A highly contagious 6FthOmyXOViFUS transmitted by GFOpISURUGIEN ~3 types of influenza: A, B, and C - Subtypes of influenza A (eg, HSN1, H1N1) Antigenic drift: Refers to small, gradual changes in surface proteins through point mutations. These small changes are sufficient to allow the virus to escape immune recognition, accounting for why individuals can be infected with influenza multiple times. “Antigenic shift: Describes an acute, major change in the influenza A subtype (significant genetic reassortment) circulating among humans. Leads to pandemics Yearly vaccination with inactivated influenza virus is currently recommended for all patients 26 months of age. Children 6 months to 8 years of age require two doses of the seasonal vaccine if they are receiving the vaccine for the first time. A high-dose flu vaccine is available for people 265 years of age or those who are immunocompromised -Acute viral infection of lungs and airways - onset fever, myalgia, chills, cough, sore throat, coryza, andweakness conjunctivitis, eye pain + photophobia Older adult patients may have atypical presentations characterized only by confusion. Rapid influenza tests have low sensitivity, and influenza is usually a clinical diagnosis. acute onset + cough + fever Leukopenia is a common finding. Antivirals such as 6Seltamivir or zanamivir are most effective when used within 2 days of onset and may shorten the duration of infection by 1 to 3 days. Severe primary viral pneumonia with ARDS/ secondary bacterial pneumonia = sinusitis = exacerbation of COPD and asthma can occur “croup, sotitis media, D&V, «myositis, encephalitis, Reye syndrome (encephalopathy + fatty degenerative liver failure failure).asc IE TANAMIVIR 5g ‘Treatment for influenza ‘Powder for orl inhalation Each bister contains: Zanamivir § mg wince x Rota | ae (4blsters per Rotadsk) AUST R 66962 PomPNEUMONIA Bacterial, fungal, or viral infection of the parenchyma of the lung. +Classic presentation: Acute onset of fever, productive cough (purulent yellow-green sputum or hemoptysis), dyspnea, night sweats, and pleuritic chest pain . Symptoms may be subtle in immunocompromised/older adult patients. Atypical presentations (gradual onset, dry cough, headaches, myalgias, sore throat, Gl symptoms) can be seen with viral pneumonias and infections with fastidious organisms(Legionella pneumophila, Mycoplasma pneumoniae, C pneumoniae) sLung examination may show ! or bronchial breath sounds, rales, wheezing, egophony, signs of consolidation (reduced expansion, dull percussion, itactile vocal fremitus/vocal resonance, bronchial breathing), and a pleural rub + the beat iia diagnostic teat: xn *CXR does not reveal clear infiltrate but suspicion for pneumonia is high, a noncontrast CT of the chest can be obtained »Routine bloodwork (CBC, metabolic panel) should be obtained for all patients »For patients treated in the hospital, blood cultures and sputum Gram stain and culture are indicated , as well as respiratory viral testing, Legionella testing, and urine streptococcal antigen testing PATIENT TYPE Those with outpatient community-acquired Pneumonia, =65 years of age, otherwise healthy, no antimicrobials within 3 months >65 years of age or comorbidity (COPD, heart failure, renal failure, diabetes, liver disease, ethanol (EtOH) abuse) or antimicrobial use within 3 months Patients with community-acquired pneumonia requiring hospitalization ‘SUSPECTED PATHOGENS ‘pneumoniae, M pneumoniae, C pneumoniae, Hinfluenzae, viral S pneumoniae, H influenzae, aerobic gram-negative rods (GNRs1 €9, Ecol, Enterobacter, Klebsiella), S aureus Legionella, viruses ‘pneumoniae, H influenzae, anaerobes, aerobic GNRs, Legionella, Chlamydia EMPIRIC COVERAGE Amoxici local pneumococcal resistance is <25%) doxycycline, or macrolide (if Combination of amoxicillin’ clavulanate or cephalosporin + mac- rolide or doxycycline OR respiratory fluoroquinolone monotherapy Respiratory fluoroquinolone OR B-lactam + macrolide ‘Community-acquired pneumonia requiring ICU care Patients with hospital-acquired pneumonia ‘pneumoniae, Legionella, H influenzae, ‘anaerobes, aerobic GNRs, Mycoplasma, Pseudomonas GNRs (including Pseudomonas and Acineto- bacten), Saureus, Legionella, mixed flora B-Lactam + macrolide OR f-actam + fluoroquinolone ‘Antipseudomonal agent to start If structural lung disease is present, addi- tion of second antipseudomonal agent If patient is critically ill (in shock or requiring ventilatory support due to Pneumonia), the physician should use ‘two antipseudomonal agents plus an ant-MRSA agentCATEGORY ETIOLOGY Typical bacteria Streptococcus pneumoniae, H influenzae, Moraxella catarrhalis, Staphylo- coccus aureus, group A Streptococcus Atypical bacteria Legionella, M pneumoniae, C pneumoniae, Chlamydia psittaci Respiratory viruses —_ Influenza A and B, SARS-CoV-2 and other coronaviruses, rhinoviruses, parainfluenza viruses, adenoviruses CONDITIONS ETIOLOGY Alcohol use disorder S pneumoniae, Klebsiella, Acinetobacter, oral anaerobes Aspiration Enteric gram negatives and oral anaerobes coPD H influenzae, Moraxella catarrhalis, S pneumoniae, Pseudomonas, Legionella Exposure to animals Birds: Avian influenza, C psittaci. Birds or bats: Histoplasma cap- sulatum. Rabbits: Francisella tularensis. Farm animals: Coxiella burnetiid HIV S pneumoniae, H influenzae, Mycobacterium tuberculosis (partic- ularly in early infection), Pneumocystis jirovecii, Cryptococcus, Histoplasma, Aspergillus, atypical mycobacteria, Pseudomonas Recent travel Hotel or cruise: Legionella. Southwest United States: Hantavirus, Coccidioides. Southeast/East Asia: Burkholderia pseudomallei. Middle East: MERS coronavirus Structural lung disease Pseudomonas, Burkholderia cepacia, S aureus Postviral Staphylococcus, S pneumoniae, H influenzae Injection drug use S aureus, anaerobes, Mycoplasma tuberculosis, S pneumoniae Endobronchial obstruction S pneumoniae, H influenzae, $ aureus, anaerobesPneumococcal vaccine At-risk groups: * All adults > 65yrs old. Chronic heart, liver, renal, or lung conditions. * Diabetes mellitus not controlled by diet. © Immunosuppression, eg 4spleen function, AlDs, or on chemotherapy or prednis- olone >20mg/d, cochlear implant, occupation risk (eg welders), CSF fluid leaks. Vaccinate every 5yrs. cr: Pregnancy, lactation, tT°, previous anaphylaxis to vaccine or one of its com- ponents. / we FIGURE 2.14-17. Lobar pneumonia. Posteroanterior (A) and lateral (B) CXRs of a 41-year-old man with cough and shortness of breath show a left lower lobe opacity consistent with lobar pneumonia. Streptococcus pneumoniae was confirmed by sputum Gram stain and culture. oe: e wi Sed 2 ¥ ” 7 wt a” : at-* Sid Sie es FIGURE 2.14-18. Common pathogens causing pneumonia. (A) Staphylococcus aureus. These clusters of gram © cocci were isolated from the sputum of a patient who developed pneumonia while hospitalized. (B) Streptococcus pneumoniae. Sputum sample from a patient with pneumonia. Note the characteristic lancet-shaped gram ® diplococci. image A reproduced withClassification and causes Community-acquired pneumonia: (CaP) May be primary or secondary to under- lying disease. Typical organisms: Streptococcus pneumoniae (commonest), Hae- mophilus influenzae, Moraxella catarrhalis. Atypicals: Mycoplasma pneumoniae, Staphylococcus aureus, Legionella species, and Chlamydia. Gram-negative bacilli, Coxiella burnetii and anaerobes are rarer (?aspiration). Viruses account for up to 15%. Flu may be complicated by community-acquired MRSA pneumonia. Hospital-acquired: Defined as >48h after hospital admission. Most commonly Gram-negative enterobacteria or Staph. aureus. Also Pseudomonas, Klebsiella, Bacteroides, and Clostridia. Aspiration: Those with stroke, myasthenia, bulbar palsies, ‘consciousness (eg post- ictal or intoxicated), oesophageal disease (achalasia, reflux), or poor dental hygiene risk aspirating oropharyngeal anaerobes. Immunocompromised patient: Strep. pneumoniae, H. influenzae, Staph. aureus, M. catarrhalis, M. pneumoniae, Gram -ve bacilli and Pneumocystis jirovecii (for- merly named P. carinii, pp400-1). Other fungi, viruses (cmv, HSV), and mycobacteria. Severity 'cuRB-65' is a simple, validated severity scoring system.* 1 point for each of: Confusion (abbreviated mental test <8) Urea >7mmol/L Respiratory rate >30/min BP <90 systolic and/or 60mmHg diastolic) Age 265. 0-1, Po antibiotic/home treatment; 2, hospital therapy; 3, severe pneumonia indicates mortality 15-40%—consider ITu. It may ‘underscore’ the young—use Clinical judgement. Other features increasing the risk of death are: comorbidity; bilateral/multilobar; RO2 <8kPa.Table 4.2 Empirical treatment of pneumonia (check local policy) at arlts PUT EU Community-acquired Mild not Streptococcus pneumoniae previously & Haemophilus influenzae CURB 0-1 Moderate CURB 2 Severe CURB >3 Atypical Streptococcus pneumoniae Haemophilus influenzae Mycoplasma pneumoniae As above Panton-Valentine Leukocidin-producing Staph. aureus (PVL-SA) Legionella pneumophilia Chlamydophila species Pneumocystis jirovecii Hospital-acquired Gram-negative bacilli Pseudomonas Anaerobes Aspiration Streptococcus pneumoniae Anaerobes Neutropenic patients Gram-positive cocci Gram-negative bacilli Fungi (p17) details: pp386-7) Oral amoxicillin 500mg-1g/8h or clarithro- mycin 500mg/12h or doxycycline 200mg, loading then 100mg/day (initially 5-day course) Oral amoxicillin 500mg-1g/8h + clarithromycin 500mg/12h or doxycycline 200mg loading then 100mg/12h Tf 1V required: amoxicillin 500mg/8h + clarithromycin 500mg/12h (7-day course) Co-amoxiclav 1.2g/8h Iv or cephalosporin IV (eg cefuroxime 1.5g/8h Iv) AND clarithromy- cin 500mg/12h Iv (7 days) Add flucloxacillin + rifampicin if Staph sus- pected; vancomycin (or teicoplanin) if MRSA suspected. Treat for 10d (14-21d if Staph, Legionella, or Gram -ve enteric bacteria suspected) Seek urgent help. Consider adding Iv linezolid, clindamycin, and rifampicin Fluoroquinolone combined with clarithro- mycin, or rifampicin, if severe. See pl68 Tetracycline High-dose co-trimoxazole (pp400-1) Aminoglycoside Iv + antipseudomonal penicillin Iv or 3rd-generation cephalosporin IV (p387) Cephalosporin Iv + metronidazole Iv Aminoglycoside Iv + antipseudomonal peni- cillin Iv or 3rd-generation cephalosporin Iv Consider antifungals after 48hGram-positive cocci Staphylococci are skin/nasal commensals in ~80% of adults use beta-lactam whenever possible 1-Coagulase-negative staphylococci: eg Staphylocoectis epidermidis are less virulent. Pathogenicity is likely only if there is underlying immune system dysfunction or foreign material (prosthetic valve/joint, lV line, PD catheter, pacemaker). 2-Staphylococcus aureus is coagulase positive: 1 Toxin release causes disease distant from infection. Includes: + scalded skin syndrome—bullae and desquamation due to epidermolytic toxins (no mucosal disease, .skin loss compared to toxic epidermal necrolysis) + preformed toxin in food—sudden D&V + toxic shock—fever, confusion, rash, diarrhoea, :BP, AKI, multiorgan dysfunction. Tampon associated or occurs with (minor) local infection #2 Local tissue destruction: impetigo, cellulitis, mastitis, septic arthritis, osteomyelitis, abscess, pneumonia, UTI. «3 Haematogenous spread: bacteraemia, endocarditis, ‘metastatic’ seeding. positive culture from relevant site of infection *Staph. aureus which produces — or an altered enzyme responsible for cell wall formation, will be resistant to beta-lactam antibiotics (penicillins, cephalosporins, carbapenems, =MRSA : meticillin-resistant Staph. aureus , it is defined by stability to metici =VISA : vancomycin-intermediate Staph. aureus =VRSA: vancomycin-resistant Staph. aureus +Risk factors for colonization include: antibiotic exposure, hospital stay, surgery, nursing home residence. Treatment of infection (not colonization): vancomycin (for MRSA), teicoplanin. Oral agents with activity against MRSA include clindamycin, co-trimoxazole, doxycycline, linezolid. Prevention: surveillance, barrier precautions, hand-hygiene, decolonization (mupirocin2%, chlorhexidine, tea tree oil), antimicrobial stewardship PAT 7 et toe.