22 - Respiratory System Infections

2 classes of respiratory system infections:

Where are upper respiratory bacteria usually found?

Symptoms - Difficulty Swallowing, Fever, Red throat with pus patches, Enlarged lymph nodes, Recovery 1 weekCausative
Agent - Stretpococcus Pyogenes, Gram +, Coccus in Chains
Pathogenesis - Wide variety of illness including Scarlet Fever and Quinsy
Epidemiology - Respiratory droplets 2 - 5 ft, only humans, nasal more potent than pharyngeal, more common in winter or spring
Prevention - No vaccine, adequate ventilation, Avoid crowds, Sore throat w/fever should be cultured
Treatment - Penicillin or Erythromycin in 10 days

Symptoms - mild sore throat, slight fever, neck swelling
Causative Agent - Corynebacterium diptheria, variably shaped, Gram +
Pathogenesis - Exotoxin released into bloodstream, A chain attaches to host cell membrane, B chain becomes enzyme that inhibits protien synthesis
Epidemiology - Inhalation, humans primary reservoirPrevention - immunization
Treatment - Penicillin and Erythromycin, 1 in 10 die with treatment

Symptoms - Increased tears and redness, swelling eyelids, large amounts
of pus, sensitivity to bright light.
Causative Agents - Haemophilus
Influenza, Stretpococcus Pneumonia
Pathogenesis - Airborne
respiratory droplets
Epidemiology - Common among school children,
crowded environments
Prevention - Handwashing, don't touch or rub
eyes,
Treatment - Antibacterial eyedrops or ointments

Symptoms - Pain, pressure, tenderness over sinus cavaties, headache,
severe malaise
Causative Agents - Mycoplasma Pneumonia, Streptococcus
Pyogenes, Staphylococcus Aureus
Pathogenesis - Infection of
nasopharynx, spreads up towards sinuses
Epidemiology - Adults and
older children due to move developed sinuses
Prevention - None
Treatment
- Treat symptoms

Symptoms - Extreme ear pain, mild fever, vomitting, rupture of ear drum
Causative
Agent - Mycoplasma pneumoniae, Streptococcus pyogenes, Staphlococcus
aureus
Pathogenesis - Infection moves to middle ear from from nasal
chamber, ear drum often bursts bringing immediate pain relief
Epidemiology
- Common before age 5
Prevention - Flu vaccine
Treatment -
Amoxicillin

Symptoms - Scratchy, mild sore throat, runny nose, cough and hoarseness,
NO FEVER, symptoms disappear in about a week
Causative Agent -
usually Rhinovirus, single stranded RNA genome
Pathogenesis - Virus
attaches in respiratory system, causing inflammation, which causes runny
nose, sneezing
Epidemiology - Humans only source, close contact with
infected person during 1st 2 - 3 days
Prevention - No vaccine
Treatment
- OTC meds may prolong symptoms instead of making them better. Let it
run its course

Symptoms - Runny nose, fever, Sore throat with pus on pharynx and
tonsils, enlarged/tender lymph nodes
Causative agent - Adenovirus,
non enveloped, double stranded DNA genome
Pathogenesis - Infects
epithelial cells, adenovirus 4 causes sore throat and lymphnode
enlargement, Adenovirus 8 causes eye infection
Epidemiology - Human
only carriers, Sporadic outbreaks in winter and spring
Prevention -
No vaccine
Treatment - No treatment

Symptoms - Cough, Chest pain, Fever, Sputum production, pale, pasty skin
Causative agent - Streptococcus Pneumoniae, Gram +, thick polysaccharide capsule
Pathogenesis - Breathed in, causes lung problems, poisoning of blood, can effect heart and cause meningitis
Epidemiology - 30% of healthy persons carry strain in their throat
Prevention - Vaccine gives immunity to 23 strains, Conjugate vaccine against 7 types available for infants
Treatment- Penicillin and Erythormycin if given early

Symptoms - Gradual onset, First fever, headache, muscle pain, fatigue,
Later dry coug and mucoid sputum
Causative Agent - Mycoplasma
pneumoniae, small, deformed, lacking cell wall
Pathogenesis - Small
infecting dose, attaches to receptors on epithelium, inflammation causes
thinkening of bronchial and alveoloar walls causing difficulty
breathing
Epidemiology - Aerosolized droplets from respiratory
secretions, accounts for 1/5th of bacterial pneumonias
Prevention -
No practical prevention
Treatment - Antibiotics, penecillin is ineffectual

Symptoms - Runny nose, uncontrolable coughing
Causative agent -
Bordetella pertussis, small, aerobic, gram negative bacillus
Pathogenesis
- Enters respiratory tract, attaches to ciliated cells, causing cough
Epidemiology
- Resperatory droplets, most infectious during runny nose period,
common in infants
Prevention - Vaccination of infants
Treatment -
Erythromycin if given early

Symptoms - Slight fever w/night sweats, weight loss, chonic cough,
bloody sputum
Causative Agent - Mycobacterium tuberculosis, gram
positive, slender bacillus, slow growing
Pathogenesis - Inhalation of
airborne organisms, taken up by pulmonary macrophages in the lungs,
carried to lymph nodes, 2 weeks later, severe immune response occurs,
causes death of tissue resulting in "cheesy" material
Epidemiology -
10M americans infected, mostly non-white, elderly poor people, need as
little as 10 inhaled organisms
Prevention - No vaccine in US due to
TB test
Treatment - Antibiotic treatment given in cases of active
tuberculosis, 6 month therapy, 2 or more medications

Symptoms - short incubation, headache, fever, muscle pain, dry cough.
Symptoms besides fatigue may leave in 1 week.
Causative agent -
Influenza A Virus, single stranded RNA genome
Pathogenesis -
Respiratory secretions, attaches to cell via hemagglutinin spikes
Epidemiology
- Outbreaks occur Fall - Spring every year, Virus undergoes antigenic
drift, causing minor changes in spikes
Prevention - Vaccination
Treatment
- Antiviral medications Amantidine and Rimantidine

Symptoms - Acute fever, lower back muscle ache, nausea/vomitting,
diarrhea. Later shortness of breath, shock and death
Causative agent
- Hantavirus, single stranded RNA genome, enveloped, lifetime infection
in rodents
Pathogenesis - Inhalation of dust contaminated with
rodent urine, feces and saliva. Infects cells that line capillaries.
Inflammation in capillaries causes fluid to leak into the lungs. 40% of
patients die from shock.
Epidemiology - Emerging disease/recent
discovery, most cases occur west of MS river, outbreaks correlate to
increase in deer mouse population
Prevention - Minimizing exposure
Treatment
- None

123 known cases between 1996 - 2004
High mortality rate among infants
H5N1
avian virus
Vaccines currently being developed