Chronic Actinomycetoma of the Lower Limb Mimicking Other Infections—A Case Report

Mycetoma is a granulomatous infection that is suppurative, progressive, and chronic; it mainly affects the skin, subcutaneous tissues, and underlying bones.  It is common in tropical and subtropical areas and is frequently linked to the traumatic implantation of bacterial or fungal infections.  The Atharva Veda, an ancient Sanskrit scripture from India, contains the first known mention of this illness. It talks of a malady called padavalmikam, which translates to "ANTHILL FOOT”[1]. More recently, in 1842, a researcher by the name of Gill discovered mycetoma as a separate illness in the southern Madura region.  For this reason, the ailment gained widespread recognition as "Madura foot." In Madras, India, Godfrey was the first to record a mycetoma case.  After learning that fungi are the source of the illness, Carter later gave it the term "Mycetoma," which translates to "fungal tumor."[2]

Although mycetoma is present worldwide, it is most prevalent in tropical and subtropical climates, particularly in the "Mycetoma belt," which is the region between latitudes 15° S and 30° N.  Sudan, Somalia, Senegal, India, Yemen, Mexico, Venezuela, Colombia, and Argentina are among these nations.  But the illness is not limited to this area.  Mexico and Sudan account for the majority of reported cases, with Sudan reporting the most cases. [3] Pinoy found in 1913 that there are two kinds of bacteria that produce mycetoma.  He separated it into eumycetoma, which is caused by fungi, and actinomycetoma, which is caused by bacteria.^[4]

The organisms responsible for mycetoma and the color of the grains they yield: [5]

Clinical Features of Actinomycetoma and Eumycetoma and Characteristics of the Principal [6]

Summary of diagnostic investigations [5]

Antibiotics are typically effective in treating actinomycetomas.  The infection has been well treated with medications such as AMOXICILLIN-CLAVULANIC ACID, TRIMETHOPRIM, STREPTOMYCIN, DAPSONE, COTRIMOXAZOLE, AND RIFAMPICIN. [7]

Treatment for Actinomycetoma. [8] Modified two-step regimen [2007]

1. Intensive Phase

Gentamicin (80 mg twice daily, IV), and cotrimoxazole (two tablets of 960 mg twice daily) for 4 weeks.

2. Maintenance Phase

Doxycycline (100 mg orally, twice daily), and cotrimoxazole (two tablets of 960 mg twice daily), until 5–6 months after complete healing of all sinuses.

CASE REPORT: -

A 32-year-old Indian male presented with a complaint of a skin lesion once left foot over the previous 2 years. Pain occurs once a lesion is intermittent in nature and increases in doing work and touch, particularly relieved on medication. There was presence of white-colored grain discharge from their lesion along with swelling of the left foot which was not relieved on taking medication. In past, 2 or 3 times the patient visited a primary care hospital with the same complaint but upon taking the medication, it got relieved.

Upon examination, the patient exhibited vital signs within normal limits: pulse rate of 78 beats per minute, respiratory rate of 18 breaths per minute, and blood pressure of 130/80 mmHg. Systemic evaluations including cardiovascular, central nervous system, endocrine, and gastrointestinal assessments were all normal. Locally, the examination revealed a shine-coloured, swelling, and pus discharge in the left foot.

Laboratory tests indicated normal complete blood count and liver function with alkaline phosphate recorded at 172 U/L. Renal function tests yield a serum creatinine level of 1.22 mg/dl. Random blood glucose measurement was 122 mg/dl.

Diagnostic test: -

• Gram Stain - Actinomycetes Positive
• Biopsy - Actinomycetoma Positive
• KOH preparation - Negative
• Culture and sensitivity - Negative

These reports gave a positive diagnosis of Actinomycetes of the patient, who was not having any previous history of such kind of signs and symptoms.

Treatment Given as per the modified 2-step regimen (2007): - (intensive phase)

• INJ. GENTAMICIN, 80 mg, IV, 12 hourly (28 days)
• TAB. TRIMETHOPRIM + SULFAMETHOXAZOLE, 960 mg, PO, 2-0-2 (28 days)

Discharge medication:

DISCUSSION

In 1842, mycetoma was discovered for the first time in Tamil Nadu, India's Madurai area. When it was discovered there, it was called "Madura Foot." Usually beginning in the foot, it is a chronic infection that affects the skin, muscles, and bones. Certain bacteria or fungi are the source of the illness, which can result in deformities, swelling, and pus-filled sores. It has the potential to spread and cause serious harm if untreated. [9] Three primary symptoms of mycetoma, a persistent infection, are swelling of the affected area, numerous lesions that drain pus, and the presence of minute grains (granules) in the discharge. Actinomycetoma (also known as actinomycotic mycetoma) is caused by bacteria belonging to the Actinomycetes group, while eumycetoma is caused by fungus. Typically, the illness affects the hands, legs, and feet; if treatment is not received, the tissues will eventually enlarge and deteriorate. [10]

In the case study, a 32-year-old man from Gujarat has a chronic lesion on his left foot that has been causing him to have periodic discomfort, swelling, and white granular discharge for the past two years.  The symptoms persisted even after several trips to the primary care physician.  Gram stain (Actinomycetes seen) and biopsy confirmed the diagnosis of actinomycetoma, but KOH preparation and culture were negative, ruling out eumycetoma.  Osteomyelitis, TB, and persistent bacterial infections were among the differential diagnoses, highlighting the importance of microbiological confirmation. An intensive phase of IV gentamicin and oral trimethoprim-sulfamethoxazole was administered for 28 days as part of a modified two-step treatment regimen. This was followed by a maintenance phase that included oral doxycycline, trimethoprim-sulfamethoxazole, pantoprazole, folic acid, and MVBC for 30 days.  After 30 days, a follow-up appointment was set up for the patient to evaluate the effectiveness of the treatment and, if need, modify it. Upon examination the patient showed improved signs and symptoms. Photos of the patient responding to the therapy is also provided.

Picture 1: Patient showing improved signs and symptoms with less pain. The pus-filled areas were treated and the pus has disappeared leaving behind dark-colored pigmented patches as shown below: