Lower Respiratory Tract Infections PDF

Lower respiratory tract infections Prof. Dr. Volkan Korten Marmara University School of Medicine Department of Infectious Diseases  Lower respiratory tract infections Acute bronchitis Bronchiolitis Chronic bronchitis and acute infectious exacerbations Pneumonia ...

Lower respiratory tract infections Prof. Dr. Volkan Korten Marmara University School of Medicine Department of Infectious Diseases  Lower respiratory tract infections Acute bronchitis Bronchiolitis Chronic bronchitis and acute infectious exacerbations Pneumonia  Acute bronchitis A self-limited inflammation of the bronchi due to upper airway infection, which is most often viral. Patients present with a cough lasting more than five days (typically one to three weeks) Diagnosis is based upon the history and physical examination 60-80% of patients are still given antibiotics. Empiric antibiotic therapy is not recommended. acute bronchitis we shouldnt give empiric antibiotic therapy  Acute bronchitis Most often associated with respiratory viruses, common cold viruses, – rhinovirus – coronavirus – parainfluenza, – respiratory syncytial virus more invasive of the lower respiratory tract – Influenza A and B – human metapneumovirus Nonviral causes of acute bronchitis – Bordetella pertussis – Mycoplasma pneumoniae – Chlamydophila (formerly Chlamydia) pneumoniae  Pathogenesis Some viruses, such as influenza, routinely invade the lower airway. This may not be the case with a common cold virus such as rhinovirus; in such infections, various inflammatory mediators may play an important role in pathogenesis Attacks of acute bronchitis may be increased by exposure to cigarette smoke and air pollutants  Symptoms and signs (1) Cough – In the usual cold and influenzal illness, nasal and pharyngeal complaints subside after 3 or 4 days, whereas the cough tends to persist and to achieve greater prominence – acute bronchitis is suggested by the persistence of cough for more than five days – Acute infectious bronchitis - 45% of patients were still coughing 2 weeks after presentation and 25% were still coughing after 3 weeks. Airway hyperreactivity may last five to six weeks – typically nonproductive - prolonged in cigarette smokers  Symptoms and signs (2) Burning substernal pain Rhonchi and coarse rales may be heard Influenza virus, adenovirus, and M. pneumoniae infections are commonly associated with fever, unusual in adults with bronchitis associated with cold viruses  Pertussis Bordetella pertussis and B. parapertussis, the etiologic agents of whooping cough The incidence of pertussis has increased worldwide over the past 15 to 20 years Patients with partial immunity from prior immunizations often have atypical cases that may resemble viral bronchitis. Patients with paroxysms of coughing and a cough of at least two weeks duration without an apparent cause may be appropriate for testing.  Influenza cough, purulent sputum, fever, and constitutional complaints during the influenza season. treatable with neuraminidase inhibitors (oseltamivir or zanamivir), although these drugs must be given within 48 hours of symptom onset for demonstrable clinical benefit- reduce symptom duration by about one day. An EIA rapid antigen test for influenza virus can be done on site, available within one hour - sensitivity of 60 to 90 % and specificity of 70 to 90 % or PCR  Treatment Symptomatic and is directed primarily at the control of cough – codeine and dextromethorphan – nonsteroidal anti-inflammatory drugs Apparent bronchospastic component - β2- adrenergic bronchodilators Antibiotics are not recommended M.pneumoniae and C.pneumoniae – newer macrolide, tetracycline, FQ Influenza - neurominidase inhibitors (oseltamivir or zanamivir) – Prevention: Vaccine, pre and postexposure prophylaxis  Bronchiolitis acute viral lower respiratory tract illness occurring during the first 2 years of life acute onset of wheezing and hyperinflation commonly associated with cough, rhinorrhea, tachypnea, and respiratory distress. Respiratory syncytial virus (RSV) - the major pathogen parainfluenza viruses, adenoviruses, rhinoviruses, and M. pneumoniae  Diagnosis and treatment characteristic clinical and epidemiologic findings. viral isolation from respiratory secretions, preferably from a nasal wash Rapid viral diagnostic techniques (viral antigen in the respiratory secretions within hours - IFA, ELISA, DNA-RNA hybridization, PCR), Good supportive care, oxygen, bronchodilating agents, corticosteroid Ribavirin aerosol for RSV  Acute Exacerbations of Chronic Bronchitis (AECB) increasing cough infection (viral) and dyspnea infection (bacterial) allergy sputum has non- infectious irritants changed in color – environmental increased in pollutants (dust or amount fumes), – cigarette smoking  AECB - causative etiologic agents Haemophilus influenzae % parainfluenzae ~ 50 Moraxella catarrhalis Streptococcus pneumoniae 30 ® 10-15 P.aeruginosa ve K.pneumoniae