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Gorgas Case 2004-10 |
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The Gorgas Course is now finished for 2004. Please find below the 10th and final Gorgas Course Case of the Week for this year. The patient was seen by the Gorgas Course participants in the outpatient department of the Tropical Medicine Institute.
Publishing a case report every Monday for 10 consecutive weeks would not be possible without the assistance of an extremely dedicated group of people. We would like to thank in particular: Dr. Carlos Seas, Clinical Rounds Coordinator for the Gorgas Courses for case selection, coordination of case summaries and images; Dr. Tine Verdonk of the Antwerp Tropical Medicine Institute for digital photography and some case histories; Drs. Jaime Cok and Juan Ferrufino for preparation and discussion of pathologic specimens; and Adam Plier of the UAB Division of Geographic Medicine for all publishing on the Gorgas Course web site. We hope you have enjoyed this year's cases. In 2005 we will be running the Gorgas Expert Course for 2 weeks prior to the regular 9-week course. We will be in touch in January 2005 at the beginning of next year's case series.
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 History: 63 yo male with 3 week history of a painless skin lesion over the left ankle beginning with a nodule which ulcerated after a few days and progressed by the end of the first week to include ascending mildly painful linear nodules up the leg to the knee. As it is an endemic area, a clinical diagnosis of leishmaniasis was made locally and he was referred to us. No significant past medical history.
Epidemiology: Farmer, born and lives in Canta in the highlands (2400 m) of Lima Department. A few cases of bartonellosis have been reported. Physical Examination: Afebrile. Chest clear. No hepatosplenomegaly. Lesions as shown in images A & B. Ipsilateral non-tender inguinal adenopathy was present. Laboratory Examination: No biochemical, hematological, or radiological, testing performed. Smears for giemsa, AFB, KOH were negative. Biopsies and cultures were sent.
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 Diagnosis: Sporotrichosis.
Discussion: Histopathology and culture of the biopsy was negative for Leishmania. Tissue cultured on Sabouraud's agar yielded hyphae and the characteristic bouquet-like conidia of Sporothrix schenkii after 2 weeks at 30°C [see Image C]. The differential diagnosis of an ulcerated lesion with linear lymphocutaneous spread in Perú includes leishmaniasis, sporotrichosis, atypical mycobacteria, and nocardiosis. Sporotrichosis is always an important consideration in areas such as Perú even where leishmaniasis is much more common. It is not possible purely on clinical grounds to differentiate the two with certainty. Our leishmania referral clinic sees hundreds of cases a year and fungal cultures are routinely performed. This patient was initially started on anti-leishmanial therapy pending cultures for leishmania and sporotrichosis. Fortunately, in culture of aspirates or biopsy material, S. schenkii grows very easily and rapidly when present. Smears or aspirates from the lesion are usually negative on direct examination and no useful serology is available. S. schenkii is a dimorphic fungus but the oval to cigar shaped yeast forms are difficult to find on biopsy specimens. Cutaneous anthrax occurs in Perú [see Gorgas Case 2001-07] and can have lymphatic spread but a lesion of this duration would consistently have a black necrotic base. Loxocelism often evolves to a large ulcer but those lesions are uniformly extremely painful unlike in the current case. Environmental reservoirs for S. schenkii include sphagnum moss (including wood or plants contaminated by moss), decaying vegetation, hay, soil and masonry. Outdoors work (including construction), gardening, and having a cat [Clin Infect Dis. 2004;38(4):529-35 and Clin Infect Dis. 2003;36(1):34-9] are risk factors. Sporotrichosis is distributed worldwide but most cases are reported from the Americas and Japan. Most cases are sporadic or occur in self-limited clusters due to some point source exposure. The area around Abancay, Perú (not where this patient lives) has recently been, perhaps uniquely, identified as an area where sporotrichosis is not only entrenched but is hyperendemic with annual incidence rates of up to 100 per 100,000 population [Clin Infect Dis. 2003;36(1):34-9 and Clin Infect Dis. 2000;30(1):65-70]. Extracutaneous manifestations of sporotrichosis include disseminated visceral, osteoarticular, meningeal, and pulmonary sporotrichosis. These are usually seen in immunocompromised hosts and in alcoholics. These manifestations are rare or even unknown in Perú. The treatment of choice for lymphocutaneous sporotrichosis is itraconazole and in severe extracutaneous or disseminated disease amphotericin can be used. Terbinafine has recently been shown to be effective therapy [Mycoses. 2004;47(1-2):62-8]. In the reality of poor countries, many patients, such as this one cannot afford itraconazole or terbinafine. The older but still effective mode of therapy with a saturated solution of potassium iodide (SSKI) is still widely used in practice. Our patient has been started on a minimum 3-month course of SSKI to progress to 150 drops (approximately 47 mg/drop) once per day in escalating doses as tolerability permits. The course can be extended depending on clinical response. SSKI and its clinical use has been recently reviewed [J Am Acad Dermatol 2000;43(4):691-7] and we have previously demonstrated the utility of once daily dosing in order to increase compliance [Pediatr Infect Dis J 1996;15(4):352-4]. The mechanism of action is unknown. SSKI can also be used for entomophthoramycosis caused by Basidiobolus and Conidiobolus. In dermatologic practice SSKI can be used for erythema nodosum, nodular vasculitis, erythema multiforme, and Sweet's disease. The main adverse effects are gastrointestinal and the SSKI can be added to larger volumes of water, juice, or milk for administration. Care must be taken to avoid potassium or iodide toxicity in those on ACE inhibitors or potassium sparing diuretics, those with renal disease, and in those on medications or with conditions making them unable to autoregulate thyroid hormone production.
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