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518
18
Pulmonary Opacities
K. E. Bloch and E. W. Russi
18
18
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519
18.1 Infectious Pulmonary Infiltrates
(Pneumonias)
521
Bacterial Pneumonia 523
Classification 523
Clinical Presentation of Bacterial
Pneumonias 524
Pneumonias Due to Gram-Positive
Microorganisms 524
Pneumonias Due to Gram-Negative
Bacteria and Microorganisms not
Identifiable under Light Microscopy 526
Pneumonia Due to Multiple Gram-Positive
and Gram-Negative Organisms (“Mixed
Flora”) 528
Pulmonary Tuberculosis 530
Primary Tuberculosis 531
Postprimary Pulmonary Tuberculosis 531
Exsudative Pulmonary Tuberculosis 531
Tuberculous Cavity 531
Miliary Tuberculosis 533
Fibroproliferative Tuberculosis 534
Tuberculoma 534
Disease Due to Mycobacteria Other
Than Tuberculosis (MOTT) 535
Viral Pneumonia 536
Influenza Pneumonia 536
Adenovirus Pneumonia 536
Severe Acute Respiratory Syndrome (SARS) 536
Hantavirus Pneumonia 536
Pneumonia Due to Nonpneumotropic
Viruses 536
Fungal Pneumonia 537
Fungus Infection in Immunocompromised
Patients 537
Pneumonia Due to Yeasts and Molds 537
Pneumocystis carinii Pneumonia 537
Endemic Fungal Infection 539
Allergic Bronchopulmonary Aspergillosis
and Mycetoma 539
Pulmonary Parasitosis 540
18.2 Noninfectious Pulmonary
Infiltrates
540
Physical or Chemical Pneumonitis 540
Radiation Pneumonitis 541
Lipoid Pneumonia 541
Infiltrates Due to Chronic Congestive Heart
Failure 541
Pulmonary Infarction − Infarction
Pneumonia 543
Pneumonia Associated with Bronchiectasis 545
Pneumonia Due to Bacterial Superinfection 545
Chronic Pneumonia 545
Other Noninfectious Pulmonary Infiltrates 545
18.3 Eosinophilic Pulmonary Infiltrates
546
Transient Eosinophilic Pulmonary Infiltrates
(Löffler) 546
Pulmonary Eosinophilia with Parasitosis
and Tropical Pulmonary Eosinophilia 546
Allergic Bronchopulmonary Aspergillosis
(ABPA) 546
Drug-Induced Pulmonary Eosinophilia 547
Acute Eosinophilic Pneumonia 547
Chronic Eosinophilic Pneumonia 547
Eosinophilic Infiltrates with Asthma 547
Allergic Granulomatosis and Angiitis
(Churg−Strauss Syndrome) 547
Hypereosinophilic Syndrome 547
Diagnostic Criteria: 547
18.4 Diffuse Parenchymal Lung Disease
(DPLD)/Pulmonary Fibrosis
548
Idiopathic Interstitial Pneumonia 549
Idiopathic Pulmonary Fibrosis (IPF) 550
Nonspecific Interstitial Pneumonia (NSIP) 551
Cryptogenic Organizing Pneumonia
(Idiopathic Bronchiolitis Obliterans
Organizing Pneumonia [BOOP]) 551
Pulmonary Opacities
520
Acute Interstitial Pneumonia (AIP,
Hamman−Rich Syndrome) 553
Respiratory Bronchiolitis-Associated
Interstitial Lung Disease (RB-ILD) 554
Desquamative Interstitial Pneumonia (DIP) 554
Lymphoid Interstitial Pneumonia (LIP) 554
Interstitial Pneumonia in Association
with Collagen Vascular Disease 554
Toxic and Drug-Induced Interstitial
Pneumonia 556
Extrinsic Allergic Alveolitis
(Hypersensitivity Pneumonitis) 556
Pneumoconiosis 557
Silicosis 557
Silicatosis and Other Pneumoconioses 559
Diffuse Granulomatous Pulmonary
Diseases 561
Other Diffuse Parenchymal Lung
Diseases and Orphan Lung Diseases 561
Alveolar Cell Carcinoma, Bronchoalveolar
Cell Carcinoma, and Pulmonary
Adenomatosis 561
Lymphangiosis Carcinomatosa 561
Kaposi Sarcoma 561
Pulmonary Hemosiderosis 561
Goodpasture Syndrome 561
Antiphospholipid Syndrome 564
Pulmonary Alveolar Proteinosis (PAP) 564
Microlithiasis Alveolaris 564
Langerhans Cell Histiocytosis 564
Lymphangioleiomyomatosis (LAM) 564
Formation of Cysts and Honeycombing 565
18.5 Pulmonary Nodules
566
Solitary Pulmonary Nodules 567
Malignant Neoplasms 567
Benign Tumors 569
Inflammatory Pulmonary Nodules 569
Tuberculoma 569
Echinococcosis 569
Pulmonary Nodules of Various Etiology 570
Multiple Pulmonary Nodules 570
Metastasis 570
Wegener Granulomatosis 570
Arteriovenous Aneurysms 572
18.6 Cavernous and Cystic Lung
Diseases
573
Tuberculous Cavitary Lesion 573
Pulmonary Abscess 573
Pulmonary Abscess Due to Aspiration 573
Pulmonary Abscess Formation as a
Complication of Bacterial Pneumonia 574
Metastatic Lung Abscess 574
Lung Cysts 574
Cavernous and Cystic Lesions
of Various Etiologies 574
18.7 Atelectasis
57 4
18.8 Middle Lobe Syndrome
576
18.9 Opacities in the Cardiophrenic
Angle
578
Cysts and Hernias 578
Lung Sequestration 578
18
Pulmonary Opacities
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521
Radiologic Morphology of Pulmonary Opacities
By definition, the diagnosis of pulmonary opacities re-
quires a radiographic examination. Although the pres-
ence of opacities may be suspected on clinical grounds,
chest percussion and auscultation are often normal or
equivocal. Opacities of the lung parenchyma may be re-
lated to extravascular fluid accumulation (exudate, tran-
sudate) and to infiltration of inflammatory, fibrotic, or
neoplastic cells. The following discussion refers to con-
ventional chest radiography. A larger amount of anatomi-
cal information, and a significantly higher spatial resolu-
tion, can be obtained by a computed tomography (CT)
scan of the chest including spiral acquisition in thin slices
and visualization in high-resolution techniques, with and
without application of a contrast agent. However, a CT
scan is generally not performed as the initial radiologic
examination due to its higher costs and radiation expo-
sure. For the description of CT images a specialized no-
menclature, different from that used to describe conven-
tional chest radiography, is applied.
Pulmonary opacities are characterized by their size, dis-
tribution, and pattern.
Size. Based on their size and extension, localized opaci-
ties (such as those found in lobar pneumonia or tuber-
culoma) are differentiated from diffuse opacities (such as
those found in fibrosing alveolitis, or pneumoconiosis).
Pattern of Infiltrates. Inflammatory or neoplastic infil-
trates are typically associated with opacities that pre-
serve the lung structure. Infiltrates may occur with an aci-
nar or interstitial pattern:
ț Acinar Infiltrates. Diseases that affect the pulmonary
acini (e. g., pneumoconioses) have the following
characteristics:
− homogeneous density
− tendency for confluence
− air bronchograms
− absence of lung volume loss.
ț Interstitial Infiltrates. Diseases that predominantly af-
fect the pulmonary interstitium (e. g., fibrosing alve-
olitis) have the following characteristics:
− ground-glass opacity
− inhomogeneous density
− linear and reticular densities (Kerley A, B, and C
lines)
− noduli
− “honeycombing”
− loss of lung volume.
Consolidation. This term refers to a dense opacity that
conceals the structure of the affected lung parenchyma.
Consolidation is seen in pneumonia, lung cancer, or
metastasis.
Mass Lesions. A typical characteristic of a pulmonary
mass is its tendency to encroach upon adjacent lung
parenchyma and other structures. This is not only seen in
neoplasia but also in inflammatory diseases (pulmonary
abscess).
Nodules. A nodule is defined as a rounded, clearly de-
lineated opacity of less than 3 cm in diameter. Solitary or
multiple pulmonary nodules may be related to cancer, in-
fection, or organic and inorganic dust exposure (such as
found in silicosis).
Opacities with Central Hypodensity. These opacities
occur due to necrotic destruction such as found in an ab-
scess (bacterial abscess, cavity due to infection with My-
cobacterium tuberculosis), pulmonary infarct, neoplasia,
or vasculitis (Wegener granulomatosis).
Mixed Patterns of Pulmonary Opacities. The simul-
taneous occurrence of various types of opacities is com-
mon.
Additional Diagnostic Criteria. Certain lung diseases
are associated with a distinct distribution and pattern of
radiologic opacities. The high-resolution CT scan may be
diagnostic in some of these diseases (e. g., Langerhans
cell histiocytosis, lymphangioleiomyomatosis, or asper-
gilloma). In contrast, other diseases occur with variable,
nonspecific findings that preclude a definitive diagnosis
by chest radiography or even by CT scan (e. g., sarcoido-
sis, or amiodarone pneumopathy).
18.1 Infectious Pulmonar y Infiltrates (Pneumonias)
Infectious pulmonary infiltrates result from an inflam-
matory response to the infection caused by microor-
ganisms. The clinical manifestation is determined by the
type of the infectious agent (bacteria, viruses, fungi, or
parasites) and the immunologic response of the host.
The following discussion is arranged according to the in-
fectious agent (Tab. 18.1).
Infectious Pulmonary Infiltrates (Pneumonias)
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522
Table 18.1 Classification of inflammatory infiltrates
Infectious pneumonia
Bacterial pneumonia
− due to Gram-positive organisms
− Streptococcus pneumoniae (pneumococci type 1−90)
− Streptococcus
− Staphylococcus
− Actinomyces
− Nocardia
− due to Gram-negative organisms and organism not identifiable by light-microscopy
− Haemophilus influenzae
− Klebsiella
− Branhamella (Moraxella) catarrhalis
− Escherichia coli
− Proteus
− Pseudomonas
− Serratia
− Mycoplasma pneumoniae
− Chlamydia pneumoniae
− Chlamydia psittaci (ornithosis)
− Brucella (Bang pneumonia)
− Legionella pneumophila
− Rickettsia (Q-fever)
− Bacillus anthracis
− due to Gram-positive and Gram-negative anerobic organisms (Bacteroides, Fusobacterium)
− due to Mycobacterium tuberculosis complex
− M. tuberculosis
− M. bovis
− M. africanum
− due to atypical mycobacteria
− M. avium-intracelluare complex
− M. kansasii
− M. fortuitum, M. abscessus, and M. chelonei
Viral pneumonia
− Influenza virus
− Adenovirus
− Coronavirus (SARS)
− Hantavirus
− pneumonia due to virus not primarily affecting the lungs (measles, Epstein−Barr virus)
Fungal pneumonia
− fungal infection in the immunocompromised host
− candidiasis (moniliasis)
− aspergillosis
− Pneumocystis carinii
− Mucor mycosis (geotrichosis)
− cryptococcosis (torulosis)
− endemic fungal infections
− blastomycosis
− histoplasmosis
− coccidioidomycosis
Pneumonia due to parasites
− Toxoplasma gondii
Noninfectious pneumonia
Physical−chemical pneumonia
Pneumonia with eosinophilia (see Eosinophilic Pulmonary Infiltrates p. 546)
Inflammatory pulmonary infiltrates in collagen vascular disease (see Diffuse Parenchymal Lung Disease/Pulmonary
Fibrosis p. 548)
Due to circulatory failure
− cardiogenic pulmonary edema
− infarction pneumonia
18
Pulmonary Opacities
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523
Prognostic Factors in Community-Acquired Pneumonia
Infectious Pulmonary Infiltrates (Pneumonias)
In a patient with community-acquired pneumonia, the
severity of the illness and the need for hospital care have
to be assessed. The following factors may aid in this
assessment:
−age 50 years
− co-morbidity such as a neoplasia, congestive heart
failure, chronic obstructive lung disease, or renal
and hepatic diseases
− altered consciousness
− tachycardia 125 beats/min.
− respiratory rate 30/min.
− systolic blood pressure 90 mmHg
− body temperature 35 °C or 40 °C.
If none of the above-mentioned risk factors is present,
the clinical course is generally favorable and treatment of
the pneumonia may be performed at home.
The following findings represent additional risk factors:
− acidosis: arterial pH 7.35
− serum urea ͧ 30 mg/dL (11 mmol/L)
− serum sodium 130 mmol/L
− serum glucose ͧ 250 mg/dL (14 mmol/L)
− hematocrit 30%
− leukocyte count 4000 × 10
6
/L or 20 000 10
6
/L
− arterial oxygen partial pressure: Po
2
60 mmHg
− multilobar pulmonary infiltrates
− pleural effusion.
Bacterial Pneumonia
Bacterial pneumonias are still among the leading causes
of death due to infectious diseases despite the wide-
spread use of antibiotics. The organisms responsible
vary according to where the infection is acquired (at
home, in the hospital or another institution, in the in-
tensive care unit), host factors such as the age of the
patient, co-morbidities, and the individual immune re-
sponse. Streptococcus pneumoniae (pneumococcus),
Haemophilus influenzae, Gram-negative enteric bacilli,
Staphylococcus aureus, and Legionella pneumophila are
the most common causes of bacterial pneumonia. To-
gether with Mycoplasma pneumoniae, Chlamydia pneu-
moniae, and the respiratory viruses, they account for the
majority of community-acquired pneumonias. In con-
trast, hospital-acquired pneumonias are more com-
monly caused by Gram-negative organisms.
Classification
According to Where the Infection Was Acquired and the
Host Defense. One of the major determinants of the type
of microorganism and course of the pneumonia is
whether it has been acquired in the community (“com-
munity-acquired pneumonia”) or in a special setting
such as in a hospital (“hospital-acquired pneumonia”),
nursing home, prison, or in other institutions where
many people live closely together.
Another major determinant of the susceptibility to
certain infections, and of particular clinical presenta-
tions, is the ability of a patient to create an effective im-
mune response. In nonimmunocompromised patients,
bacterial pneumonias generally occur with an acute
course (with high fever, cough, and production of putrid
sputum), whereas bacterial pneumonias may initially
have a less dramatic course in the immunocompromised
host. Nevertheless, neither the clinical presentation,
laboratory tests, nor the radiographic appearance allows
a reliable diagnosis of the infectious agent of pneumonia.
Thus, the term atypical pneumonia is inappropriate and,
at best, of historical interest. Originally, atypical pneu-
monias were thought to be caused by microorganisms
other than Streptococcus pneumoniae. The first recog-
nized “atypical agents” were Mycoplasma pneumoniae;
subsequently Chlamydia pneumoniae and Legionella
pneumophila were identified. Since pneumonia caused
by Streptococcus pneumoniae and other bacteria may
have a clinical and radiologic presentation similar to in-
fections by the “atypical agents,” the distinction between
typical and atypical pneumonia is clinically useless.
According to the Infectious Agent. Another classification
of pneumonia is based on the microorganism. However,
the identification of the agents responsible is often not
feasible or successful. Even in patients hospitalized for
treatment of pneumonia, the microorganism is iden-
tified in less than half of cases.
Other Classifications. These are based on the mode of
transmission of the infection and the radiologic appear-
ance. These classifications may help to identify the
potential spectrum of microorganisms responsible: for
example, community-acquired aspiration pneumonia is
generally caused by a mixed flora of anaerobic and aero-
bic bacteria. In contrast, in hospital-acquired aspiration
pneumonia, Gram-negative bacteria are often involved.
Hematogeneous pneumonias are often caused by
Staphylococcus spp. Special conditions predispose the
patient to certain infections. Examples are HIV infection
(Pneumocystis carinii, Mycobacterium tuberculosis, and
mycobacteria other than tuberculosis), chemotherapy-
induced agranulocytosis (bacterial pneumonias, inva-
sive fungal infections), prolonged corticosteroid therapy
(Pneumocystis carinii), and immunoglobulin def iciency
(infections by capsulated microorganisms).
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524
a b
Fig. 18.1 Pneumococcal pneumonia. Homogeneous confluent
infiltrate of the right upper lobe (lobar pneumonia) in a 32-
year-old man.
a Posterio-anterior view.
b Lateral view.
18
Pulmonary Opacities
Although often used, the radiologic classification
based on the extension and pattern of infiltrates is clini-
cally of minor relevance. The following patterns may be
identified: localized or diffuse forms, unilateral or bi-
lateral, and lobar or segmental pneumonic infiltrates. If
the opacities are confluent and show an air broncho-
gram the pattern is called acinar. If the infiltrates are ill-
defined of linear, reticular, or nodular shape, and if there
is no air bronchogram, the pattern is called interstitial. A
solitary abscess is a typical complication of aspiration
pneumonia. Multiple pulmonary abscesses suggest a
hematogenic spread, such as occurs in staphylococcal
infection. Pulmonary infarction may occur as a con-
sequence of an invasive Aspergillus infection or may
occur in Pseudomonas aeruginosa pneumonia.
Clinical Presentation of Bacterial Pneumonias
Pneumonias Due to Gram-Positive
Microorganisms
As already observed by Hans Gram in 1884, the majority
of bacterial pneumonias are caused by Gram-positive
bacteria, namely Streptococcus pneumoniae, staphylo-
cocci, and streptococci. Peptococci and peptostreptococci,
Actinomyces israelii, Nocardia asteroides, Bacillus an-
thracis, and Mycobacterium tuberculosis are also positive
for staining.
Pneumococcus Pneumonia. Currently, 20−60 % of com-
munity-acquired bacterial pneumonias are caused by
Streptococcus pneumoniae, and 5% of patients with this
infection still die as a consequence. Patients with a com-
promised immune defense system, immunoglobulin
deficiency, hemoglobinopathies, or following splen-
ectomy are at particular risk.
The clinical presentation of Pneumococcal pneumonia
classically starts with sudden onset, high fever, chills,
and pleuritic chest pain. Untreated, the fever remains at
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525
Fig. 18.2 Staphylococcus pneumonia with focal
and confluent infiltrates in the middle and lower
lobes in a patient with Hodgkin lymphoma (lobu-
lar pneumonia or bronchopneumonia) in a 33-
year-old man.
Infectious Pulmonary Infiltrates (Pneumonias)
temperatures up to 39−40 °C. The pulse rate is also ele-
vated.
The following findings can occur:
➤ Chest percussion: dullness, increased fremitus.
➤ Auscultation: bronchial breath sounds, end-inspira-
tory rales, often perioral herpes infection, leukocyto-
sis up to 30 000/μL (30 × 10
9
/L) with pronounced left
shift, toxic granulations, and lymphopenia.
➤ Radiologic: in the chest radiograph the infiltrates are
dense, homogeneous, and clearly delineated with air
bronchograms. They may extend to entire lobes
(lobar pneumonia) (Fig. 18.1) or consist in one, or
more rarely, in multiple ill-defined infiltrates.
➤ Sputum: microscopic examination of the frothy
sputum reveals Gram-positive diplococci. Abundant
amounts of Gram-positive diplococci identified in
putrid sputum are diagnostic for Streptococcus pneu-
moniae. Since pneumococci are normal saprophytes
of the oropharyngeal mucosa (carrier rate 5−70%),
only moderate or minor amounts of Gram-positive
diplococci do not allow a definitive identification of
Streptococcus pneumoniae.
➤ Blood cultures: in hospitalized patients blood
cultures are positive in one-fourth to one-third of
cases.
The resorption of infiltrates takes place within four to
eight weeks. Delayed resorption of infiltrates may indi-
cate another diagnosis (tuberculosis, neoplasia) or a
complication, and may occur in patients in a reduced
general condition, such as from alcohol abuse, diabetes,
or chronic obstructive airway disease.
Complications of Pneumococcal pneumonia include
atelectasis, pleural empyema, parapneumonic effusion,
delaye d resorption, pulmonary abscess formation (in
approximately 2% of cases), and pericarditis. Minor ef-
fusions are common (60%), major effusions are rare
(5%). Metastatic spread of the infection leading to septic
arthritis, endocarditis, meningitis, or peritonitis is
mainly seen in immunocompromised patients or after
splenectomy.
Streptococcal and Staphylococcal Pneumonia. While
streptococcal pneumonias are relatively rare in adults,
staphylococcal infection accounts for 3−5% of bacterial
pneumoniasinoutpatients,andfor 6−24 %inhospitalized
patients. Streptococcal and staphylococcal pneumonias
mayoccurasacomplicationofinfluenzaviralinfection.In
addition, streptococcal pneumonia may result from a
spread of an upper airway infection to the lungs. Strepto-
coccal and staphylococcal pneumonias generally have an
acute course with severe febrile illness. The chest radio-
graph shows multiple patchy infiltrates spreading over
one or several lobes (bronchopneumonia; Fig. 18.2). Ab-
scess formation is a common complication that typically
occurs in staphylococcal pneumonia. The diagnosis is
confirmed by blood cultures, which are positive in
approximately 20% of staphylococcal pneumonias.
Pulmonary Actinomycosis and Nocardiosis. Pulmonary
actinomycosis has a prolonged course with fever,
phlegm, pleural pain, and leukocytosis. It is commonly
associated with manifestation of the infection at other
sites, in particular in the oral cavity and the jaw. The
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526
Fig. 18.3 Combined Pneumocystis
carinii and Nocardia asteroides pneu-
monia in a in a 50-year-old male
patient receiving chemotherapy.
18
Pulmonary Opacities
typical radiologic manifestation includes pleural-based
infiltrates that may extend beyond the visceral pleura to
the chest wall or to adjacent lobes. The microscopical
identification of Actinomyces in the sputum or bronchial
washings suggests the diagnosis (yellow sulfur granula
corresponding to Actinomyces israeli colonies). The
definitive cultural diagnosis may require several weeks.
Pulmonary infection by the mandatory aerobic and
weakly acid-fast staining Nocardia spp. (Nocardia
asteroides, Nocardia brasiliensis) predominantly occurs
in the immunocompromised host or in patients with
preexisting chronic lung diseases, e. g., pulmonary alve-
olar proteinosis (Fig. 18.3).
Pneumonias Due to Gram-Negative
Bacteria and Microorganisms not
Identifiable under Light Microscopy
ThisincludespneumoniasduetoHaemophilusinfluenzae,
Gram-negative Enterobacteriaceae (Klebsiella pneu-
moniae, Escherichia coli, Proteus, Enterobacter, and Serra-
tia), Pseudomonas aeruginosa, and Branhamella (Morax-
ella) catarrhalis. Legionnaires disease, Q-fever, and Bang
disease are also caused by Gram-negative bacteria (i. e.,
Legionella pneumophila, Rickettsia, and Brucella, respec-
tively). Mycoplasma pneumoniae and Chlamydia pneu-
moniae are both common causes of community-acquired
pneumonias.Thesemicroorganismscannot bevisualized
by light microscopy due to their small size. It has been
estimated that 9−20% of community-acquired pneu-
monias and more than 40 % of hospital-acquired pneu-
monias are due to Gram-negative bacteria.
Haemophilus influenzae Pneumonia. Haemophilus influ-
enzae in its capsulated or uncapsulated form is thought
to cause 3−10% of community-acquired pneumonias. It
commonly occurs in patients with chronic lung disease,
such as chronic obstructive pulmonary disease (COPD)
or bronchiectasis, who are also susceptible to Klebsiella
infection.
Pneumonias Due to Gram-Negative Enterobacteria. Kleb-
siella spp. along with Haemophilus influenzae are the
most common Gram-negative microorganisms causing
community-acquired pneumonia. Alcoholics, diabetics,
and patients with chronic airway disease are most sus-
ceptible. The clinical presentation is similar to that of
other bacterial pneumonias such as caused by Strepto-
coccus pneumoniae. The diagnosis is made by identifica-
tion of Klebsiella pneumoniae (Gram-negative, capsu-
lated diplobacillus) in the sputum or blood culture (50−
70% of blood cultures are positive).
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Infectious Pulmonary Infiltrates (Pneumonias)
Pseudomonas aeruginosa Pneumonia. This predomi-
nantly occurs in severely ill, hospitalized patients, and
in patients with bronchiectasis. More than 40% of hospi-
tal-acquired pneumonias are due to Pseudomonas and
other Gram-negative bacteria. These nosocomial pneu-
monias may be related to long-term antibiotic therapy,
immunosuppression, cytotoxic chemotherapy, or me-
chanical ventilation. Bacteriemic Pseudomonas aerugi-
nosa pneumonia is associated with a high mortality rate
(i. e., 60−70 %) despite appropriate antibiotic treatment.
Mycoplasma Pneumonia. Mycoplasma pneumoniae are
estimated to be the causative agent in 3−35% of commu-
nity-acquired pneumonias. The microorganisms are
spread to close contacts by aerosol formation during
coughing. Mycoplasma pneumonias are therefore com-
monly observed in preschools and schools, and among
military personnel. The incubation period is approxi-
mately three weeks. Following the infection, lifelong
immunity develops.
Mycoplasma pneumoniae infections may pass
without apparent symptoms, but more severe infec-
tions, with fever, bronchitis, and pneumonia, may also
occur. The disease usually starts with headaches,
malaise, and fever. The cough is usually nonproductive.
Less than 10% of patients present clinically with a typi-
cal pneumonia. Pulmonary auscultation may be normal.
Associated symptoms may include pharyngitis, rhi-
nosinusitis, and otitis (sometimes with protracted
hemorrhagic, bullous myringitis).
The chest radiograph in Mycoplasma pneumonia
shows nonspecific alterations, usually consisting in
bronchopneumonic infiltrates. Mycoplasma infections
may be associated with extrapulmonary manifestations
such as hemolysis (cold agglutinins), a rash, and arthritis.
This small microorganism cannot be seen under light
microscopy. A cultural identification may take several
weeks and is therefore clinically not useful. Instead, a
serologic examination (complement fixation) may sug-
gest a Mycoplasma infection by an increase in IgM and,
subsequently, in IgG antibodies. A four-fold increase in
antibody titers over the course of the disease or an in-
dividual titer of 1:32 are suggestive of the diagnosis.
An increase in antibodies may be expecte d within seven
to nine days after infection with a maximal response
after three to four weeks.
Chlamydia Pneumonia. Chlamydia are mandatory intra-
cellular microorganisms. Worldwide, their main mani-
festation consists of genitourinary and ophthalmic in-
fections (Chlamydia trachomatis). Pulmonary infections
are due to Chlamydia pneumoniae and, less frequently,
Chlamydia psittaci.
The clinical presentation of Chlamydia pneumoniae is
nonspecific. Symptoms may start acutely with pharyn-
gitis and a hoarse voice. Pulmonary infiltrates may
occur as ground-glass opacities and be unilatral or bi-
lateral.
A serologic diagnosis is not feasible, since immuniza-
tion without previous clinical manifestation is common.
Legionella Pneumonia (Legionnaires disease). Legionella
are ubiquitous organisms that are commonly found in
water from sprinklers, air conditioners, and humidifica-
tion systems. The infection occurs by inhalation of aero-
sol of water containing Legionella. It is not always as-
sociated with clinical disease; 1.5−20% of healthy sub-
jects have circulating antibodies.
Legionella pneumonia may be acquired in the com-
munity and in the hospital and its prevalence varies
largely, i. e., 1−22.5%. Men are more commonly affected
than women and there is a seasonal predilection in the
period from June through November.
Symptoms at the beginning of the disease include
fatigue, malaise, joint pain, and headache. One to two
days after infection, the disease manifests fever, nonpro-
ductive cough, pleuritic chest pain, nausea, vomiting, di-
arrhea, abdominal pain, and abnormal neurologic signs.
A laboratory examination may reveal a moderate
leukocytosis, proteinuria hematuria, and hypophos-
phatemia.
Radiologically, diffuse, patchy, and homogeneous
confluent infiltrates are found (Fig. 18.4). Pleural ef fu-
sion is present in 50% of patients, but abscess formation
is rare. The diagnosis of Legionella infection is based on
culture, serologic, and immunologic testing. In clinical
practice, identification of Legionella antigen in the urine
is most useful, as it provides a rapid diagnosis within
hours, whereas the cell culture diagnosis takes several
days.
Rickettsia Pneumonia. This is caused by Coxiella burnetii,
a Gram-negative coccus, which presents clinically as
Q-Fever. Although Q-fever was first described in
Queensland the letter Q stands for query, alluding to the
unknown etiology of the disease at that time. As Coxiella
is found in animal milk and secretions, farmers, animal
dealers, and veterinarians are exposed to the infection.
It can present as a flulike disease with fever, cough, my-
algia, and headaches. During physical examination
splenomegaly, enlarged and tender cervical lymph
nodes, and bradycardia may be found. Rickettsia pneu-
monia cannot be distinguished clinically, radiologically,
or histologically from pneumonia due to Mycoplasma
pneumoniae. The chest radiograph may show segmental
consolidation of lower lobes, patchy infiltrates, and
ground-glass opacities.
The differential diagnosis includes infectious mono-
nucleosis. Additional information on Q-fever is provided
in Chapter 4.
Brucella Pneumonia. Pulmonary infiltrates in Bang dis-
ease are rare and have no typical appearance. Infiltrates
may appear in the perihilar area. Diagnosis is made
serologically. Clinical presentation is described in Chap-
ter 4.
Branhamella catarrhalis Pneumonia. Branhamella or
Moraxella catarrhalis, a Gram-negative diplococcus,
may cause bronchopneumonia in patients with COPD or
with immunosuppression.
Siegenthaler, Differential Diagnosis in Internal Medicine, © 2007 Thieme
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[...]... made in spontaneous sputum or 537 Siegenthaler, Differential Diagnosis in Internal Medicine, © 2007 Thieme All rights reserved Usage subject to terms and conditions of license 18 Pulmonary Opacities Fig 18.14 Invasive aspergillosis of the lung in a patient with ill-defined pneumonic infiltrates in both lower lobes a Right lower lobe b Left lower lobe a b 538 Siegenthaler, Differential Diagnosis in Internal. .. Diagnosis in Internal Medicine, © 2007 Thieme All rights reserved Usage subject to terms and conditions of license 18 Pulmonary Opacities Fig 18.18 Interstitial pulmonary infiltrates in a patient with congestive heart failure a b Fig 18.19 Right-sided interlobar effusion (vanishing tumor) in a 46-year-old man Before (a) and after (b) treatment 542 Siegenthaler, Differential Diagnosis in Internal Medicine, ... pathogenesis is similar Initially, the alveolar epithelium and the capillary endothelium are damaged directly by toxic substances such as oxygen radicals, cytotoxic drugs (bleomycin), or indirectly by immunologic mechanisms that results in release of mediators from inflammatory cells Subsequent to the injury to epithelial and endothelial cells, inflammatory cells migrate into the interstitium and the... typical symptoms, including minor hemoptysis, suggest the diagnosis of pulmonary emboli with infarction A typical, wedge-shaped infiltrate extending from the hilum to the chest wall is not always seen and the infiltrates may be difficult to differentiate from a bronchopneumonia of another origin However, spiral-angio-CT demonstrates the intravascular emboli and confirms the diagnosis Major pulmonary infarction... result from hematogeneous spread from an intra-abdominal abscess Elderly persons and patients with impaired upper airway reflexes (due to neurologic disease or after upper airway surgery [such as tonsillectomy]), alcoholics, and 528 Siegenthaler, Differential Diagnosis in Internal Medicine, © 2007 Thieme All rights reserved Usage subject to terms and conditions of license Infectious Pulmonary Infiltrates... The differential diagnosis of aspiration pneumonia related to infection with anaerobic organisms includes massive aspiration of acidic gastric content, which may cause an acute respiratory distress syndrome (ARDS) by chemical irritation The radiologic findings include varying diffuse, patchy, or confluent infiltrates and consolidation (Fig 18.6) 529 Siegenthaler, Differential Diagnosis in Internal Medicine, ... uncomplicated pulmonary infarction without secondary infection, and bronchopneumonia In pericarditis and myocardial infarction, the character of chest pain is not pleural, i e., it is not influenced by respiration and dyspnea is not the main symptom In pulmonary edema, the sputum may be frothy but frank hemoptysis does not occur 544 Siegenthaler, Differential Diagnosis in Internal Medicine, © 2007 Thieme... inorganic dust exposure are discussed below 545 Siegenthaler, Differential Diagnosis in Internal Medicine, © 2007 Thieme All rights reserved Usage subject to terms and conditions of license 18 Pulmonary Opacities 18.3 Eosinophilic Pulmonary Infiltrates Definition and Classification These infiltrates are due to a heterogeneous group of diseases that have in common a pulmonary infiltration with eosinophilic... Churg−Strauss syndrome have to be considered Drug-Induced Pulmonary Eosinophilia Eosinophilic pulmonary infiltrates have been described with the use of various drugs, most commonly with nonsteroidal anti-inflammatory drugs (NSAIDs), certain antibiotics, L-tryptophan, and recombinant granulocyte− macrophage colony stimulating factor (GM-CSF) Acute Eosinophilic Pneumonia Clinical Features Symptoms include fever,... reaction) are common, in particular in persons with repetitive or chronic exposure wool, or by contaminated meat The most common form is cutaneous infection Gastrointestinal manifestations include abdominal pain, diarrhea, and life-threatening gastrointestinal hemorrhage Recently, anthrax has gained renewed interest since it has been used in biological warfare and bioterrorism Inhalation of even small . Russi 18 18 Siegenthaler, Differential Diagnosis in Internal Medicine, © 20 07 Thieme All rights reserved. Usage subject to terms and conditions of license. 519 18.1 Infectious Pulmonary Infiltrates (Pneumonias) 521 Bacterial. chest pain. Untreated, the fever remains at Siegenthaler, Differential Diagnosis in Internal Medicine, © 20 07 Thieme All rights reserved. Usage subject to terms and conditions of license. 525 Fig the infection at other sites, in particular in the oral cavity and the jaw. The Siegenthaler, Differential Diagnosis in Internal Medicine, © 20 07 Thieme All rights reserved. Usage subject to
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