Histoplasma capsulatum

Dimorphic fungi

Adrenal glands are the most commonly involved organs in patients with acute disseminated histoplasmosis. This diagnosis should be considered in patients with bilateral adrenal enlargement who are either immunocompromised or resides in endemic areas.

Ans. is ‘a’ i.e., Cryptococcus neoformans; ‘b’ Histoplasma capsulatum; ‘c’ Paracoccidioides bresilensis

Ans. is ‘a’ i.e., Coccidioides immitis; ‘c’ i.e., Histoplasma

Endemic mycoses

.   Mycosis that is geographically restricted to specific area of endemicity.

.   Fungus causing endemic mycosis are : –

I. Coccidioidomycosis                 3. Blastomycosis

2. Histoplasmosis                         4. Paracoccidioidomycosis

Ans. is ‘a’ i.e., Dimorphic fungus

Histoplasma capsulatum

. A dimorphic fungus

. Non encapsulated The only medically important capsulated fungus is cryptococcus.

. Infection is acquired by inhalation of microconidia (small spores) in dust contaminated with bird or bat dropping.

. It causes intracellular infection of reticuloendothelial system.

Clinical manifestations: —> Majority of patients are asymptomatic

Histoplasmosis

Acute pulmonary                    Chronic pulmonary                      Disseminated                                 Presumed ocular histopla‑

histoplasmosis                        histoplasmosis                                                                                  smosis syndrome (PONS)

.       Pneumonitis                        . U/L or B/L fibronodular            – Fever                                    – Discrete atrophic

.       Hilar adenopathy              apical infiltrates                            – Emaciation                           choroidal scar

.       Erythema nodosum                                                                    – Hepatosplenomegaly       – Peripapillary atrophy

.       Erythema multiforme                                                                – Lymphadenopathy          – Choroidal neovasculari‑

.       Subacute pericarditis                                                                  – Anemia, leukopenia            zation

Thrombocytopenia                 

– Loss of central vision

–    Ganulomatous hepatitis

– Addison’s diseases

–   GI ulcers

– Endocarditis

– Chronic meningitis

Ans. is ‘a’ i.e., Histoplasma

• Histoplasmosis is also known as Darling’s disease or Cave’s disease or Caver’s disease.

Ans. is ‘a’ i.e., In early stages it is indistinguishable from TB

• Caseation necrosis and calcification may mimic tuberculosis.                                                                          
  
• Harrison About other options
• Culture is the preferred method for diagnosis.
• Spores are the infective form and infection is acquired by inhalation of spores.

.   Histoplasma infection never transmits from man to man.

Ans. is ‘b’ i.e., Histoplasma

• On Sabourauds agar, at room temperature, white cottony mycelia growth appears, with large (8-20 micrometer) thick walled, spherical spores with tubercles or finger-like projections. This appearance of “tuberculate spores” is diagnostic of Histoplasma capsulatum.

Ans. is ‘a’ i.e., Cryptococcus neoformans; ‘b’ i.e., Histoplasmosis

Fungi infecting the brain are

• Cryptococcus neoformans            
• Blastomyces dermatitidis
• Coccidioides immitis                   
• Aspergillus sp.
• Candida sp.                            
• Sporothrix schenckii
• Histoplasma capsulatum

Ans. is ‘a’ i.e., Very rare in patients with AIDS

Granulomatous Conditions with caseous necrosis : ‑

1. Tuberculosis,                

2. Histoplasmosis,              

3. Coccidiodomycosis       

4. Syphilis

Note – In wegner’s granulomatosis, there is central necrosis in granuloma but it is not caseous necrosis.

Ans is ‘b’ i.e., TB; ‘c’ i.e., Histoplasmosis

o Granuloma with necrosis

TB

Syphilis

Caseous necrosis Coccidiodomycosis

Histoplasmosis

o Wegner’s granulomatosis – Non-caseous necrosis.

A i.e. Histoplasmosis; B i.e. Sarcoidosis; C i.e. Secondaries from CA colon

Ans. is ‘b’ i.e., Histoplasma 

Ans. is ‘c’ i.e., Capsulated

Histoplasma capsulatum

• A dimorphic fungus

• Non encapsulated → The only medically important encapsulated fungus is cryptococcus.

• Infection is acquired by inhalation of microconidia (small spores) in dust contaminated with bird or bat dropping.

• It causes intracellular infection of the reticuloendothelial system.

• Clinical manifestations → Majority of patients are asymptomatic