Respiratory Flashcards
(232 cards)
In which lung is an aspiration more likely to happen?
Right lower lung
The right bronchus is more vertical and wider so a foreign object is likely to fall down this path over the left bronchus
What cells are involved in the mucociliary apparatus?
Goblet cells - secrete mucus to trap pathogens
Ciliated columnar cells - move mucus towards main bronchi and trachea to be expelled by coughing or swallowed
How does the innate immune system act as a defence mechanism for the respiratory tract against inhaled pathogens?
Alveolar Macrophages - recognise microbes via surface receptors - immobilise + destroy bacteria
Type II alveolar cells - secrete surfactant proteins to enhance phagocytosis and agglutination of gram-positive bacteria
Neutrophils - chemoattraction to alveolar space - phagocytose bacteria and kill via respiratory burst
What are neuraminidase and haemaglutinin and is their function?
Glycoproteins on influenza membranes
Haemaglutinin binds to sialic acid receptors on host respiratory epithelial cells for fusion and neuraminidase cleaves sialic acid residues to promote release and spread of viruses
What is the role of spike proteins on coronavirus?
A glycoprotein that facilitates the fusion and penetration of host cell by binding to ACE2 along our airways
S1 - recognise and bind to receptors on the host cell
S2 - fuses envelope of the virus with the host cell membrane
What is Antigenic Drift?
Small changes or mutations in the genes of influenza virus that can lead to changes in the surface proteins of the virus - HA, NA
Loss or reduction in protection from existing antibodies and vaccines - susceptible to the flu again
What is Antigenic Shift?
A major change where 2 or more strains combine to form new subtypes of HA, NA glycoproteins
e.g. When an zoonotic virus gains the ability to infect humans
Normally would result in a pandemic, no previous immunity, occurs infrequently
How can soap kill corona virus?
Tear apart the lipid shell surrounding the virus to make the inside susceptible to our immune system
What is the role of furin in viruses?
A protease released by the golgi apparatus
Cleaves glycoproteins once bound to host cell to allow for fusion and penetration into membrane
Increasing infectious and pathogenic nature of virus
What are common pathogens that cause a sore throat?
Influenza, Rhinovirus, Coronavirus
Adenovirus
EBV
CMV
Strep A
What are infections of the URT?
Common cold
Tonsilitis
Laryngitis
Pharyngitis
Sinusitis
Otitis Media
Mainly viral pathogens as causative agent
What are infections of the LRT?
Pneumonia
Tuberculosis
Lung abscess
Bronchiolitis
Mainly bacteria pathogens as causative agent
How can you distinguish between URT and LRT infections?
URTI - normal chest x-ray and breath sounds on auscultation
Symptoms - runny nose, dry cough, headache, sore throat, sneezing, myalgia
LRTI - changes/consolidation on x-ray and coarse crackles on auscultation
Symptoms - productive cough, SOB, breathlessness, wheezing, tight chest
What is the most common infective cause of COPD exacerbations?
Haemophilus Influenzae
What is the common causative bacteria of Pneumonia in HIV?
Pneumocystis jiroveci - PCP
What is the common causative bacteria of Pneumonia in alcoholics and diabetics?
Klebsiella pneumoniae
What type of bacteria are asplenic patients more susceptible to and why? Give 3 examples.
Insufficient splenic macrophages to opsonise and phagocytose encapsulated bacteria
Streptococcus pneumoniae
Haemophilus influenzae
Neisseria meningitis
What is the common causative bacteria of Pneumonia in someone recently exposed to air con and hot tubs?
Legionella pneumophilia
What is the difference between tuberculosis and sarcoidosis?
TB - caseating granuloma
Sarcoidosis - non-caseating granuloma
What are similarities in tuberculosis and sarcoidosis?
Granulomatous disease
Erythema nodosum
Hilar lymphadenopathy
Arthralgia
Systemic symptoms - fever, malaise, weight loss
Affect upper lobes of lungs
What is the management of active TB?
Isoniazid, rifampicin, ethambutol, and pyrazinamide
for 2 months
Isoniazid and rifampicin for a further 6 months
Longer courses if extra-pulmonary TB, HIV, immunosuppressed
What is the pathophysiology of the primary infection in TB?
M.tuberculosis inhaled as aerosolized droplets
M.T lodge in the alveoli and engulfed by macrophages
M.T continues proliferating intracellulary
AM travels to lymph nodes = hilar lymphadenopathy
Granuloma forms with caseous necrosis (TNF-alpha and IFN-Gamma activate to mature macrophages) = ghon focus
If healthy patient - heals by fibrosis and disease becomes latent
Ranke complex once Ghon focus calcified
What is a Ghon complex?
Primary lesion/ghon focus in the lungs and hilar lymphadenopathy
What is secondary and miliary TB?
Secondary - reactivation of TB - cavitating lesions of upper lobes of lung + systemic symptoms (Weight loss, fever, haemoptysis)
Miliary - haematogenous spread of TB (Potts disease - in spinal cord, meninges, kidneys, hepititis)
Mainly in immunocompromised