Sporothrix schenckii: Difference between revisions

Revision as of 00:57, 21 November 2019

Dimorphic fungus that causes rose-handler's disease

Background

Microbiology

Dimorphic fungus with a hyaline, hyphated mold phase at 25ºC, and a round-to-oval budding yeast phase at body temperature
Produces melanin, a virulence factor

Epidemiology

Found in soil, decomposing plant matter, and peat moss worldwide
Acquired by traumatic implantation or inoculation of a preexisting wound

Clinical Presentation

Lymphocutaneous

Common cause of nodular lymphangitis
Incubation period 7 to 30 days
Nodules can be 2 to 4 cm, and appear along the lymphatics, typically in the arms and legs (and face, in children)
- They become indurated, then ulcerated
May have regional lymphadenopathy
Usually mild or no systemic symptoms

Fixed cutaneous

Only a single lesion, fixed at the point of inoculation
Lesions may be papular, plaques, nodular, verrucoud, or ulcerated

Disseminated or multifocal

Only occurs in patients with immunodeficiency, including alcoholism, diabetes, sarcoidosis, tuberculosis, transplantation, malignancy, immunosuppressive medication, or advanced HIV
Lesions can include ulcerations, aceniform, plaques, or crusts
Worst prognosis is with dissemination to lungs or meninges

Extracutaneous

Rare presentation without skin lesions, caused either by inhalation or deep inoculation
Musculoskeletal infections are the most common, with septic arthritis followed by osteomyelitis or tenosynovitis
Pulmonary sporotrichosis is more common in men aged 30 to 60 years, and presents similarly to pulmonary tuberculosis
Sporotrichotic meningitis is rare and occurs in immunocompromised patients
Can also affect eyes, genitals, or oropharyngeal mucosa

Diagnosis

Direct microscopy
- May see yeast forms or characteristic asteroid bodies (especially from deep swabs
Culture
- Sab + chloramphenicol at 25ºC for 5 to 7 days for mold form followed by BHI at 35-37ºC for 5 to 7 days for yeast form
Molecular tests
- Some labs have developed PCR diagnostics
Serology
- Tube or latex agglutination have specificity (95%) and sensitivity (98-100%)
- Immunoassays also exist
Sporotrichin skin test
- Essentially like a TB skin test but for sporotrichosis
- Only useful for epidemiologic surveys

Management

First-line: Itraconazole 100 to 200 mg po daily until 2 to 4 weeks after the lesions resolve (around 3 to 6 months)
- Dose may be increased to 400 mg if there's a poor response, there are extracutaneous infections including osteoarticular or pulmonary disease, or the host is immunocompromised
Alternatives include amphotericin B, fluconazole, and maybe terbinafine
For pregnant women, use amphotericin B
For osteoarticular infection, use itraconazole 200 mg po bid
- Can use amphotericin B as induction
- Duration is at least 12 months
For severe pulmonary infection, use amphotericin B 3 to 5 mg/kg daily (liposomal), stepped down to itraconazole 200 mg po bid when better, to complete at least 12 months total
Same treatment for disseminated disease
For meningeal infection, use amphotericin B 5 mg/kg daily for 4 to 6 weeks, followed by itraconazole 200 mg po bid until at least 12 months
For children, use itraconazole 6 to 10 mg/kg (max 400 mg) daily
For severe disease in children, use amphotericin B 0.7 mg/kg daily induction then itraconazole 6 to 10 mg/kg (max 400 mg) daily
Can also do local hyperthermia, especially for patients who are unable to take the above medications

@@ Line 48: / Line 48: @@
 ** Essentially like a TB skin test but for sporotrichosis
 ** Only useful for epidemiologic surveys
+== Management ==
+* First-line: [[Is treated by::Itraconazole]] 100 to 200 mg po daily until 2 to 4 weeks after the lesions resolve (around 3 to 6 months)
+** Dose may be increased to 400 mg if there's a poor response, there are extracutaneous infections including osteoarticular or pulmonary disease, or the host is immunocompromised
+* Alternatives include [[Is treated by::amphotericin B]], [[Is treated by::fluconazole]], and maybe [[Is treated by::terbinafine]]
+* For pregnant women, use [[Is treated by::amphotericin B]]
+* For osteoarticular infection, use [[itraconazole]] 200 mg po bid
+** Can use [[amphotericin B]] as induction
+** Duration is at least 12 months
+* For severe pulmonary infection, use [[amphotericin B]] 3 to 5 mg/kg daily (liposomal), stepped down to [[itraconazole]] 200 mg po bid when better, to complete at least 12 months total
+* Same treatment for disseminated disease
+* For meningeal infection, use [[amphotericin B]] 5 mg/kg daily for 4 to 6 weeks, followed by [[itraconazole]] 200 mg po bid until at least 12 months
+* For children, use [[itraconazole]] 6 to 10 mg/kg (max 400 mg) daily
+* For severe disease in children, use [[amphotericin B]] 0.7 mg/kg daily induction then [[itraconazole]] 6 to 10 mg/kg (max 400 mg) daily
+* Can also do [[Is treated by::local hyperthermia]], especially for patients who are unable to take the above medications
 == Further Reading ==