Diseases of the Respiratory System

Question 1

Normal Microbiota of the Respiratory System

Answer 1

suppress pathogens by competitive inhibition in upper respiratory system;

upper:
Haemophilus sp;
Veillonella sp;
S. aureus;
G. positive diphtheroids

Question 2

Upper Respiratory Tract Infections

Answer 2

pharyngitis (Strep throat; diphtheria);
sinusitis and otitis media;
laryngitis;
tonsillitis;
epiglottitis

Question 3

Strep Throat

Answer 3

inflamed mucous membranes of the throat;
inflammation of tonsils (w/ bacteria present), rheumatic fever, and sore throat;
tender, swollen lymph nodes;
headache;
loss of appetite and nausea;

causative agent: Streptococcus pyogenes;

virulence factors: resilience to phagocytosis;

streptokinases: lyse fibrin clots;

streptolysins: cytotoxic to tissue cells, RBCs and protective leukocytes;

incubation time: 92 hours (for symptoms to develop);
once infected , can pass the infection for up to 2 to 3 weeks even w/ no symptoms;

treatment: penicillin V

Question 4

Viral Upper Respiratory Tract Infection

Answer 4

common cold;

causative agents:
over a 100 types of rhinoviruses (30-50%; positive sense ssRNA);
viruses that cause similar symptoms;
coronaviruses (10-15%; can hide from immune response due to small size and attachment to deep parts of nasal cavities; symptoms: cough, runny nose, nasal congestion and a sore throat; treatment: symptomatic relief)

Question 5

Bacterial Lower Respiratory Infections

Answer 5

bacterial pneumonias:
pneumococcal;
mycoplasmal;
klebsiellas;

other:
plague;
chlamydial;

Legionnaire’s;

TB;

Whooping cough;

Inhalational Anthrax

Question 6

Pneumococcal Disease

Answer 6

inflammation of lung w/ accompanying alveoli fluid buildup;

causative agent: Streptococcus pneumoniae (about 90% of all bacterial pneumonias);

symptoms:
high fever;
difficulty breathing;
chest pain;
lungs have reddish appearance due to dilated blood vessels

Question 7

Streptococcus pneumoniae

Answer 7

constant inflammation because a capsule makes it difficult to phagocytose;
sputum is often rust-colored from blood coughed up from the lungs;

diagnosis: culture of Gram+ diplococci from sputum that is optochin sensitive;

treatment: penicillin. macrolides, fluoroquinolones;

prevention: usually for children and elderly patients

Question 8

Rheumatic Fever (Post Strep Infection)

Answer 8

inflammatory disease following a strep infection;

causative agent: Streptococcus pyogenes;

develops two to three weeks after infection;

cross-reactivity of antibody to heart, joints, skin, and brain;

treatment: anti-inflammatory agents

Question 9

Klebsiellal Pneumoniae

Answer 9

causative agent: Klebsiellal Pneumoniae (G- rod);

symptoms: cough, fever, chest pain; destroys lungs (currant jelly sputum (blood);

associated w/ alcoholism, AIDS, very young;

diagnosis: isolation, special media for nutritional requirements;

treatment:
cephalosporins (often resistant to multiple antibiotics);
surgical clearing is often needed after patient is started on antimicrobial agents

Question 10

Tuberculosis

Answer 10

causative agent: Mycobacterium Tuberculosis;
chronic infection of lower respiratory tract;

symptoms: low grade fever; chronic cough; tiredness; night sweat; weight loss; green/bloody sputum;

inactive:
organism growing in lung but no symptoms;
bacteria live inside of macrophages = tubercules;
necrotic tissue held by calcifying;
when the tubercules rapture, infection is re-activated;

active:
macrophages spread through bloodstream to other tissues where secondary lesions can develop (kidneys, bone marrow, spinal cord);

treatment:
antibiotics to kill bacteria: rifampicin and isoniazid;

60% of death in untreated