caused by a parainflenza virus

causes hoarseness and a burning retrosternal pain

dry cough, inspiratory stidor ("crowing" or croup)

Diptheria

(Corynebacterium diptheriae)

can colonize pharynx, larynx, nose, genital tract, skin

bacteria does not invade deep tissues

toxin destroys epithelial cells and polymorphs

ulcer forms w/ false membrane of necrotic exudate and soon becomes dark and malodorous w/ bleeding

bull neck, constitutional upset (fever, pallor, exhaustion), myocarditis, polyneuritis (CN IX=soft palate paralysis and regurgitation of fluids)

Toxic fragment B: carboxy end, "binding" fragment

Toxic fragment A: amino end; formed by protease cleavage & reduction of disulfide bonds; inactivates EF-2 by ADP-ribosylation-->inhibits protein synthesis

can be life-threatening (nasopharyngeal is most severe form); tx w/ antitoxin + penicillin/erythromycin

dx is clinical; confirmed by isolation and (+) Elek test

Whooping cough/pertussis

(Bordatella pertussis)

organisms are spread by air-borne droplets and attach to ciliated respiratory mucosa

toxins: pertussis toxin, adenylate cyclase toxin, tracheal cytotoxin, endotoxin

catarrhal illness followed by dry non-productive cough

cough becomes paroxysmal (series of short coughs producing copious mucous) follwed by a whoop of inspiratory air

tx with erythromycin (penetrates repiratory mucosa)

inflammatory condition of the tracheobronchial tree usually caused by rhinoviruses, coronaviruses, influenza virus, adenoviruses, or M. pneumoniae

influenza virus infxn = extensive, leaves host prone to secondary bacterial infxn

M. pneumoniae = organisms attach to bronchial mucosal epithelium and release of toxic substances causes sloughing of affected cells; 4 year cycle, occuring 2 yrs after Olympic games; dry cough; tx with tetracyclines or macrolides

acute infxn is viral, chronic infxn is bacterial

cough and excessive mucus secretion in the tracheobronchial tree

Streptococcus pneumoniae, unencapsulated H. influenzae

disease of childhood, usually under 2 yrs

fine bore of bronchioles makes inflammation severely restrictive for air passage

infxn results in necrosis of the epithelial cells, leading to peribronchial infiltration and potentially interstitial pnemonia

75% caused by respiratory syncytial virus (RSV), remainder is viral

paramyxovirus that causes bronchiolitis and pneumonia in infants; has group A and group B strains

surface spikes bear G protein for cell attachment and

F (fusion) protein for viral entry and syncytia formation

transmitted by air droplets, hands; winter outbreaks

infants develop cough, tachypnea, and cyanosis

young children, adults = cold-type illness, otitis media

CMI response is essential for clearance

Dx by immunofluorescence or ELISA of nasopharyngeal aspirates, PCR better for throat swabs

Tx is mainly supportive (hydration, bronchodilateors, oxygen if needed), ribavirin, or prophylactic palivizumab 

caused by Sin Nombre virus (SNV), a New World hantavirus found in the deer mouse of North America

flu-like symptoms due to viral invasion of pulmonary capillary endothelium, which increases vascular permeability and causes fluid to pour into the lungs

can result in second pulmonary edema, hypotension, and cardiogenic shock

transmitted by inhalation of infected rodent feces, saliva, or urine

Old world strain causes hemorrhagic fever with renal sydrome

disease due to aberrant immune responses by SNV-infected endothelial cells

involvement of a distinct region of the lung

plymorph exudate is formed in response to infection clots in the alveoli and renders them solid

may spread until constrained by anatomical barriers

diffuse patchy consolidation

often a result of pathology originating in the small airways

invasion of the lung interstitium

particularly characteristic of viral infections

necrotizing pneumonia

cavitation and destruction of the lung parenchyma

pneumonia that is NOT caused by Strep. pneumoniae

general and respiratory symptoms

unresponsive to penicillin or ampicillin

causes include Mycoplasma pneumoniae, Chlamydophila pneumoniae, Chlamydophila psittaci, Legionella pneumophila, Coxiella burnetti

dx by serology rather than culture for detection of high titers of specific antibodies

In the morning before breakfast

Essential to ensure sputum collection and not just saliva

viral cause of lower respiratory tract disease, croup, and pneumonia in children

hemagglutinin and neuraminidase are on one kind of spike; fusion proteins are on the other type

spread by respiratory droplets

viral cause of pharyngitis, croup, otitis media, bronchiolitis, and pneumonia

dx by detection of antigens in respiratory washings followed by viral culture or real-time PCR

tx with ribavirin

less common viral cause of common-cold type illness in children

dx by detection of antigens in respiratory washings followed by viral culture or real-time PCR

tx with ribavirin

causes 5% of acute respiratory tract illness (lower and upper)

non-specific symptoms

types 3,4,7 cause outbreaks associated with crowding and stress (military recruits)

paramyxovirus responsible for spectrum of illness from mild infection to brochiolitis and pneumonia

peaks in winter months

closely related to RSV

most common in young children, elderly, and immunocompromised

symptoms include fever, runny nose, cough, sore throat, wheezing

accounts for up to 15% of respiratory tract infections

virus of the subfamily Parvoviridae 

minor cause of lower respiratory tract infxns

influenza strain that causes epidemics and occasional pandemics

animal reservoir in birds

orthomyxovirus with single-stranded RNA w/ H & N spikes

 restricted to coldest months of the year

transmission by respiratory droplets

virus attaches to sialic acid receptors on epithelial cells via the H glycoprotein of the viral envelope

cytokines released by damaged cells and infiltrating leukocytes cause chills, malaise, fever, muscle aches

dx by real-time PCR, typing requires sequence analysis

Type A only = rimantadine, amantadine

Type A and B = zanamivir, oseltamivir

caused by coronavirus

high fever, cough, shortness of breath/difficulty breathing

spread primarily through respiratory droplets

dx by viral-CoV RNA detection via PCR of respiratory samples

no specific tx; some success with ribavirin, corticosteroids, inferferons, protease inhibitors

can cause giant cell pneumonia

viral replication occurs in the lower respiratory tract, nasopharynx, and middle ear

causes fever, runny nose, conjuctivitis, cough, otitis media, Koplik's spots are seen

dx clinically, but can use IgM response detection, virus isolation, viral RNA detection

tx with ribavirin if severe, vitamin A; vaccine exists

caused by inhalation of Mycobacterium aerosols and dust

body reacts to infectious foci by forming tubercles (small granulomas consisting of epithelioid and giant cells; may become necrotic and caseous; radiopaque)

NOTE: nearly all pathology is due to the CMI response

Infection causes by lack of mycobacterium containment within tubercles

Instead, invade the bloodsteam to cause disseminated disease

necrotizing pneumonia

most common cause is aspiration of respiratory or gastric secretions as a result of altered consciousness

Bacteroides and Fusobacterium anaerobes

swinging fever, copious, malodorous sputum production

tx with metronidazole for 2-4 months

Common complication of pneumonia

Accumulation of fluid between the pleural layers

demonstrated radiologically

tx drainage of fluid, potentially antibiotics

Common complication of pneumonia

Accumulation of purulent exudate between the pleural layers

Detection not always possible radiologically

Tx: drainage of pus, eradication of infection, lung expansion

fungus that can cause:

allergic bronchopulmonary aspergillosis - allergic response to fungal antigen in the lungs; occurs in asthmatics

aspergilloma - growth of fungal ball in pre-existing lung cavity, forming a mass of entangled hyphae

disseminated aspergillosis - fungal invasion from the lungs

Tx: difficult, but aims to improve neutrophil count

atypical fungus that causes pneumonia in AIDS pts

infection spreads by droplet transmission

three developmental forms: trophic, precyst (sporocyst), cyst (spore case)

spores are released when the cysts rupture

causes an interstitial pneumonitis with plasma cell infiltration

Nematodes (Ascaris, hookworms; transient pneumonitis)

Schistosome larvae (mild symptoms)

Filarial nematodes (Wuchereria or Brugia) microfilariae (tropical pulmonary esoinophilia/Weingarten's syndrome)

Strongyloides (pulmonary eosinophilia)

Echinococcus granulosus (hydatid cysts in lungs)

Entamoeba histolytica (rarely)

Paragonimus westermani (oriental lung fluke; acquired by eating crustaceans containing metacercariae)