| Literature DB >> 30097030 |
Pembi Emmanuel1,2,3, Shyam Prakash Dumre1, Stephen John4, Juntra Karbwang5, Kenji Hirayama1.
Abstract
BACKGROUND: Mycetoma is a chronic mutilating disease of the skin and the underlying tissues caused by fungi or bacteria. Although recently included in the list of neglected tropical diseases by the World Health Organization, strategic control and preventive measures are yet to be outlined. Thus, it continues to pose huge public health threat in many tropical and sub-tropical countries. If not detected and managed early, it results into gruesome deformity of the limbs. Its low report and lack of familiarity may predispose patients to misdiagnosis and delayed treatment initiation. More so in situation where diagnostic tools are limited or unavailable, little or no option is left but to clinically diagnose these patients. Therefore, an overview of clinical course of mycetoma, a suggested diagnostic algorithm and proposed use of materials that cover the exposed susceptible parts of the body during labour may assist in the prevention and improvement of its management. Furthermore, early reporting which should be encouraged through formal and informal education and sensitization is strongly suggested. MAIN TEXT: An overview of the clinical presentation of mycetoma in the early and late phases, clues to distinguish eumycetoma from actinomycetoma in the field and the laboratory, differential diagnosis and a suggested diagnostic algorithm that may be useful in making diagnosis amidst the differential diagnosis of mycetoma is given. Additionally, a proposed preventive measures which may be helpful in the community is also provided. Since treatment is currently based on expert opinion, we encourage active research to establish treatment guideline for it.Entities:
Keywords: Actinomycetoma; Clinical dilemma; Dermatological diseases; Disability; Eumycetoma; Mycetoma; Neglected tropical diseases; Social stigma
Mesh:
Substances:
Year: 2018 PMID: 30097030 PMCID: PMC6085652 DOI: 10.1186/s12941-018-0287-4
Source DB: PubMed Journal: Ann Clin Microbiol Antimicrob ISSN: 1476-0711 Impact factor: 3.944
Characteristic features of eumycetoma and actinomycetoma
| Characteristics | Eumycetoma | Actinomycetoma |
|---|---|---|
| Causative agents | Fungi [ | Bacteria [ |
| Geography | Common in Africa and India [ | Common in Latin America [ |
| Occupation | Field workers [ | Field workers [ |
| Age group | Common in 20–40 years [ | Common in 20–50 years [ |
| Anatomical parts affected | Usually hand, feet and other parts of arms and legs [ | Usually chest, abdomen and head [ |
| Course of progression | Slow [ | More rapid and inflammatory [ |
| Sinus (number, morphology) | Few, proliferative, protuberant [ | Many, depressed, flat [ |
| Fistula | Few [ | Many [ |
| Bone invasion | Delayed [ | Rapid [ |
| Bone cavities on radiograph | Fewer but larger with clear margins [ | Numerous, small with unclear margins [ |
| Lymphatic spread | Occassional [ | Frequent [ |
| Veins proximal to lesion | Commonly dilated | Seldom dilated |
| Grains size | Larger (0.5–2 mm) [ | Smaller (20–100 μm) [ |
| Grain texture | Coarse [ | Fine [ |
| Pigment | Melanin [ | Absent [ |
| Hyphae [ | Septate (4–5 μm thick) | Fine, branching filaments (< 1 μm) |
| Acid fast staining | Negative [ | Weakly acid fast (e.g. |
| Masson–Fontana silver staining | Positive [ | Negative [ |
| PAS staining | Positive [ | Negative [ |
| GMS staining | Positive [ | Positive [ |
| B and B staining | Negative [ | Gram positive [ |
| Ultrasound features | Hyperechogenic [ | Less echogenic [ |
| Treatment | Drugs (antifungal) + surgery [ | Drugs (antibiotics) [ |
GMS Grocotts Methenamine silver Stain, B and B Brown and Brenn stain, PAS periodic-acid Schiff staining
Usefulness and pitfalls of diagnostic tools used in mycetoma
| Diagnostic methods | Usefulness | Pitfalls |
|---|---|---|
| Clinical | Utilised in endemic areas where diagnostic facilities are lacking | Does not identify the etiologic agent |
| Imaging | ||
| X-ray | Can determine the extent of lesions | Requires expert for interpretation |
| Ultrasound | Determine the extent of lesions | Cannot differentiate between different causative agents |
| MRI | Determine the extent of lesions | Unsuitable for discrimination |
| CT | Determine the extent of lesions | Not specific for early bony involvement |
| Laboratory | ||
| Microscopy | Cheaper and easy to use | Cannot identify specific etiologic agents |
| Culture | Gold standard for aetiology identification | Time consuming, contamination is common, high expertise needed |
| Histology/FNAC | Simple, rapid, sensitive and invasive but well tolerated by most patients | Requires expert to perform the procedure |
| Serology | Less invasive procedure | Cannot reliably diagnose mycetomca |
| Molecular-PCR | Fast, reliable and easy identification of causative agents | Expensive, not readily available in endemic areas |
| Molecular-LAMP | Reliable identification of causative agents | Less specific than PCR in identifying etiologic agents, possibility of field application |
MRI magnetic resonance imaging, CT computed tomography, PCR polymerase chain reaction, FNAC fine needle aspiration cytology, LAMP loop-mediated isothermal amplification
Fig. 1Schematic diagram showing: a a normal foot and b foot disfigured by the destructive nature of mycetoma due to delay in instituting clinical management. Figures are schematic presentation and may not scale to actual measurements
Fig. 2Diagnostic algorithm for mycetoma
Major clinical differences between eumycetoma and actinomycetoma: summary of key findings
| Characteristics | Eumycetoma | Actinomycetoma |
|---|---|---|
| Affected body parts [ | Usually hand, feet and other parts of arms and legs | Usually chest, abdomen and head |
| Lesion [ | Well encapsulated with a clear margin | Diffuse, no clear margin |
| Disease progression [ | Slow | More rapid and inflammatory |
| Sinus morphology [ | Proliferative, protuberant | Depressed, flat |
| Sinuses [ | Few | Many |
| Bone invasion [ | Delayed | Rapid |
| Bone radiograph [ | Fewer but larger cavities with clear margins | Numerous, small cavities with unclear margins |
| Color and texture of grains | Different colors, but mostly white or black; coarse texture | Different colors but not black; fine texture |
| Lymphatic spread [ | Occassional | Frequent |
| Drugs (e.g.) [ | Antifungals (ketoconazole, voriconazole, posaconazole, etc.) | Antibiotics (sulfamethoxazole–trimethoprim, rifampicin, amikacin, etc.) |
| Recurrence [ | More | Less |
Infectious and non-infectious diseases mimicking mycetoma: consideration for differential diagnosis
| Infectious diseases | Non-infectious diseases |
|---|---|
| Parasitic | Tumours |
| Elephantiasis | Acral melanoma |
| Bacterial | Bone cyst |
| Actinomycosis | Fibro lipomas |
| Chronic bacterial osteomyelitis | Fibroma |
| Syphilis | Foreign body granuloma |
| Tuberculosis | Ganglion cyst |
| Yaws | Giant cell tumour |
| Fungal | Gouty typhus |
| Blastomycosis | Kaposi’s sarcoma |
| Botryomycosis | Lipomas |
| Chromoblastomycosis | Malignant melanoma |
| Coccidioidomycosis | Nerve sheath tumours |
| Lobomycosis | Osteosarcoma |
| Paracoccidioidomycosis | Rhabdomyosarcoma |
| Phaeohyphomycosis | Sarcomas (others) |
| Sporotrichosis | Subdermal abscess |
| Occupational | |
| Podoconiosis |
Disease names are given in alphabetical order
Level of health care facilities and possible diagnostic approach for mycetoma
| Facility | Method of diagnosis |
|---|---|
| Field | Clinical |
| Peripheral | Clinical, microscopy, radiology (X-ray) |
| District | Clinical, microscopy, radiology (X-ray, ultrasound) |
| Tertiary and referral centres | Clinical, microscopy, radiology (X-ray, ultrasound, MRI, CT), culture, histology, serology, molecular (PCR, LAMP) |
MRI magnetic resonance imaging, CT computed tomography, PCR polymerase chain reaction, LAMP loop-mediated isothermal amplification
Fig. 3Recommended prevention and control strategies for mycetoma
(Source of photograph of mycetoma affected leg: http://www.who.int/neglected_diseases/diseases/massive_foot_mycetoma.jpg)