1070 www.japi.org © JAPI • VOL. 53 • DECEMBER 2005
Case Report
Pulmonary Hydatid Cyst in HIV-1 Disease
VV Shenoy*,  SR Joshi**, AP Aklujkar***,  VS Kotwal***, NA Nadkarni***, NN Ramraje+
Abstract
A 36-year-old male patient, a known case of retroviral disease, presented with clinical   features suggestive of
pneumonia and was found to have bilateral lower zone lung consolidation which on resolution showed a
cystic change on the chest radiograph. A subsequent CT scan revealed the true nature of these cysts to be
ruptured pulmonary hydatid cysts showing a ‘water lily sign’. The rare association of pulmonary hydatid
cyst and HIV from India is described.  ©
INTRODUCTION
Pulmonary hydatid disease caused by Echinococcus
areas world over, including Eastern Europe, Australia,
Parts of South America, and South Asia.1 In India higher
prevalence is reported from areas of Andhra Pradesh,
Tamil Nadu and Punjab. However bilateral pulmonary
hydatid cysts are relatively uncommon.2  Its association
with HIV retroviral diseases is rare.
CASE REPORT
A 36-year-old man presented with cough since 7 days
associated with minimal mucoid expectoration. He also
had left sided chest pain and high-grade intermittent
fever since 3 days. He was detected to have retroviral
infection 6 months back and had 2 prior episodes of
respiratory infections, which settled to local treatment.
He was a non-smoker, but had a past history of high-
risk sexual behavior. A labourer by occupation, he had
noticed mild wheezing in the last fortnight, but had no
prior history of asthma. There was no history of reduced
weight, appetite or other constitutional symptoms.
Clinical examination revealed an averagely built and
nourished man with normal vital parameters and a
respiratory rate of 20 per minute. There were scattered
crackles bilaterally and reduced breath sounds with
increased vocal resonance in the left inframammary and
infrascapular areas suggestive of left lower lobe
consolidation.
A chest roentgenogram revealed bilateral lower zone
and parahilar infiltrates which were extensive as
compared to the clinical signs (Fig. 1). Blood counts were
normal and the absolute CD4 count of the patient was
*Ex-Lecturer; **Ex-Hon. Asst. Professor, ***Residents;
Department of Medicine; +Professor and Head, Department
of Chest Disease; Grant Medical College and Sir J.J. Group of
Hospitals, Mumbai, India.
Received :10.12.2004; Revised : 1.4.2005; Accepted :2.5.2005
found to be 112 cells/cu mm. Arterial blood gas analysis
did not reveal hypoxia, but he had mild compensated
respiratory alkalosis. The patient was started on
intravenous cefotaxime and oral doxycycline to cover
gram positive as well as atypical organisms and
prophylactic cotrimoxazole in view of the low CD4
counts. He had a normal ESR (12mm) and sputum for
acid-fast bacilli (AFB) was negative. Sputum
examination revealed gram positive and negative mixed
infection with adequate sensitivity to the therapy already
started.
Patient’s symptoms subsided and a review chest film
after 2 weeks revealed resolution of the parenchymal
opacities, but two cavities were seen bilaterally in the
same areas (Fig 2). A repeat blood count now revealed
eosinophilia of 12% with absolute eosinophil count being
840-cells/cu mm. A CT scan of the thorax, revealed two
well-defined thick walled cavities with air fluid levels
(Fig 3), in the lower lobes of both lungs with detached
membranes floating on the fluid in the right-sided cavity,
(Fig 4) suggestive of ruptured hydatid cyst.
Fig. 1 : Chest film PA view showing bilateral infiltrates at
presentation.
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An ultrasound of the abdomen did not reveal any
hydatid cysts in the liver. The patient was started on
anti-retroviral therapy with lamuvudine, stavudine and
effavirenz and surgery was advised for the hydatid cysts.
However the patient was not willing for surgery. Hence
he was started on albendazole at a dose of 10 mg/kg/
day for 28 days. Being symptomatically better, he insisted
on discharge and was follow-up regularly.
DISCUSSION
The lung is involved in 2 forms of human hydatidosis
caused by the cystic larval stage of the tapeworm,
Echinococcus. Cystic hydatid disease is caused by
Echinococcus granulosus and alveolar hydatid disease
by Echinococcus multi-locularis.3 65% to 70% hydatid
cysts occur in liver and 15 to 30% in lungs while 5-13%
patients have involvement of both organs.4 Pulmonary
hydatid cysts are characteristically solitary and three-
fourths of patient’s cysts are in one lobe, more often lower
lobes, posterior more than anterior and more common
on the right. 4 Our patient was having bilateral hydatid
cysts, which is seen in 6 – 10 % of patients. 1, 2
Cough and chest pain are the commonest symptoms,
1 and clinical signs are rarely definitive except for an
occasional fluid thrill in very large cysts. 3 There are
occasional case reports of pulmonary hydatid cysts
presenting as non-resolving pneumonia, especially
when the cysts are ruptured or infected as was in our
case. 5 Radiology remains the mainstay of diagnosis,
being 98-100% accurate in most cases.3
Our patient had underlying retroviral disease and
therefore the commonest differentials of bilateral lower
zone and parahilar pulmonary infiltrates were
tuberculosis or pneumocystis carinii (PCP). However the
short history and absence of constitutional features for
tuberculosis and lack of respiratory distress, hypoxia or
toxic appearance and leukocytosis made PCP or
bacterial infection an unlikely cause of this bilateral
pneumonitis with cavitations. The CT scan of the thorax
unexpectedly revealed ruptured hydatid cysts.
Retrospectively however, the eosinophilia, the recent
history of mild wheezing and the radiographic changes
could be explained on the basis of asymptomatic hydatid
cysts, which got secondarily infected and ruptured,
thereby manifesting clinically. Treating the
superimposed infection cleared the infiltrates on the
earlier chest film and the cysts could now be visualized
(Fig. 2 - arrows);  contrary to the impression of
pneumonia with secondary cavitations obtained
initially.
Within the lung the cyst ruptures in two ways: (1)
rupture through pericysts only; and (2) rupture of
pericysts, exocysts, and endocysts, the contents being
expelled in airways. When there is dissection of air
between the pericyst and parasitic membrane, usually
due to erosion of a bronchiole by an expanding cyst, it
presents radiologically as an ‘Air-Bubble’ sign.  However
when the entire cyst ruptures, the ruptured pericyst
Fig. 2 : Chest film PA view suggestive of two cavities, one in right
lower lobe and other in left lower lobe with resolution of earlier
infiltrates.
Fig 3 : CT scan of thorax showing the ruptured hydatid cysts with
air fluid level on the left side.
Fig 4 : CT scan of thorax showing the torn germinal layer in the
right hydatid cyst: the ‘water-lily sign.’
1072 www.japi.org © JAPI • VOL. 53 • DECEMBER 2005
membranes float on the fluid in cysts and give rise to
“water lily sign”or “sign of camalotte”, 6 classically seen
in our patient’s scan on the right side (Fig 4- arrow).
Though aggressive course of liver hydatidosis with
early manifestation as well as disseminated pulmonary
hydatid cysts have been described in patients with
acquired immunodeficiency syndrome (AIDS),7,8 our
patient remained asymptomatic and manifested only
with secondary infection masquerading as pneumonia
with subsequent cavitation. The manifestations of
anaphylaxis that typically occur with rupture were also
subdued probably due to the poor immune response.
Surgery is the treatment of choice for pulmonary
hydatid cysts and medical treatment is beneficial in cases
which are inoperable or when patients do not consent
for surgery. Albendazole is recommended at doses of
10-15 mg/kg/day for 4 weeks separated by 14-day
intervals for 2 or more courses. However protease
inhibitors and benzimidazoles interfere stongly at the
CYP3A4-level. Hence very low doses of albendazole/
mebendazole achieve sufficient therapeutic levels in HIV
patients taking protease inhibitors.9
Thus pulmonary hydatid cysts, though uncommon
bilaterally, can present as pulmonary infiltrates
especially with secondary infection, in Indian patients
more so in those with AIDS. This case highlights the
importance of clinico-radiological correlation in medical
diagnosis.
Acknowledgements
We would like to acknowledge Dr. AA Chowdhury,
Professor  and Head, Department of Medicine, Grant
Medical   College and Sir J.J. Group of Hospitals, Mumbai,
Dr. PH Shingare, Dean, Grant Medical College and Sir
J.J. Group of Hospitals, Mumbai for allowing us to publish
the case.
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