Philip
C. Goodman,
MD
Pulmonary
Lynn
M. Schnapp,
Toxoplasmosis
The chest radiographs obtained in nine patients with acquired immunodeficiency syndrome (AIDS) and pulmonary toxoplasmosis were reviewed. In three patients, a bilateral, diffuse, fine to medium reticulonodubar pattern indistinguishable from that seen in Pneumocystis carinii pneumonia (PCP) was observed. In six patients, however, a bilateral, predominantly coarse, nodular pattern was observed. This type of abnormality is unusual with PCP, and its presence may help in distinguishing between pulmonary infections caused by Toxoplasma gondii and P carinii. Other opportunistic pneumonias occurling in patients with AIDS, including tuberculosis, histoplasmosis, and coccidioidomycosis, might show similar coarse, nodular opacities on chest radiographs and thus may not be differentiated from pulmonary toxoplasmosis. No hilar or mediastinab adenopathy was observed. Two patients had pleural fluid. Radiologists familiar with the chest radiographic appearance of Tgondii pneumonia could be first to suggest this unusual complication of AIDS. Index
terms:
Acquired
immunodeficiency
syn-
drome 60.2074,
(AIDS), 60.2518 #{149} Lung, diseases, 60.2075 #{149}Pneumocystis cannii, 60.2075 . Toxoplasmosis, 60.2074 Radiology
1992;
MD
184:791-793
in AIDS’
variety
of organisms
sible
for
80% of the AIDS pathogens have etiobogic agents
population (2), gained notoriety of lung disease.
cipabby
Histoplasma
ioides mans;
immitis, and and pyogenic
Streptococcus
influenzae, Toxoplasma nized cause (CNS)
gondii of central
disease
tients with toxoplasmosis.
Durham,
NC 27710 (P.C.G.)
and the Medical
Address reprint requests RSNA, 1992
to P.C.G.
such
as
a well-recognervous system
in patients
with
AIDS
AIDS.
with this reported, of articles suggests (3-10). Raof the abseen in pa-
in the
features
AND
literature
on
AIDS
(eight
pulmonary
were
observed
patients
3 years). The diagnosis was made from stains
were
toxoplasin a 7-year
seen
in the last
patients
exhibited
findings of Kaposi lymphoma. The
and
The recent
brief
was
literature
toxoplasmosis reviewed,
radiographic
picted cussed.
chest
concerning in patients
and
the
pulmowith
reported
radiographic
AIDS
or de-
patterns
are dis-
RESULTS The chest radiographic features in our nine patients were as follows: The chest radiographs obtained in six demonstrated bilateral, predominantly dium to coarse, poorly defined opacities (Figs 1, 2). A secondary
of medium
to coarse
was occasionally opacities were
reticular
menodular pattern
opacities
observed. approximately
The
nodular
3-5 mm in diameter and were distributed mostly in the middle to bower area of the lungs in three patients, diffusely in two patients, and predominantly in the upper lobes patient. In some patients involvement, coalescence
nodular
opacities
neous grams. diffuse,
resulted
with of the
in homoge-
opacification and air bronchoIn the remaining three patients bilateral, fine to medium reticu-
bar pattern
was observed.
or mediastinal
demonstrated. served in two
METHODS
with
of these
pathologic or non-Hodgkin
descriptions in six of these patients were previously reported (3). Chest radiographs were evaluated for parenchymal, pleural, hibar, and mediastinab abnormalities. When available, followup chest radiographs were interpreted for evidence of disease progression or improvement.
hilar
patients and
recent
clinical
in one profuse
and pulmonary This article describes findings of T gondii
the radiographic and pneumonia in nine patients with AIDS and summarizes the observa-
period
Service, San Francisco General Hospital Medical Center and Department of Medicine, University of California, San Francisco (L.M.S.). Received February 24, 1992; revision requested March 19; revision received March 30; accepted April 7.
is
or
Coccidneofor-
bacteria
Pulmonary involvement parasite is less frequently but an increasing number describing this complication that its incidence is rising diobogists should be aware normalities that might be
mosis Duke Erwin Rd.
capsulatum, Cryptococcus
None
clinical sarcoma
nary
pneumoniae, Haemophilus and Staphylococcus aureus.
tions noted the subject.
of Radiology, Box 3808,
other as
Among these are mycobacterial speaes such as Mycobacterium tuberculosis and M avium intracellulare; fungi, prim-
Nine
the Department Medical Center,
infections
in patients with the acquired immunodeficiency syndrome (AIDS) (1,2). The lung is often the principal organ involved, and the ensuing pneumonia is frequently the index diagnosis for AIDS. While Pneumocystis carinii remains the leading cause of pneumonia in these patients, affecting 60%-
MATERIALS
1 From University
negative.
are respon-
opportunistic
sis was culture
diagnosed in both
were unilateral in amount.
No definite
adenopathy
Pleural patients,
was
fluid was oband toxoplasmo-
on stains of the cases. The effusions
and
a
small
fluid
to moderate
of toxoplasmosis of bronchoalveolar
bavage (BAL) fluid, transbronchial biopsy material, pleural fluid, and open-lung biopsy
specimens.
The
diagnosis
tient was made from autopsy the time of diagnosis, stains ganisms, including P carinii, species, fungi, and pyogenic
in one
pa-
samples. At for other ormycobacterial bacteria were
Abbreviations: AIDS = acquired immunodeficiency syndrome, BAL = bronchoalveolar lavage, CNS = central nervous system, HIV = human immunodeficiency virus, PCP = Pneutnocystis carinii pneumonia.
791
Of our nine patients, four died before follow-up chest radiographs were obtamed. The fate of one patient remains unknown. The chest radiographs in two patients, both with fine to medium reticubar opacities, were normal 10 days and 1 Y2 years
later,
patient terval.)
respectively.
(The
was lost to follow-up In two patients with
ular
opacities
a decrease
latter
in the incoarse nod-
in size of the
nodules was observed on chest graphs obtained 14 and 21 days respectively.
The
radiographic
findings
viously reported and pulmonary
reviewed
radiolater,
in 20 pre-
patients with toxoplasmosis
(4-6,8,10).
The
AIDS were
literature
con-
tains few illustrations and little descriptive analysis of the radiographs. Commonly reported are bilateral infiltrates, inhomogeneous and homogeneous consolidation, or interstitial infiltrates. In
two
cases,
a bower
lobe
distribution
and
some right-left asymmetry was either illustrated or implied (4,5). In five of 13 patients with bilateral infiltrates, “nodubar features” were seen but are neither illustrated nor further described (8).
These possibly are similar to the coarse nodular opacities we observed. One patient was first seen with a solitary lung nodule (10). No adenopathy or pleural fluid was described, but these articles
were
primarily
concerned
with
clinical
features of toxoplasmosis, and negative findings may not have been recorded. With appropriate therapy, most patients recovered, but comments regarding radiographic changes are, again, scarce. In
one
patient,
“rapid
clinical
graphic improvement” for toxoplasmosis was
patient series
and
was incorporated (8), which
provement no mention graphs.
into
reported
The
other
a larger
clinical
in 10 of 13 patients of follow-up chest series
ted radiographic
radio-
after treatment reported (9). This im-
but made radio-
similarly
descriptions
omit-
after
ther-
apy.
DISCUSSION T gondii
is an obligate,
protozoan Felines
are
that
exists
the
definitive
man infection undercooked
Figure 2. eral, coarse
intracellular
in three host
(11).
of
or sporulated oocysts (12). The organism dwells in a variety of nucleated cells and requires am intracellular envi-
ronment
to multiply. tissues
Most
are
matter of the brain but alveolar lining
gray
commonly and
white
and the retinal cells, cells as well as skebe-
cytes
and
of toxoplasmosis
brain,
but
pendent
of the
lung
in the protooccurs, and even-
cause
792
Radiology
resistance
chronic
macrophages,
cence
on the native
anteroposterior
tually a chronic state of latent infection is established. In general, the brain harbors most of the parasite burden, but residual organisms may also be observed in the lung (14). After infection with the human immunodeficiency virus (HIV) and subsequent depletion of CD4 T-cell lympho-
tab muscle and the heart are also affected (13,14). In the short term, proliferation of the organism leads to parasitemia that lasts for a period deindividual. A reduction zoan population then
An
chest
radiograph
demonstrates
bilat-
Hu-
is initiated by ingestion meats containing tissue
involved
toxoplasmosis. opacities.
forms.
cysts p
Pulmonary nodular
Tgondii
reactivation
without
a person
infestation of disease.
may
primary occur
Most
will
reactivation
have
recrudes-
involve
the
in the
and is postulated as a pneumonia in patients symptoms (6). Even if the
of T gondii
CNS
with
may
organism and
most
proliferated
has
spread
to
the
patients,
necessarily
lungs,
CNS precede
in the
brain
as is the
symptoms
case
may
respiratory
in
not
diffi-
culties (6,8). In fact, of six patients recently reported by one of the authors, a majority were first seen with pulmonary toxoplasmosis as their first indication of HIV infection (3). The prevalence of the organism in adult populations is strongly related to geographic location and diet. In Europe as many as 90% of adults harbor the parasite frequent
are
(12).
In
the
United
manifestations
expected.
Nevertheless,
States of
this
bess disease
in American
September
1992
urban environments seropositivity for T gondii approaches 11%-16% of adults who are in high-risk categories for HIV infection (11). Thus, there is a well-established
and
pool
abroad
of individuals
who
toxoplasmosis. the AIDS-defining
may CNS
both
develop
here
AIDS
and
was of patients in the United States, and T gondii encephalitis was seen in 25% of AIDS patients in some European countries
(11). In a French
toxoplasmosis illness in 3.7%
study,
the frequency
of
and, within this group, lung involvement in five of 14 (36%) patients with disseminated toxoplasmosis (7). The that
the
incidence
of T gondii
infection is increasing is discussed in another French review, in which the ratio of pulmonary toxoplasmosis to Pneumocystis carinii pneumonia (PCP) cases increased from 1 :284 for the years to 1:128 in 1987 1 :38 by 1988 (8).
1984-1986
mately
and
approxi-
The clinical features of T gondii pneumonia are indistinguishable from those of PCP; a more rapid onset of symptoms,
however,
may
the pathogen are first seen productive occasionally,
favor
T gondii
as
(8). In general, patients with fever, dyspnea, noncough, night hemoptysis
sweats, and, (3,4,8-10). Hy-
poxemia is common, but physical ination abnormalities are unusual two patients an acute pulmonary caused ticemia
by toxoplasmosis was rapidly fatal
In our series
the diagnosis
plasmosis was made tients by identifying
choalveolar
(BAL)
biopsy
biopsy tissue
samples, at autopsy.
the diagnosis tients zoites
of toxo-
fluid,
and
was
by identification in BAL fluid
tient, BAL fluid and examination
material,
open-
pleural fluid, In another
made
number
of patients.
diagnostic
tool
and series,
in 10 of 11 pa-
of T gondii tachy(8). In the other pa-
analysis was negative of an open-lung bi-
methamine, is effective (8). The nosis, however, may be delayed
tissue
in a
It provided within 2 days
proof of T gondii infection and was recommended
as an adjunctive
this
References
cause
that
able from however,
may
diffuse
lung
ab-
ordering
of differential
In the case of pulmonary sis versus
PCP,
the
quality
diag-
3.
mab abnormality may provide a clue to the nature of the underlying pneumonia. As noted in our series and as implied by others (8), pulmonary toxoplas-
appearance
has been
ported in a non-AIDS monary toxoplasmosis only rarely produce much more typically
ticular opacities fine to medium
nodular A similar
incidentally
patient with pub(16). PC? would this pattern and produces fine re-
in three
of our
patients
are
indistinguishable from those seen with PCP. While capable of producing lymph node enlargement in other hosts (18), T gondii infections in AIDS patients appear to rarely if ever cause radiographically visible hilar or mediastinal adenopathy. P carinii similarly rarely is seen with lymph node enlargement. While pleural fluid is rarely observed with P carinii infection, in our series, effusions were observed in two of nine (22%)
with
patients
Coarse
nodular
it is seen
mosis
with
may
also
toxoplasmosis. parenchymal
(20).
pose
a more
Thus,
toxoplas-
be observed
in AIDS
these
may
messes.
may
also
infections radiographic
be observed
If present,
favor
may chal-
in these
of tuberculosis.
plasmosis
that
It has been for pulmonary
was
organism
necessary
for diag-
is usually
detected
after preparations of BAL fluid or tissue material with Giemsa stain or standard
Thus
culture
may
some
not provide
authors
should
suggest
be performed
tissue
to identify
dard
Volume
184
Number
#{149}
3
coarse,
atypical
ra-
nodu-
for PCP,
radiologist to the toxoplasmosis.
possiU
PC. AIDS. In: Freundlich IM, Bragg 0G. eds. A radiologic approach to diseases of the chest. Baltimore: Williams & Wilkins, 1992; 489-506. Murray JF, Felton CP, Garay S, et al. Pulmonary complications of the acquired immunodeficiency syndrome: report of a National Heart, Lung and Blood Institute workshop. N Engl J Med 1984; 310:1682-1688. Schnapp LM, Geaghan 5, Campagna A, et al. Toxoplasma gondii pneumonitis in patients infected with the human immunodeficiency virus. Arch Intern Med 1992; 152:1073-1077. Mendelson MH, Finkel LF, Meyers BR, Lieberman JP, Hirschman SZ. Pulmonary toxoplasmosis in AIDS. Scand J Infect Dis 1987; 19:703706. Cohen BA, Pomeranz S, Rabinowitz JG, et al. Pulmonary complications of AIDS: radiologic features. AJR 1984; 143:115-122. Derouin F, Sarfati C, Beauvais B, Iliou M-C, Dehen L, Lariviere M. Laboratory diagnosis of pulmonary toxoplasmosis in patients with acquired immunodeficiency syndrome. J Clin Microbiol 1989; 27:1661-1663. Tschirhart D, Klatt EC. Disseminated toxoplasmosis in the acquired immunodeficiency syndrome. Arch Pathol Lab Med 1988; 112:
11.
15.
16.
17. 18. 19. 20.
Oksenhendler E, Cadranel J, Sarfati C, et al. Toxoplasma gondii pneumonia in patients with the acquired immunodeficiency syndrome. AmJ Med 1990; 88:18-21. Tourani
D, Venet
A, Andrieu
6:28-35.
21. 22.
shown that timely therapy toxoplasmosis, with stan-
JM, Israel-Biet
JM. Unusual pulmonary infection in a puzzling presentation of AIDS (letter). Lancet 1985; 1:989. Tawney S, Masci J, Berger HW, Subietas A. Pulmonary toxoplasmosis: an unusual nodular radiographic pattern in a patient with AIDS. Mt Sinai] Med 1986; 53:683-685. Israelski DM, Dannemann BR, Remington JS. Toxoplasmosis in patients with AIDS. in: Sande MA, Volberding PA, eds. The medical management of AIDS. 2nd ed. Philadelphia: Saunders, 1990; 241-264. Evans TG, Schwartzman JD. Pulmonary toxoplasmosis. Semin Respir Infect 1991; 6:51-57. Gleason HL, Hamlin WB. Disseminated toxoplasmosis in the compromised host. Arch Intern Med 1974; 134:1059-1062. Remington JS, Jacobs L, Kaufman HE. Toxoplasmosis in the adult. N Engl J Med 1960; 262: 180-186, 237-241. Derouin F, Sarfati C, Beauvais B, Garin YJF, Lariviere M. Prevalence of pulmonary toxoplasmosis in HIV-infected patients (letter). AIDS 1990; 4:1036. Prosmanne 0, Chalaoui J, Sylvestre J, Lefebvre R. Small nodular pattern in the lungs due to opportunistic toxoplasmosis. J Can Assoc Radiol 1984; 35:186-188. Goodman PC. Pneumocystis carinii pneumonia. J Thorac Imaging 1991; 6:16-21. Theologides A, Kennedy BJ. Clinical manifestations of toxoplasmosis in the adult. Arch Intern Med 1966; 117:536-540. Goodman PC. Pulmonary tuberculosis in patients with acquired immunodeficiency syndrome. J Thorac Imaging 1990; 5:38-45. Stansell JD. Fungal disease in HIV-infected persons: cryptococcosis, histoplasmosis and coccidioidomycosis. J Thorac Imaging 1991; Goodman Imaging
(22).
regimens
10.
ill-
a diagnosis.
The
9.
14.
BAL fluid
specimen
opportunisA chest
1237-1241.
8.
pa-
lymphadenopathy
a diagnosis
7.
13.
benge than does PCP. Adding to the problem is the observation that pleural fluid
6.
12.
pulmonary
difficult
5.
disease
tients with disseminated tuberculosis (19), histoplasmosis, or coccidioidomycosis
4.
re-
(17). In this regard, the reticubonodular abnor-
seen
2.
toxopbasmoof parenchy-
mosis frequently causes coarse opacities on chest radiographs.
findings
alert the of pulmonary
PCP.
diagbecause
1. Goodman
be indistinguish-
each other. Certain features, may help in establishing a
reasonable noses.
malities
should
to other
notably
demonstrating
bility
population
similarity
infections,
bar opacities,
(6).
stains such as hematoxylin-eosin. The cyst walls also show an affinity to silver stains (12). With mild infection and a small number of organisms, staining of
nosis.
tic
diograph
Kaposi sarcoma may also produce a diffuse coarse linear and nodular pattern on chest radiographs, but the nodules are larger and less numerous than those in toxoplasmosis (21). Nodules seen in AIDS patients with non-Hodgkin lymphoma are well-defined and are larger and less numerous than those in toxo-
opsy
of clinical
The chest radiograph in patients with AIDS presents a difficult diagnostic problem. Many of the illnesses seen in
as
in the other four patients parasites in BAL fluid and
transbronchiab lung lung
sep-
in five of nine paorganisms in bron-
Iavage
individually by observing
exam(3). In illness
simulated (8).
small
normalities
pulmonary toxoplasmosis in patients with HIV-positive serologic findings was estimated to be 4.1% (15). An autopsy series from the United States reported T gondii in 7.7% of AIDS patients
possibility
the T gondii organisms. A special culture technique has been tried
Haskal phoma Radiol
PC. 1991;
Kaposi’s
sarcoma.
J Thorac
6:43-48.
ZJ, Lindan CE, Goodman PC. Lymin the immunocompromised patient. Clin North Am 1990; 4:885-899.
of sulfadiazine-pyri-
Radiology
e
793
C. Goodman,
MD
Pulmonary
Lynn
M. Schnapp,
Toxoplasmosis
The chest radiographs obtained in nine patients with acquired immunodeficiency syndrome (AIDS) and pulmonary toxoplasmosis were reviewed. In three patients, a bilateral, diffuse, fine to medium reticulonodubar pattern indistinguishable from that seen in Pneumocystis carinii pneumonia (PCP) was observed. In six patients, however, a bilateral, predominantly coarse, nodular pattern was observed. This type of abnormality is unusual with PCP, and its presence may help in distinguishing between pulmonary infections caused by Toxoplasma gondii and P carinii. Other opportunistic pneumonias occurling in patients with AIDS, including tuberculosis, histoplasmosis, and coccidioidomycosis, might show similar coarse, nodular opacities on chest radiographs and thus may not be differentiated from pulmonary toxoplasmosis. No hilar or mediastinab adenopathy was observed. Two patients had pleural fluid. Radiologists familiar with the chest radiographic appearance of Tgondii pneumonia could be first to suggest this unusual complication of AIDS. Index
terms:
Acquired
immunodeficiency
syn-
drome 60.2074,
(AIDS), 60.2518 #{149} Lung, diseases, 60.2075 #{149}Pneumocystis cannii, 60.2075 . Toxoplasmosis, 60.2074 Radiology
1992;
MD
184:791-793
in AIDS’
variety
of organisms
sible
for
80% of the AIDS pathogens have etiobogic agents
population (2), gained notoriety of lung disease.
cipabby
Histoplasma
ioides mans;
immitis, and and pyogenic
Streptococcus
influenzae, Toxoplasma nized cause (CNS)
gondii of central
disease
tients with toxoplasmosis.
Durham,
NC 27710 (P.C.G.)
and the Medical
Address reprint requests RSNA, 1992
to P.C.G.
such
as
a well-recognervous system
in patients
with
AIDS
AIDS.
with this reported, of articles suggests (3-10). Raof the abseen in pa-
in the
features
AND
literature
on
AIDS
(eight
pulmonary
were
observed
patients
3 years). The diagnosis was made from stains
were
toxoplasin a 7-year
seen
in the last
patients
exhibited
findings of Kaposi lymphoma. The
and
The recent
brief
was
literature
toxoplasmosis reviewed,
radiographic
picted cussed.
chest
concerning in patients
and
the
pulmowith
reported
radiographic
AIDS
or de-
patterns
are dis-
RESULTS The chest radiographic features in our nine patients were as follows: The chest radiographs obtained in six demonstrated bilateral, predominantly dium to coarse, poorly defined opacities (Figs 1, 2). A secondary
of medium
to coarse
was occasionally opacities were
reticular
menodular pattern
opacities
observed. approximately
The
nodular
3-5 mm in diameter and were distributed mostly in the middle to bower area of the lungs in three patients, diffusely in two patients, and predominantly in the upper lobes patient. In some patients involvement, coalescence
nodular
opacities
neous grams. diffuse,
resulted
with of the
in homoge-
opacification and air bronchoIn the remaining three patients bilateral, fine to medium reticu-
bar pattern
was observed.
or mediastinal
demonstrated. served in two
METHODS
with
of these
pathologic or non-Hodgkin
descriptions in six of these patients were previously reported (3). Chest radiographs were evaluated for parenchymal, pleural, hibar, and mediastinab abnormalities. When available, followup chest radiographs were interpreted for evidence of disease progression or improvement.
hilar
patients and
recent
clinical
in one profuse
and pulmonary This article describes findings of T gondii
the radiographic and pneumonia in nine patients with AIDS and summarizes the observa-
period
Service, San Francisco General Hospital Medical Center and Department of Medicine, University of California, San Francisco (L.M.S.). Received February 24, 1992; revision requested March 19; revision received March 30; accepted April 7.
is
or
Coccidneofor-
bacteria
Pulmonary involvement parasite is less frequently but an increasing number describing this complication that its incidence is rising diobogists should be aware normalities that might be
mosis Duke Erwin Rd.
capsulatum, Cryptococcus
None
clinical sarcoma
nary
pneumoniae, Haemophilus and Staphylococcus aureus.
tions noted the subject.
of Radiology, Box 3808,
other as
Among these are mycobacterial speaes such as Mycobacterium tuberculosis and M avium intracellulare; fungi, prim-
Nine
the Department Medical Center,
infections
in patients with the acquired immunodeficiency syndrome (AIDS) (1,2). The lung is often the principal organ involved, and the ensuing pneumonia is frequently the index diagnosis for AIDS. While Pneumocystis carinii remains the leading cause of pneumonia in these patients, affecting 60%-
MATERIALS
1 From University
negative.
are respon-
opportunistic
sis was culture
diagnosed in both
were unilateral in amount.
No definite
adenopathy
Pleural patients,
was
fluid was oband toxoplasmo-
on stains of the cases. The effusions
and
a
small
fluid
to moderate
of toxoplasmosis of bronchoalveolar
bavage (BAL) fluid, transbronchial biopsy material, pleural fluid, and open-lung biopsy
specimens.
The
diagnosis
tient was made from autopsy the time of diagnosis, stains ganisms, including P carinii, species, fungi, and pyogenic
in one
pa-
samples. At for other ormycobacterial bacteria were
Abbreviations: AIDS = acquired immunodeficiency syndrome, BAL = bronchoalveolar lavage, CNS = central nervous system, HIV = human immunodeficiency virus, PCP = Pneutnocystis carinii pneumonia.
791
Of our nine patients, four died before follow-up chest radiographs were obtamed. The fate of one patient remains unknown. The chest radiographs in two patients, both with fine to medium reticubar opacities, were normal 10 days and 1 Y2 years
later,
patient terval.)
respectively.
(The
was lost to follow-up In two patients with
ular
opacities
a decrease
latter
in the incoarse nod-
in size of the
nodules was observed on chest graphs obtained 14 and 21 days respectively.
The
radiographic
findings
viously reported and pulmonary
reviewed
radiolater,
in 20 pre-
patients with toxoplasmosis
(4-6,8,10).
The
AIDS were
literature
con-
tains few illustrations and little descriptive analysis of the radiographs. Commonly reported are bilateral infiltrates, inhomogeneous and homogeneous consolidation, or interstitial infiltrates. In
two
cases,
a bower
lobe
distribution
and
some right-left asymmetry was either illustrated or implied (4,5). In five of 13 patients with bilateral infiltrates, “nodubar features” were seen but are neither illustrated nor further described (8).
These possibly are similar to the coarse nodular opacities we observed. One patient was first seen with a solitary lung nodule (10). No adenopathy or pleural fluid was described, but these articles
were
primarily
concerned
with
clinical
features of toxoplasmosis, and negative findings may not have been recorded. With appropriate therapy, most patients recovered, but comments regarding radiographic changes are, again, scarce. In
one
patient,
“rapid
clinical
graphic improvement” for toxoplasmosis was
patient series
and
was incorporated (8), which
provement no mention graphs.
into
reported
The
other
a larger
clinical
in 10 of 13 patients of follow-up chest series
ted radiographic
radio-
after treatment reported (9). This im-
but made radio-
similarly
descriptions
omit-
after
ther-
apy.
DISCUSSION T gondii
is an obligate,
protozoan Felines
are
that
exists
the
definitive
man infection undercooked
Figure 2. eral, coarse
intracellular
in three host
(11).
of
or sporulated oocysts (12). The organism dwells in a variety of nucleated cells and requires am intracellular envi-
ronment
to multiply. tissues
Most
are
matter of the brain but alveolar lining
gray
commonly and
white
and the retinal cells, cells as well as skebe-
cytes
and
of toxoplasmosis
brain,
but
pendent
of the
lung
in the protooccurs, and even-
cause
792
Radiology
resistance
chronic
macrophages,
cence
on the native
anteroposterior
tually a chronic state of latent infection is established. In general, the brain harbors most of the parasite burden, but residual organisms may also be observed in the lung (14). After infection with the human immunodeficiency virus (HIV) and subsequent depletion of CD4 T-cell lympho-
tab muscle and the heart are also affected (13,14). In the short term, proliferation of the organism leads to parasitemia that lasts for a period deindividual. A reduction zoan population then
An
chest
radiograph
demonstrates
bilat-
Hu-
is initiated by ingestion meats containing tissue
involved
toxoplasmosis. opacities.
forms.
cysts p
Pulmonary nodular
Tgondii
reactivation
without
a person
infestation of disease.
may
primary occur
Most
will
reactivation
have
recrudes-
involve
the
in the
and is postulated as a pneumonia in patients symptoms (6). Even if the
of T gondii
CNS
with
may
organism and
most
proliferated
has
spread
to
the
patients,
necessarily
lungs,
CNS precede
in the
brain
as is the
symptoms
case
may
respiratory
in
not
diffi-
culties (6,8). In fact, of six patients recently reported by one of the authors, a majority were first seen with pulmonary toxoplasmosis as their first indication of HIV infection (3). The prevalence of the organism in adult populations is strongly related to geographic location and diet. In Europe as many as 90% of adults harbor the parasite frequent
are
(12).
In
the
United
manifestations
expected.
Nevertheless,
States of
this
bess disease
in American
September
1992
urban environments seropositivity for T gondii approaches 11%-16% of adults who are in high-risk categories for HIV infection (11). Thus, there is a well-established
and
pool
abroad
of individuals
who
toxoplasmosis. the AIDS-defining
may CNS
both
develop
here
AIDS
and
was of patients in the United States, and T gondii encephalitis was seen in 25% of AIDS patients in some European countries
(11). In a French
toxoplasmosis illness in 3.7%
study,
the frequency
of
and, within this group, lung involvement in five of 14 (36%) patients with disseminated toxoplasmosis (7). The that
the
incidence
of T gondii
infection is increasing is discussed in another French review, in which the ratio of pulmonary toxoplasmosis to Pneumocystis carinii pneumonia (PCP) cases increased from 1 :284 for the years to 1:128 in 1987 1 :38 by 1988 (8).
1984-1986
mately
and
approxi-
The clinical features of T gondii pneumonia are indistinguishable from those of PCP; a more rapid onset of symptoms,
however,
may
the pathogen are first seen productive occasionally,
favor
T gondii
as
(8). In general, patients with fever, dyspnea, noncough, night hemoptysis
sweats, and, (3,4,8-10). Hy-
poxemia is common, but physical ination abnormalities are unusual two patients an acute pulmonary caused ticemia
by toxoplasmosis was rapidly fatal
In our series
the diagnosis
plasmosis was made tients by identifying
choalveolar
(BAL)
biopsy
biopsy tissue
samples, at autopsy.
the diagnosis tients zoites
of toxo-
fluid,
and
was
by identification in BAL fluid
tient, BAL fluid and examination
material,
open-
pleural fluid, In another
made
number
of patients.
diagnostic
tool
and series,
in 10 of 11 pa-
of T gondii tachy(8). In the other pa-
analysis was negative of an open-lung bi-
methamine, is effective (8). The nosis, however, may be delayed
tissue
in a
It provided within 2 days
proof of T gondii infection and was recommended
as an adjunctive
this
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that
able from however,
may
diffuse
lung
ab-
ordering
of differential
In the case of pulmonary sis versus
PCP,
the
quality
diag-
3.
mab abnormality may provide a clue to the nature of the underlying pneumonia. As noted in our series and as implied by others (8), pulmonary toxoplas-
appearance
has been
ported in a non-AIDS monary toxoplasmosis only rarely produce much more typically
ticular opacities fine to medium
nodular A similar
incidentally
patient with pub(16). PC? would this pattern and produces fine re-
in three
of our
patients
are
indistinguishable from those seen with PCP. While capable of producing lymph node enlargement in other hosts (18), T gondii infections in AIDS patients appear to rarely if ever cause radiographically visible hilar or mediastinal adenopathy. P carinii similarly rarely is seen with lymph node enlargement. While pleural fluid is rarely observed with P carinii infection, in our series, effusions were observed in two of nine (22%)
with
patients
Coarse
nodular
it is seen
mosis
with
may
also
toxoplasmosis. parenchymal
(20).
pose
a more
Thus,
toxoplas-
be observed
in AIDS
these
may
messes.
may
also
infections radiographic
be observed
If present,
favor
may chal-
in these
of tuberculosis.
plasmosis
that
It has been for pulmonary
was
organism
necessary
for diag-
is usually
detected
after preparations of BAL fluid or tissue material with Giemsa stain or standard
Thus
culture
may
some
not provide
authors
should
suggest
be performed
tissue
to identify
dard
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Number
#{149}
3
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(22).
regimens
10.
ill-
a diagnosis.
The
9.
14.
BAL fluid
specimen
opportunisA chest
1237-1241.
8.
pa-
lymphadenopathy
a diagnosis
7.
13.
benge than does PCP. Adding to the problem is the observation that pleural fluid
6.
12.
pulmonary
difficult
5.
disease
tients with disseminated tuberculosis (19), histoplasmosis, or coccidioidomycosis
4.
re-
(17). In this regard, the reticubonodular abnor-
seen
2.
toxopbasmoof parenchy-
mosis frequently causes coarse opacities on chest radiographs.
findings
alert the of pulmonary
PCP.
diagbecause
1. Goodman
be indistinguish-
each other. Certain features, may help in establishing a
reasonable noses.
malities
should
to other
notably
demonstrating
bility
population
similarity
infections,
bar opacities,
(6).
stains such as hematoxylin-eosin. The cyst walls also show an affinity to silver stains (12). With mild infection and a small number of organisms, staining of
nosis.
tic
diograph
Kaposi sarcoma may also produce a diffuse coarse linear and nodular pattern on chest radiographs, but the nodules are larger and less numerous than those in toxoplasmosis (21). Nodules seen in AIDS patients with non-Hodgkin lymphoma are well-defined and are larger and less numerous than those in toxo-
opsy
of clinical
The chest radiograph in patients with AIDS presents a difficult diagnostic problem. Many of the illnesses seen in
as
in the other four patients parasites in BAL fluid and
transbronchiab lung lung
sep-
in five of nine paorganisms in bron-
Iavage
individually by observing
exam(3). In illness
simulated (8).
small
normalities
pulmonary toxoplasmosis in patients with HIV-positive serologic findings was estimated to be 4.1% (15). An autopsy series from the United States reported T gondii in 7.7% of AIDS patients
possibility
the T gondii organisms. A special culture technique has been tried
Haskal phoma Radiol
PC. 1991;
Kaposi’s
sarcoma.
J Thorac
6:43-48.
ZJ, Lindan CE, Goodman PC. Lymin the immunocompromised patient. Clin North Am 1990; 4:885-899.
of sulfadiazine-pyri-
Radiology
e
793
