can cause allergy to beta lactam risk)

Question 19

What causes epiglotitis commonly?

Answer 19

Haemophilius influenzae capsular type B (this is rare due to immunization)

Question 20

What are the clinical features of epiglotitis?

Answer 20

Common in children (2 - 4)

Common cold like symptoms during prodromal period

Sudden onset high fever and sore throat

Usually bacteraemic at presentation.

Dysphagia prominent and drool

Question 21

What precaution must be taken when investigating epiglotitis?

Answer 21

Do not try to visualize larynx, it can cause condition to get worse suddenly.

Question 22

How should epiglotitis be treated?

Answer 22

Antibiotic therapy - Ceftriaxone or amoxycillin

Question 23

How does diptheria cause damage?

Answer 23

Bacterium adheres to mucosa, releases exotoxin (2 subunits A and B which are very potent. This condition has local and systemic effects:

Local effects induce formation of necrotic tissue membrane (pseudomembrane)

Systemic effects include myocardial toxicity and neurotoxicity.

Question 24

What are the 3 clinical forms of diphtheria?

Answer 24

Nasal

Pharyngo-tonsillar

Laryngeal

Question 25

What characteristic feature is seen in diphtheria patients?

Answer 25

Bull neck and pseudomembraner

Question 26

How is diphtheria treated?

Answer 26

Antitoxin Penicillin or erythromycin for 14 days Prophylaxis in family members (still causes death in 2 - 3% despite the treatment)

Question 27

What are the clinical features of pharyngitis with vesicles/ulcers?

Answer 27

Fever + skin rash Shallow mucosal ulcers Both of these are often seen over soft palate buccal surfaces

Question 28

What commonly causes pharyngitis with vesicles/ulcers?

Answer 28

Viruses such as herpangina (enteroviruses such as coxsachie A) Primary herpes simplex virus

Question 29

What is vincent's angina?

Answer 29

Known as "trench mouth" it is a pharyngitis that causes halitosis, ulceration, and exudate in tonsils.

Question 30

How is vincent's angina treated?

Answer 30

Antibiotics

Question 31

Which bacteria cause Vincent's angina?

Answer 31

Borrelia vincenti, anaerobic fusiform bacilli

Question 32

Who most commonly gets Vincent's angina?

Answer 32

Teens and young adults

Question 33

What causes lemierres disease?

Answer 33

Fusobacterium necrophorum which is a bacteria found in people's mouths normally. It spreads and invades jugular vein and causes clotting of blood in brain and other places.

Question 34

What is croup? How does it present?

Answer 34

A clinical syndrome caused by several respiratory pathogens (most commonly parainfluenza viruses) which usually presents as a fever, hoarseness (laryngitis), and a barking cough.

Question 35

What are the clinical features of croup?

Answer 35

Usually mild but can be severe and can cause obstruction and cyanosis. Inflammatory obstruction of subglottic area. Laryngitis, laryngotrachietis, laryngotracheobronchitis

Question 36

What is cyanosis?

Answer 36

A bluish discoloration of the skin due to poor circulation or inadequate oxygenation of the blood.

Question 37

How is croup treated?

Answer 37

Airway dilators, steroids, moisture (hot showers or steam) In severe cases intubation may be necessary.

Question 38

What is sinusitis?

Answer 38

Infection of air filled sinuses of the skull.

Question 39

Which bacteria can be involved in sinusitis?

Answer 39

Strep pneumoniae Haemophilus influenzae Moraxella catarrhalis Anaerobes

Question 40

What are the clinical features of sinusitis?

Answer 40

Fever and coryzal symptoms Unilateral facial swelling Pain Headache Blocked nose Purulent post nasal drip or nasal discharge

Question 41

How is sinusitis managed?

Answer 41

Antibiotics can be beneficial but not always (unclear that they do anything useful) Topical intranasal corticosteroids are useful for inflammation. Surgical drainage can be done in severe and prolonged cases

Question 42

What are potential complications of sinusitis?

Answer 42

Mastoiditis Cranial osteomyelitis Meningitis Brain Abscess Orbital cellulitis and cavernous sinus thrombosis

Question 43

Who often gets chronic sinusitis?

Answer 43

People with allergic disorders Diabetics Immunocompromised people

Question 44

What pathogens can cause chronic sinusitis?

Answer 44

Gram negative bacteria Fungi

Question 45

What is otitis media?

Answer 45

An infection of the air-filled space behind the eardrum

Question 46

How often do people get otitis media?

Answer 46

Most children have one episode and up to 50% have more than 3

Question 47

Which ethnic groups have a high prevalence of otitis media?

Answer 47

Indigenous Australians

Question 48

Which bacteria commonly cause otitis media?

Answer 48

Most commonly S.pneumoniae Gram -ve anaerobes H.Influenzae Moraxella catarrhalis S.pyo S.aureus

Question 49

Which bacteria that cause otitis media are 100% resistant to otitis media?

Answer 49

Moraxella catarrhalis Gram -ve anaerobes

Question 50

What conditions does otitis media follow?

Answer 50

Viral URTIs

Question 51

What are the clinical features of otitis media?

Answer 51

Ear pain + fever Hearing impairment Discharge through external canal due to perforation of ear drum

Question 52

What happens during otitis media?

Answer 52

Congestion of the nasopharyngeal mucosa Inflammatory obstruction of the Eustachian tube at the narrowest point Followed by fluid trapping and effusion formation in middle ear Ear drum becomes inflamed and bulging Overgrowth of nasopharyngeal bacteria in the Eustachian tube/middle ear Middle ear effusion persists 1-3 months (“glue ear”)

Question 53

How is otitis media diagnosed?

Answer 53

Clinical history and examination of ear drum Sample is taken from middle ear fluid and then bacteriological studies (this procedure is rarely done)

Question 54

What is the treatment for otitis media?

Answer 54

Most cases are self limiting and end within 24 hours. No point in using nasal decongestants, antibiotics or antihistamines

Question 55

What communities have highest rate of complications?

Answer 55

Indigenous Australians

Question 56

What antibiotics are used for otitis media?

Answer 56

Amoxycillin

Question 57

What are potential complications of otitis media?

Answer 57

Mastoiditis Labrynthitis Meningitis and brain abscess Chronic Otitis Media with effusion Persistent effusion or perforation of ear drum. Mild to moderate conductive hearing loss. Adverse effects on speech and language.

Question 58

How is chronic OM managed?

Answer 58

Preventing deafness by maintaining aerated middle ear Antibiotics and decongestants Surgical management (myringotomy with or without tympanostomy tube or adenoidectomy)

Question 59

What is otitis externa?

Answer 59

Infection of the external ear canal

Question 60

What are the symptoms of otitis externa?

Answer 60

Severe pain and/or discharge Swelling, erythema Infection is exacerbated by moisture

Question 61

How is otitis externa treated?

Answer 61

Topical broad spectrum antibiotics/antifungals, usually IV initially

Question 62

What pathogens cause otitis externa?

Answer 62

Staphylococcus aureus Streptococcus pyogenes Candida albicans Pseudomonas aeruginosa Proteus species, Water-borne organisms e.g Aeromonas