Clinical respiratory infections

Question 1

Pharyngitis

Answer 1

inflammation of the back of the throat (pharynx), resulting sore throat & fever. Acute tonsillar pharyngitis –> symmetrically inflamed tonsils and pharynx (+/- fever +/- headache)
Commonly caused by viruses, however in a third of people, no cause can be found. Common infectious causes include: -Viruses: Rhinovirus, Coronovirus, Parainfluenza, Influenza
management: Oral analgesics (paracetamol, ibuprofen) and +1 week then antibiotics

Question 2

Otitis media

Answer 2

Middle ear inflammation. Fluid present in middle ear. V. common in children
Symptoms: Uncomplicated acute OM is defined as: mild pain <72hours duration and an absence of severe systemic symptoms, with a temperature of less than 39°C and no ear discharge. Complicated acute OM is defined as the presence of: severe pain, perforated eardrum and/or purulent discharge, bilateral infection, mastoiditis
Aetiology: viruses

Question 3

Otitis externa

Answer 3

Inflammation of the external ear canal presenting with pruritis and non mucoid discharge.
Acute = unilateral
Malignant = more severe pain –> ENT
Chronic = no wax, bilateral. caused by chemicals.
Risk factors = swimming

Question 4

Pinnal cellulitis

Answer 4

Associated with trauma (including ear piercing & acupuncture), surgery or burns. Perichondritis: may be a complication of high ear piercing (puncture through the cartilage of the upper third of the pinna.
Usual infective agent(s) in auricular perichondritis: Pseudomonas aeruginosa and/or Staphylococcus aur.
Diagnosis: A swab of the area and blood cultures (if in secondary care) should be obtained prior starting antibiotics

Question 5

Mastoiditis- complication of OM

Answer 5

Infection of the mastoid bone and air cells. The most common complication of AOM – incidence significantly reduced with the use of antibiotics for OM/ Mastoiditis and other severe complications of AOM are very rare in adults,
Symptoms: fever, posterior ear pain and/or local erythema over the mastoid bone, oedema of the pinna, or a posteriorly and downward displaced auricle.
CT scan always required. Mastoidectomy may be needed.

Question 6

Pneumonia

Answer 6

Infection affecting the most distal airways and alveoli. Formation of inflammatory exudate. Two anatomical patterns:

1) Bronchopneumonia: Characteristic patchy distribution centred on inflamed bronchioles & bronchi then subsequent spread to surrounding alveoli
2) Lobar pneumonia: Affects a large part, or the entirety of a lobe. 90% due to S.pneumoniae

Question 7

Symptoms of pneumonia

Answer 7

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 8

Community acquired pneumonia

Answer 8

20-40% cases require hospital admission. Person-to-person or from a person’s existing commensals (S.pneumoniae, H.influenzae) from the environment (L. pneumophilia)/ animals (C.psittaci

Question 9

Hospital acquired pneumonia

Answer 9

Pneumonia developing >48hrs after hospital admission. Additional causative organisms to CAP, especially if >5days after admission: enterobacteriaceae

Question 10

Ventilator associated pneumonia

Answer 10

Subgroup of HAP. Pneumonia developing >48hrs after ET intubation & ventilation. Pseudomonas spp. may be implicated

Question 11

Aspiration pneumonia

Answer 11

Pneumonia resulting from the abnormal entry of fluids e.g. food, drinks, stomach contents, etc. into the lower respiratory tract. Patient usually has impaired swallow mechanisms. Anaerobes may be implicated

Question 12

Atypical pneumonia

Answer 12

describes cases and no organism could be identified which failed to respond to penicillin (organisms without a cell wall). ‘Atypical’ organisms (no cell wall): Mycoplasma pneumonia, Legionella pneumophilia, Chlamydophila pneumonia.
Investigations: Chest X-ray (can take 6 weeks+ for radiological changes to resolve) and sputum & bloods and pneumococcal urinary antigen, legionella urinary antigen and serology for influenza etc.

Question 13

Influenza

Answer 13

produces uncomplicated disease: Fever, headache, myalgia, dry cough, sore throat. Convalescence takes 2-3 weeks. Primary viral pneumonia occurs more commonly in patients with pre-existing cardiac & lung disorders: Cough, breathlessness, cyanosis. Secondary bacterial pneumonia then may develop after initial period of improvement: S.pneumoniae, H.influenzae, S.aureus#
Diagnosis: viral antigen detection in respiratory samples using PCR

Question 14

Rhinovirus

Answer 14

Agent responsible for most “common colds”. Can cause LRTI & trigger exacerbations of asthma. Tests: PCR on NPA/throat swab. Treatment: supportive

Question 15

Varicella zoster virus

Answer 15

Complication of VZV (chicken pox) infection. Rare in children, significant morbidity & mortality in adults with varicella. Those at greatest risk are the immunocompromised, adults with chronic lung disease, smokers and pregnant women. Insidious onset 1-6 days after the rash has appeared with symptoms of progressive tachypnoea, dyspnoea, and dry cough. Tests: Chest X-ray typically reveals diffuse bilateral infiltrates. Treatment: Supportive & prompt administration of IV acyclovir

Question 16

CMV

Answer 16

Rarely described in immunocompetent hosts. Can cause severe illness in transplant recipients & HIV patients (uncommon). Tests: Chest-Xray, Broncho-alveolar lavage & viral load PCR. Treatment: Supportive, anti-viral (e.g. ganciclovir) & consider immunosuppression reduction (transplant pts).

Question 17

LRTI with bronchiectasis

Answer 17

Bronchiectasis: acquired disorder of the major bronchi and bronchioles that is characterised by permanent abnormal dilatation and destruction of bronchial walls. Antibiotics are recommended for exacerbations with acute deterioration with worsening symptoms: Chronic cough, mucopurulent sputum production and recurrent infections ( e.g. S.aureus, H.influenzea
Non-Antimicrobial Management -Effective clearance of respiratory secretions e.g. physiotherapy, postural drainage, Nutritional support, Identification and treatment of underlying cause and -Annual influenza vaccination

Question 18

LRTI with cystic fibrosis

Answer 18

inherited disease caused by a genetic mutation on chromosome 7 resulting in abnormal production and function of the cystic fibrosis transmembrane conductance regulator (CFTR). The defective CFTR chloride channel function results in viscous secretions.
Colonising organisms & resistance change over time: Staphylococcus aureus in childhood, Pseudomonas aeruginosa in childhood/early adolescence (attempts will be made to eradicate), Burkholderia cepacia complex: very resistant & transmissible, Non tuberculous mycobacteria & Fungi
Acute exacerbations: Use most recent sputum culture results to guide treatment

Question 19

Aspergillosis

Answer 19

infection caused by Aspergillus, a common mold (a type of fungus) that lives indoors and outdoors.
Immunocompromised patients & those with lung disease are at a higher risk of developing health problems due to Aspergillus.

Question 20

Allergic bronchoplulmonary aspergillosis:

Answer 20

occurs in people with a background of atopy, asthma & cystic fibrosis. Presents with worsening asthma & lung function. Diagnostic features include a high total IgE, specific IgE to Aspergillus and positive serum IgG to Aspergillus. CT imaging of the thorax may demonstrate central bronchiectasis.Treatment of ABPA is with corticosteroids and antifungal therapy

Question 21

Aspergilloma:

Answer 21

Mobile mass (of Aspergillus) within a pre-exisiting lung cavity. Old cavities left by previous TB or sarcoidosis become colonised with Aspergillus spp.
•Symptoms include: cough, haemoptysis, weight loss, wheeze & clubbing. Some are asymptomatic. Can be demonstrated on either chest X-ray or CT thorax.
Diagnosis: confirmed by a positive test for Aspergillus IgG antibody

Question 22

Pneumocystis jiroveciii pneumonia

Answer 22

a fungus! But lacks ergosterol in its cell wall & is not susceptible to a number of antifungals. Ubiquitous in the environment. Principle mode of transmission is airborne route. Pneumonia: insidious onset of fever, dyspnoea, non-productive coughs & reduced exercise tolerance

Question 23

Nocardia asteroids

Answer 23

Nocardia is a genus of bacteria found in the environment. Pulmonary nocardiasis is acquired through inhalation of the organism. More common in the immunosuppressed & those with pre-existing lung disease (esp. alveolar proteinosis) – but still rare!
Presentation & clinical/radiological findings: avariable, making diagnosis difficult. Lung abscesses can develop The most suitable specimens are the sputum, or if necessary, broncho-alveolar lavage or biopsy.
Treatment: as with all pneumonic infections- supportive Rx (ABC)

Question 24

Mycobacterium tuberculosis

Answer 24

Infects 1/3 of the world’s population & is the most frequent infectious cause of death worldwide. Infection is acquired by inhalation of infected respiratory droplets, the bacilli lodge in alveoli & multiply, resulting in the formation of a Ghon focus. Depending on the host’s immune response the infection will either become quiescent or progress and/or disseminate. 90% of primary infections are asymptomatic. The risk of disease progression is highest at the extremes of age and in the immunocompromised (inc. HIV). Reactivation of disease may occur later in life, particularly in the immunocompromised.