Respiratory Infection 1

Question 1

Symptoms of influenza infection?

Answer 1

Fever - high with abrupt onset
Malaise - generally feeling unwell
Myalgia - muscle pain
Headache - could be mistaken for meningitis
Cough - initially, dry and painful; becomes productive but painless
Prostration

Inferferons produced can result in systemic symptoms (virus is restricted to respiratory epithelium)

Question 2

What causes classical flu and ‘flu-like’ illnesses?

Answer 2

Classical flu - influenza A viruses and influenza B viruses

‘Flu-like’ illnesses - (occur outside of major epidemics) para-influenza viruses and many others

Question 3

Describe haemophilus influenzae

Answer 3

A bacterium that is not a primary cause of flu and may be a secondary invader

Question 4

Transmission of influenze?

Answer 4

By DROPLETS or through DIRECT CONTACT with respiratory secretions of someone with the infection

Question 5

Examples of places where influenza can spread and where infection control precautions would be used?

Answer 5

Also include aerosol protection for aerosol generating procedures only:
Intubation, extubation and related procedures - e.g: manual ventilation and open suctioning
Cardiopulmonary resuscitation
Bronchoscopy
Surgery & post-mortem procedures in which high-speed devices are used
Dental procedures
Non-Invasive Ventilation (NIV), e.g: Bilevel Positive Airway Pressure Ventilation (BiPAP) and Continuous Positive Airway Pressure Ventilation (CPAP)
High Frequency Oscillatory Ventilation (HFOV)
Induction of sputum

Question 6

Complications of flu?

Answer 6

Primary influenzal pneumonia - seen most during pandemic years and can be a disease of young adults; high mortality

Secondary bacterial pneumonia - cause of mortality in ALL influenza epidemics (more common cause of death in fatal influenza); more common in infants, elderly and debilitated, those with pre-existing disease and pregnancy women

Bronchitis - may be initial presentation
Otitis media - may be initial presentation, esp. in children

Question 7

Influenza during pregnancy?

Answer 7

May be associated with perinatal mortality, pre-maturity, smaller neonatal size and lower birth weight

Question 8

Treatment of flu?

Answer 8

Symptomatic - bed rest, fluids, paracetamol
Antivirals - oseltamivir and zanamivir (NICA guidelines - only given in patients with high risks of complication, in addition to the vaccine)

Question 9

Describe flu epidemics

Answer 9

Seen in association with MINOR MUTATIONS, in surface proteins of the virus
AKA ANTIGENIC DRIFT

Question 10

Describe flu pandemics (world-wide effect)

Answer 10

Rare, unpredictable - INFLUENZA A ONLY
AKA ANTIGENIC SHIFT (arises due to segmented genome)
There must be an animal reservoir/mixing vessel

Question 11

Describe how a pandemic arises

Answer 11

Segmented genomes of viruses that affect two different species , e.g: humans and ducks, mix to create a new virus, e.g: one that can spread amongst pigs and can be transmitted to humans to cause a pandemic

Question 12

Swine flu virus?

Answer 12

H1N1 virus

Question 13

Future threats?

Answer 13

Highly pathogenic avian flu is influenza A, H5N1

Bird to human transmission seen (high mortality) but it is not readily transmitted from human to human

Question 14

Lab confirmation of influenza?

Answer 14

Direct detection of the virus:
PCR - nasopharyngeal/throat swabs in virus transport medium or other respiratory samples can be taken (must know how to do this as it is a delicate/invasive procedure)

Other labs/hospitals may use immunofluorescence, antigen detection (near patient), antibody detection (may need paired acute and convalescent bloods and is often retrospective) or virus culture

Question 15

Prevention of flu methods?

Answer 15

Killed vaccine - virus grown in hen’s eggs/cell culture, then inactivated and combined with an adjuvant; currently contain 2 different influenze A viruses and one B virus; given annually to adult patients, and children aged 6 mnths to 2 yrs, at risk of complications and to health care workers

Live, attenuated vaccine - more effective than killed vaccine in children 2-17 yrs; administered intra-nasally

Question 16

What determines the effectiveness of a vaccine?

Answer 16

Protective efficacy depends on match of vaccine to circulating virus and on patient group

Question 17

Other causes of community acquired pneumonia?

Answer 17

Microbiological causes (call bacteria):
Mycoplasma pneumoniae - often in teens
Coxiella burnetii
Chlamydophilia psitacci

Question 18

Describe treatment and mortality of Mycoplasma, coxiella and Chlamydophilia psittaci

Answer 18

AKA atypical pneumonia
Therapy - all respond to tetracycline and macrolides, e.g: clarithromycin
Mortality - varies with pathogen, but generally lower than classical bacterial pneumonia

Question 19

Lab confirmation of Mycoplasma, coxiella and Chlamydophilia psittaci

Answer 19

Serology - send acute and convalescent bloods to the lab; gold top vacutainer
Virus detection - PCR on respiratory swabs/secretions; use in gradually increasing

Question 20

Describe Mycoplasma pneumoniae

Answer 20

Common cause of community acquired pneumonia and is spread from person to person; children and young adults have highest incidences

Question 21

Describe Coxiella burnetti

Answer 21

Causes:
Pneumonia
Pyrexia of unknown cause (Q-fever)

Uncommon, sporadic zoonosis (between animals, sheep and goats and humans)
Complication - culture negative endocartitis

Question 22

Describe Chlamydia and respiratory disease

Answer 22

Chlamydophilia psittaci causes Psittacosis
Uncommon, sporadic, zoonosis
Caught from pet birds and psittacosis usually presents as penumonira

Question 23

Clinical presentation of bronchiolitis?

Answer 23

> 90% of cases are due to Respiratory Syncytial Virus

Clinically presents in 1st or 2nd year of life with fever, coryza, cough and wheeza

Sever cases - grunting, decreased PaO2 and intercostal/sternal indrawing

Question 24

Complication of bronchiolitis?

Answer 24

Respiratory and cardiac failure due to pre-maturity or pre-existing respiratory/cardiac disease

Question 25

Lab confirmation of bronchiolitis?

Answer 25

PCR on throat/pernasal swabs

In some labs, direct immunofluorescence on nasopharyngeal aspirate is used

Question 26

Treatment of bronchiolitis?

Answer 26

Supportive

Question 27

Describe the epidemiology and control of bronchiolitis

Answer 27

Epidemics every winter and is very common; nosocomial spread in hospital wards so prevention involves cohort nursing and hand washing. gowns and gloves
No vaccine
Passive immunisation (with a monoclonal antibody) has poor efficacy and is not widely used

Question 28

Describe metapneumovirus

Answer 28

Most children are antibody +ve by age 5; found in a wide range of ages
World-wide distribution and highest incidence is in winter

Question 29

Disease of metapneumovirus?

Answer 29

May be second only to respiratory syncytial virus (RSV) in bronchiolitis and it present with similar symptoms to RSV, in both adults and children; causes 2% of influenza-like illness cases

Range of severity - from mild to requiring ventilation

Question 30

Lab confirmation of metapneumovirus?

Answer 30

PCR

Question 31

Current respiratory tests?

Answer 31

Sample for PCR
Throat swabs in viral transport medium
Bronchoalveolar lavage (BAL)
Endotracheal aspirate

Question 32

Describe Chlamydia trachomatis

Answer 32

Sexually-transmitted infection can cause INFANTILE pneumonia

Diagnosed by PCR on urine of mother or pernasal/throat swabs of child

Question 33

Describe Chlamydophilia pneumoniae

Answer 33

Person to person transmission

Mostly causes mild respiratory infection and may be picked up a by a test for Psittacosis

Question 34

Describe Middle East Respiratory Syndrome coronavirus

Answer 34

AKA MERS CoV
Most prevalent in Saudi Arabia and has an important reservoir in dromedary camels
25% of cases in health care workers

Virus in group is known as coronaviruses (other members can cause common cold)