Pulmonary infections
Dept. of Pathology
Three Gorges University Medical College
Lu Hua
•Pneumonia
•Abscess of lung
Pulmonary infections
Pneumonia(specific name)
Definition:
Acute exudative inflammation of lung
Three types:
•lobar pneumonia
•lobular pneumonia (bronchopneumonia)
•Interstitial pneumonia (viral and mycoplasmal pneumonia)
Type of pneumonia(The class are based on the area of changes)
1 、 lobular pneumonia
2 、 confluent bronchopneumonia
3 、 4 、 Interstitial pneumonia
5 、 lobar pneumonia
lobar pneumonia
• Definition:
lobar pneumonia is a widespread fibrinous consolidation of large areas and even whole lobes of the lung by acute bacterial infection.
lobar pneumonia• This pattern of acute bacterial
infection involves a large portion of lung or an entire lobe of lung.
• It is an acute fibrinous inflammation .
Etiology:• Most lobar pneumonias(90%) are
caused by pneumococci (type Ⅲ ), which enter the lungs via the airways.
• Other organisms: klebsiella , staphylococci, streptococci.
Etiology
Pneumonia can result whenever the defense mechanisms are impaired or whenever the resistance of the host in general in lowered e.g. catch cold 、 drunkenness and tiredness.
Etiology
•Defense mechanisms are impaired
•The Bacterium came into pulmonary alveolus
EtiologyThe Bacterium came into pulmonary alveolus
increasing
allergy
Vascular engorgement, serous fluid exude
Transudate with bacterium diffused via alveolar poreand involves a large portion of lung or an entire lobe of
lung.
Morphology
• Four stages of the inflammatory response include
• Congestion
• red hepatization
• gray hepatization
• resolution
Morphology
• Congestion– Predominates in the
first 24-48 hours.– The lung is heavy,
big and red.– Vascular
engorgement, intra-alveolar fluid with few neutrophils.
– Often presence of numerous bacteria.
Clinical course
Symptom of toxemia
1. shakes
2. hyperpyrexia
• Red hepatization (consolidation)– Predominates in the
3th–4th day – Describes lung tissue
with confluent acute exudation containing neutrophils and red cells, giving a red, firm, liver-like gross appearance.
Red hepatization
Red 、 firm
Red hepatization
Red hepatization
Clinical course
1. Rusty sputum (RBC disintegrate .)
2. Hypoxia
• Grey hepatization
– Predominates in the 5th-6th day
– Follows, as the red cells disintegrate and the remaining fibrinous exudate persists, giving a gray-brown gross appearance.
图 9-17 实变期 灰色肝样变期镜下改变
Grey hepatization
Clinical course1. White purulent sputum
• RBC disappeared
• Much fibrin
2.Hypoxia relieve .
• Alveolar pore are filled with exudation .
• Cavity of vessel are obliteration .
Morphology• Resolution
–The final stage –consolidated exudate undergoes
enzymatic digestion and cellular degradation and clearance.
– Normal structure is restored.
•The four stages is "classic" but infrequently seen because of antibiotic therapy.
•The injury of the alveolar wall usually don’t appear and the normal structure will be restored easily.
Complications
• Abscess formation
• Empyema(spread of infection to pleural cavity)
Complications
• Carnification: organization of exudate into fibrotic scar tissue (incomplete resolution).
• Bacteremia, septicemia and sepsis, with infection of other organs.
Carnification
Clinical course• The major symptoms: malaise,
fever, and cough productive of sputum. Pleuritic pain and pleural friction rub.
• The characteristic radiologic appearance: radiopaque well-circumscribed lobe.
lobular pneumonia (bronchopneumonia)
• This pattern of bacterial pneumonia is an acute purulent inflammation in lung parenchyma, caused most commonly by staphylococci, streptococci, pneumococci, and coliform bacteria.
lobular pneumonia
• It tends to occur in the more vulnerable two extremes of life --infancy and old age, particularly in those already suffering from some serious disorder.
• Grossly, the lungs show dispersed, elevated, focal areas of palpable consolidation and suppuration.
confluent bronchopneumonia
Morphology
• Histologic features consist of an acute (neutrophilic) suppurative exudate filling air spaces and airways, usually about bronchi and bronchioles.
4 、镜下:肺泡内大量中性粒细胞,少量红细胞,周围
肺组织充血、浆液渗出
Morphology
• Resolution of the exudate usually restores normal lung structure, but organization may occur and result in fibrous scarring in some cases, or aggressive disease may produce abscesses.
Clinical course
• 1. The major symptoms: fever, and cough productive of sputum. Abscess formation. Empyema.
• 2. The characteristic radiologic appearance: focal opacities.
typetype
featurefeaturelobar pneumonialobar pneumonia lobular pneumonialobular pneumonia
main targetmain target young adultsyoung adults childrenchildren 、、 elderly elderly peoplepeople 、、 Long illness Long illness who lie in bedwho lie in bed
pathogenesispathogenesis pneumococcuspneumococcus mixed infectionmixed infection
extentextent Lobe Lobe Lobule Lobule
charactercharacter fibrinous fibrinous inflammationinflammation
Purulent inflammationPurulent inflammation
clinical clinical featuresfeatures
Rusty sputumRusty sputum mucopurulent sputummucopurulent sputum
complicationcomplication Carnification heart failure, heart failure, bronchiectasisbronchiectasis
prognosisprognosis goodgood ,, most healmost heal badbad ,, most diemost die
Interstitial pneumonia
(viral and mycoplasma pneumonia)
Interstitial pneumonia
• Infections by viruses (e.g., influenza A or B, respiratory syncytial virus, adenovirus, rhinovirus, herpes simplex, cytomegalovirus) or mycoplasma pneumonic .
Morphology
• Grossly, patchy or lobar areas of congestion without the consolidation of bacterial pneumonias(hence the term "atypical" pneumonia).
Morphology
• 1. A predominance of interstitial with widened, edematous alveolar walls containing a mononuclear inflammatory cell infiltrate.
interstitial pneumonia. The alveolar septa are widened and edematous and infiltrated with mononuclear cells.
图 9-21 病毒肺炎(间质性肺炎)
The formation of hyaline membranes, reflecting diffuse alveolar damage.
Morphology
Morphology
• Certain viruses cause necrosis of bronchial or alveolar epithelium in severe infections (herpes simplex, adenovirus).
Morphology
Characteristic cytopathic changes are seen with some, e.g., giant cells and viral inclusion body in the cytomegalovirus infection.
viral inclusion body is round or oval shape, erythrocyte-like in size, eosinophilic cytoplasmic or nuclear
viral inclusion body
Clinical course
• The major symptoms: fever, headache, muscle aches.
• Low mortality rate(<1%) in the sporadic form and high mortality in epidemic form.
lung abscess
• It is a localised area of necrosis of lung tissue with
suppuration .
• It is a purulent inflammation of lung caused by
bacterium(Include anaerobe and aerobe)
• It is 2 types .
Types
• Primary lung abscess
• Secondary lung abscess
Primary pulmonary abscess
• The bacterium came into lung via the airway during the process of breath.
• Anaerobe (80%) is the main bacterium .• Usually have some cause e.g. resistance of
the host in lowered .
Secondary pulmonary abscess
• Some diseases of lung
• Foreign body obstruct the bronchi
• Spread of the purulent inflammation
of the adjacent organs to lung .
Morphology
•Abscess may be of variable size from a few millimeters to large cavities .5-6 cm in diameter .
•The cavity contains exudate .
Chronic lung abscess : The cure of acute lung abscess is not thorough .(more than 3-6 months)
• Much necrotic tissue stay in vomica.• The thickness of the wall of vomica increased .• Bronchiole deform or the cavity expand .• Lymphocytes 、 plasma cells and macrophages .
Morphology
Morphology
• Bronchiole can be obstructed
• Liquefactive necrosis and vomica 。
• pleurisy
• empyema
Clinical course• suddenly , chilly 、 hyperpyrexia(3
9 ~ 40 )℃ 。• cough 、 expectoration 、 chest
pain 、 breath lessness 。• Sputum :purulent 、 foul and with
much necrotic tissue .
• Emptysis