Respiratory Infections PDF

 The respiratory system serves a vital function: RESPIRATORY TRACT: Upper respiratory Passageways that carry AIR tract Structurally divided into UPPER Lower...

 The respiratory system serves a vital function: RESPIRATORY TRACT: Upper respiratory Passageways that carry AIR tract Structurally divided into UPPER Lower and LOWER tracts respiratory tract Upper Respiratory System, Sinuses, Ears FUNCTIONS: Ciliated membranes Air filled spaces Ciliated membranes and hairs Upper Respiratory System, Sinuses, Ears Ducts Ears to pharynx Cell and chemicals Mucous of upper respiratory system contains antimicrobials  Lower Respiratory System Vocal cords; Trachea, bronchi, bronchioles, Major respiratory epiglottis alveoli; protective membranes muscle  Lower Respiratory System Contraction and relaxation of the diaphragm Within alveoli, O2 enters the blood, CO2 diffuses from capillaries into alveoli Normal Microbiota of Respiratory System NOSE NASAL CAVITY PHARYNX Diphtheroids, Haemophilus Staphylococcus aureus, Staphylococcus spp., Diphtheroids Diphtheroids Streptococcus pneumoniae  Bacterial Diseases of the URT, Sinuses, Ears STREPTOCOCCAL RESPIRATORY DISEASE Depends on infection site, strain, host immunity 1. Streptococcal pharyngitis “strep throat” Inflammation Laryngitis Bronchitis 2. Scarlet fever “scarlatina” Strain carries _____________________ toxins Rash spreads from chest across body → strawberry red  Bacterial Diseases of the URT, Sinuses, Ears COMPLICATIONS  3. Rheumatic Fever Inflammation Damage of heart valves and muscle Autoimmune PATHOGEN: Streptococcus Differentiated by: antigens, hemolysis, physiological properties Group A Group B Group C S. pyogenes S. agalactiae S.equisimilis  Bacterial Diseases of the URT, Sinuses, Ears VIRULENCE FACTORS: M protein, capsule, kinase, pyrogenic toxins TRANSMISSION: Respiratory droplets DIAGNOSIS, TREATMENT, PREVENTION: Requires serological testing Antibacterial drug treatment Host produces antibodies against M protein  Bacterial Diseases of the URT, Sinuses, Ears DIPHTHERIA Sore throat → OOZING fluid Fluid thickens into a ___________________________________ PATHOGEN: Corynebacterium diphtheriae Divides by _________________________________ VIRULENCE: diphtheria toxin TRANSMISSION: respiratory droplets, skin contact Immune Immunocompromised Nonimmune Antitoxin, immunization, antibiotics  Bacterial Diseases of the URT, Sinuses, Ears SINUSITIS and OTITIS MEDIA PATHOGENS: Streptococcus pneumoniae S. pyogenes Staphylococcus aureus Haemophilus influenzae Given opportunities TREATMENT: Antibacterial drugs Immunization  Viral Diseases of UPPER Respiratory System COMMON COLD MALAISE PATHOGENS: Most common in genus ____________________________(Corona-, Adeno-) 33°C mucous membranes → infect neighbours Extremely infective... via contaminated fomites Antihistamines, decongestants, pain relievers, rest, fluids  Bacterial Diseases of LOWER Respiratory System BACTERIAL PNEUMONIAS Lungs Pleurisy Numerous organisms – ____________________________ most serious 1. PNEUMOCOCCAL PNEUMONIA Streptococcus pneumonia Adhesin, capsule, phosphorylcholine, IgA protease Sputum smears  Bacterial Diseases of LOWER Respiratory System 2. PRIMARY ATYPICAL PNEUMONIA Fever, headache, sore throat, _________________________________ Unproductive cough Spread through nasal secretions PATHOGEN: Mycoplasma pneumoniae Aerobic – lacks cells walls – very small Gram positive Adhesive protein – binds and stops cilia TREATMENT: antibiotics → no vaccine  Bacterial Diseases of LOWER Respiratory System 3. KLEBSIELLA PNEUMONIA Cough, fever, chest pain, ____________________________________ PATHOGEN: Klebsiella pneumoniae Gram-negative Inhalation kills alveolar cells → invades blood → bacteremia → death The susceptible: alcoholics, elderly, AIDS patients, very young TREATMENT: Supportive care, antimicrobials may work  Bacterial Diseases of LOWER Respiratory System LEGIONNAIRE’S DISEASE “Legionellosis” Common features of pneumonia, complications 50 % mortality in untreated PATHOGEN: Legionella pneumophila – ______________________________ Tolerates: heat, chlorination Antimicrobial drugs  Bacterial Diseases of LOWER Respiratory System TUBERCULOSIS Minor cough, mild fever Difficulty breathing, weight loss, blood sputum PATHOGEN: Mycobacterium tuberculosis Gram-positive, lipid cell wall Unique ___________________________ 1. PRIMARY TUBERCULOSIS – formation of _________________________ Bacteria can remain DORMANT → ________________________________________ Infectious dose ~10 cells Asymptomatic – mild Triggers Tuberculous inflammation cavity  Bacterial Diseases of LOWER Respiratory System TUBERCULOSIS 2. SECONDARY TUBERCULOSIS (Reactivated) 3. DISSEMINATED TUBERCULOSIS (consumption) Macrophages carry bacteria through body RISK FACTORS: poor nutrition/immunity, crowds, alcohol, drugs DIGANOSIS: Tuberculin skin test Chest X rays Sputum smear TREATMENT: Combination of drugs – MDR and XDR Researchers developing a subcutaneous implant  Bacterial Diseases of LOWER Respiratory System PERTUSSIS “Whooping Cough” Resembles common cold... ___________________ may appear, death possible PATHOGEN: Bordetella pertussis Adhesins Toxins: 4 – mucous, defenses, blood vessels, cilia PATHOGENESIS: highly ________________________ (inhaled) Survives in phagocytes SUSCEPTIBILITY: children < 5 yrs. Reemerging disease...  Bacterial Diseases of LOWER Respiratory System PERTUSSIS progression... 1. INCUBATION 2. CATARRHAL Cold-like symptoms 3. PAROXYSMAL Coughing spells 4. CONVALESCENT Supportive treatment DTaP vaccine  Bacterial Diseases of LOWER Respiratory System INHALATION ANTHRAX Cold or flu...rapid progression PATHOGEN: Bacillus anthracis Endospore-forming Capsule Secretes _________________________________ – trigger edema Aggressive treatment Antimicrobials PLUS drainage Monoclonal antibody Vaccine Viral Diseases of LOWER Respiratory System INFLUENZA Pandemic in winter of 1918-1919 SIGNS and SYMPTOMS: Day 0: infection Day 1: incubation Day 2: symptomatic Day 7-14: recovery Respiratory route → lung cells die→ 2° infections Viral Diseases of LOWER Respiratory System INFLUENZA Orthomyxoviruses → Type A and B Envelope HEMAGGLUTININ (HA) NEURAMINIDASE (NA) Viral Diseases of LOWER Respiratory System INFLUENZA ANTIGENIC DRIFT: single strain mutates ANTIGENIC SHIFT: genomes of different A strains mix A. DRIFT A. SHIFT Strains named: A/Singapore/1/80 (H1N2) Common names Viral Diseases of LOWER Respiratory System in late 2019….. SARS-CoV-2 Zoonotic in Single strand RNA Enveloped Intermediate animal Spike protein _______________________ ACE-2 Receptor Viral Diseases of LOWER Respiratory System in late 2019….. SARS-CoV-2 SIGNS & SYMPTOMS: TRANSMISSION: 1◦ Respiratory droplets Direct contact Airborne TREATMENT/PREVENTION: Supportive care Antivirals – stop viral multiplication MAbs– neutralize virus mRNA vaccine  Viral Diseases of LOWER Respiratory System RESPIRATORY SYNCYTIAL VIRUS (RSV) INFECTION Infants: mild URT to respiratory failure Older children and adults: cold-like symptoms PATHOGEN: Pneumovirus genus Syncytia to form in lungs Plugs bronchioles Contact with nasal and oral secretions TREATMENT: Supportive care RSV prophylaxis (high-risk infants) Vaccine (LTC, >60 yo)  Mycoses of the LOWER Respiratory System BLASTOMYCOSIS Flu-like symptoms Cutaneous, painless lesions 30 % cases – spreads PATHOGEN: Blastomyces dermatitidis Dimorphic Inhale spores → multiply in lungs → lesions → respiratory failure → death Treat with Amphotericin B  Mycoses of the LOWER Respiratory System HISTOPLASMOSIS 95 % cases: asymptomatic 5 % cases: severe cough, bloody sputum, skin lesions AIDS patients PATHOGEN: Histoplasma capsulatum Dimorphic Found in soil (from bats and bird feces) Inhale spores → alveolar macrophages → disseminates Treat with Amphotericin B  Mycoses of the LOWER Respiratory System PNEUMOCYSTIS PNEUMONIA (PJP) SIGNS and SYMPTOMS: Increasingly difficult to breathe, hypoxia, mild anemia, fever PATHOGEN: Pneumocystis jirovecii Life-threatening opportunistic Attaches to lungs, increased permeability Carriers can spread organism via respiratory droplets Multiplies rapidly immunocompromised Treatment and maintenance therapy using trimethoprim and sulfamethoxazole (TMP-SMX)  Structure and Function Components of the Upper Respiratory Tract (URT) Components of the Lower Respiratory Tract (LRT) Human host innate defenses, location of normal microbiota URT Diseases Bacterial D. – streptococcal diseases, diphtheria, sinusitis, otitis media Viral D. – common cold LRT Diseases Bacterial D. – pneumonia (3), Legionnaire’s, TB, Pertussis, Anthrax Viral D. – influenza, SARS-CoV-2, RSV Fungal D. – blastomycosis, histoplasmosis, pneumocystis pneumonia For each D. → pathogen, pathogenesis, transmission, treatment