URTI Flashcards
what are some examples of upper respiratory tract infections?
1) Epiglottitis
2) Laryngitis
3) Tonsilitis
4) Pharyngitis
What is the mechanism for professional invaders?
1) adhesion to the mucosa
2) avoiding host defence
3) damaging local tissue by the production of toxins
What is the mechanism for secondary invaders of URT?
1) they cause disease when host defences are impaired
2) compromised immune response due to: cancer chemo, AIDS
3) foreign body: they enter due to medical tubes/ medical ventilation
What is the clinical manifestation for a common cold (coryza)
1) nasal discharge, sneezing and sore throat, temperature
2) may cause infection of larynx and trachea
3) incubation period = 2-4 days
What are some causative organisms for the common cold (coryza) ?
Rhinovirus, RSV, Coronavirus
What is the treatment for a common cold?
Supportive medicine: paracetamol
What is the manifestation for oral candidiasis (thrush) ?
1) changes in flora can upset the balance allowing for overgrowth of fungi
2) raw inflamed mucous membranes + white fungal plaques
What are some predisposing factors for oral thrush?
contraceptive pills, systemic steroids, chemotherapy, HIV
What is the causative microorganism for oral thrush?
Candida albicans
What is the clinical manifestation for Sinusitis and the causative organisms?
1) facial swelling and localised tenderness
2) usually viral, but may occur due to secondary invaders such as streptococcus pneumoniae
What is the treatment for oral thrush?
1) Nystatin/ clotrimazole pastilles
2) for severe oral thrush: fluconazole (inhibits the growth of candida by disrupting the production of ergosterol which is a component of fungal cell membranes)
What is the treatment for Sinusitis?
NO TREATMENT FOR VIRAL INFECTION
Bacterial: amoxicillin, Doxycycline, erythromycin
What are the clinical manifestations and causative microorganisms for pharyngitis/ tonsillitis
1) fever, sore throat, cervical lymphadenopathy (swelling of lymph nodes in the neck), discharge
2) Viruses: adenovirus
Bateria: streptococcus pyogenes
What is the treatment for viral tonsillitis?
Pain relief medication, ibuprofen, humidifier, salbutamol (inhaler)
What is the clinical manifestation and causative virus for viral tonsillitis?
1) Scratchy sore throat, stuffy or runny nose, purulent discharge
2) rhinovirus, adenovirus, influenza virus
What are the complications associated with streptococcal tonsillitis?
1) peritonsillar abscess
2) rheumatic fever
3) glomerulonephritis
4) scarlet fever
What is the mechanism of streptococcal pathogenicity?
1) ability to colonise the host and invade tissues
2) ability to bypass host defences
3) ability to damage host through production of toxins
What is the function of the F protein in adhesion?
1) binds to fibronectin which allows S.pyogenes to attach to epithelial cells in the throat/skin -> allows bacteria to anchor itself to host tissues
2) facilitates invasion and initiating infections
What is the role for the M protein?
1) plays a role in immune evasion
2) binds to fibrinogen -> activates platelets and leukocytes = inflammation
3)interferes with phagocytosis by maintaining survival of bacteria
4) is a key virulence factor -> causes rheumatic fever
5) found in group A strep
What is the purpose of the hyaluronic acid capsule?
1) it is identical to human substance and is used to avoid immune detection
What are some virulence factors secreted by strep?
streptomycin O
DNAase
streptokinase
hyaluronidase
Which toxins are responsible for scarlet fever?
streptococcal pyrogenic exotoxins AKA superantigens
Which blood culture should be used for S. Pyrogens?
Blood agar enriched
