Keywords
hydatid disease - Syria - innovation - gluteal abscess - VAC pump
Introduction
Hydatid disease is an endemic parasitic infection caused by the canine tapeworm, mostly
Echinococcus granulosus, and it is an important public health problem in the Mediterranean, Middle East,
Africa, South America, Asia, and Australia.[1] The definitive hosts for E. granulosus are dogs and the intermediate hosts are most commonly sheep though other animals
including cattle, horses, goats, and camels are also potential intermediate hosts.[1] Humans become infected when they ingest eggs; the larva then burrow through the
intestinal wall, entering the bloodstream. They may enter the portal venous system
affecting the liver (in 60–70% of cases) or the pulmonary circulation affecting the
lungs (5–27% of cases) manifesting as cysts.[1] Hydatid cysts can, however, occur in other organs including the central nervous
system, bone, kidney, or in the subcutaneous tissue.[2]
[3] Subcutaneous hydatid cysts are rare but present the same concern about the risk
of rupture resulting in anaphylaxis or the presence of daughter cysts.[1] Treatment approaches include conservative, drug treatment, surgery, or PAIR (puncture,
aspiration, injection, re-aspiration) depending on the stage. Here we present a case
from a hospital in northwest Syria noting the successful use of a manual vacuum-assisted
closure (VAC) pump for wound management.
Case Report
A woman in her 50s with a body mass index (BMI) of 35 kg/m2 presented to a hospital in northwest Syria with a 10-day history of a painful right
gluteal mass. She had no medical history, and there was no history of a recent intramuscular
injection. She lived with her extended family and did not smoke or drink. She took
no regular medication and had no known drug allergies. On physical examination, there
was a swelling in the upper lateral quadrant of the right gluteal region with signs
of erythema, tenderness, and warmth. Abdominal, chest, and neurologic examinations
were normal.
She was initially diagnosed with a pyogenic gluteal abscess, and an incision and drainage
were done on the same day. During the operation, about 500 mL of fluid was drained
from the abscess and a hydatid cyst germinal membrane was noted during irrigation
and suction of the cavity, raising suspicion of hydatid disease ([Fig. 1]). Postoperatively, the cavity was treated with daily dressings for 4 days, then
manual negative pressure wound therapy (NPWT) was applied using a PragmaVAC device
for 7 days due to the size of the wound ([Fig. 2a]). Afterward, an endoscope was used to show the entire cavity, which revealed good
and healthy granulation tissue without infection ([Fig. 2b]). The wound was closed by stitching on layers ([Fig. 3]).
Fig. 1 Gluteal hydatid disease cavity postsurgery.
Fig. 2 (a) PragmaVAC device and pump. (b) Wound after PragmaVAC device removal.
Fig. 3 Final outcome of the wound.
Due to the diagnosis of a likely hydatid subcutaneous cyst, the patient had a chest
X-ray, which was unremarkable, and then went on to have an ultrasound and then computed
tomography (CT) scan of her liver; this revealed the presence of an active solitary
hydatid cyst without daughter cysts in the liver of 7.5 cm ([Fig. 4a]). This was treated with PAIR with adjunctive albendazole 400 mg twice daily for
3 months as per the WHO standard guidance for stage CE3a for a cyst greater than 5 cm.[4]
[5] An ultrasound of the gluteal area was performed after 3 weeks, and it showed no
residual cavity and no other cysts. After about 1 month, a gluteal CT scan was performed
for the area to ensure cavity closure and to look for other cysts ([Fig. 4b]). The patient was reviewed 1 month later and was noted to have no complications
or evidence of recurrence.
Fig. 4 (a) Computed tomography (CT) scan showing the hepatic hydatid cyst. (b) CT scan showing gluteal abscess postsurgery.
Discussion
Subcutaneous hydatid cysts in the gluteal region are an extremely rare event even
in areas where the disease is endemic.[2] It usually presents as a chronic, painful lump, and hydatid disease must be considered
in the differential diagnosis in endemic areas.[2] Serology may also be helpful although it may not be widely available. Imaging can
be helpful as it may show the characteristic features of a hydatid cyst, which include
double echogenic lines of the cyst wall separated by a hypoechogenic layer, multiple-echogenic
foci, detachment of the endocyst from the pericyst, and the presence of daughter cysts.[6]
For a large hydatid cyst in the gluteal region that is symptomatic or at risk of rupture,
most experts would recommend complete excision. Interestingly, Kayaalp et al's review
of 22 cases of subcutaneous hydatid cyst noted that none were associated with anaphylaxis,
something that is of concern in liver or lung hydatid cysts. In this case, identifying
it to be a hydatid cyst avoided the unnecessary use of antibiotics and meant that
adjunctive medical treatment with antihelminthic drugs, such as mebendazole or albendazole,
is used to reduce risk of local recurrence.[1] This is usually continued for at least 3 months with patients followed up at intervals
to monitor progress or complications.
In this case, we also highlight the therapeutic potential of NPWT to support closure
of the cavity. Both randomized controlled trials and retrospective cohort studies
report benefits such as reduced wound volume, accelerated granulation formation, and
a lower incidence of postoperative complications including infection, dehiscence,
and necrosis.[7]
[8] Its clinical applications currently encompass exposed bone or joints, deep sternal
wounds, open abdomen, or intra-abdominal infections, as well as ulcers from pressure
injuries, vascular insufficiency, or as complications of diabetes.[7] Manual NPWT (PragmaVAC) is a novel device that generates negative pressure by manual
pressing, without electrical power. The generated pressure level is –100 mm Hg on
average, which is compatible with the standard commonly used in treatment of open
wounds. It consists of a medical grade standard plastic bellow (pump) attached to
the wound dressing via a tube.[8] The NPWT technique proved to be effective in such cases, especially where the cavity
is large or the patient has a large BMI. It is also useful in low-resource settings
where electricity sources may be unreliable.
Conclusion
Despite being rare, primary subcutaneous hydatid cyst should be considered for the
differential diagnosis of soft-tissue masses or abscesses particularly for patients
who live in regions where hydatid disease is endemic. Manual NPWT (PragmaVAC) can
be effective in treating large cavities without any adverse consequences, help accelerate
granulation tissue formation, and significantly reduce in wound dressing frequency.
Manual NPWT can be a practical and cost-effective device in settings of conflict where
electricity is in short supply, making it a useful adjunct in such settings.
