acute inflammation Flashcards
What is the general definition of acute exudative inflammations?
Acute inflammations with principal histologic findings including exudation of blood serum and extravasation of blood cells into the inflamed area.
What are the classifications of acute exudative inflammation based on the principal components of the exudate?
- Serous inflammation
- Fibrinous inflammation
- Suppurative/purulent inflammation
- Hemorrhagic inflammation
How can the components of acute exudative inflammation combine?
- Sero-mucous inflammation
- Sero-fibrinous inflammation
- Fibrinous purulent inflammation
What are the possible courses of acute inflammation?
- Dissolution of the exudate (eliminated by macrophages)
- Regeneration of the damaged tissue (restitutio ad integrum)
- Post-infectious disorders (circulating Ag-Ab complexes trigger HSR III)
- Chronic inflammation (when acute inflammation fails to heal)
- Hematogenous dissemination (bacteremia, fungemia, sepsis)
What characterizes acute serous inflammation?
Acute inflammation with exudate of fibrin-free serum.
What are the etiologic factors of acute serous inflammation?
- Hypersensitivity reactions
- Bacterial and viral tissue injury
- Physical and chemical tissue injury
What are some examples of conditions involving acute serous inflammation?
Urticaria in skin
Laryngeal edema
Edema and hyperemia on serous membranes
Serous hepatitis
Serous alveolitis
Acute nephritis
What characterizes seromucous inflammation?
Acute inflammation with a watery exudate of serum and mucus.
What are the etiologic factors of seromucous inflammation?
Back:
- Hypersensitivity reactions
- Bacterial and viral tissue injury
- Physical and chemical tissue injury
What are some examples of conditions involving seromucous inflammation?
- Acute rhinitis (common cold)
- Acute catarrhal bronchitis
- Enteritis
What is the definition of acute fibrinous inflammation?
Acute inflammation with exudation of fibrinogen-containing serum.
What are the etiologic factors of acute fibrinous inflammation?
- Infectious toxic tissue injury
- Chemical and toxic tissue injury
- Excretion of toxic metabolites (uremic toxins)
- Ischemic tissue injury
What are the classifications of acute fibrinous inflammation?
- Fibrinous Serosal Inflammation (e.g., fibrinous pleuritis, fibrinous pericarditis, fibrinous peritonitis)
- Fibrinous Mucosal Inflammation
- Pseudomembranous Croupous Form (Influenza Type)
- Pseudomembranous Necrotizing Form (Diphtheria Type)
- Fibrinous Parenchymal Inflammation (e.g., lobar pneumonia)
Give examples of conditions involving fibrinous serosal inflammation.
Fibrinous pleuritis
Fibrinous pericarditis
Fibrinous peritonitis
What are the two forms of fibrinous mucosal inflammation?
- Pseudomembranous Croupous Form (Influenza Type)
- Pseudomembranous Necrotizing Form (Diphtheria Type)
What is fibrinous pleuritis?
Acute inflammation of the pleura with fibrinous exudate.
What are the causative agents of fibrinous pleuritis?
- Bacteria: Pneumococcus, Haemophilus, Klebsiella, M. Tuberculosis
- Viruses: Coxsackie, echoviruses, adenoviruses
What might be revealed in the aspiration of infected pleural effusion in fibrinous pleuritis?
- High-protein exudate
- Neutrophils in bacterial infections
- Lymphoid cells in viral infections or tuberculosis
What are the clinical presentations of fibrinous pleuritis?
- Auscultatory findings include sounds of pleural friction resembling creaking leather.
- Respiratory excursion is painful.
Describe the macroscopic appearance of fibrinous pleuritis.
- Fibrinous deposits form reticular white-grey membranes resembling “cat’s tongue” (Laenec).
- Variable exudation of fluid.
What are the microscopic features of fibrinous pleuritis?
Filaments of fibrin arranged in a plexiform meshwork.
What are the complications of fibrinous pleuritis?
- The initial serous exudate may become purulent due to superimposed bacterial infection (empyema).
- The fibrinous exudate may become organized to form fibrous pleural adhesions.
- Calcification may be seen in the pleura as a result of old tuberculous pleurisy.
What is fibrinous mucosal inflammation?
It’s an acute inflammation where a wide area of fibrinous exudate forms a pseudomembrane covering the necrosis, limited to the mucosal epithelium.
What are the examples of the pseudomembranous croupous form (Influenza Type)?
- Influenzal tracheobronchitis
- Amebic dysentery
- Ischemic pseudomembranous colitis
What is the clinical presentation of the pseudomembranous croupous form?
In influenzal tracheobronchitis, it presents as croup, with shortness of breath, stridor (whistling sound during inspiration), and a barking cough. Complications include bacterial superinfection.
What characterizes the pseudomembranous necrotizing form (Diphtheria Type)?
It’s an acute inflammation where necrosis extending into the submucosa is covered by a wide area of fibrinous exudate, forming an adhesive pseudomembrane.
What are the examples of the pseudomembranous necrotizing form?
- Diphtheric laryngotracheitis (diphtheria)
- Antibiotic enterocolitis
What is the clinical presentation of the pseudomembranous necrotizing form?
In diphtheric laryngotracheitis, it presents as croup with neuritis of the cranial nerves, leading to aphonia (loss of voice) and development of a pseudomembrane. There’s a risk of asphyxiation, and emergency tracheotomy may be indicated.
what is pneumonia?
Fibrinous purulent inflammation of the lung
What are the main features of pneumonia?
- Monomorphic lesions per stage
- Involvement of a whole segment or lobe
- Bacteria spread through Cohn pores
How is pneumonia clinically classified?
- Community-acquired disease: Usually caused by Gram-positive bacteria.
- Hospital-acquired disease: Usually caused by Gram-negative bacteria.
- Disease acquired in special environments: 4. Usually caused by Legionella (after exposure to contaminated air-conditioning), Chlamydia Psittaci (after exposure to birds’ excreta, especially parrots).
- Disease in immunosuppressed patients: Usually caused by mycobacteria, viruses, and fungi (Pneumocystis Carinii).
- Aspiration pneumonia.
Who is prone to developing pneumonia with Klebsiella?
Homeless and alcoholics
What causes bronchopneumonia following a viral infection (such as influenza)?
S. Aureus
What are the complications of pneumonia?
- Lung scarring with respiratory dysfunction (due to organization of the exudate in the alveoli)
- Lung abscess
- Pleurisy with pleural empyema
- Septicemia
Describe the macroscopic appearance of pneumonia.
A whole segment or lobe becomes consolidated, airless, and well-shaped.
What are the microscopic stages of pneumonia?
- Congestion: Exudative alveolitis with capillary vasodilatation.
- Red hepatization: Fibrin network with erythrocytes in alveoli.
- Grey hepatization: Fibrin network with leukocytes in alveoli.
- Resolution: Phagocytosis of the fibrin by alveolar macrophages and removal of cellular debris with healing.
What are the main features of bronchopneumonia?
Pleomorphic lesions
Involvement of lobules
Bacteria spread through bronchiole
Which individuals are most predisposed to bronchopneumonia?
Infants, elderly, debilitated individuals, and patients who are immobile and develop retention of secretion.
Describe the two types of bronchopneumonia
- Bronchopneumonia with disseminated areas.
- Bronchopneumonia with confluent areas.
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What is the recovery process for treated bronchopneumonia?
Recovery involves focal organization of lung by fibrosis.
What are the complications of bronchopneumonia?
Lung abscess
Acute pleurisy
Septicemia
What are the macroscopic features of bronchopneumonia?
Firm, airless areas with a dark red or grey appearance associated with pus in peripheral bronchi.
What is the general definition of suppurative inflammation?
Inflammation with exudate consisting primarily of neutrophils and cellular debris (detritus).
Describe the necrotic zone in suppurative inflammation.
A necrotic zone is a central focus of proteolytic liquefaction with lipid-rich detritus producing yellowish pus.
What characterizes the pus zone in suppurative inflammation?
The pus zone contains large numbers of neutrophils and surrounds the central necrotic area.
What is the hyperemic zone in suppurative inflammation?
The hyperemic zone has perifocal edema of serous exudate.
Define mucopurulent inflammation.
Acute inflammation of a mucous membrane with exudate of mucus, granulocytes, and cellular detritus, usually secondary to viral infection.
What is empyema?
Suppurative inflammation in a body cavity, such as pleural empyema, gallbladder empyema, and pyosalpinx.
Define phlegmon.
Diffuse suppurative inflammation without tissue liquefaction that spreads primarily in loose fibrous connective tissue.
What is an abscess?
An abscess is an accumulation of pus from tissue destruction
What is a hepatic abscess?
A hepatic abscess is a circumscribed acute purulent inflammation of the liver.
What are the three main routes of bacterial infection in the liver leading to hepatic abscess?
- Ascending spread from colonization of the biliary tract due to biliary obstruction (colangitic abscess).
- Infection ascending in the portal vessels from a sepsis focus in the abdomen, such as appendicitis (pyemic abscess).
- Systemic blood spread in septicemia (miliary abscess), which may cause severe acute liver failure.
How are colangitic abscesses identified morphologically?
Colangitic abscesses are seen as green collections due to a mixture of pus and bile.
What characterizes pyemic abscesses in the liver?
Pyemic abscesses are seen as multiple, large purulent collections (5-6 cm) resembling a “sponge” liver; these abscesses may become confluent, giving rise to Chauffard’s areolar abscess.
Describe the appearance of miliary abscesses in the liver.
Miliary abscesses are seen as multiple, small, yellowish nodules (3-4 mm)
What can cause severe acute liver failure in the context of hepatic abscess?
Severe acute liver failure can be caused by miliary abscesses due to systemic blood spread in septicemia.
What are the two types of acute purulent meningitis?
- Leptomeningitis: inflammation centered on the subarachnoid space.
- Pachymeningitis: inflammation centered on the dura mater.
What causes leptomeningitis?
- Acute purulent meningitis: caused by bacterial infection.
- Lymphocytic meningitis: caused by viral infection.
- Chronic granulomatous meningitis: caused by Mycobacterium tuberculosis.
What are the routes of infection for acute purulent meningitis?
- Direct spread from penetrating wounds or fracture of the skull.
- Blood borne spread.
- Spread from nearby infections such as otitis media, mastoiditis, or sinusitis.
What are the main causes of acute purulent meningitis in neonates?
E. Coli, Streptococci, Listeria Monocytogenes.
What are the main causes of acute purulent meningitis in children?
H. Influenzae & Neisseria Meningitidis.
What are the main causes of acute purulent meningitis in adults?
Neisseria Meningitidis & Streptococcus Pneumoniae.
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What are the main causes of acute purulent meningitis in the elderly?
S. Pneumoniae, L. Monocytogenes.
What are the clinical symptoms of acute purulent meningitis?
Fever, headache, neck stiffness, photophobia
What are the typical CSF examination findings in acute purulent meningitis?
Turbid fluid with many neutrophil polymorphs, low glucose, and bacteria visible with Gram stain.
What is the macroscopic appearance of the exudate in acute purulent meningitis?
Creamy white yellowish purulent exudate in the subarachnoid space.
Where is the pus localized in acute purulent meningitis caused by Neisseria Meningitidis?
The pus is localized on the convexity of the brain.
Where is the pus localized in acute purulent meningitis caused by Haemophilus Influenzae?
The pus is localized at the base of the skull.
What is the definition of acute hemorrhagic inflammation?
Acute inflammation involving microvascular injury with massive microvascular bleeding, producing an exudate with a high erythrocyte content.
What is the morphology of acute hemorrhagic inflammation?
The inflamed area is usually necrotic and filled with blood.
What are the etiologic factors of acute hemorrhagic inflammation?
Bacterial exotoxins and endotoxins
Viral cytopathic effect on endothelium
Proteolytic tissue destruction
Cytotoxic injury in hypersensitivity type III
What causes Scarlet Fever and what are its effects?
Scarlet Fever is caused by β-hemolytic group A streptococci, which create erythrogenic toxins that damage capillary walls and cause hemolysis, producing patchy erythema of the skin (exanthema).
What is Waterhouse-Friderichsen Syndrome and its effects?
It is caused by sepsis with Neisseria meningitidis in children, leading to bilateral hemorrhagic adrenal necrosis, disseminated intravascular coagulation, and septic shock.
What is the cause and effect of the Plague in acute hemorrhagic inflammation?
Infection with Yersinia pestis produces exotoxin leading to painful hemorrhagic lymphadenitis (bubonic plague) and hemorrhagic pneumonia (pneumonic plague).
What are some examples of viral hemorrhagic fevers?
Viral hemorrhagic fevers include diseases such as Ebola, Dengue fever, and Marburg virus disease.
What characterizes acute necrotizing inflammation?
Acute inflammation in which tissue necrosis predominates.
What are the classifications of acute necrotizing inflammation?
Ulcerous necrotizing type
Diffuse necrotizing type
Gangrenous type
Nonreactive necrotizing type
Describe the ulcerous necrotizing type of acute necrotizing inflammation.
Acute inflammation with focal necrosis extending into the submucosa or deeper and covered with fibrinous exudate (scab). Examples include acute necrotizing ulcerous gingivitis (Vincent angina), ulcerous colitis, and peptic gastro-duodenal ulcer.
What is diffuse necrotizing inflammation?
Acute inflammation with rapidly spreading necrosis and an ineffective or absent leukocyte reaction. An example is necrotizing fasciitis.
What is gangrenous type inflammation?
Putrid disintegration of a necrotizing inflammation due to infestation with anaerobic putrefactive bacteria. Gangrene may occur as ischemic dry gangrene or putrefactive wet gangrene.
What is nonreactive necrotizing inflammation?
A type of acute necrotizing inflammation where tissue necrosis occurs without a significant inflammatory response.
