Diagnosis

Leishmaniasis

Etiology

Cause [hin][1sm]

• An intracellular protozoa parasite transmitted by the bite of a female sandfly (Phlebotomus and Lutzomyia) that require blood meals

Pathophysiology [1sm][hin]

1. Clinical spectrum depends:

   • Which subtype of phagocytic cells are infected

   • Host immune status (deficient cell-mediated immunity, malnutrition, AIDS)

   • Species of parasite (visceral leishmaniasis species are able to grow at core temperatures, while cutaneous leishmaniasis species grow best at lower temperatures)

2. Cutaneous leishmaniasis:

   • The parasites infect resident macrophages within the skin

   • Localized or widespread cutaneous papules and nodules

3. Visceral leishmaniasis (kala-azar):

   • The parasites spread hematogenously to mononuclear cells of the liver, spleen, bone marrow, and lymph nodes of the intestine

   • Potentially lethal systemic disease

Epidemiology

Incidence per 100.000 [cde][m4m][wrg][b6s][v2o][my1]

Approach

• Blood test

• Biopsy

• Culture of infected tissue

• Serelogy

• PCR

• Electrophoresis

• Leishmanin Skin Test (Montenegro Test)

Treatment

1. Prevention: [1sm]

   • Knowledge of endemic areas

   • Awareness of nocturnal sandfly activity --> small size pattern bed net

   • Exposure to animals in areas known to harbor disease

   • Impregnation with permethrin

   • Vaccinating dogs and utilizing insecticide dog collars

2. Pharmacologic therapies include the following: [hin]

   • Pentavalent antimony (sodium stibogluconate or meglumine antimonate): Used in cutaneous leishmaniasis

   • Liposomal amphotericin B (AmBisome): Effective against pentavalent antimony ̶ resistant mucocutaneous disease and visceral leishmaniasis

   • Oral miltefosine (Impavido): for visceral leishmaniasis due to L donovani; cutaneous leishmaniasis due to L braziliensis, L guyanensis, and L panamensis; and mucosal leishmaniasis due to L braziliensis

   • Intramuscular pentamidine: Effective against visceral leishmaniasis but associated with persistent diabetes mellitus and disease recurrence

   • Orally administered ketoconazole, itraconazole, fluconazole, allopurinol, and dapsone: None is as effective as the pentavalent antimony compounds, but they may be useful in accelerating cure in patients with cutaneous leishmaniasis that does not progress to mucosal disease and tends to self-resolve

   • Topical paromomycin: Shown to be effective against cutaneous leishmaniasis caused by L major and L mexicana

3. Local therapies for cutaneous leishmaniasis:

   • Cryotherapy

   • Local heat therapy at 40-42°C

   • Often resolves spontaneously

4. Other important issues in the management of leishmaniasis are as follows:

   • Correction of malnutrition

   • Treatment of concurrent systemic illness (eg, HIV disease or tuberculosis)

   • Control of local infection

Differential diagnoses

African trypanosomiasis, Basal cell carcinoma, Blastomycosis, Brucellosis, Chromoblastomycosis, Cutaneous T-cell lymphoma, Diphtheria, Eczema, Endocarditis, Furuncular myiasis, Hemolytic anemia, Histoplasmosis, HIV, Impetigo, Leprosy, Leukemia, Lobomycosis, Lymphoma, Malaria, Mycobacterium avium, Mycobacterium marinum, Nasopharyngeal carcinoma, Orf, Paracoccidioidomycosis, Pinta, Polymorphic reticulosis, Portal hypertension, Psoriasis, Pyoderma gangrenosum, Pyogenic granuloma, Rhinoscleroma, Sarcoidosis, Schistosomiasis, Sporotrichosis, Squamous cell carcinoma, Syphilis, Systemic lupus erythematosus, Tropical pyoderma, Tropical splenomegaly syndrome, Tuberculosis, Tularemia, Typhoid fever, Wegener's granulomatosis, Yaws