T8-L3: Clinical Respiratory Infections

Question 1

Give causes of pharyngitis and Tonsillar pharyngitis.

Answer 1

Most are caused by viruses such as:

• Rhinovirus
• Coronavirus
• Influenzas (A&B)
• Parainfluenza
• Adenovirus

Bacterial causes make up 15-30% in children and 10% in adults. The most common bacterial cause is Group A strep. Rarer causes include Neisseria gonorrhoea, HIV and diphtheria.

Question 2

What is the Centor criteria?

Answer 2

This determines the likelihood of an RT infection being bacterial in origin. It uses the following indicator features:

• Tonsillar exudate
• Fever over 38 degrees
• Absence of a cough
• Tender anterior cervical lymphadenopathy

Question 3

What are the characteristic features of infective mononucleosis? What is its aetiology?

Answer 3

Infective mononucleosis is caused by the Epstein Barr Virus most commonly.

It is characterised by:

• Tonsillar exudate
• Tender cervical lymphadenopathy
• Tonsillar pharyngitis

Question 4

Give causes of epiglottis.

Answer 4

Epiglottitis is inflammation of the structures above the epiglottis.

Common causes include:

• Haemophillus Influenzas in children under 0, before the vaccine
• Strep. Pneumoniae
• Group A strep.

It can lead to sepsis and so investigations include blood cultures and epiglottic swabs.

It is treated with cephalosporins and analgesics,

Question 5

For Ortitis externa, give:

(a) Defintion
(b) Caustive agents
(c) Treatment

Answer 5

(a) This is an inflammation of the external ear canal presenting with a combination of otalgia (ear pain), pruitis and non-mucoid ear discharge. It can be acute or chronic. Risk factors include swimming, trauma, scratching, ear phones, allergic contact dermatitis due to shampoos and dermatological conditions such as psoriasis.
(b) Most common cause is Psuemodomas aerguninosa and Staph. aureus. 2% are fungal.
(c) Removal of modifiable risk factors; removal or pus and debris; topical antibiotics and analgesics.

Question 6

What is necrotising external otitis?

Answer 6

This is when external otitis spreads to the skull base (soft tissue, cartilage, bone or the temporal region). It can be life threatening. It is commonly found in elderly diabetic patients or other immunocompromised patients. It can lead to severe pain, otorrhoea, granulation tissue in the canal floor and cranial nerve palsies. Treated for a minimum of 6 weeks with iv ceftazidime (pseudomonas cover) and po ciprofloxacin (cover pseudomonas and in the oral form). Need to be referred to ENT.

Question 7

What is a common cause of chronic otitis externa?

Answer 7

Common cause is allergic contact dermatitis. Patients with generalised skin conditions such as atopic dermatitis or psoriasis can also predispose to chronic OE. You need to treat the underlying cause.

Question 8

What are common causes of otitis media?

Answer 8

Unlike OE, OM is usually caused by viruses. It can be caused by bacteria of which include Step. Pneumoniae, H. influenzae and Moraxella catarrhalis.

This is a middle ear infection - fluid is often present in the middle ear. It is very common in children.

Question 9

Give a complication of acute otitis media.

Answer 9

Mastoiditis.

Question 10

What are common infective causes of Pina cellulitis?

Answer 10

Usual infective agent(s) in auricular perichondritis include Pseudomonas aeruginosa and/or Staphylococcus aureus like in AOE.

This is often associated with trauma such as ear piercing, but also surgery and burns.

Empirical treatment: ciprofloxacin (pseudomonas) + flucloxacillin (for the staph. Aureus) (or vancomycin if penicillin allergy)

Question 11

What are the two anatomical patterns of pneumonia?

Answer 11

• Bronchopneumonia - this is characteristically patchy distribution cantered on inflamed bronchioles and bronchi then subsequent spread to surrounding alveoli
• Lobular pneumonia - this effects a large part, or an entire lobe. 90% are due to Step. pneumoniae

Question 12

What are common causes of:

a) Hospital acquired pneumonia
(b) Ventiliator acquired pneumonia
(c) Community acquired pneumonia (typical

Answer 12

(a) HAP - Pseudomonas, Klebsiella and E.coli
(b) VAP - Pseumodomas species
(c) Step. Pneumonia, COVD-19, Haemophilus Influenzae, Morexaella, Staph. aureus and Klebsiella

Question 13

Give causes of atypical pneumonia.

Answer 13

• Mycoplasma pneumoniae
• Leigonella pneumophillia
• Chalmydophilla spp.
• Coxiella

Question 14

Give the clinical presentation of pneumonia.

Answer 14

Symptoms:

• Usually rapid onset
• Fever / chills
• Productive cough
• Mucopurulent sputum
• Pleuritic chest pain
• General malaise: fatigue, anorexia

Signs:

• Tachypnoea, tachycardia, hypotension
• Examination findings consistent with consolidation:
• Dull to percuss
• Reduced air entry, bronchial breathing

Question 15

Give complications of pneumonia.

Answer 15

• Pleural effusion
• Empyema
• Lung abscess

Question 16

What are causative agents of viral LRT in the immunocompromised?

Answer 16

• Measles
• HSV
• Cytomegalovirus
• Varicellar Zoster Virus
• HHV-6

Question 17

What bacteria can cause secondary bacterial pneumonia after influenza?

Answer 17

Secondary bacteria pneumonia can then develop after the initial period of improvement - tends to be due to S. pneumoniae, H. influenzas and S. aureus (S. aureus is an uncommon cause of CAP but there is an association with influenza)

Question 18

How is VZV pneumonia treated? Who is most at risk?

Answer 18

VZV pneumonia is a complication of the VZV infection. Those greatest at risk are the immunocompromised, adults which chronic lung disease, smokers and pregnant women.

It is treated with supportive therapies and prompt administration of IV acicolvir.

Question 19

In which population do we see CMV pneumonia?

Answer 19

Immunocompromised host

Question 20

Which organisms do we see in patients with cystic fibrosis?

Answer 20

In childhood we see Staphylococcus aureus.

In adults colonising organisms change to Pseudomonas in early adulthood and Burkholderia. We also see non-tuberculous mycobacteria and fungi.

Question 21

What is allergic bronchopulmonary aspergillosis?

Answer 21

Aspergillosis is an infection caused by Aspergillus, a common mold (a type of fungus) that lives indoors and outdoors. Most people breathe in Aspergillus spore every day without getting sick.

The allergy topically presents in patients with background of atrophy asthma and cystic fibrosis. It presents with worsening asthma and lung function. Diagnostic features include a high IgE, specific IgE to aspergillus and positive serum IgG to aspergillus. CT imaging may demonstrate bronchiectasis.

Treatment is with steroids and antifungals.

Question 22

Which pathogen does this description best describe:

• This is a fungus that lacks ergosterol in its cell wall and so is not susceptible to antifungals. It is ubiquitous in the environment. Its principle mode of travel is through the air.
• Pneumonia present with an insidious onset of fever, dyspnoea, non-productive cough and reduced exercise tolerance. Exercise induced hypoxia is a classic finding.
• Treatment is supportive and antimicrobials (including co-trimoxazole) and steroids.
• Some at risk groups include HIV patients with a CD4 count of less than 200. They are therefore given prophylaxis.

Answer 22

Pneumocystis jiroveci pneumonia