Clinical and Epidemiological Profile of Mycetoma Foot: Observations from Eastern India

INTRODUCTION

Mycetoma is a chronic granulomatous infection that affects the skin, subcutaneous tissue, and bones. It is a disease in tropical and subtropical countries [1]. The earliest documentation of the disease dates back to the ancient Indian Sanskrit text of Atharva Veda mentioning it as padavalmikam: “anthill foot.” Gill first recognized mycetoma as an entity in 1842 in the south of Madura, since then the term “Madura foot” has become prevalent. The first mycetoma case was reported from Madras, India by Godfrey.  “Mycetoma” (meaning fungal tumour) name was given by Carter and thereafter, this name is used for this disease entity [2]. Mycetoma may be caused by true fungi (eumycetoma) or by the filamentous bacteria (actinomycetoma). It is clinically characterized by a classical triad of tumefaction, draining sinuses and discharging colonial grains [3].   Actinomycotic  mycetoma is caused by aerobic  species of actinomycetes which belong to genera Nocardia, Streptomyces, and Actinomadura with Nocardia brasiliensis, Actinoma duramadurae,Actinomadura pelletieri and Streptomyces somaliensis being most common.  Eumycotic mycetoma is  caused  by    varied    fungi,    most  commonly Madurellamycetomatis. Clinically, different colours of grains are produced which varies according to the species [4].

Almost all cases present initially as small, painless, subcutaneous nodules at the site of injury which ulcerates later to produce a viscous, purulent, or serosanguinous fluid discharge containing characteristic granules. The granules made of colonies of the etiological organism, constitute the hallmark of mycetoma and vary in size, colour, and consistency depending on the causative species. With time, papules, pustules and nodules appear which break down to form draining sinuses developing on the skin surface. The overlying skin is usually smooth and shiny, and fixed to the underlying tissue. Hyper-pigmented skin may be present, with signs of both old healed, and active sinuses. The disease gradually progresses to involve the surrounding tissues which get swollen, indurated, and deformed by fibrous tissue reaction and multiple sinus formation. The condition is usually painless but can be painful in the event of bone involvement or secondary bacterial infection. Nerves and tendons are rarely affected [1].

Mycetoma is a localized disease usually but can spread slowly by direct contiguity along the fascial planes, invading the subcutaneous tissue, fat, ligaments, muscles, and bones. Gross swelling with deformity of the affected part occurs [1]. If left untreated, the disease progresses, and bacterial superinfection occurs which results in increased morbidity due to local abscess formation, cellulitis, and bacterial osteomyelitis. In advanced cases, deformities or ankylosis may occur [1]. Diagnosis of mycetoma is based on the presence of the classic triad. Diagnosis of the etiological organism can be made by microscopic observation of grain only. Histopathology and culture are usually not necessary for diagnosis [1].

The exact burden of the disease is not very clear due to sparse data. However, a review reported Mauritania and Sudan as countries with the highest prevalence with prevalence of the disease being 3.49 and 1.81 cases per 100,000 inhabitants respectively. The prevalence of mycetoma cases in India was reported as

In India, most of the cases documented are from Rajasthan and South India. While actinomycetoma is reported more from South India, Rajasthan, and Chandigarh, eumycetoma is reported mainly from Northern India and central Rajasthan [6]. There is scanty literature regarding mycetoma foot from Eastern India. The present study explored the cases of mycetoma foot in a tertiary care set-up in eastern India.

PATIENTS/MATERIALS AND METHODS

A prospective, observational, single-centre study was carried out over 3 years in the department of tropical medicine of a tertiary care hospital. The study included diagnosed cases of mycetoma foot which were treated in the facility. Those not consenting to be part of the study were excluded.

Epidemiological data and detailed clinical data were noted in all cases. The discharging materials: purulent exudates with  grains (granules) were sent for staining and culture to the microbiology department and microbiological data were noted. All patients were commenced on treatment as per the standard protocol (detailed in the results).

Data was statistically analysed. Descriptive statistics were represented as mean, standard deviation, frequency, and percentages. All statistical tests were conducted on standard statistical software like GraphPad Prism (GraphPad Prism 8.0.2, San Diego, CA, USA) and Microsoft Excel.

Statistical analysis

Data was statistically analysed. Descriptive statistics were represented as mean, standard deviation, frequency, and percentages. All statistical tests were conducted on standard statistical software like GraphPad Prism (GraphPad Prism 8.0.2, San Diego, CA, USA) and Microsoft Excel.

RESULTS

Our study noted 10 cases of mycetoma. The mean age presentation was 38.4 years, ranging from 28 years to 51 years. Out of 10 cases, there were 2 females, hinting at male preponderance. The majority of the cases were employed in agricultural occupations. Duration is grossly varied from 6 to 11 months, with the mean being 8.35 months. 6 cases affected the right foot and the rest the left one. Each case had a firm, non-tender swelling with sinus and discharging grains of yellow colour and yellowish white colour (Table 1).

The initial lesion started as a single nodule over the dorsum of the foot, followed by multiple nodules that appeared within the next few months (2 to 3). Nodules first burst to develop sinuses with the intermittent discharge of yellow-coloured granules and pain development in the foot leading to walking difficulty and grossly swollen feet (Figure 1).

On microbiological examination, gram-positive narrow filamentous branching bacilli were seen.  Surgical debridement was necessitated in all cases except one, and bone debridement was needed in three cases. Parenteral Amikacin (15 mg/kg/day divided into 2 daily doses) was given during the first 3 weeks along with oral trimethoprim+ sulfamethoxazole (TMP-SMX) (2 DS tablets twice daily), followed by oral trimethoprim+ sulfamethoxazole (TMP-SMX) (2 DS tablets twice daily) for a total of 6 to 12 months depending on response (Table 1).

Table 1. Characteristics of the Cases Observed

DISCUSSION