Pulmonary infections by Dr. Amit Rauniyar

1. PULMONARY INFECTIONS
DR. AMIT RAUNIYAR
1ST YEAR RESIDENT

2. Outline
• Pneumonia
• Types of pneumonia
• Viral infections
• Fungal infections
• Parasitic infections
• Rickettsial infections

3. Pneumonia
• Pneumonia is an acute infection of the
pulmonary parenchyma that is associated with
at least some symptoms of acute infection,
accompanied by the presence of an acute
infiltrate on a chest radiograph

4. Types of pneumonia
• Lobar pneumonia
• Bronchopneumonia(Lobular) pneumonia
• Interstitial(Atypical) pneumonia

5. Lobar pneumonia
• Typical of pneumococcal pulmonary infection.
• In this pattern of disease, the inflammatory exudate
begins within the distal airspaces.
• The inflammatory process spreads via the pores of
Kohn and canals of Lambert to produce non-segmental
consolidation.
• If untreated, the inflammation may eventually involve
an entire lobe
• Because the airways are usually spared, air
bronchograms are common.
• S. pneumoniae is by far the most common cause of
complete lobar consolidation

7. Lobular or bronchopneumonia
• Inflammation is centered primarily in the terminal and
respiratory bronchiole.
• Tends to spread segmentally
• As the inflammation progresses, exudative fluid extends
peripherally along the bronchus to involve the entire
pulmonary lobule.
• Radiographically, multifocal opacities that are roughly
lobular in configuration produce a "patchwork quilt"‘ or
patchy appearance because of the interspersion of normal
and diseased lobules
• Exudate within the bronchi accounts for the absence of air
bronchograms in bronchopneumonia
• Most typical of staphylococcal pneumonia

9. Interstitial pneumonia
• Inflammation centred at alveolar walls and
interstitium.
• This results in a radiographic pattern of
airways thickening and reticulonodular
opacities.
• Air bronchograms are absent because the
alveolar spaces remain aerated.
• The usual causes of interstitial pneumonia are
viral and mycoplasmal infections.

10. • Chest radiography remains an important component of the evaluation
of a patient with a suspicion of pneumonia, and usually is the first
examination to be obtained.
• Radiograph is important for
– confirmation of pneumonia,
– location ,
– following its course
– and complications.
• CT has been shown to be more sensitive than radiography in the
• detection of subtle abnormalities.
• CT may show findings suggestive of pneumonia up to 5 days earlier
than chest radiographs.

11. • CT is recommended
– in patients with clinical suspicion of infection and
normal or non-specific radiographic findings
– in patients with increased risk of pulmonary
infection (e.g. neutropenia).
– in patients with pneumonia and persistent or
recurrent pulmonary opacities to diagnose or rule
out underlying or alternative disease processes.

12. Viral infections
• Viruses are a major cause of upper respiratory
tract and airways infection, although
pneumonia is relatively uncommon.
• In infants and children viral pneumonia are
common
• Viral pneumonia are uncommon in adult
unless immunocompromised.
• Viral infections may predispose to secondary
bacterial pneumonia.

13. • Viral pneumonia usually commences in distal
bronchi and bronchioles as an interstitial
process
• Chest radiographic features are nonspecific
and usually demonstrate a pattern of
bronchopneumonia or interstitial opacities
• The clinical course of infection depends on
the overall immune status of the host.

14. • The radiological appearances of a viral
pneumonia are very varied, but often include:
1. Peribronchial shadowing
2. Reticulonodular shadowing
3. Patchy or extensive consolidation

15. Influenza
• Influenza is the most common cause of viral
pneumonia in adults.
• Outbreaks of influenza can occur in pandemics,
epidemics, or sporadically
• It is transmitted by aerosolised or respiratory
droplets.
• Infection due to H1N1 influenza or swine flu was
first described in 2009 and has produced a
spectrum of illness from self-limited disease to
fatal pneumonia.

16. • In adults there is often bilateral lower lobe
patchy airspace opacification.
• In children, a diffuse interstitial
reticulonodular pattern is commonly seen.
• The development of lobar consolidation,
pleural effusion, or cavitation suggests
bacterial superinfection.

17. • Typical radiographic and CT findings in swine
flu pneumonia include patchy ground glass or
airspace consolidation involving the central
and lower lungs , with progression to
confluent bilateral airspace consolidation in
the most severely affected patients .
• Occasionally especially during epidemics a
fulminating haemorrhagic pneumonia may be
seen.

20. Varicella-zoster virus
• Varicella pneumonia occurs more often in
adults than in children.
• Pneumonia, although rare(1 in 400 cases), is
the most serious complication affecting adults
with chickenpox.
• Clinically pneumonia will be concurrent with
the typical skin rash.

21. Varicella-zoster virus
• Chest radiographs characteristically show
diffuse bilateral ill-defined nodular opacities 5
to 10 mm in diameter.
• These opacities usually resolve completely;
however, in some patients these opacities
involute and calcify to produce innumerable
small (2 to 3 mm) calcified nodules

23. Herpes Simplex Virus
• Herpes simplex virus type 1 (HSV-1) pneumonia may be
a life threatening infection seen almost exclusively in
immunocompromised and/or mechanically ventilated
patients,
• CT findings-
• patchy lobular, subsegmental or segmental
consolidation
• ground-glass opacities;
• associated small centrilobular nodules
• tree-in bud pattern,
• nodules surrounded by a ‘halo’ of ground-glass opacity

27. Adenovirus
• Adenovirus accounts for 5 to 10% of acute
respiratory infections in infants and children but
for less than 1% of respiratory illnesses in adults.
• Overinflation and bronchopneumonia
acompanied by lobar atelectasis are the most
frequent radiographic manifestations of
adenovirus pneumonia;
• However adenovirus in children may present as
lobar or segmental consolidation.

28. • Swyer–James–MacLeod syndrome is
considered to be a post-infectious
bronchiolitis obliterans (BO) secondary to
adenovirus infection in childhood.
• CT findings in post-infectious BO consist of
– sharply marginated focal areas of increased and
decreased lung opacity
– with reduced vessel size in lucent lung regions,
– bronchial wall thickening and bronchiectasis.

31. Respiratory Syncytial Virus (RSV)
• Respiratory syncytial virus (RSV) –MCC viral
respiratory tract infection in infants.
• Risk factors are prematurity (< 37 weeks
gestation), congenital heart disease, chronic
lung disease, immunocompromised status and
multiple congenital abnormalities.
• CT findings consist of small centrilobular
nodules, airspace consolidation, ground-glass
opacities and bronchial wall thickening.

32. Epstein–Barr Virus (EBV)
• Primary infection with EBV occurs early in life and
presents as infectious mononucleosis
• Typical triad of fever, pharyngitis and
lymphadenopathy,
• often accompanied by splenomegaly.
• Less than 10 percent have intrathoracic
manifestations.
• Commonest radiographic abnormality is lymph
node enlargement and the lungs may show an
isolated opacity or reticulonodular shadows.

33. Hantaviruses
• Hantavirus infection may cause diffuse
airspace disease, termed hantavirus
pulmonary syndrome (HPS).
• The mortality rate of treated patientsis high,
approaches 35%.
• Imaging findings may be initially normal, but
progressively worsen, displaying signs of
pulmonary oedema and acute respiratory
distress syndrome.

34. Cytomegalovirus (CMV)
• Cytomegalovirus pneumonia is a major cause of
morbidity and mortality following hematopoietic stem
cell (HSC) and solid organ transplantation and in
patients with AIDS in whom CD4 cells are decreased to
fewer than 100 cells/mm3.
• Cytomegalovirus infection occurs in up to 70% of BMT
recipients, and approximately one-third develop CMV
pneumonia.
• This complication characteristically occurs during the
post-engraftment period (30–100 days after
transplantation), with a median time onset of 50–60
days post-transplantation.

35. • CT features of CMV pneumonia consist of
lobar consolidation, diffuse and focal ground-
glass opacities, irregular reticular opacities,
and multiple miliary nodules or small nodules
with associated areas of ground-glass
attenuation(‘halo’)

36. New Emerging Viruses
• Human Metapneumovirus (hMPV).
• Human metapneumovirus (hMPV) is a
recently identified RNA virus.
• It is usually associated with acute respiratory
tract infections including upper airway
disease, lower airway bronchitis and
bronchiolitis, influenza-like syndrome and
pneumonia.

37. • CT findings consist of patchy areas of ground-
glass attenuation, small nodules and
multifocal areas of consolidation in a bilateral
asymmetric distribution .
• Pulmonary parenchymal involvement during
the course of hMPV pneumonia infection may
result in interstitial lung disease and fibrosis.

39. SARS
• Severe Acute Respiratory Syndrome
• Caused by SARS-associated coronavirus (SARS-
CoV)
• A systemic infection that clinically manifests
as progressive pneumonia.
• Histologically, acute diffuse alveolar damage
with airspace oedema is the most prominent
feature in patients who die before the 10th
day after onset of illness.

40. • The imaging features of SARS-CoV infection
consist of unilateral or bilateral ground-glass
opacities, focal unilateral or bilateral areas of
consolidation, or a mixture of both.

42. Avian Flu (H5N1)
• Avian influenza is caused by the H5N1 subtype of
the influenza A virus.
• Most human infections due to close contact with
infected birds, usually poultry or their products.
• The overall case fatality rate for H5N1 infections
exceeds 60%.
• Most chest radiographs are abnormal at the time
of presentation, with multifocal consolidation the
commonest radiographic finding.

43. • The most common CT findings consist of focal,
multifocal, or diffuse ground-glass opacities or
areas of consolidation.

44. Fungal infections
• Fungal Pneumonia
– Are now seen with increased frequency
• Increase in the incidence of disease caused by
pathogenic fungi in healthy hosts
• Emergence of opportunistic species in immuno-
compromsied hosts

45. Fungal Infections:
Saprophytic Fungi
Candidiasis
Pneumocystis
Cryptococcosis
Mucormycosis
Aspergillus
Pathogenic Fungi
Histoplasmosis
Coccidioidomycosis
Blastomycosis
Paracoccidioidomycosis

46. 1. Histoplasmosis
• Histoplasma capsulatum
• Inhalation of soil or dust contaminated by bird or
bat excreta
• The overwhelming majority (95% to 99%) of
infections caused by H capsulatum are
asymptomatic.
• A routine chest film demonstrating multiple well-
defined calcified nodules less than 1 mm in size,
with or without calcified hilar or mediastinal
lymph nodes, may be the only indication of prior
infection.

47. • Acute histoplasma infection most often
presents with the abrupt onset of flu-like
symptoms.
• The chest radiograph in such patients may be
normal or may show nonspecific changes,
including subsegmental airspace opacities
with or without associated hilar lymph
enlargement

48. • Massive inhalation of organisms:
– May show fairly discrete, nodular opacities 3-4
mm in diameter with hilar adenopathy

49. Fig. acute histoplasmosis
widespread bilateral well-defined 3-5 mm
nodules

50. Fig. Histoplasmosis
incidental finding of multiple calcified
pulmonary nodules

52. • Histoplasmoma:
– A solitary, sharply defined nodule <3 cm
– Most common in lower lobes-frequently calcify
• Fibrosing Mediastinitis (chronic pulmonary
disease):
– Uncommon late manifestation
– Stenosis of venacava, oesophagus, trachea, bronchi or
central pulmonary vessels
– CXR: widened mediastinum

53. • H capsulatum can also cause chronic
pulmonary disease, usually in patients with
underlying emphysema.
• Unilateral or bilateral upper lobe cicatrizing
atelectasis with marked hilar retraction may
be seen.
• Mimic postprimary TB.
• Similarly, chronic upper lobe fibrocavitary
disease may be seen

54. • Asymptomatic blood-borne dissemination of H
capsulatum is common, as judged by the frequency of
calcified splenic granulomas in residents of endemic
areas.
• Clinically apparent disseminated histoplasmosis,
however, is extremely rare and is usually seen in infants
or immunocompromised adults.
• The chest film most commonly shows widespread 2- to
3-mm nodules that are indistinguishable from those of
miliary TB, although reticular opacities and patchy
areas of consolidations may also be seen

55. 2. Coccidioidomycosis
• Coccidioides immitis
• Found in soil
• 4 types of clinical and radiographic pulmonary
infections:
a) Acute Coccidioidomycosis
b) Persistent Coccidioidomycosis
c) Chronic progressive disease
d) Disseminated (Miliary) Coccidioidomycosis

56. a) Acute coccidioidomycosis
• Develops in 40% of infected adults
• Self-limiting viral type illness: Valley fever
• Associated with erythema nodosum and Arthralgia
• CXR: may be normal or
 Focal or multifocal segmental air-space opacities
 Associated with Hilar and mediastinal adenopathy and pleural effusion
b) Persistent coccidioidomycosis (infection beyond 6-8
weeks)
• Coccidioidal masses or nodules (coccidioidomas)
• Areas of round pneumonia- subpleural regions of upper lobes
• Cavitate rapidly-produce characteristic thin-walled cavities

57. c) Chronic progressive disease
• Upper lobe fibro-cavitatory disease
– Thin-walled cyst : Grape-skin sign
• Similar to Post-primary TB and Histoplasmosis
d) Disseminated (Miliary) coccidioidomycosis
• Relatively rare
• Affects the immuno-compromised patients

58. Fig. coccidioidomycosis
a non-specific patch of consolidation present in left
lower lobe. One year later a thin-walled cavity is

59. Fig. Chest x-ray showing Grape-skin sign
thin-walled grape-skin cyst
over time cavity may deflate and acquire slightly thicker
wall

60. 3. Blastomycois
• Caused by Blastomyces dermatidis
• Chronic systemic disease
• Primarily affects the lungs and the skin
• Pulmonary infections often asymptomatic

61. • Radiographically:
– Usually non-specific
• Most common presentation:
– Homogeneous non-segmental air space opacification
with propensity for upper lobes
• Less common presentation:
– Single or multiple masses
– Cavitate in 15% of cases
– Tend to occur in patients with prolonged symptoms (1
months)-may mimic Bronchogenic Ca

62. • Less common presentation:
– Diffuse reticulo-nodular opacities
• Pleural effusion and lymph node enlargement
– uncommon
• Disseminated miliary form
– In immunocompromised hosts

63. Fig. Blastomyces dermatidis infection
chest radiograph shows an ill-defined mass in the left
upper lobe. CT scan through the upper lobes shows an
irregular mass in the left upper lobe with surrounding
ground glass opacity. Biopsy revealed Blastomyces
dermatidis infection

64. 4. Paracoccidioidomycosis(PCM)
• Also known as South American Blastomycosis
• Endemic disease caused by dimorphic fungi
– Paracoccidioides brasiliensis
• Most frequent systemic mycosis in Latin
America esp. in Brazil
• HRCT:
– Areas of ground-glass opacities, nodules,
interlobular septal thickening, air-space
consolidation, cavitation and fibrosis

65. 5. Candidiasis
• Candida albicans
• Important pathogen esp. in
Immunocompromised patients:
– Particularly in patients with underlying
malignancy, IV drugs abuser, AIDS, following Bone
marrow transplant
• Lung infection is usually due to
hematogeneous spread

66. • Radiographically, may present as
– Chronic pneumonia
– Abscess formation
– Mycetoma formation
• CT
– Multiple bilateral nodular opacities often associated
with areas of consolidation and ground glass
opacities-CT halo sign
• Less common presentations:
– Pleural effusion, thickening of bronchial walls,
cavitation

67. Fig. disseminated candidiasis with CT
halo sign

68. 6. Pneumocystis carinii
• Opportunistic fungal pathogen
• Cause pneumonia in patients with
– AIDs
– Organ transplant
– Undergoing chemotherapy
– Immunosuppressive treatment
– Long term corticosteroids

69. • Radiographically,
– May have normal findings
– Classic features: diffuse, bilateral interstitial infiltrates
in peri-hilar distribution
• CT:
– Done in a highly suspicious case for confirming the
diagnosis
– Peri-hilar ground glass opacities, in a patchy or
geographic distribution with areas of superimposed
interlobular septal thickening: Crazy Paving pattern
– May rapidly progress to involve entire lung

71. Fig. Pneumocystis Pneumonia in an HIV patient:
Crazy paving sign

72. 7. Cryptococcosis (Torulosis)
• Cryptococcus neoformans (yeast form fungi)
• Found in soil or bird droppings
• Mostly asymptomatic
• Cryptococcal pneumonia
– Common in AIDS (when CD4 <100)

73. • Chest radiography:
– Homogeneous, segmental or lobar opacifications
– Miliary, reticular or reticulo-nodular interstitial
patterns
– Pulmonary masses-5 mm to large (usually pleura-
based) with ill-defined edge known as Torulosis
• May show Halo sign
• May cavitate
– Lymph node enlargement and calcification is
unusual

74. Fig. cryptococcus
a pleurally based mass like area of consolidation in the
left upper lobe is present in a patient who also had
cryptococcal meningitis

75. 8. Mucormycosis
• Opportunistic fungal infection of order
Mucorales
• Broad, non-septated hyphae that randomly
branch at right angles
• Spreading destructive infections in Diabetics
and immuno-compromised

76. • Radiographically,
– Lobar or multi-lobar areas of consolidation and
solitary or pulmonary nodules and masses with
Cavitation in 26-40 % cases-air crescent sign
suggestive of invasive fungal infection in found in 5-
12.5 % cases
• CT:
– Non-specific
– Solitary or multiple areas of consolidation or
– solitary of multiple nodules surrounded by a Halo of
ground-glass attenuation and cavitation

77. 9. Aspergillus infection
• Caused by Aspergillus species, usually A.
fumigatus
• Can take different forms, depending on an
individual’s immune response to the
organism, classically:
– Aspergilloma or Mycetoma form
– Invasive forms
– Allergic forms

78. Aspergilloma
• Also known as fungus ball
• Aspergillus mycetomas are saprophytic
growths which colonise a pre-existing cavity in
the lung (e.g. from sarcoidosis or tuberculosis)
• Usually in the upper lobes or superior
segments of the lower lobes
• The mass is typically separated from the cavity
wall by an air space -air crescent sign or
monad sign

79. • A ball of hyphae, mucus and cellular debris
that colonizes a pre-existing bulla or a
parenchymal cavity created by some other
pathogen or destructive process
• Invasion into lung parenchyma does not occur
unless the host defense mechanisms are
compromised
• Usually asymptomatic
• May cause Hemoptysis-which can be massive

80. • Radiographs or CT findings:
– Solid round mass within an
upper lobe cavity, with an area
of Air-crescent separating the
mycetoma from the cavity wall-
roll dependently on decubitus
radiographs
– Progressive apical pleural
thickening adjacent to a cavity is
common
• should prompt a search for a
complicating mycetoma

81. Fig. Air-crescent or Monad sign of
Aspergillus
gravity dependence of fungus ball

82. Invasive Aspergillosis
• Angio-invasive:
– Occlusion of small-to-medium pulmonary arteries
– Developing necrotic hemorrhagic nodules or
infarcts
– CT:
• Multiple nodules surrounded by a Halo of ground glass
attenuation CT HALO sign or
• Pleural-based wedge-shaped areas of consolidation
• Air crescent sign

83. Halo sign: Angio-Invasive aspergillosis
PA radiograph and axial CT image show right upper lobe mass
with peripheral ground glass opacity constituting Halo sign

84. • Broncho-invasive:
– In patients with severe
neutropenia and in patients
with AIDS
– Chest X-ray:
bronchopneumonia,lobar
consolidation or multiple
nodules.

85. Allergic Bronchopulmonary
Aspergillosis (ABPA)
• A hypersensitivity reaction-type III
• Associated with asthma, elevated serum IgE
levels, positive precipitins and skin reactivity to
aspergillus
• Chest X-ray:
– Non-segmental areas of opacities most common in
upper lobes
– Lobar collapse
– Thick tubular opacities due to bronchi distended with
mucus and fungus- Finger-in-gloves sign
– Occasional cavitation

86. • CT:
– Usually, hypodense mucus plugs
– 20% cases- hyperdense mucus plugs
– Recurrent attacks:
• Pulmonary fibrosis and bronchiectatic changes

87. Fig. allergic broncho-pulmonary aspergillosis
NECT axial (left) and oblique sagittal (right) chest

88. Fig. allergic bronchopulmonary aspergillosis
HRCT scan demonstrating finger-like opacities
due to dilated mucus-filled bronchi

89. • PARASITIC INFECTIONS

90. Protozoan infections
• Toxoplasmosis
• Toxoplasmosis rarely involves lungs
• Occasionally responsible for interstitial
pneumonia
• Chest radiograph shows patchy consolidation
and mediastinal lymphadenopathy.

91. Amoebiasis
• Entamoeba histolytica is usually secondary to
liver involvement.
• The lung is the second most common
extraintestinal site of amoebic involvement
after the liver.
• Pleuropulmonary amoebiasis is a significant
complication of amoebic liver abscess.
• Liver abscess can extend directly into the lung,
causing pulmonary consolidation.

92. • Right-sided found in 86% of cases and
consists of hemidiaphragmatic elevation,
pleural effusion or empyema, and/or
thickening and plate-like atelectasis.
• If communication with a major bronchus
occurs, haemoptysis can develop, containing
the ‘anchovy paste’ pus coming from the
amoebic abscess.
•

93. Metazoan Infections:
• Loeffler’s Syndrome-
– Transient pulmonary opacities of predominantly
eosinophilic histology associated with blood eosinophilia
– Cause: Parasitic worms that lodge in or migrate through
the lungs at some stage of its life-cycle.
– Ascaris, Taenia, Strongyloides, Ankylostoma

94. Paragonimiasis
• Caused by a fluke Paragonimus westermani.
• infestations are acquired from eating raw or
incompletely cooked fresh water crabs and crayfish
• Radiological changes tend to be bilateral, including a
mixture of consolidation, nodules and band, tubular
and ring opacities.
• In the lower lobes parenchymal changes mimic
bronchiectasis, and in the upper lobes, tuberculosis.
• The constellation of focal pleural thickening and
subpleural linear opacities leading to a necrotic
peripheral pulmonary nodule is another frequent CT
finding of paragonimiasis.

95. • Burrow sign
• A linear track extending from the pleural
surface or hemidiaphragm to a cavitary or
cystic pulmonary nodule.
• The linear track represents the path followed
by the worms within the lung, and
• the cavitary or cystic pulmonary nodule
contains both the adult worms and their eggs

96. Schistosomiasis
• Schistosomiasis may cause pulmonary eosinophilia.
• If the eggs lodge in pulmonary arteries of less than 100
μm, the lesions they cause are small granulomas like
miliary tuberculosis or sarcoidosis,
• If they lodge in arteries a larger size the irritation
causes vascular necrosis and fibrotic occlusion results
in pulmonary hypertension if sufficient vessels are
occluded.
• A third type of reaction results in diffuse interstitial
fibrosis.

97. Echinococcosis (Hydatid Disease)
• Hydatid disease (echinococcosis) is caused by
the larval forms of Echinococcus granulosus,
Echinococcus multilocularis and Echinococcus
vogeli.
• Echinococcus granulosus (unilocular cystic
echinococcosis) is the most common form
affecting man

98. • Humans are accidental hosts and acquire
infection by ingesting ova from fomites or
contaminated water and by direct contact
with dogs.
• Symptoms are usually non-specific.
Complications occur because of cyst rupture.

99. • Hydatid cysts are usually solitary but may be
multiple and/or bilateral in 20% of cases.
• 10 percent are associated with hepatic cysts.
• In contrast to hepatic cysts pulmonary hydatid
cysts do not have a calcified wall.
• They may be ruptured (two-thirds) or
unruptured (one-third) at the time of
presentation.

101. • The larval organisms travel to the liver and the
lungs and, if they survive host defenses, encyst
and gradually enlarge.
• Pulmonary echinococcal cysts are composed of
three layers:
• exocyst –acellular laminated chitinous layer,
which is a protective membrane;
• endocyst-inner germinal layer which produces
the "daughter cysts"; and
• Pericyst- a surrounding capsule of compressed,
fibrotic lung.

102. • Uncomplicated Pulmonary echinococcal cyst
characteristically present as well-
circumscribed, round spherical soft tissue
masses.
• Pulmonary hydatid cysts may vary from 1 to
20 cm.

103. • Cyst growth produces erosions in the bronchioles that are included
in the pericyst, and as a result, air is introduced between the
pericyst and the exocyst
• This air collection appears as a thin, radiolucent crescent in the
upper part of the cyst and is known as the crescent sign or
meniscus sign
• Some authors consider this to be a sign of impending rupture and
an indication for emergency thoracotomy
• As air continues to enter this space, the two layers separate
completely and the cyst shrinks and ruptures, allowing the passage
of air into the endocyst .
• An air-fluid level inside the endocyst and air between the pericyst
and the endocyst with an “onion peel” sign or Cumbo sign or
Double arch sign

104. • After partial expectoration of the cyst fluid and
scolices, the cyst empties and the collapsed
membranes can be seen inside the cyst -serpent sign
• When it has completely collapsed, the crumpled
endocyst floats freely in the cyst fluid -water lily sign or
camolate sign .
• If the fluid is entirely evacuated by expectoration, the
remaining solid components will fall to the most
dependent part of the cavity- mass within a cavity
• After the complete expectoration of the cyst fluid and
membranes, the cyst appears only air filled, known as
the “dry cyst sign” or empty cyst sign.

109. • Secondary infection of a hydatid cyst may
produce a lung abscess with or without
surrounding lung opacity.
• Rupture into the pleural space causes an
effusion or, if there is airway communication,
a hydropneumothorax.

110. References
• Text book of Imaging and radiology, David
sutton
• Fundamentals of diagnostic radiology, Brant
and Helms
• Grainger and Allison’s Diagnostic radiology
• Christopher M. et al, Imaging Pulmonary
Infection: classic signs and patterns (2014)
American journal of radiology

111. THANK YOU