Keywords
myiasis - infestation - construction band syndrome
Introduction
Myiasis is a Greek-derived term (myia = fly) that describes infestations caused by maggots from Diptera order, as opposed to other infestations caused by general insects.[1] Those diseases may present in several ways, the most common being the cutaneous
form,[2] that is further subdivided into furuncular, migratory and wound-associated forms.
Despite the recognized beneficial effects of maggots as a means of wound biological
debridement, such as popularized by William Baer during the First World War,[3] along with the fact of helping to prevent severe, infectious events and sepsis,
not always those agents behave so innocuously. There are several reports of secondary
bacterial infection, mainly due to Staphylococcus aureus and group-B Streptococcus,[4]
[5] together with the invasion of noble structures and patient death.[6]
Parasite infestation due to Diptera order insects (myiasis) is a scaring event for patients and even for the assisting
healthcare team. There are several predisposing factors, including low income status,
poor hygiene, physical or mental vulnerabilities, and pre-existing skin pathology.
We describe the first case of a healthy patient submitted to hand elective surgery
that evolved to an early postoperative myiasis infestation.
Case Description
We treated a two-year-old female patient who presented with syndactyly due to congenital
constriction bands ([Fig. 1]).
Fig. 1 Clinical aspect of two-year-old female patient with syndactyly due to congenital
constriction bands (A and B). Affected hand radiograph (C).
The patient did not present any other immunodeficiency-predisposing illness, and resided
at a low-income, urban settlement. She was submitted to syndactyly-correction surgery
by means of a dorsal flap to create an interdigital space associated to full-thickness,
autologous skin grafting from the groin region. Procedure had been uneventful, and
the patient was discharged the next day with protection dressing; the parents were
instructed to keep dry and clean the surgical site ([Fig. 2]).
Fig. 2 Early postoperative after treatment for syndactyly due to congenital constriction
bands where a dorsal digital skin flap was performed to create the interdigital space
employing full-thickness skin grafting from the groin (A and B).
Around ten days after discharge, the patient returns for assessment and dressing change;
at this time, extensive migratory maggot infestation was observed ([Figs. 3A] and [3B]).
Fig. 3 Dressing change after 10 days postoperatively showing extensive operative wound infestation
with maggots (A and B). Patient was admitted after cleaning and debridement and treated with ivermectin
and antibiotics.
After cleaning, devitalized tissue debridement and careful parasite removal, the pediatric
infection service was called to scene and they decided for adjuvant treatment with
oral ivermectin and first-generation cephalosporin antibiotics due to the great extension
of the disease (under close supervision, as the age group was not ideal for the use
of the first agent). Hospital admission lasted ∼96 hours, and the patient was discharged
in good clinical condition. Around 30 days after discharge, the wound was in an advanced
healing stage, with signs of neither infestation nor secondary bacterial infection
([Fig. 4]).
Fig. 4 Patient clinical appearance after wound cleaning and maggot removal (A). Complete wound healing, with no infection signs after 30 days (B).
Discussion
Maggot infestations of Diptera insect order, the so-called myiases are relatively common events, especially in tropical,
underdeveloped countries; they bring about a strong stigma, as the general population
– and even health professionals – feel greatly repulsed the illness. Those insects
need live, warm tissue for egg-laying and maggot production in short-duration cycles.
It is also a problem associated to endemic zone travel and may represent, along with
systemic febrile diseases and acute diarrhea, up to 12% of travel-associated illnesses.[7] The typical host is either a low-income individual or someone with any kind of vulnerability
(such as mental retardation, immunosuppression, or visual impairment), which favors
the contact of the fly with the crude area to deposit the eggs and to develop such
opportunistic diseases. Bad hygiene is also associated to myiases.
There are thousands of insect types that may cause myiasis, but very few species comprise
most diagnosed cases; the Dermatobia hominis is the most common cause of myiasis in the Americas.[8]
Myiasis, in its cutaneous form, may present in three forms: furuncular; migratory;
and associated to wounds.[8]
This case presents a maggot-infested operatory wound, as it has been reported that
larvae show predilection for hemorrhaged, necrotic, or purulent-draining tissue, along
with their preference for alkaline environments.[9]
The standard treatment for this kind of disease consists of complete agent removal[10]; an ether or chloroform oily solution may be employed as a parasite immobilizer
agent. Topical application of ivermectin may be associated as an alternative or adjuvant
modality. Oral ivermectin has also been described and was employed for the treatment
of our patient.[11]
Correct agent identification is not always possible, and involves a careful, professionally
trained macro- and microscopic analysis of the maggot. Correct larvae preservation
depends on their termination with hot (not boiling) water immersion and subsequent
conservation in an alcoholic solution12.
There are literature reports on myiasis of a hand wound, but this is the first case
reported after elective surgery of a healthy patient.
Conclusion
There should be awareness regarding patient orientation and supervision, especially
for those submitted to surgical treatment and in a situation of social vulnerability
to avoid such stigmatizing condition.
Given the risk of potential complications such as bacterial superinfection, prompt
prophylactic antibiotic therapy must be implemented.
