Respiratory Tract Infections 1 Flashcards
What are the sources of respiratory infections?
- humans: family social contact
- environment: air conditioning systems
- animals: psitaccosis
What aspect of anatomy makes children under 7 more susceptible to infection?
- shorter flatter eustachian tube (more likely to be blocked)
- can spread infection to middle ear (through build up of fluid)
What are the common symptoms of an upper respiratory tract infection?
- nasal congestion
- chest congestion
- sinus pressure
- cough
What are the common pathophysiologies of an upper respiratory tract infection?
- swollen mucosa
- vascular enlargement
- arrested cilia
- clogged osta
Ottitis media infection
- can rupture and release pus and damage hearing
- acute and chronic infection can rupture into the mastoid sinuses (causing sinusitis)
- infection can ascend the eustachian tube
Sinusitis
sinuses must drain so inflammation due to allergy/infection can block drainage and cause a secondary infection
What are the respiratory innate defenses?
- nasal mucus
- ciliated cells
- mucociliary clearance elevator
- alveolar macrophages
- polymorphonuclear leucocytes
- complement
Describe the mucociliary clearance elevator defence mechanism and what disruption of this causes
- particles trapped in mucus covering respiratory tract
- ciliary action drags mucus upwards
- material is expelled
- disruption results in chronic infections (like CF, bronchiectasis)
What are the respiratory tract host defences?
- saliva
- mucus
- cilia
- nasal secretions
- antimicrobial peptides
How can the common cold be transmitted and what are its causative agents?
transmission:
- aerosol
- virus contaminated hands
causative agents:
- rhinoviruses
- coronaviruses
What are the clinical features of the common cold?
- tiredness
- slight pyrexia
- malaise
- sore nose and pharynx
- sneezing
- profuse, watery nasal discharge becoming mucopurulent
- generally mild
What are the causative agents of acute pharyngitis and tonsilitis?
Virus:
- Epstein-Barr virus (EBV)
- cytomegalovirus (CMV)
Bacteria:
- streptococcus pyogenes
How is cytomegalovirus transmitted and what is the severity of it?
Transmission:
- body secretions
- organ transplants
- can reactivate and cause disease if cell-mediated immunity is compromised
Severity:
- mild/asymptomatic in healthy adults
How would you go about diagnosing a secondary CMV infection and CMV pneumonitis?
- secondary infection: look at IgM levels in blood
- CMV pneumonitis: look for CMV antigen in bronchoalveolar lavage (BAL)
What is the treatment for cytomegalovirus infections?
- ganciclovir
- foscarnet
- cidofvir
What virus causes glandular fever and how is it transmitted?
- Epstein-Barr virus
- saliva
- aerosol
Describe the progression of glandular fever
- occurs in 2 peaks: 1-6 yo, 14-20 yo
- incubation: 4-8 weeks
- illness: 4-14 days
What are the clinical features of glandular fever?
- fever
- headache
- malaise
- sore throat
- anorexia
- palatal petechiae
- cervical lymphadenopathy
- splenomegaly
- mild hepatitis
- swollen tonsils and uvula
- white exudate
How would you diagnose glandular fever?
- detection of heterophile IgM antibodies specific for EBV through:
- monospot test
- Paul-Bunnell test
- if negative consider HIV
What is the treatment for glandular fever?
- NOT antibiotics
- contact sports and heavy lifting should be avoided during first month of illness and until splenomegaly has resolved
What are the complications of glandular fever?
- Burkitt’s lymphoma
- nasopharyngeal carcinoma
- Guillain-Barre syndrome
How can tonsilitis be transmitted and who is mainly affected?
transmission:
- air-droplets
- contact
- affects mainly children
What is the treatment for tonsilitis?
penicillin
What are the clinical features of tonsilitis?
- fever
- sore throat
- enlargement of tonsils
- tonsillar lymphadenopathy
