Histoplasma capsulatum ,Dimorphic Fungi,Morphology, Pathogenesis, Lab Diagnosis

Описание: Histoplasmosis is an important systemic granulomatous fungal infection caused by the dimorphic fungus Histoplasma capsulatum and is a high-yield topic for B.Sc. MLT, BMLT, Nursing, MBBS, and Microbiology exams.

In this video, you will get a complete, step-by-step, exam-oriented explanation of Histoplasmosis, strictly based on standard medical textbooks (Paniker, Ananthanarayan, Jawetz) and explained in a simple, easy-to-remember manner.

📌 Topics Covered in This Video

🔹 Introduction

What is Histoplasmosis?

Why Histoplasma capsulatum is called a misnomer

Darling’s disease & historical background

Varieties of Histoplasma capsulatum

🔹 Epidemiology

Endemic areas (Ohio–Mississippi valley, India, Nepal context)

Source of infection (bird & bat droppings)

Mode of transmission
🔹 Morphology

Dimorphic nature (25°C mould vs 37°C yeast)

Tissue form: intracellular yeast in macrophages

Culture form: microconidia & tuberculate macroconidia

Exam-favorite morphological points

🔹 Pathogenesis (Stepwise Flowchart)

Inhalation of microconidia

Intracellular survival inside macrophages

Lympho-hematogenous spread

Role of cell-mediated immunity

Granuloma formation vs disseminated disease
🔹 Clinical Manifestations

Pulmonary histoplasmosis (acute & chronic)

Mucocutaneous histoplasmosis (important for Indian/Nepalese cases)

Disseminated histoplasmosis (HIV & immunocompromised patients)

🔹 Laboratory Diagnosis

Best specimens (bone marrow, sputum, lymph node)

Direct microscopy (Giemsa, PAS, GMS)

Culture on SDA (gold standard)

Serology (CFT, Immunodiffusion – M & H bands)

Antigen detection & PCR

Differential diagnosis with TB & Leishmania
🔹 Treatment

Itraconazole vs Amphotericin B

Treatment according to severity

Management in HIV patients

Important exam points & mnemonics

🎯 Why This Video is Important?

✅ Perfect for 10–15 mark exam answers
✅ Includes high-yield points & mnemonics
✅ Explained exactly in Nepali university exam pattern
✅ Useful for theory + viva + practical correlation

📚 Recommended For

B.Sc. MLT / BMLT students

Medical Laboratory Technology exams

Medical Microbiology revision

Competitive exams (PSC, entrance, licensing)

References

Paniker’s Textbook of Medical Mycology

Ananthanarayan & Paniker’s Microbiology

Jawetz, Melnick & Adelberg

Bailey & Scott