Sporothrix schenckii: Difference between revisions

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Sporothrix schenckii
(Created page with "* Dimorphic fungus that causes '''rose-handler's disease''' == Background == === Epidemiology === * Found in soil, decomposing plant matter, and peat moss * Acquired by inocu...")
 
 
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* Dimorphic fungus that causes '''rose-handler's disease'''
 +
*Dimorphic fungus that causes '''rose-handler's disease'''
   
−
== Background ==
 +
==Background==
−
=== Epidemiology ===
 +
===Microbiology===
  +
⚫
* Found in soil, decomposing plant matter, and peat moss
  
  +
*Dimorphic fungus with a hyaline, hyphated mold phase at 25ºC, and a round-to-oval budding yeast phase at body temperature
⚫
* Acquired by inoculation of a preexisting wound or penetration of intact skin
  
  +
*Produces melanin, a virulence factor
  +
  +
===Epidemiology===
  +
  ⚫
*Found in soil, decomposing plant matter, and peat moss worldwide (but most often in moist tropical or subtropical zones)
  +
**Increasing frequency in Italy
  ⚫
*Acquired by traumatic implantation or inoculation of a preexisting wound
  +
*Can also be acquired by cat scratches
  +
*Hosts include humans, cats, horses, dogs, rodents, cattle swine, camels, etc.
  +
  +
==Clinical Manifestations==
  +
===Lymphocutaneous===
  +
  +
*Common cause of [[nodular lymphangitis]]
  +
*Incubation period [[Usual 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, verrucous, or ulcerated
  +
  +
===Disseminated or multifocal===
  +
  +
*Only occurs in patients with immunodeficiency, including alcoholism, diabetes, sarcoidosis, tuberculosis, transplantation, malignancy, immunosuppressive medication, or advanced HIV
  +
**Can be in the context of HIV IRIS
  +
*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]]
  +
**Major risk factors: alcohol (1/3); sarcoidosis, TB, or diabetes (1/3); otherwise healthy (1/3)
  +
*'''Sporotrichotic meningitis''' is rare and occurs in immunocompromised patients
  +
*Can also affect eyes, genitals, or oropharyngeal mucosa
  +
  +
== Differential Diagnosis ==
  +
  +
* See [[nodular lymphangitis]]
  +
  +
==Diagnosis==
  +
  +
*Sample collection
  +
**Deep swab or aspirate, if possible
  +
**Punch biopsy, can be with sterile saline if needed (not in formalin)
  +
*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
  +
**Colony appearance is a white mold that becomes dark
  +
*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: [[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
  +
**Check for drug-drug interactions
  +
*Alternatives include [[Is treated by::amphotericin B]], [[Is treated by::fluconazole]], and maybe [[Is treated by::terbinafine]]
  +
*Can also do [[Is treated by::local hyperthermia]], especially for patients who are unable to take the above medications
  +
  +
===Special populations===
  +
  +
*For '''pregnant women''', use [[Is treated by::amphotericin B]]
  +
*For '''osteoarticular infections''', 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
  +
  +
===Potassium iodide===
  +
  +
*Used more outside of developed countries, since it is cheap
  +
*Poorly tolerated, though, with numerous side effects
  +
  +
==Further Reading==
  +
  +
*[https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/sporothrix-schenckii.html Pathogen Safety Data Sheets: Infectious Substances – Sporothrix schenckii].
   
 
{{DISPLAYTITLE:''Sporothrix schenckii''}}
  
{{DISPLAYTITLE:''Sporothrix schenckii''}}

Latest revision as of 09:59, 5 August 2020

  • 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 (but most often in moist tropical or subtropical zones)
    • Increasing frequency in Italy
  • Acquired by traumatic implantation or inoculation of a preexisting wound
  • Can also be acquired by cat scratches
  • Hosts include humans, cats, horses, dogs, rodents, cattle swine, camels, etc.

Clinical Manifestations

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, verrucous, or ulcerated

Disseminated or multifocal

  • Only occurs in patients with immunodeficiency, including alcoholism, diabetes, sarcoidosis, tuberculosis, transplantation, malignancy, immunosuppressive medication, or advanced HIV
    • Can be in the context of HIV IRIS
  • 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
    • Major risk factors: alcohol (1/3); sarcoidosis, TB, or diabetes (1/3); otherwise healthy (1/3)
  • Sporotrichotic meningitis is rare and occurs in immunocompromised patients
  • Can also affect eyes, genitals, or oropharyngeal mucosa

Differential Diagnosis

Diagnosis

  • Sample collection
    • Deep swab or aspirate, if possible
    • Punch biopsy, can be with sterile saline if needed (not in formalin)
  • 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
    • Colony appearance is a white mold that becomes dark
  • 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
    • Check for drug-drug interactions
  • Alternatives include amphotericin B, fluconazole, and maybe terbinafine
  • Can also do local hyperthermia, especially for patients who are unable to take the above medications

Special populations

  • For pregnant women, use amphotericin B
  • For osteoarticular infections, use itraconazole 200 mg po bid
  • 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

Potassium iodide

  • Used more outside of developed countries, since it is cheap
  • Poorly tolerated, though, with numerous side effects

Further Reading

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