Cardiac Hydatid Cyst

[Guest guest]

http://www.ijri.org/articles/archives/2003-13-2/cns203.htm

 

 

 

CNS

 

Imaging Of Ruptured Cardiac Hydatid Cyst Located On The

Interventricular Septum With Pulmonary Embolism, A Case Report

M Mohapatra, PK Sahoo, SC Pattnaik, S Sahoo, MR Pattnaik, S Behera

Ind J Radiol Imag 2003 13:2:203-205

 

Key words: Hydatid cyst, Pulmonary Embolism, Cardiac Mass

 

INTRODUCTION

 

Hydatid disease is caused by the tapeworm Echinococcus granulosus and

E multilocularis. The life cycle involves primary and the intermediate

mammalian hosts. Dogs are the usual primary host and the intermediate

host is usually a sheep or cow but sometimes human. In the intestine

the eggs hatch and the embryo cross the intestinal mucosa, enters into

blood vessel and lymphatic system. Liver and lungs together filters

the majority (approximately 85 to 90%) of the embryo. Via systemic

circulation approximately 10 to 15% may reach other organs including

the cardiac chambers, interventricular septum and the pericardium

(0.02-2%)[1-3]. Hydatid cysts locations in the pulmonary arteries are

exceptional [4-5]. Wherever the embryo settles, it forms a hydatid

cyst. The cyst wall secreted by the embryo is consists of two layers,

the outer ectocyst and the inner endocyst. The endocyst is the vital

layer of the cyst responsible for formation of brood capsule,

scolices, fluid inside the cyst and outer layer. A granular deposit

found to settle at the bottom of fluid is called hydatid sand which is

composed of brood capsules, free scolices and loose hook lets [7]. The

present report describes a case of hydatid cyst localized on the

interventricular septum, in bilateral pulmonary arteries and lungs.

The CT, Ultrasonography and echocardiography helped to localize and

characterize the lesion in different location and in some locations

the imaging findings were characteristic of hydatid cyst, but

presentation with hemoptysis is very rare [6]

 

CASE REPORT.

 

A 22 years female presented with cough and severe episodes of blood

tinged sputum of one-month duration. In addition she has low grade

pyrexia. She was treated with several antibiotics and antitubercular

medications, till she was referred to our hospital. On clinical

examination she was found to have tachycardia, hypotension, raised JVP

with diminished breath sound in upper part of chest with scattered

crepitations. There were no cardiomegaly or conduction disturbances

but pulmonary component of second heart sound was exaggerated with a

right ventricular gallop. Abdominal examination revealed no

organomegaly. There was no neurological deficit. There was no history

of swelling of both lower limbs.

 

Chest radiograph revealed multiple rounded homogenous well

circumscribed nodular opacities of varying sizes in bilateral lung

fields and the left cardiac outline is displaced downwards and

medially (fig-1). Non contrast and contrast enhanced CT scan of thorax

shows a large hypodense well circumscribed mass lesion in left lung

with enhancing wall (fig-2a,2b). Multiple similar lesions were seen on

bilateral lung fields. A well marginated hypodense intraluminal lesion

in right pulmonary artery with enhancement of its wall was seen on non

contrast and contrast enhanced CT study (Fig2a,2b). Additionally

intraluminal hypodense lesions with enhancement of its wall was seen

in the interlobular branches of both right (not shown in the figure)

as well as left pulmonary arteries (Fig-3). The CT sections at the

level of cardia shows expanded interventricular septum with non

enhancing hypodense lesion on it, which has got finger like

projections into right ventricular lumen (fig 3). Echocardiography

appearance of the same lesion on the interventricular septum was

multicystic cartwheel like with echogenic finger like projection from

it into right ventricular lumen in addition to the expanded

interventricular septum (fig-4). Ultrasonographic appearance of the

lung lesions were cystic thin walled masses with internal solid

echogenic material in the dependant part suggestive of hydatid sand

(fig-5). No other cystic lesion detected in abdominal examination on

ultrasonography. With these findings a provisional diagnosis of

cardiac hydatid cyst with metastatic Echinococcosis in lungs and

pulmonary artery was diagnosed. Serological finding was suggestive of

echinococcosis. The serum Echinococcus IGG antibody titer was >800

(Titer >15 is positive , Speciality Ranbaxy Limited, Clinical

reference Laboratories, Mumbai-93, India). She was planned for

surgical removal of the cyst from the heart and pulmonary arteries,

but on the night previous to surgery she suddenly developed

tachycardia, hypotension and breathlessness suggestive of anaphylaxis

and died.

 

 

FIGURE No1: Chest radiograph shows multiple well circumscribed nodular

opacities of varying sizes in both the lung fields.

 

FIGURE No2a,b

a)CTscan non contrast study shows a hypodense lesion in left lung

field. Another similar lesion seen in right pulmonary artery.

b) Contrast scan shows same lesions with enhancement of wall.

 

 

 

 

FIGURE No 3

Contrast enhanced CT scan of thorax at lower levels shows hypodense

lesion on the interventricular septum, which is expanded and shows

fingerlike projections from this into right ventricular cavity. The

interlobular branches from left pulmonary artery shows central

intraluminal filling defect with peripheral enhancement. Left Pleural

effusion present.

 

FIGURE No 4.

Echocardiography shows a multiseptated cystic lesion(cart wheel

appearance) on the interventricular septum, which is expanded.

 

FIGURE No 5.: Ultrasonography of chest lesion reveals a cystic mass

with solid echogenic debris (hydatid sand) in the dependant part.

 

DISCUSSION

 

Hydatid cyst localization inside the lumen of pulmonary arteries is

very rare and is a consequence of embolism from primary cardiac

location [3]. The other pathway for entry into pulmonary artery is

from liver into inferior vena cava and from there via right cardiac

chamber into pulmonary arteries [5]. In the present case the cysts

were observed on the interventricular septum and membranes from this

projecting into right ventricular cavity was seen, suggestive of

rupture. Once the cyst gets entry into the lumen of pulmonary arteries

it grows progressively to occlude the lumen (which is approximately

2-3cm per year). This process last long enough for adequate pulmonary

perfusion to be established through the bronchial arteries and may

initially be asymptomatic before presenting dyspnoea of long

evolution. (6). Symptoms may also be produced when the cysts compress

a vital structure or rupture and produce anaphylaxis. In our case the

first symptom was repeated hemoptysis and the chest radiograph was

showing multiple well marginated nodular lesions of varying sizes, for

which reason a hydatid disease was not initially suspected, rather she

underwent CT study to rule out metastasis. Cysts on interventricular

septum may produce conduction disturbances, which was also not present

in our case. Noncomplicated cysts usually appear hypodense and well

marginated on non contrast CT. Contrast study is essential to

demonstrate the enhancement of the cyst wall and also to localize the

cysts in interlobular pulmonary arterial branches. The lesion in

pulmonary arteries and its branches are detected on cross sectional

imaging like CT. A Differential diagnosis should be performed with

intraluminal defects of pulmonary arteries, such as pulmonary

thromboembolism and primary arterial tumor such as sarcoma [8,9]. The

cysts in pulmonary artery confuses with a thrombus. On contrast study

the cyst wall enhances strongly and this does not normally so happen

in case of thrombus. The cardiac lesion is difficult to characterize

on CT study because firstly the membranes are not well delineated due

to cardiac motion and secondly the cystic nature of the lesion is not

confirmed on CT. The cardiac lesions are better evaluated on

echocardiography. The lesion on interventricular septum with

fingerlike projection from it into ventricular lumen should be

differentiated from septal tumor with thrombus. In this case it

represents ruptured hydatid cyst on the interventricular septum and

the fingerlike projections represents membrane. The hypodense lesion

on lungs detected on CT should be differentiated from any other cystic

lesion. But the lesions that are peripheral and are accessible to

ultrasound examination may show mobile echogenic material in the

dependant part of the lesion, which suggest hydatid sand.

Ultrasonography can also detect any other cystic lesion in abdominal

viscera. This information helps proper surgical planning.

 

CONCLUSION

 

In hemoptysis patients with multiple nodular opacities on chest

radiograph, hydatid cyst should be considered in the differential

diagnosis preferably in endemic areas. Because of the possibility of

multiple locations of hydatid cysts, a combination of different

imaging modalities are essential. Cardiac hydatid cysts with cysts in

lungs and pulmonary artery and its branches are better evaluated by

combination of different imaging modalities like chest radiograph,

ultrasound, CT and echocardiography. The lesions in the pulmonary

artery is better evaluated on cross sectional imaging like CT and the

enhancing wall on contrast study is highly suggestive of cysts and not

thrombus.

 

REFERENCE

 

1.

 

BeggsI (1985). The radiology of hydatid disease. AJR 1, 639-648

2.

 

Cantoni S, Frola C, Gatto R, Loria F, Terzi MI et al (1993).

Hydatid cyst of interventricular septum of heart, MR findings. AJR

161: 753-754

3.

 

Alper H, Yunten R, Sener NR (1995). Intramural hydatid cysts of

pulmonary arteries: CT and MR findings. Eur J Radiology, 666-668

4.

 

Von Sinner WN, te Strak L, Clark D, Sharif H (1991) MR finding

in hydatid disease. AJR 157: 741-745

5.

 

Ozturk C, Agildere AM, Cila A, Balkanci F (1992) Pulmonary

arterial embolism secondary to hydatid cyst of liver. Can A soc Radiol

J43 (5): 374-6

6.

 

D Yague, M.P Lozano, C. Lampe, M.E Nunez, F Sanchez Bilateral

hydatid cyst of pulmonary arteries: MR and CT findings. Eur Radiol

1998; 8(7): 1170-1172.

7.

 

D Chattarjee, Echinococcus granulosus, Textbook of parasitology,

12th edition, Calcutta, India, Chatterjee Medical Publishers, April

1980: 121-127

8.

 

Tardivon AA, Musset D, Maitre S et al (1993) Role of chronic

pulmonary embolism: comparison with pulmonary angiography. J comput

Assist Tomogr, 17: 345-351.

9.

 

Bressler EL, Nelson JM (1992). Primary pulmonary artery sarcoma:

diagnosis with CT, MR imaging, and transthoracic needle biopsy. AJR

159: 702-704

 

 

Home Back to TOC

 

Previous Article Next Article