Feeding gastrostomy stoma site cutaneous myiasis: a rare entity

Abstract

Infestation of any dead or necrotic tissues by the larvae of flies (maggots) is myiasis. This form of habitation is not restricted to any particular tissues in the body and can occur anywhere. However, myiasis at the surgical stoma site is very rare. We present a 55-year-old woman diagnosed with metastatic carcinoma of the oesophagus who underwent feeding gastrostomy (FG). The patient later presented with worms at the FG site. We removed the FG tube, cleared all the maggots, thoroughly cleaned the wound and placed a new FG tube. Although its occurrences have been reported enough in medical history, there are only two documented cases of percutaneous endoscopic gastrostomy stoma site myiasis. Hence, we present the first case in the literature of cutaneous myiasis around an FG stoma site.

Background

Myiasis was first described in the medical armamentarium by Hope in 1840, where he documented the infestation of maggots of various species under Diptera in various living or necrotic tissues. The disease is usually a result of poor personal hygiene, with other main contributory factors being unhealthy surroundings and underlying immunosuppression.^{1 2} The disease is usually benign and requires prompt sterilisation and surgical debridement, following which it has an excellent prognosis. Cutaneous myiasis is the most common among the various types, there are documented cases in medical history, but its occurrence at a surgical stoma site is infrequent. We describe the case of surgical stoma site myiasis following a feeding gastrostomy (FG).

Case presentation

A 55-year-old woman with no comorbidities presented with progressive dysphagia for 4 months. The patient also gave a history of significant weight loss and appetite. The patient was not a known smoker or alcoholic. The patient was evaluated with an endoscopy which showed growth at 25 cm, and the biopsy was diagnostic of poorly differentiated squamous cell carcinoma. Subsequent investigations with CT showed the presence of distant metastasis with bony lesions. The patient underwent FG for nutrition and was planned for palliative radiotherapy.

The patient again presented to us 2 months later with pain at the FG site with worms in the FG stoma and foul-smelling discharge. There was no history of febrile spikes or abdominal distension. The patient gave a history that she rarely changed the dressing around the stoma site, and there was contamination of the FG site from the predominant liquid FG feeds. She also gave a history of cleaning the FG site with tap water (? unclean water).

On examination, the patient was conscious and oriented with a pulse rate of 92 beats/min, blood pressure of 120/70 mm Hg with no evidence of pallor, icterus, lymphadenopathy or oedema. All systemic examinations were within normal limits. The FG tube seemed to be mobile, and the stoma was retracted with adjacent cavitation. The peritubal tissue was inflamed, indurated and hyperpigmented. Multiple maggots of length 8–12 mm were seen exiting from the stoma site and the adjacent cavity (figure 1; video 1).

Figure 1.

Clinical image showing the feeding gastrostomy tube with stoma site myiasis (maggots).

Video 1.

Download video file ^{(3.9MB, mp4)}

DOI: 10.1136/bcr-2021-244352.video01

The FG tube was removed, and the wound was cleaned. Visible maggots were removed manually. Turpentine oil dressing was applied to the FG stoma site to expel the maggots from the cavity. Around 45–50 maggots were removed. The stoma site and adjacent cavity were debrided, and the entire slough was removed. A new FG tube was placed through the previous stoma site after thoroughly cleaning the wound. The position of the FG tube was confirmed with fluoroscopy. Ultrasonography of the abdomen was done, and any intra-abdominal collection or extension was ruled out. The patient was educated about the care of the FG stoma and the proper techniques of feeding. The patient was discharged with advice for follow-up in the palliative clinic.

Outcomes and follow-up

The patient is on regular follow-up without any maggots at the FG stoma site. The stoma site is healthy, and the cavity healed completely. The patient is continuing the treatment at the palliative clinic.

Discussion

Myiasis being a breed of putrid hygiene, is common among immunocompromised, malnourished people with poor personal hygiene and people staying in poor sanitary conditions.^{1 2} The most common infestation is the larvae of a fly species found in the arthropod order Diptera.³ The presentation is in the form of a facultative or obligatory parasite part of the life cycle where they feed on the dead and necrotic tissues after the female Diptera lays eggs and morphs into the larval stage.

Cutaneous myiasis has been clinically classified into three entities: furuncular, migratory and traumatic wound myiasis. The Dermatobia hominis (human bot fly) and Cordylobia anthrophophaga (tumbu fly), being the most common organisms causing furuncular myiasis, are the usual suspects in most cases.⁴ Nevertheless, the domicile of the wound myiasis stays with screwworms, which include Cochliomyia hominivorax and Chrysomya bezziana, which would refer to the new world and old world screwworms, with the latter being the most important causative organism in the Indian subcontinent.

While Cochliomyia restricts itself in the western hemisphere, Chrysomya is spread extensively over the Afrotropical and Oriental continents.⁵ Usually rare in humans, they rapidly turn fatal due to their ability to move through the subdermal layers and remain undetected. At the same time, oviposition occurs in numbers of 150–500 eggs, resulting in multiple infestations. Humans being accidental hosts, the larvae of C. bezziana is markedly different from others in the family given its broad base and sharply pointed recurved spines. The larval form inherits strong mouth hooks, which help in deeper intrusions. The adults are approximately 1 cm in length with narrow longitudinal thoracic stripes.

The life cycle of these arthropods consists of the human being as an accidental host. They lay eggs near the edge of the warm mammalian wounds, with each containing approximately 3000 larvae. The eggs hatch in 15 hours and are buried 4-5 cm deep inside the human skin. The larvae feed on living tissues causing extensive tissue destruction. The larvae emerge from the dermal abode and pupate over the next 4–7 days. The adult worm conversion takes one more week, making the life cycle a total of 24 days.⁵

The larval stage becomes the predominant creature in the system after hours to days.⁶ The larva feeds on decaying organic substances. After a suitable period, the larval stage reaches enough maturity to displace through tiny spaces around the wounds they infest and return to the soil to pupate and continue the life process.⁷ In our patient, myiasis probably occurred due to poor personal hygiene, cleaning the stoma site with tap water (? unclean water), improper care of the FG site, improper way of feeding through the FG with a predominantly liquid diet, contamination of the FG site liquids and poor nutrition.

Humans inherit the disease in multiple ways, such as when the eggs get deposited in a wound or the larva churns its way deep into the skin and the subcutaneous space. Guleryuzlu et al described wound myiasis related to percutaneous endoscopic gastrostomy feeding tube and introduced this unfortunate complication to the world.⁸ Entomological diagnosis is required to identify the type of maggot, and further molecular investigations can also help identify the causative breed and have high specificity.^{9 10} Nevertheless, the generalised approach towards the disease in terms of management remains the same.

Once meticulous manual extraction of the maggots and thorough localised debridement of the lesion inhabited by the organisms is performed, the lesion is seen to heal with accelerated granulation. In the initial stage, a smear dressing of turpentine oil or chloroform can be used around the affected side, which would either suffocate or paralyse the maggots. While the former forces them to crawl out of the wound, the latter helps in easy manual mechanical extraction.

Alternatively, the role of any form of antibiotics comes into play once there is an incidence of secondary infection in and around the area or any evidence of localised sepsis. In such cases, initially, the patients should be offered tetanus vaccination with or without oral/topical ivermectin, which has proven useful for cutaneous myiasis.⁹

In case any peritubal pus discharge is present, and suspicion of any intra-abdominal extension of the lesion is anticipated, ultrasonography of the abdomen can be performed, and the feeding tube can be replaced and refixed depending on the duration of the surgery. The minimum time duration given for the tract to mature in such a case would be nearly 6 weeks. In our case, turpentine oil application followed by manual extraction and povidone–iodine antisepsis was the mainstream treatment offered to the patient. The tube was replaced with a new tube, and its flow patency was confirmed with fluoroscopic evidence.

Patient’s perspective.

I had come to the hospital in an emergency with maggots at the feeding gastrostomy tube site. My doctors examined me and said that this was because of poor hygiene and improper care of the tube site. The treating surgeons removed the tube, cleaned the stoma site and reinserted a new tube. I was advised to take care of the stoma site properly and maintain good hygiene.

Learning points.

• Feeding gastrostomy (FG) stoma site myiasis is a very rare entity, and to the best of our knowledge, this is the first case to be reported.

• The aetiologies for FG stoma site myiasis are immunocompromised state, malnutrition, poor personal hygiene, poor sanitary conditions and inadequate local care.

• It is a preventable condition with proper patient education. A primary lookout into stoma site hygiene, regular cleaning of the peritubal area, maintaining proper personal hygiene and maintaining a healthy lifestyle can evade such an unfortunate complication.

• Treatment is by manual removal of the larvae, local debridement of the wound, use of the turpentine or chloroform to expel the maggots from cavities, and the replacement of the FG tube.

Ethics statements

Patient consent for publication

Obtained.