RESP-Pneumonia

What are the etiologies of lung abscesses (5)? What is the most common cause? Describe the typical presentation and responsible organism of a lung abscess caused by aspiration.

-Aspiration most common cause; tend to involve RLL caused by mixed oral flora -Anaerobic bacteria almost always present -Complication of particularly S. aureus or K. pneumoniae infection and associated with septicemia -Bronchial obstruction due to tumor or foreign body -Septic emboli from thrombophlebitis or infective endocarditis

Which members of the chlamydia species cause community acquired atypical pneumonia (3)?

-C. pneumoniae -C. psittaci -C. trachomatis

What are the clinical features of coccidioiodomycosis, histoplasmosis and blastomycosis? What type of fungi causes it? What kind of symptoms? Are there granulomas and hilar lymph nodes present? What immune response is critical for containg the infection? What disease does it resemble? What stains are necessary to differentiate them from TB and make a diagnosis?

-Caused by dimorphic fungi present in soil in endemic areas (C. immitis in West and Southwest, H. capsulatum and B. dermatitidis in Ohio, central Mississippi River valleys and Appalachian mountains) Isolated lung involvement in immunocompetent patients with acute "flu"-like symptoms and self-limiting primary pulmonary infection with granuloma(s) in lungs and hilar lymph nodes Chronic granulomatous cavitary pulmonary infection in patients with massive exposure or less robust immune response. Miliary disease without well-formed granulomas in multiple organs in immunocompromised patients Intact T cell-mediated immune response is critical for containing the infection Resembles tuberculosis; identification of the organisms by PAS or silver stain is necessary for diagnosis -Resembles tuberculosis

Which laboratory results come with a diagnosis of bacterial pneumonia? WBC count? Is the sputum gram postive or negative? If you see a negative blood culture can you eliminate pneumonia? What patterns will the chest x-ray show for lobar pneumonia? Bronchopneumonia? If there is severe involvement what will you see?

-Elevated peripheral blood WBC count with a left shift = increased neutrophils, with usually also increased number of young neutrophils (bands) -Sputum Gram stain positive (Note: S. pneumoniae occurs in normal pharyngeal flora) -Blood cultures positive in 20-30% patients X-ray: Lobar pneumonia: lobar or segmental consolidation Bronchopneumonia: patchy consolidation Pleural effusion, if severe involvement

List the organisms that cause hospital acquired (nosocomial) pneumonia (3).

-Enterobacteriaceae (Klebsiella spp, Serratia marcescens, Escherichia coli) -Pseudomonas spp -Staphylococcus aureus (usually MRSA = methicillin-resistant)

Which organisms cause pneumonia in patients with COPD ?

-H influenzae -M. catarrhalis Cause pneumonia in what patients?

List examples of opportunistic pulmonary pathogens (10).

-P. aeruginosa -Mycobacterium spp. -L. pneumophila -L. monocytogenes -CMV -HSV -P. jiroveci -Candida spp. -Aspergillus spp. -Cryptococcus neoformans

List the immunocompromized hosts in which pneumonia frequently occurs (4).

-Patients on immunosuppression for transplants -Cancer patients receiving chemotherapy or irradiation -HIV patients -Sick neonates or elderly

Staph aureus is linked with causing pneumonia in which conditions (2)?

-Post-viral superinfection -IV-drug users together with right-sided staphylococcal endocarditis

List the complications that can occur with lung abscesses (3).

-Pulmonary hemorrhage -Amyloidosis -Empyema

Community acquired atypical pneumonia. Where is inflammation confined to? What are the most common causes? (hint: a KEY fever)

-Respiratory distress is out of proportion to the clinical and radiological signs -Inflammation is predominantly confined to alveolar septa with clear alveoli (unless there is necrosis) -Most common causes: - Mycoplasma pneumoniae - Chlamydia spp. and Coxiella burnetti (Q-fever - Several viruses, including RSV, adenovirus (military recruits), influenza A and B (adults), and parainfluenza (children)

Which viruses are known to cause community acquired atypical pneumonia (7)?

-Respiratory syncytial virus -Parainfluenza -Influenza A and B -Adenovirus -SARS (coronavirus) -Varicella -CMV

What is the most common cause of CAABP? What is the usual distribution? What are the stages of morphology?

-S. pneumoniae is the most common cause -Distribution is usually lobar with intra-alveolar acute inflammatory cells -Morphologic stages: congestion, red hepatization, gray hepatization, resolution

Which organisms are linked with causing pulmonary abscesses and empyema as a result of a pneumonia infection (2)?

-Staphylococcus -Klebsiella

List the organisms that cause community acquired acute pneumonia (7). Which organism causes "classic" lobar pneumonia, but is also a common cause of bronchopneumonia, particularly in the elderly?

-Streptococcus pneumoniae: Causes "classic" lobar pneumonia, but is also a common cause of bronchopneumonia particularly in the elderly -Haemophilus influenzae -Staphylococcus aureus -Legionella pneumophila -Klebsiella pneumoniae -Pseudomonas spp -Moraxella catarrhalis

Which types of debilitated patients most commonly get aspiration pneumonia (2)? Which types of bacteria can cause a bacterial pneumonia to be superimposed on an aspiration pneumonia (2)? Describe the clinical features of aspiration pneumonia (2). List the complications of pneumonia (3).

-Unconscious (post-anesthesia and stroke patients) and Alzheimer patients -Anaerobic oral flora and Aerobic bacteria: Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa -Necrosis of bronchial epithelium and lung parenchyma is common with abscess formation. Fulminant course with high mortality -Pulmonary abscesses and empyema, Bacteremia, Organization (repair with fibrosis)

What is empyema and how does it differ from a lung abscess?

A collection of pus within a naturally existing anatomical cavity, such as the lung pleura. It must be differentiated from an abscess, which is a collection of pus in a newly formed cavity.

Image of a Pneumocystis jiroveci pneumonia. Note the characteristic foamy and granular lumps in bronchoalveolar lavage fluid. (MULTIPLE MYELOMA PATIENT RECEIVING STEROIDS) What stain is used to expose the organisms?

A crocotts silver stain can show the organisms.

Describe the epidemiology of bronchopneumonia. Which organisms most commonly cause bronchopneumonia (4)? Describe the microscopic features of bronchopneumonia.

Affects the young, old, and terminally ill. -Staphylococci -Streptococci -Haemophilus influenzae -Pseudomonas aeruginosa Acute inflammation of bronchioles and the surrounding alveoli.

Why are the classic stages of lobar pneumonia seldom seen in a clinical setting such that, microscopically, lobar pneumonia and bronchopneumonia look the same?

Antibiotics. It is more important to identify the causative agents.

Debilitated patients, Chemical pneumonia due to gastric acid, and Bacterial pneumonia superimposed all result in this type of pneumonia.

Aspiration pneumonia

Acute inflammation and consolidation of the lung due to a bacterial agent. Alveolar filling disease. Fever and chills. Productive cough with rusty (bloody early in pneumococcal pneumonia), or yellow-green sputum. Tachypnea. Pleuritic chest pain. Decreased breath sounds, rales, and dullness to percussion.

BACTERIAL PNEUMONIA

Staphylococci, Streptococci, Haemophilus influenzae, Pseudomonas aeruginosa and others. Scattered patchy consolidation centered around bronchioles. Usually bilateral, multilobar, and basilar. Affects the young, old, and terminally ill. Acute inflammation of bronchioles and the surrounding alveoli. What type of pneumonia?

Bronchopneumonia

What is anthracosis?

Coal workers' pneumoconiosis (CWP), colloquially referred to as black lung disease, is caused by long exposure to coal dust.

What do these cause? -Chlamydia species: C. pneumoniae, C. psittaci, C. trachomatis -Mycoplasma pneumoniae -Coxiella burnetti (Q FEVER) -Viruses: RSV, especially in young children, Parainfluenza, Influenza A and B, adenovirus, SARS (coronavirus), varicella, CMV, especially in immunocompromised patients, others

Community Acquired Atypical Pneumonia

Describe the following stages of lobar pneumonia: -Congestion -Red hepatization -Gray hepatization -Resolution

Congestion: Heavy, boggy, red, hyperemic lungs with many bacteria but few neutrophils. Red hepatization: Massive confluent alveolar filling with RBCs, neutrophils and fibrin. Grey hepatization: Disintegration of RBCs, fibrinopurulent exudate. Resolution: Macrophages mop up debris.

Image of the red hepatization stage of lobar pneumonia.

Cut surface of the affected lobe is dense, airless and homogeneously red.

Diffuse or Focal Lung Disease in HIV? CMV Pneumocystis Drug reactions Bacteria Aspergillus Cryptococcus Malignancy

Diffuse

What are cowdry inclusions?

Eosinophilic nuclear inclusions composed of nucleic acid and protein seen in cells infected with Herpes simplex virus, Varicella-zoster virus, and Cytomegalovirus. (Type A inclusions are seen with herpes).

Diffuse or Focal Lung Disease in HIV? -Gram-negative rods -Staph. Aureus -Aspergillus -Candida -Malignancy -Cryptococcus -Mucor -Pneumocystis -Legionella pneumophila

Focal

Image of Pneumocystis jiroveci pneumonia with diffuse alveolar damage. Consolidated parenchyma with cysts.

Holes in the upper right hand corner are cysts

CMV is especially linked with causing pneumonia in which type of patients?

Immunocompromised patients.

Atypical pneumonia. What part of the lung is involved? What patient group is it more common found in? Describe the chest film of someone with atypical pneumonia. What laboratory findings come with a diagnosis of atypical pneumonia?

Interstitial pneumonia without consolidation (if uncomplicated). More common in children and young adults. Diffuse interstitial infiltrates. Elevated cold-agglutinin titers (in Mycoplasma)

What is Aspergillosis?

It is the name given to a wide variety of diseases caused by infection by fungi of the genus Aspergillus. The most common forms are allergic bronchopulmonary aspergillosis, pulmonary aspergilloma, and invasive aspergillosis. Most humans inhale Aspergillus spores every day. Aspergillosis develops mainly in individuals who are immunocompromised, either from disease or from immunosuppressive drugs, and is a leading cause of death in acute leukemia and hematopoietic stem cell transplantation.

Which organism is the most common cause of pneumonia in patients with chronic alcoholism and also the most frequent cause of Gram-negative bacterial pneumonia?

K. pneumoniae.

Which organism mostly commonly causes gram-negative bacterial pneumonia?

K. pneumoniae.

Which organism is the most common cause of pneumonia in organ transplant patients?

L. pneumophila

What type of pneumonia does Streptococcus pneumoniae (95%) and Klebsiella pneumoniae cause?

Lobar pneumonia-Consolidation of the entire lobe.

Disruption of normal continuity of the parenchyma by necrosis and localized collection of neutrophils.

Lung Abscess

RESPIRATORY SYNCYTIAL VIRUS (RSV) PNEUMONIA

MULTINUCLEATED VIRUS-INFECTED CELLS = "SYNCYTIA Green image with fish looking cells and a nest of cells in the center.

What are the microscopic features of viral pneumonia (4)? What are the complications of viral pneumonia (3)?

Microscope: -Interstitial mononuclear cell inflammatory infiltrate within the alveolar walls -Widened, edematous septa -Cytopathic effects (e.g. HSV) and intranuclear inclusions (CMV) -Neutrophils, if necrosis (HSV,varicella, adenovirus) Complications: -Diffuse alveolar damage -Superimposed bacterial infection (common) -Fibrosis

Although over one hundred strains of microorganism can cause pneumonia, only a few of them are responsible for most cases. Which agents most commonly cause infectious pneumonia? Which agents are the least common causes of infectious pneumonia?

Most: Viruses and bacteria. Least: Fungi and parasites.

Image of acute bacterial pneumonia. What are the CARDINAL signs of acute bacterial pneumonia?

Note the hyperemia (middle), edema (right) and neutrophilic granulocytes (PMNs) in alveoli (left).

Patients with Cystic fibrosis, burn patients, or neutropenics are most susceptible to this bacteria?

P. aeruginosa

Describe the involvement of P. aeruginosa in the development of bacteremia with a pneumonia infection.

P. aeruginosa invades blood vessels and can cause coagulation necrosis of lung parenchyma and fulminant sepsis.

Image of invasive aspergillosis (CLL patient). Septate hyphi grow into pulmonary artery wall. Clinical findings: Aspergillus sepsis. Chronic lymphatic Leukemia. Stain: Grocott's silver stain.

PA lumen bottom left. PA wall bordering it. Outside see a necrotic lung.

Which virus is commonly linked with causing pneumonia in young children?

Respiratory syncytial virus.

Image of CMV pneumonia. Note the intranuclear inclusion body with halo (owl's eye). What is the diagnostic cell? What stain?

The owls eye is the diagnostic cell. Papanicolaou stain.

Image of Pneumocystis carinii pneumonia in an immunosuppressed patient. Note the granular, foamy PAS positive masses of organisms in alveoli with remarkably little host reaction. PAS stain.

What are the aveoli filled with?

Image of lobar pneumonia with fibrinous pleuritis (anthracosis). Fibrinous pleuritis can occur in either bacterial lobar or bronchopneumonia or in viral pneumonia. Diffuse change with intra-alveolar fibrin and granulocytes. Fibrin covered pleura. Carbon in subpleural lymphatics. Patient is a smoker.

What are the dark pigments? What do they signify about the patient?

Image of the grey hepatization stage of lobar pneumonia. All alveoli are filled with fibrin, edema and neutrophils. Some siderophages (hemosiderin-containing macrophages) are present.

What disease? What stage?

Image of the grey hepatization stage of lobar pneumonia. Diffuse change extends through the entire lobe. Alveoli are filled with fibrin and granulocytes.

What disease? What stage?

Image of the grey hepatization stage of lobar pneumonia. Note the siderophages.

What type of cell is the arrow pointing at?