MB 8 Respiratory Infections Flashcards Preview

Pathology > MB 8 Respiratory Infections > Flashcards

Flashcards in MB 8 Respiratory Infections Deck (29):
1

Learning Outcomes (for general perusal)

* Describe Upper respiratory Tract (URT) infections with examples (colds / sinusitis / otitis media / mumps / pharyngitis / epiglottitis)

* Describe Upper respiratory Tract (URT) infections with systemic complications (IM / diphtheria/streptococcal pharyngitis)

* Outline the principles of treating URT infections.

* Describe Lower respiratory tract (LRT) infections: Laryngitis/ tracheitis/bronchitis/ bronchiolitis

* Describe types of pneumonia including the concept of atypical pneumonia and legionella infection

* Describe the major pathogens of URT and LRT infections 

2

Infectious agents are continuously entering the respiratory tract, which is an extensive mucous membrane surface exposed to the environment.

What are the defences?

 

 

What is the combined action of mucuous and cilia?

 

 

Which pathogens interfere with cilary action?

•Nasal Hairs   

•Mucus-secretion

•Cilia   

•Cough Reflex

•Alveolar macrophages

 

Microbes stick to mucous => travel to back of throat by cilliary action => swallowed

 

Bordetella pertussis and Mycoplasma pneumoniae

3

What are the main

  1. UPPER Respiratory Tract Infections (URTIs)
  2. LOWER Respiratory Tract Infections (LRTIs)

  1. •Sinusitis

    •Otitis media

    •Pharyngitis

    •Epiglotitis

  2. •Laryngitis

    •Tracheitis

    •Bronchiolitis

    •Pneumonia

4

URTI - Common Cold

  1. What causes the common cold?
  2. What symptoms does the common cold have?
  3. What are URTIs important in triggering?
  4. Outline the mechanism of spread of the common cold,  between persons and within the body.

  1. Rhinoviruses, coronaviruses, adenoviruses (75%, other causes exist)

  2. Mucosal irritation- sneezing & coughing

  3. LRTIs

  4. 'Coughs and Sneezes spread diseases'

    -Sneezing reflex – hand contamination                   - Inflammatory virus-rich secretions

    -Viruses bind to host cells or to cilia or microvilli

    -Spread from cell to cell, damage epithelial cells - inflammatory mediators released                  

5

What is the guiding principle for UTRIs in terms of treatment?

Most URTIs don't need an antibiotic

6

  1. What is Otitis Media?
  2. What are the symptoms?
  3. Who is it common in?
  4. What causes it?
  5. What is the first line treatment?
  6. What is diagnosis?

  1. URTI - Middle ear infection
  2. Fever, pain
  3. Children. Glue ear = hearing and learning problems
  4. Streptococcus pneumoniae

    Haemophilus influenzae

  5. Amoxicillin

  6. Clinical, usually no microbiological diagnosis

7

URTI - Sinusitis

  1. Who does it effect?
  2. What are the symptoms?
  3. What viruses cause it?
  4. What is the firstline treatment?
  5. What is diagnosis?

  1. All ages
  2. Facial pain, Localised tenderness, Fever

  3. Streptococcus pneumoniae

    Haemophilus influenzae

  4. Amoxicillin (only if persistent/severe)

  5. Generally clinical, no microbiological diagnosis 

8

URTI - Acute Epiglotitis

  1. Who is this seen in?
  2. Why is it a MEDICAL EMERGENCY?
  3. What causes it?
  4. What does treatment involve?
  5. How is it diagnosed?
  6. Why is it more uncommon now?

  1. Young children
  2. Acute Epiglotitis
  3. Haemophilus influenzae capsular type B (gram-negative bacillus)

  4. Intubation and antibiotics (Cefotaxime / chloramphicol)

  5. Blood culture normally positive

  6. Hib vaccine (Haemophilus influenzae type B vaccine)

9

URTI - Mumps (Virus)

  1. What are the symptoms?
  2. What is the treatment?
  3. How is it prevented?
  4. How is it diagnosed?

  1. Parotitis

    Respiratory spread

  2. No specific treatment

  3. Vaccine preventable (MMR)

  4. RT-PCR for mumps RNA in saliva, cerebrospinal fluid (CSF) or urine. Mumps-specific IgM antibody (serum or saliva) 

10

URTI- Pharyngitis

  1. What are the symptoms?
  2. What causes glandular fever?
  3. What normally causes pharyngitis?
  4. What causes strep sore throat
  5. What can diphteria cause?

  1. Sore throat and fever
  2. Epstein Barr Virus
  3. Viral causes 70% of sore throats
  4. Streptococcus pyogenes
  5. toxin induced damage to brain and heart - very serious

11

URTI- Pharyngitis

Infectious mononucleosis (IM)

  1. What virus causes this, and from what family is it from?
  2. How is it transmitted?
  3. Who gets it?
  4. What are the symptoms?
  5. What are the tests?
  6. What are the complications

  1. Epstein Barr Virus- Herpes family

  2. Transmitted in saliva- infects B lymphocytes

  3. –Teenagers and young adults get IM

    –Babies get asymptomatic infection

  4. Fever, sore throat, lymphadenopathy

    Splenomegally, lethargy, hepatitis

    Symptoms immunologically mediated

  5. Monospot serology test Or EBV IgM

  6. encephalitis, nearly always with complete recovery

12

URTI- Pharyngitis

Streptococcus pyogenes

  1. What are the symptoms?
  2. What can the Strep pyogenes cause?
  3. What does diagnosis involve?
  4. What is the treatment?

  1. Sore throat and fever. Peritonsillar abscess ('quinsy') 
  2. •Scarlet fever. 

    –Rheumatic fever.

    –Rheumatic heart disease

    –Acute glomerulonephritis. (ASOT)

  3. Throat Culture 

    ASOT (serology)

  4. Penicillin  (Erythromycin)

13

URTI - Pharyngitis

Diphtheria

  1. What is the causal agent?
  2. What are the dangers?
  3. What is treatment?

  1. Corynebacterium diphtheriae - gram positive bacillus
  2. toxin can cause fatal heart failure and a polyneuritis. Toxin is phage coded

  3. Effective vaccination is in use - prevalent in other areas of the world

    antitoxin

    + Penicillin or Erythromycin 

14

LRTIs

What causes the following?

  1. Whooping Cough
  2. Laryngitis and Tracheitis 
  3. Acute Bronchitis 
  4. Bronchiolitis 
  5. Pneumonia
    1. Typical
    2. Atypical

  1. Bordella Pertussis 
  2. Parainfluenza Viruses
  3. Streptococcus pneumoniae and Haemophilus influenzae
  4. RSV (Respiratory syncytial virus)

  5. Pneumonia

    1. Streptococcus pneumoniae, Staph aureus, Haemophilus influenzae

    2. Mycoplasma pneumoniae, Chlamydophila pneumoniae, Chlamydophilia psittaci, Legionella pneumophila

15

LRTI - Whooping cough 

  1. What causes it?
  2. What are the symptoms?
  3. What can occur as a result?
  4. How is it spread?
  5. What is the treatment?

  1. Bordetella pertussis - Gram negative coccobacillus attach to respiratory epithelium
  2. Catarrhal illness then paroxysms of coughs, Followed by a 'whoop' sound due to inspiratory gasp of air. Can go on for weeks

  3.  

    Lobar or segmental collapse of the lungs can occur. exhaustion and secondary pneumonia, fatal outcomes seen 

  4. Person to person by airbourne droplets

  5. Supportive, Erythromycin. Immunisation – acellular vaccine.

 

 

16

LRTIs - Laryngitis and tracheitis

  1. Give an example
  2. What is the answer given to 1? Who is it seen in?
  3. What causes it?
  4. How is it diagnosed?
  5. What is the treatment?

  1. Croup
  2. laryngotracheobronchitis causing inspiratory stridor due to laryngeal narrowing – young children
  3. Parainfluenza virus
  4. PCR
  5. Paracetamol & fluids

    Corticosteroids if severe

    Adrenaline if hospitalised

17

LRTIs - Acute Bronchitis

  1. What causes it?
  2. What are the signs of Viral acute bronchitis
  3. What are the signs of bacterial bronchitis?
  4. What can lead to acute exacerbations of chronic bronchitis?
    1. What can be useful in this case?

  1. Viruses and Streptococcus pneumoniae and Haemophilus influenzae

  2. Non-productive cough

  3. Productive cough

  4. COPD (chronic obstructive pulmonary disease)

    1. Antibiotic therapy may be helpful – also bronchodilators / steroids

18

LRTIs - Bronchiolitis 

  1. What is the main causal agent?
  2. Who is it common in, why?
  3. What are the symptoms and what can it lead to?
  4. What other viruses can cause it?

  1. RSV (respiratory syncitial virus)
  2. <2 years of age- narrow bronchioles. 

  3. Cough, wheeze, low O2,raised resp rate, cyanosis, consolidation. interstitial pneumonia

  4. Rhinovirus

19

RSV (Respiratory Syncytial Virus)

  1. How is it transmitted?
  2. When is it most seen?
  3. What is the prevalence?
  4. Who is it severe for?
    1. How are they treated?
  5. What is the treatment if the infection is severe/life threatening?

  1. by large droplets and by hands
  2. Oct-Feb
  3. About 1 in every 100 infants with RSV bronchiolitis or pneumonia requires admission to hospital. 

  4. Severe in children with heart and lung problems

    1. these are given prophylatic paluvizumab each winter - monoclonal antibody specific to RSV

  5. ribavirin

20

LRTIs- Pneumonia 

  1. What are the symptoms?
  2. What are the common causes?
  3. What is a cause in immunocompromised patients?

  1. Cough. Sputum, Breathlessness, Fever

  2. Streptococcus pneumoniae - 50%

    Legionella pneumophila - 1%

    Mycoplasma and chlamydia - 10%

    Haemophilus influenzae - 10%

    Moraxella catarralis - 3%

    Staphylococcus aureus - 5%

    Viral - 10%

  3.  

    Pneumocystis jirovecii

21

LRTI - Pneumonia

What is...

  1. Lobar pneumonia
  2. Bronchopneumonia
  3. Interstitial pneumonia
  4. Lung abscess

  1. refers to involvement of a distinct region/lobe of the lung. Bacterial

  2. refers to a more diffuse patchy consolidation, which may spread throughout the lung as a result of the original pathologic process in the small airways. Bacterial

  3. involves invasion of the lung interstitium and is particularly characteristic of viral infections of the lungs. Viral 

  4. sometimes referred to as necrotizing pneumonia, is a condition in which there is cavitation and destruction of the lung parenchyma. Bacterial

22

LRTI - Pneumonia 

Typical Pneumonia

  1. What are the causal agents?
  2. What type of pneumonia does it give rise to?
  3. What is the diagnosis?
  4. What other bacteria causes this?
    1. What are the presentation for these types?

  1. Streptococcus pneumoniae
  2. Lobar pneumonia- clinical and radiological, Productive cough with rust coloured sputum.
  3. •Gram stain – polymorphs and gram positive diplococci (positive blood cultures)

    •Culture – pneumococcus 

    •Urinary antigen

  4. Staph aureus, Haemophilus influenzae

    1. these tend not to be clasical lobar pneumonia and are more patchy in distribution of consolidation 

23

LRTI - Pneumonia

Atypical Pneumonia

  1. What are the agents?
  2. What are the atypical symptoms?

  1. Mycoplasma pneumoniae,

    •Chlamydophila pneumoniae, Chlamydophilia psittaci, Legionella pneumophila, Coxiella burnetii (Q fever) Mycoplasma pneumoniae

  2. •Extrapulmonary symptoms (confusion, diarrhoea) (especially with legionella penumophilia)

    •Little or no sputum – Dry cough

    •No evidence of lobar consolodation

24

LRTIs- Pneumonia

Atypical Pneumonia

Legionella pneumophila pneumonia

  1. What is the source of the agent?

  1.  

    Source: water at 20-45oC

    –Humans inhale droplets of contaminated water mist in the air

    eg showers, cooling towers, taps

    Hotels, hospitals, leisure centres

25

LRTIs - Pneumonia 

  1. What is the clinical presentation of pneumonia?
  2. What are the diagnostic findings?

1. •Patients with pneumonia usually present feeling unwell and with a fever  (chest pain, ~ pleuritic, cough, sputum, SOB

•N.B. Legionella infection is associated with extra pulmonary symptoms - confusion, diarrhoea and evidence of renal or liver dysfunction.

2. O/E Crackling sounds, evidence of Consolidation

•Patients with pneumonia usually have shadows in one or more areas of the lung  

•Most patients with pneumococcal pneumonia have positive blood cultures

•Sputum (NOT SALIVA) best collected in the morning and before breakfast May need  physiotherapist

•The usual laboratory procedures on sputum specimens from patients with pneumonia are Gram stain and culture

•Urinary antigen (ELISA) for Streptococcus pneumoniae and Legionella 

26

LRTIs - Pneumonia

  1. What specimens are used for diagnosis?
  2.  

  • Bloods – WCC / DWCC / CRP
  • Blood Culture - pneumococcus
  • Respiratory Secretions – Nasal/Throat Swab; Sputum; BAL, Lung Biopsy. Viral = PCR;  Bacterial = Gram/ZN Stains.  Culture & Sens
  • Urine – antigens – Legionella and pneumococcus
  • Acute and Convalescent sera – Monospot (EBV) / ASOT (GAS) / Cold aggluttinins (M. pneumoniae) / Antibody Titires
  • Chest X-ray 

27

LRTIs - Tuberculosis

  1. What are the problems with TB?
  2. What is the causal agent?
  3. How is it diagnosed?
  4. How is it treated?
  5. How long does treatment continue for?

  1. Dormancy and reactivation. Kills 3 million/year in world. HIV and TB is a bad combination!- Africa. Primary infection often asymptomatic

  2. Mycobacterium tuberculosis

  3. Zeihl Neelson stain on sputum- Quick

    Culture – Slow – weeks – special media              PCR

  4. 3  drug combination to prevent resistance (increasing problem)

  5.  

    months

     

       

28

Influenza

  1. Which part of the resp. system does it affect?
  2. Why is it a worry?
  3. What is antigentic drift?
  4. What is antigenic shift?

  1. URT and LRT
  2. Big killer every year

    •Epidemics each year

    •Pandemics every 10-40 years

  3. Accumulation of point mutations selected by population immunity

  4. Sudden new virus – reassortment between human and animal influenza viruses

29

SARS

  1. What is it?
  2. What causes it?
  3. Why is it a worry?
  4. What is MERS?

  1. Severe pneumonia. Severe acute respiratory syndrome
  2. SARS Cornavirus
  3. World spread of a new virus 8000 cases and 800 deaths

  4. Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (MERS‐CoV) that was first identified in Saudi Arabia in 2012.

    1. Suggested mechanism = bats to camels to humans.