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147 Cards in this Set
- Front
- Back
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What are the top 6 infections responsible for death globally? |
acute respiratory infection HIV/AIDS diarrheal diseases TB malaria measles |
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Which microbiota are common (>50%)? |
bacteroides spp. candida albicans oral strep haemophilus influenzae |
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What microbiota are occasional? (<10% normal people) |
streptococcus pyogenes steptococcus pneumoniae neisseria meningitidis |
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What viruses will lie in a latent state in tissues? |
HSV EBV CMV TB |
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What are the main host defences of the respiratory tract? |
salive mucus cilia nasal secretions antimicrobial peptides |
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What is acute coryza? |
runny nose |
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What is the transmission of the common cold? |
aerosol virus contaminated hands |
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What are the main causative agents of the common cold? |
rhinoviruses coronaviruses coxsackie virus A echovirus parainfluenza virus |
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When is the common cold most likely to be prevalent? |
early autumn and mid to late spring |
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What is the pathogenesis of the common cold? |
infection virus adsorbed viral replication viral shedding ( cell damage spreads infection ) low grade overgrowth of bacterial commensals and phagocytosis recovery |
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What are the main clinical features of a cold? |
tiredness slighy pyrexia malaise sore nose profuse watery nasal discharge becoming mucopurulent sneezing in early stages |
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What is the main treatment for the common cold? |
generally self limited NO antibiotics (viral) |
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What are the main viral causative agents of acute pharyngitis and tonsillitis? |
EBV CMV HSV-1 rhinovirus coronavirus adenovirus |
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What are the main bacterial causative agents of acute pharyngitis and tonsillitis?
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strep pyogenes haemophilus influenzae corynebacterium diphtheriae |
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How is CMV transmitted? |
in body secretions and organ transplants |
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How does CMV usually present? |
asymptomatic or mild in healthy adults but may reactivate if cell mediated immunity is compromised |
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How might a secondary CMV infection be diagnosed? |
IgM in blood |
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How is CMV pneumonitis diagnosed? |
CMV Ag in BAL (broncho alveolar levage) |
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How would CMV be treated? |
ganciclovir, foscarnet cidofovir |
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What is EBV? |
epstein barr virus causes glandular fever |
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Where does EBV replicated?
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specifically in B lymphocytes |
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How is EBV transmitted? |
saliva and aerosol |
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What are the two peaks of EBV? |
1-6 years old 14-20 years old |
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What is the incubation period of EBV? |
4-8 weeks |
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What is the illness period of EBV? |
4-14 days |
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What are the clinical features of glandular fever?
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fever, headache, malaise, sore throat, anorexia palatal petechiae ( little red dots on roof of mouth caused by burst vessels) white exudate containing dead bacteria and epithelial cells cervical lymphadenopathy splenomegaly mild hepatitis swollen tonsils and uvula |
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How would one detect heterophile antibodies (IgM) specific for EBV? |
monospot test Paul Bunnell test |
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What is the treatment for glandular fever? |
not antiobiotis contact sports should be avoided until splenomegaly has resolved |
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What are the most common complications of EBV? |
Burkitts lymphoma nasopharyngeal carcinoma Guillain Barre syndrome |
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Which infectious agent causes tonsillitis? |
streptococcus pyogenes |
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What is the transmission of tonsillitis? |
aerosol |
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What percentage of people infected with strep progenes become asymptomatic carriers? |
15-20% |
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What can be used to treat tonsillitis? |
penicillin |
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What is tonsillitis becoming increasingly resistant to? |
erythromycin and tetracycline |
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What are the clinical features of tonsillitis? |
fever pain in throat enlargement of tonsils tonsillar lymphadenopathy |
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What is streptococcus pyogenes? |
A group A strep gram positive cocci in chains cultured on blood agar haemolytic activity |
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What causes the haemolytic activity of strep pyogens? |
exotoxin streptolysin |
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What are the complications associated with strep pyogenes? |
otitis media/sinusitis
rheumatic heart disease glomerulonephritis scarlet fever peritonsillar abscess (quinsy) |
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What is parotitis?
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primarily affecting school aged children
a condition causing fever, malaise, headache, anorexia, trismus and severe pain or swelling of the parotid gland |
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What is trismus?
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lock jaw spasm of muscle |
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What causes parotitis? |
mumps virus |
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What is the transmission of parotitis? |
droplet spread fomites |
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When is parotitis communicable? |
2 days before disease onset |
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What is diagnosis of parotitis? |
based on clinical features IgM serology can be performed |
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What is the treatment regime for parotitis? |
mouth care nutrition analgesia |
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What complications might be associated with parotitis? |
CNS involvement epididymo-orchitis |
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What causes acute epiglottis? |
h. influenzae |
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What are the clinical features of acute epiglottis? |
high fever oedema severe airflow obstruction bacteraemia |
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What is H. influenzae? |
a gram negative bacillus pasteurellaceae family may have beta lactamases |
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What percentage of people have H.influenzae in their nasopharynx? |
75% |
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What is special about Hib? |
it has a polysaccharid capsule |
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How should acute epiglottis be diagnosed? |
not through throat swabs take blood cultures |
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What is the treatment of acute epiglottis? |
require urgent endotracheal intubation IV antibiotics |
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Which antibiotics should be used to treat acute epiglottis? |
ceftriaxone or chroramphenical |
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What is diphtheria?? |
usually a childhood disease that is present in 3-5% healthy throats |
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What is the incubation period of diphtheria? |
2-7 days |
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What are the clinical features of diphtheria? |
sore throat fever formation of pseudomembrane lymphadenopathy oedema of anterior cervical tissue |
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What is the diagnosis of diphtheria? |
clinical grounds because therapy is urgently requires |
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What is the treatment of diphtheria? |
prompt anti toxin therapy administered intramuscularly concurrent antibiotics strict isolation |
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What antibiotics might be used to treat diphtheria? |
penicilin or erythromycin |
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What is the prevention method for diphtheria? |
childhood immunisation and booster doses |
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What causes diphtheria? |
corynebacterium diphtheriae |
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What toxins are present in the diphtheria bacterium?? |
subunit A- repsonsible for clinical toxicity subunit B- transport toxin to receptors on myocardial and peripheral nerve cells |
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What is the transmission of diphtheria? |
aerosol |
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Where does diphtheria colonise? |
pharynx, larynx and nose |
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What is the viral origin of laryngitis and tracheitis? |
parainfluenza virus respiratory syncytial virus influenza virus adenovirus |
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What are the clinical symptoms of laryngitis and tracheitis? |
hoarseness, retrosternal pain in adults children- dry cough, swelling |
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What causes whooping cough? |
bordatella pertussis |
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Who does whooping cough mostly affect? |
children under 5 |
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How is whopping cough transmitted? |
aerosol |
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What is the incubation period of whooping cough? |
1-3 weeks |
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What are the clinical features of whooping cough? |
Catarrhal stage- 1 week -highly contagious -malaise -mucoid rhinorrhoea -conjunctivits Paroxysmal stage- 1-4 weeks -paroxysms of coughing with inspiratory whoop -lumen of RT compromised by mucous secretion and mucosal oedema |
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How is whooping cough diagnosed? |
by characteristic whoop and bacterial isolation of nasopharyngeal swabs NAAT |
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What is the treatment of whooping cough? |
catarrhal stage treated with erythromycin paroxysmal stage- antibiotics have no effect isolation supportive care |
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What is the prevention of whooping cough? |
vaccination |
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What is bordetella pertussis? |
a gram negative aerobic coccobacillus attaches to and replicates in ciliated resp epithelium does not invade |
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What is the specific attachment of bordetella pertussis due to? |
surface components eg filamentous haemagglutinin (FHA) |
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What are the toxic factors of bordetella pertussis? |
pertussis toxin adenylate cyclase toxin tracheal cytotoxin endotoxin |
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What is the incidence of whooping cough? |
epidemics approx every 4 years |
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What is acute bronchitis? |
inflammation of the tracheobronchial tree |
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Which infection usually caused acute bronchitis? |
rhinovirus coronovirus adenovirus mycoplasma pneumoniae |
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What secondary infections might be associated with acute bronchitis? |
strep pneumoniae H. influenzae |
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How is chronic bronchitis characterised? |
cough and excessive mucus secretion |
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What might cause chronic bronchitis? |
immune deficit ciliary deficit excessively thick mucous |
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What is bronchiolitis? |
restricted to children less than 2 infection may lead to epithelial cell necrosis bronchioles have such a fine bore |
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What is the main caused of bronchiolits? |
RSV |
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What causes pneumonia most commonly? |
strep pneumoniae |
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What is the definition of pneumonia? |
inflammation of the substance of the lungs |
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How might pneumonia be confirmed? |
on a chest radiograph |
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What is the main cause of pneumonia in children and adults? |
adults- bacterial
children- viral |
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How might neonates develop pneumonia?
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chlamydia trachoma tis acquired from the mother during birth |
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What are the common causes of viral pneumonia? |
influenza measles coronaviris parainfluenza RSV CMV adenovirus |
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What the common causes of bacterial pneumonia? |
TB
H. influenzae pseudomonas aeruginosa staph aureus strep pneumoniae |
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What might cause atypical pneumonia? |
mycoplasma pneumoniae legionella pneumphilia chlamydia psittaci chlamydia pneumoniae coxiella burnetti (fails to repsond to treatment with penicillin) |
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How might pneumonia be classified anatomically? |
lobar broncho interstitial necrotising |
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What are the clinical features of pneumonia caused by streptococcus pneumonia? |
abrupt onset fever malaise tachycardia dry cough productive cough with rusty sputum spiky temperature lobar consolidation |
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What are the clinical features of pneumonia caused by mycoplasma pneumonia? |
fever dry cough dyspnoea lymphadenopathy |
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What are the clinical features of pneumonia caused by H.influenzae? |
mainly occurs in children consolidation or patchy bronchopneumonia persistent purulent sputum and malaise |
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What causes legionnaire's disease? |
legionella pneumphila |
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What is legionnaires? |
severe systemic infection with pneumonia |
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What are the clinical features of legionnaires? |
tachypnoea purulent sputum chest x ray with consolidation |
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What is the bacteria that causes legionnaires? |
legionella pneumophila gram negative bacillus secretes protease causing lung damage |
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How is legionnaires transmitted? |
aerosol but not person to person usually occurs in outbreaks |
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What is the lab diagnosis of legionnaires? |
culture of legionella on cystine yeast extract agar
detection of antigen in urine (4 fold rise in antibody) gram staining of sputum recognition with serotype specific fluorescent antibody |
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What are the clinical features of measles?
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fever runny nose Kopliks sports ( rash in the prodromal phase) may result in neurological complications can cause giant cell pneumonia in immunocompromised patients |
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How is the measles virus spread?
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paramyxovirus by aerosol |
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what is the incubation period of the measles virus?
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10-14 days |
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How is measles diagnosed? |
serology for measles specific IgM virus isolation viral RNA detection |
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What is the treatment for measles? |
if severe ribavirin and use antibiotics for secondary bacterial infections |
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What is the prevent on measles? |
immunisation |
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What is an endemic? |
present in the community at all times at a relatively low to medium steady state |
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What is an epidemic? |
sudden severe outbreak within a region or group |
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What is a pandemic? |
occurs when an epidemic becomes widespread and affects a whole region, continent or the world |
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What are the 3 types of influenza virus? |
Type A- epidemics and pandemics with an animal reservoir Type B- epidemics with no animal host Type C- minor respiratory illness |
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What are the type specific antigens on cell surfaces? |
haemagglutinin neuraminidase |
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What type of DNA is found in the influenza virus? |
ssRNA segmented reassortment gives rise to combinations of H and N |
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What is antigenic drift? |
small point mutations in the H and N antigens that are occurring constantly allowing the virus to multiply and create subtypes that will infect communities |
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What is antigenic shift? |
sudden major change based on recombination produces a virus with novel surface glycoproteins new strain can spread through previously immune populations |
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What are the H N combos of the following flus? spanish asain hong kong bird swine |
H1N1 H2N2 H3N2 H5N1 H1N1 |
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What is likely to cause a pandemic? |
antigenic shift most people have no immunity attack rate is high so rapid spread mortality can be high |
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What is swine flu? |
H1N1 virus infection largely limited to individuals under 40 because many older people had been infected in childhood |
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What is the diagnosis of influenza? |
nasopharyngeal aspirate serum |
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What is treatment for influenza? |
amantadine zanamavir oseltamavir |
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What is SARS? |
severe acute respiratory distress syndrome |
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What are the clinical features of SARS? |
high fever cough SOB CXR consistent with pneumonia |
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What is the incubation period for SARS? |
2-7 days |
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What is the transmission of SARS?
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droplets faeces infected animals |
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What is SARS CoV? |
SARS associated coronavirus |
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How is SARS CoV identified? |
virus isolation in cell culture electron microscopy molecular techniques |
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What is the coronavirus?
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enveloped RNA virus with a characteristic halo receptor for spike protein is ACE2 |
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What is treatment for SARS? |
there is no specific antiviral treatment ribavirin corticosteroids interferons antiretro viral therapies such as protease inhibitors |
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What causes TB? |
mycobacterium tuberculosis |
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What is TB associated with? |
immunosuppression decreased socio economic conditions increased immigration from areas of endemicity MDR overcrowding poor nutrition |
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What are the clinical features of primary TB? |
usually symptomless cough and wheeze small transient pleural effusion may occur |
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What are the clinical features of miliary TB? |
results from acute diffuse dissemination of bacillus |
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What are the clinical features of post primary TB? |
onset of symptoms over weeks/months malaise fever weight loss mucoid, purulent or blood stained sputum pleural effusion |
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What is mycobacterium tuberculosis? |
not gram positive or negative acid fast bacilli obligate aerobe spread by inhalation may affect other sites like GI tract |
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What is the mantoux test? |
used to detect latent TB tuberculin injected intradermally and immune response elicited if individual previously exposed to bacterium |
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What is the importance of bacterial load on diagnostics of TB? |
symptoms- differ at different loads diagnostics- some tests become positive at certain bacterial loads reducing the load may delay diagnosis |
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How is primary diagnosis made of TB? |
visualising acid fast bacilli in sputum |
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What are the methods for visualising acid fast bacilli in sputum? |
AURAMINE positive organisms fluoresce bright yellow whole smear examined under low power magnification determine presence or absence Z/N (ZIEHL-NEELSEN) carbol fuschin stain and methylene blue counter stain semi quantification |
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How might TB be cultured? |
SOLID lowenstein-Jensen slopes - 6 weeks middlebrook agar plates- 2-3 weeks LIQUID MGIT- 5-15 days allows continuous monitoring of positive cultures |
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What is Xpert MTB/RIF? |
a two hour test that can detect TB bacilli determines RIF resistance |
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What is the treatment for TB? |
-Combination therapy isoniazid, rifampicin, ethambutol and pyrazinamide -Prolonged therapy minimum of 6 months to eradicate slow growing organisms |
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What is the prevention of TB?
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live attenuated BCG vaccine |
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What fungal infection may affect the respiratory tract? |
aspergillus fumigatus pneumocytosis jiroveci |
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What parasitic infections may affect the RT? |
ascaris stronyloides schistosoma echinococcus granulosus |
