Lecture 3: Fever and Cough- Upper Respiratory Tract Infection

Question 1

What are the different types of Respitaroy infections?

Answer 1

Upper -> Lower

Sinusitis

Otitis media

Pharyngitis

Trachetitis

Bronchitis

Penumonia

Question 2

What does the Stretococcus pyogenes cause?

Answer 2

Pharyngitis/tonsilitis (and nothing else!)

= Sore throat

Question 3

What can Streptococcus penumoniae cause?

Answer 3

Fluid in middle ear- Otitis Media

Maxillary or sinusitis - Sinusitis

Alevoli - Lung parchyma - Pneumonia

Bronchi- Bronchitis

(All except for Pharyngitis)

Question 4

What are the Common causes of respiratory infections?

Answer 4

Bacteria

• Streptococcus pyogenes*
• Streptococcus pneumoniae*
• Haemophilus influenzae
• Moraxella catarrhalis
• Bordetella pertussis

Virus

• Rhinoviruses
• Coronaviruses
• Respiratory Syncytial Virus (RSV)
• Influenza virus
• Others

Question 5

A 4 year old NZ European girl is brought to your
practice by her mother because she has had a
‘runny nose’ for two days and is now
complaining of a sore throat.

What is the aetiology?

Answer 5

You cannot be certain what the cause is. In general, Streptococcus Pyogenes affect the throat and causes a more severe illness than the viruses. Respiratory viruses affect but throat but also the nose and the sinuses and the trachea (more widespread)

Two parts of the respiratory tract (nose and throat) are affected. = more likely to be a viral cause.

= Pharyngitis
= Tonsillitis

May involve soft palate, uvula, tonsils
May have associated cervical lymphadenopathy

Question 6

If someone comes in with respiratory infection symptoms, what is the general rule in determining if this is a viral or bacterial cause?

Answer 6

In general, Streptococcus Pyogenes affect the throat and causes a more severe illness than the viruses + more focal pharyngeal infection.

Respiratory viruses affect but throat but also the nose and the sinuses and the trachea (more widespread) and less severe.

Question 7

What are the aetiologies/causes of pharyngitis?

Answer 7

1) Pharyngitis due to rhinoviruses + other viruses

2) Pharyngitis due to S.Pyogenes

3) Influenza
4) Glandular Fever due to EBV
5) Other viruses
6) Acute HIV (v. v. v. unlikely)

Approximately 50% are due to a virus - often with no therapeutic implications

Approximately 50% are due to Stretococcus pyogenes- with potential therpeautif implications

Question 8

What are the features of Stretococcus pyogenes and Streptococcus Penumoniae on histology?

Answer 8

Purple + Round = Gram positive Streptococci (can be any of the streptococci- not nessarily S. pyogenes)

S. Penumoniae

• Partial haemolysis
• Green
• Alpha haemolysis

S. Pyogenes

• Complete haemolysis
• Clear
• Beta haemolysis
  
  • We are interested in group A, but this can show in group B, C and G)

Question 9

What type of S. Pyogenes are we interested in?

What happens when you’re first infected by it?

Answer 9

_Group A (beta haemolytic) streptococcus
**GAS**_

1) Immune response (feel sick)

2) Asymptomatic colonisation of pharynx - approx 16% population
approx 30% in 2 NZ studies!

2) Repeated episodes of infection due to different M types
3) Risk of Rheumatic Fever

100% susceptible to penicillin, (most susceptible to erythromycin)

Question 10

Describe the process of Serogrouping

Answer 10

Lancefield grouping is a method of grouping catalase-negative, coagulase-negative bacteria based on the carbohydrate composition of bacterial antigens found on their cell walls.

All s_erotypes of GAS_ express the Lancefield group A carbohydrate (GAC) (positive agglutination for group A)

Question 11

If a 9 year old Pacific girl is brought into the practice with “runny nose” and “sore throat” and has a family history of rhemtatic fever what would you do?

Answer 11

culture for GAS (S. Pyogenes)

If GAS is cultured froma throat swab, she should be given treatment that will eradicate this infection and reduce her chance of developing rhematic fever e.g. oral penicillin for 10 days

Question 12

A 39 year old European woman attends your
practice because she has had a ‘runny nose’ for
two days and is now complaining of a sore
throat.

What should you do?

Answer 12

Regardless of whether Streptococcus pyogenes
(GAS) is present in her throat she should NOT be
given treatment because her chance of
developing rheumatic fever is essentially zero.

Question 13

What is another name for “colds”

What is it?

Answer 13

Rhinosinusitis

Colds = Nose and adjacent sinus infections

Question 14

What are some symptoms of Rhinosiusitis?

Answer 14

• Purulent anterior nasal discharge
• Purulent posterior nasal discharge
• Nasal congestion or obstruction
• Facial congestion or fullness
• Facial pain or pressure
• Reduced or absent smell
• Fever

Question 16

What are the aetiologies of sinusitis?

Answer 16

Viral = 90-98%

Bacterial = 2-10%

After they get over this, occassionally the organisims will cause a fluid accumulation and may cause a bacterial infection.

Question 17

What are the typical course of symptoms for viral URI?

Answer 17

2-3 days at onset: May have a fever

7-10 days: Cough (usually improving after 5 days)

1-2 weeks: Rhinorrhoea that progresses from clear to purulent to clear over this timeframe (e.g. runny nose)

Bacterial infection: fever comes up a bit later and persists for longer