clinical relevance / extra pbl Flashcards
which airway is an aspirated object more likely to end up
right - it is less angulated
ECG signs of sinus invertus
R axis deviation; Positive QRS complexes (with upright P and T waves) in aVR; Lead I: inversion of all complexes, aka ‘global negativity’; Absent R-wave progression in the chest leads
what are the main defense mechanisms against inhaled pathogens
mucociliary escalator
disease affecting cilia (4)
primary cilia diskinesia; cartagenous syndrome; CF; young’s syndrome (yellow nails, pleural effusion)
4 components of the immune response to an infection and how to they work
cytotoxic T cells (respond to MHC1 and release perforin);
Natural killer cells (responds to downreg of MHC1 on cells, makes membrane porus);
Interferons (released later e.g. CRP, IL6);
Antibodies (B cells produce specific antibodies, work in numerous ways)
3 actions of interferons
signal neighboring cells to put up barriers; signal infected cells to die; recruitment of white blood cells to stimulate long lasting immunity
what should be considered along side CURB65 criteria when deciding whether to admit
O2 stats/score; CURB65 alone does not take into all factors
which type pf H.influenzae is fata
HI B is fatal -> ear infections + meningitis can be seen in children
what lobes does TB usually affect
upper lobes (due to V/Q ratio)
tetracyclines MOA
protein synthesis inhibitors - inhibit the initiation of translation in variety of ways by binding to the 30S ribosomal subunit
penicillin MOA (similar for other β-lactams e.g. amoxacillin, cephalosporin etc.)
specifically inhibiting the transpeptidase that catalyzes the final step in cell wall biosynthesis, the cross-linking of peptidoglycan (i.e. cell wall synthesis inhibition)
antimycobacterials (Rifampicin) MOA
inhibition of the cell wall synthesis and RNA polymerase blockade
quinolones (ciprofloxican) MOA
interfere with DNA replication by preventing bacterial DNA from unwinding and duplicating
what is a B-lactam and give some examples
antibiotics are antibiotics that contain a beta-lactam ring in their chemical structure - e.g. penicillin, amoxacillin, Oxacillin, cephalosporin
trimethoprim MOA
blocking the reduction of dihydrofolate to tetrahydrofolate, the active form of folic acid, by susceptible organisms - works best on gram +ve cocci
Macroldies (erythromyocin, clarythromyocin etc.) MOA
binds to the bacterial 50S ribosomal subunit causing the cessation of bacterial protein synthesis
what non-tuberculosis mycobacterium is essential to look out for in CF pts
Mycobacteroides abscessus
Bacteria
what treatment cannot be given is M.abscessus is grown from the pt
lung transplant
what can pts w an absent spleen not produce
loss of ability to filter out infected red blood cells;
reduced number of white blood cells as the spleen is also responsible for controlling the levels of blood cells
asplenic pt vaccines (4)
Pneumococcal infections, such as pneumonia with a booster every 5 years;
Flu vaccine annually;
MenACWY;
MenB;
asplenic pts antibiotics recommendation
recommended to take prophylactic antibiotics for the rest of the life to prevent bacterial infections
what RTIs are HIV more likely to develop
sinusitis, bronchitis, bronchiectasis and pneumonia
how does cough arise
postnasal mucous drip, also known as upper airway cough syndrome (UACS), other contributing factors may include bronchial hyperresponsiveness
causes of chronic cough (8)
astroesophageal reflux disease (GERD); ACE Inhibitor use; asthma; bronchiectasis; COPD; chronic lung infection (e.g. tuberculosis); lung cancer and chronic micro aspiration
how thick is the mucous blanket covering the RT
5 μm
how is resistance reduced in cilia
Sublayer of water below mucus
what does lactoferrin do?
binds to iron, limiting the growth of certain pathogenic bacteria that require it to create transport proteins; promotes the growth of beneficial low-iron requiring bacteria
what are the 4 stages to macrophage defense in the alveoli
- recognition - surface receptors or from complement cascade (C3b);
- migration - neutrophils move from capillaries to alveolar space;
- ingestion - Microbes englufed but not fully killed until certain signals are received (activation signals from NKCs releasing GMCSF or inteferons);
- secretion of mediators - defensins (non-oxidative mech that kills many gram +/-ve species, fungi and certain viruses), surfactant proteins (type II Alveolar cells secrete surfactant proteins A and D to enhance phagocytosis)
what is the main way in which neutrophils kills pathogens
Oxidation - Neutrophils phagocytose bacteria and kill them with reactive oxygen
metabolites like H2O2
what is the effect of the enzyme elastase on the muco-cilia (secreted during an infection)
which causes excessive mucus, epithelial cell
damage and significant slowing of beat frequency in cilia
what is the purpose of coughing
to clear material such as
sputum from the airways; It also helps protect the lungs against aspiration
7 causes of cough
COUGHIN’
C - COPD
O - oedema
U - upper airways coughing syndrome
G - gastro-oesophageal reflux disease
H - hypertension medications (ACEi etc.)
I - infection
N - non-asthmatic eosinophilic bronchitis
sensory components of cough
C fibres (affected by factors like bradykinin, histamines, prosoglandins etc.);
RAR (rapidly adapting airway mechanoreceptors) and SAR - mechanically driven due to bronchoconstriction, #oedema, high mucous levels etc.;
vagus nerve relays signals to brain
“computing” component of cough
tractus solitarus (has nay afferent imputs incl ear, heart etc.); signal sent to pons -> cough signal recieved
motor components of cough
Inspiratory centre: goes to muscle, pull diagram down, larynx closes -> pressure increase in lungs above 300 mmHg -> Expiratory phase: larynx open, and we cough as pressure changes
4 phases of coughing
irritation, inspiraiton, compression, expulsion
rifapentine side effects (7)
Black, tarry stools
coughing up blood
skin rash
sore throat
trouble breathing with exertion
ulcers, sores, or white spots in the mouth
unusual tiredness or weakness
Rifampicin side effects
thrombocytopaenia; nausea; psychosis
Isoniazid side effects
hepatic disorder; Severe cutaneous adverse reactions (SCARs)
Ethambutol hydrochloride side effects
Hyperuricaemia; nerve disorders; visual impairment
Pyrazinamide side effects (7)
Appetite decreased; arthralgia; dysuria; hepatic disorders; peptic ulcer aggravated; photosensitivity; skin reactions etc.
