PATHO - Respiratory System 2 (Infections)

Pneumonia

What is any infection of the lung parenchyma called?

Cough reflex

What host mechanism clears aspirated secretions by coughing?

Mucociliary apparatus

What airway mechanism removes mucus by coordinated beating?

Alveolar macrophage

What cell type performs phagocytosis in alveoli?

Pulmonary edema

What pulmonary condition provides fluid that breeds microbes?

Increased susceptibility

What occurs when systemic resistance of host is lowered?

Hot gas inhalation

What inhaled injury predisposes to pulmonary infections?

Cigarette smoking

What lifestyle factor injures ciliary function?

Altered sensorium

What neurologic state suppresses cough reflex?

Ciliary dysfunction

What genetic defect leads to impaired ciliary movement?

By clinical setting

How is pneumonia commonly categorized clinically?

50%

What percentage of pneumonia cases often lack isolated organism?

Procalcitonin

What test is more elevated in bacterial than viral pneumonia?

Spleen

What organ’s absence increases risk for encapsulated organisms?

Macrophage reservoir

What feature of the spleen clears encapsulated bacteria?

Streptococcus pneumoniae

What is the most common cause of community bacterial pneumonia?

Gram positive lancet

What is the Gram stain appearance of Streptococcus pneumoniae?

Haemophilus influenzae

What bacterium is pleomorphic and may have type b capsule?

Type b

Which Haemophilus influenzae serotype is most virulent?

Haemophilus influenzae

Which organism commonly causes acute exacerbations of chronic obstructive pulmonary disease?

Moraxella catarrhalis

What organism commonly causes exacerbations of chronic obstructive pulmonary disease in elderly?

Staphylococcus aureus

What organism causes secondary bacterial pneumonia after viral illness?

Klebsiella pneumoniae

What Gram negative bacillus produces thick mucoid blood-tinged sputum?

Pseudomonas aeruginosa

What organism is frequent in hospital-acquired pneumonia and cystic fibrosis?

Legionella pneumophila

What organism causes Legionnaires’ disease from aquatic reservoirs?

Mycoplasma pneumoniae

What organism spreads in closed communities and causes atypical pneumonia?

Urine antigen

What testing detects Legionella antigen in urine?

Polymerase chain reaction

What nucleic acid test detects Legionella DNA in sputum?

High fever

What symptom is a hallmark of acute bacterial pneumonia?

Mucopurulent sputum

What sputum color is typical in bacterial pneumonia?

Pleuritic pain

What pleural sign may accompany pneumonia chest pain?

Empyema

What serious intrapleural complication involves pus?

Bacteremic dissemination

What systemic spread can follow severe bacterial pneumonia?

Endocarditis

What complication involves infection of heart valves?

Suppurative arthritis

What complication involves purulent joint infection?

Extremes of age

What group of patients more often require hospitalization for pneumonia?

Immune deficiency

What underlying status increases pneumonia risk due to impaired defenses?

Lobar pneumonia

What pneumonia pattern involves an entire lobe consolidation?

Lobular pneumonia

What pneumonia pattern shows patchy basal consolidations?

Streptococcus pneumoniae

Which organism most commonly causes lobar pneumonia?

Congestion

What stage of lobar pneumonia is heavy, boggy, and congested?

Red hepatization

Which stage of lobar pneumonia resembles a liver in color?

Gray hepatization

Which stage of lobar pneumonia is grayish and fibrin predominant?

Resolution

Which stage involves enzymatic resorption and macrophage cleanup?

Bronchopneumonia

What type of pneumonia begins in bronchi and spreads to alveoli?

Whole lobe opacity

What radiographic sign corresponds to lobar pneumonia?

Focal opacities

What radiographic sign corresponds to bronchopneumonia?

Myalgia

What general symptom often accompanies viral pneumonias?

Ventilation perfusion mismatch

What ventilation problem often results from viral exudation?

Supportive care

What is the usual treatment approach for viral pneumonia?

Mononuclear cells

What inflammatory cell predominates in viral interstitial pneumonia?

Alveolar septa

What compartment is primarily involved in viral pneumonia?

Diffuse alveolar damage

What severe viral change can result in hyaline membrane formation?

Obliterative bronchiolitis

What lesion may viral infection cause in small airways leading to obstruction?

Adenovirus family

What viruses cause necrosis of bronchial and alveolar epithelium?

Hemagglutinin

What influenza protein mediates viral attachment to host cells?

Neuraminidase

What influenza protein facilitates release of new virions?

Antigenic drift

What process describes minor antigenic changes in influenza proteins?

Antigenic shift

What process describes major antigenic replacement producing new subtypes?

Antigenic drift

What antigenic event typically causes epidemics?

Antigenic shift

What antigenic event typically causes pandemics?

Cytotoxic T cells

What immune cells kill virus-infected host cells?

Young children and elderly

In which populations is human metapneumovirus most severe?

Reinfection common

What is the pattern of immunity after initial human metapneumovirus infection?

SARS-CoV-2

What coronavirus caused the 2019 pandemic?

Droplets

What is the dominant transmission route for coronaviruses?

Aerosols

What additional airborne route can transmit coronaviruses in enclosed spaces?

Anosmia

What symptom uniquely associated with SARS-CoV-2 is loss of smell?

Cytokine storm

What immune overreaction occurs in severe coronavirus infection?

TNF and IL-6

What two cytokines are characteristically elevated in severe coronavirus disease?

ACE 2

What host receptor does the spike protein bind?

Type II pneumocytes

On which alveolar cells is ACE2 highly expressed?

Diffuse alveolar damage

What epithelial change commonly occurs in COVID-19 lungs?

Microvascular thrombosis

What vascular lesion is prominent in COVID-19 compared with classic ARDS?

Acute fibrinous organizing pneumonia

What fibrinous pattern can occur in COVID lungs?

Lymphopenia

What systemic finding in severe COVID contributes to multi-organ damage?

During hospitalization

Where is hospital-acquired pneumonia contracted?

Staphylococcus aureus

Which organism is a common Gram positive cause in hospitals?

Pseudomonas aeruginosa

Which Gram negative organism frequently causes ventilator-associated pneumonia?

Mechanical ventilation

What device increases risk of hospital-acquired pneumonia?

Prolonged catheter use

What patient factor predisposes to hospital pneumonia via invasive devices?

Suppressed gag reflex

What patient condition predisposes to aspiration of gastric contents?

Gastric acid and oral flora

What mixture causes chemical and bacterial lung injury in aspiration?

Necrotizing pneumonia

What type of pneumonia commonly follows aspiration?

Right lung

Which lung is more often involved in aspiration pneumonia?

Polymicrobial organisms

What common microbiology pattern is found in aspiration cultures?

Lung abscess

What process produces necrosis and cavitation of lung tissue?

Bacteroides species

What anaerobic oral organisms commonly cause abscesses?

Streptococci

What common Gram positive cause can lead to lung abscess?

Foul smelling sputum

What typical sputum feature suggests lung abscess?

Clubbing

What chronic sign indicates long-standing pulmonary suppuration?

Cavitary lesion

What radiographic feature confirms lung abscess diagnosis?

Aspiration

What is a common predisposing event for right-sided lung abscesses?

Underlying carcinoma

What neoplastic condition must be excluded in elderly with abscess?

Histoplasma capsulatum

What organism causes histoplasmosis?

Inhalation of microconidia

How is Histoplasma capsulatum acquired?

Bird and bat droppings

What environmental material harbors Histoplasma?

Thin walled yeast

What microscopic form does Histoplasma show in tissue?

Blastomyces dermatitidis

What organism causes blastomycosis?

Thick double wall

What cell wall feature characterizes Blastomyces in tissue?