Mycoses and Fungal Infections Overview

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Questions and Answers

What color do colonies of Hortaea werneckii initially appear before changing to a darker shade?

Gray

Brownish (correct)

Greenish black

Olive

What is the primary causative agent of Tinea versicolor?

Malassezia furfur (correct)

Cladosporium werneckii

Phaeoannellomyces werneckii

Hortaea werneckii

What is a common feature of the microscopic examination of colonies of Hortaea werneckii?

One to two celled cylindrical to spindle shaped cells (correct)

Hyaline cylindrical cells with extensive branching

Large spherical cells with no budding

Small oval cells without anuptial structures

What does KOH preparation help to identify in cases of superficial mycoses?

Budding yeast and septate hyphae Signup and view all the answers

Which of the following is NOT a treatment option for Tinea Nigra caused by Hortaea werneckii?

Lemon juice Signup and view all the answers

What is the primary causative agent of Black Piedra?

Piedraia hortae Signup and view all the answers

Which treatment is mentioned as a temporary remedy for Tinea versicolor?

Selenium sulfide Signup and view all the answers

Which statement accurately describes the lesions of Tinea nigra?

They are brown or black macular patches. Signup and view all the answers

What characteristic describes the nodules formed by Piedraia hortae?

Firmly attached to the hair shaft Signup and view all the answers

Which statement best describes the treatment for Black Piedra?

Involves removal of infected hair shafts Signup and view all the answers

What is a serious condition that may be confused with Tinea nigra during diagnosis?

Malignant melanoma Signup and view all the answers

What is the microscopic appearance of the nodules in White Piedra compared to Black Piedra?

Larger, softer, and lighter colored Signup and view all the answers

Which of the following is NOT an associated disease of Malassezia furfur?

Syphilis Signup and view all the answers

Which of the following solutions is used to identify Piedraia hortae in a KOH preparation?

10-20% KOH Signup and view all the answers

What microscopic feature is characteristic of Hortaea werneckii?

Dematiaceous hyphae with chlamydospores Signup and view all the answers

What is a distinguishing feature of Tinea versicolor when compared to other skin conditions?

Color changes and scaling of the skin Signup and view all the answers

What is the primary causative agent of keratitis?

Aspergillus Signup and view all the answers

Which of the following is NOT a common factor predisposing individuals to systemic mycoses?

Get regular exercise Signup and view all the answers

Which clinical presentation is characteristic of mycotic keratitis?

White plaque formation on the cornea Signup and view all the answers

What is the common treatment for keratitis despite its retinal toxicity?

Amphotericin B Signup and view all the answers

Which fungal genus is most frequently associated with otomycosis?

Aspergillus Signup and view all the answers

What are the typical characteristics of the fungi involved in keratitis according to microscopic examination?

Clear, septate hyphae and some yeast cells Signup and view all the answers

Which of these conditions is classified as a superficial mycosis?

Keratitis Signup and view all the answers

What is a common initial symptom of otomycosis?

Minor irritation in the ear Signup and view all the answers

Which characteristic is true for colonies of Trichosporon spp.?

They resemble colonies of Cryptococcus neoformans. Signup and view all the answers

What type of cells do septate hyphae of Trichosporon spp. break into?

Arthrospores or yeast-like cells. Signup and view all the answers

What clinical manifestations are most common in patients with systemic infections caused by Trichosporon spp.?

Non-specific febrile illness or pneumonia. Signup and view all the answers

Which of the following biochemical reactions is positive for Trichosporon spp.?

Urease positivity. Signup and view all the answers

What appearance do the colonies of Trichosporon mucoides typically have?

Creamy or velvety, and varied in texture. Signup and view all the answers

In which patient population are infections caused by Trichosporon spp. most frequently fatal?

Immunocompromised individuals. Signup and view all the answers

Which media is used for the rapid growth of Trichosporon spp.?

Primary Fungal Media. Signup and view all the answers

Which feature distinguishes Trichosporon spp. under KOH mounting?

Intertwined septate hyphae. Signup and view all the answers

Study Notes

Mycoses

Mycoses are fungal diseases, typically chronic.
Factors influencing identification of mycotic disease include:
- Patient history (e.g., diabetes, cancer, alcoholism, AIDS)
- Medical treatments (e.g., immunosuppressants, antibiotics, surgery)
- Presence of specific fungal diseases like sporotrichosis, which exhibits lesions that line up along lymphatic channels.
- Microscopic examination of tissue samples for fungal presence.

Superficial Mycoses

Superficial mycoses are fungal infections affecting the outer layers of the skin, hair, and nails.
Types of superficial mycoses:
- Cutaneous mycoses (affect the skin):
  - Dermatophytoses
- Non-dermatophytic tinea:
  - Tinea versicolor
  - Tinea nigra
  - Piedra

Keratitis

Mycotic keratitis, also called keratomycosis, is a fungal infection affecting the cornea of the eye.
A serious mycotic disease, it can lead to vision loss.
Causative agents include Fusarium, Aspergillus, Curvularia, Penicilium, Cephalosporium, and Candida species.
Treatment involves topical application of antifungal agents. Amphotericin B, potent but toxic to the retina, or Natamycin, is a frequently used option.

Otomycosis

Otomycosis is a chronic fungal infection of the outer ear and ear canal.
Common causative agents include Aspergillus, Mucor, Penicillium, and Rhizopus.
Initial symptoms are often mild, resulting in only minor irritation. As the condition progresses, the infected area and surrounding ear tissue become inflamed, and pus may develop, along with debris accumulation.
The treatment involves cleaning and airing the ear canal with a cotton swab saturated in Burrow's solution.

Tinea Versicolor (Pityriasis Versicolor)

Characterized by discoloration (depigmentation or hyperpigmentation) and scaling of the skin.
More commonly apparent in individuals with darker complexions or those with reduced tanning ability.
Caused by the yeast Malassezia furfur.
Treated with topical antifungal agents.

Tinea Nigra

Characterized by brown or black macular patches, predominantly on the palms of the hands.
Diagnosis often requires biopsy and culture to distinguish it from melanoma, a much more severe nonfungal skin disease.
Causative agent is Phaeoannellomyces werneckii.
Treatment involves topical antifungals.

Piedra

Piedra is a fungal infection confined to the hair shaft.
Characterized by nodules composed of hyphae and a cement-like substance adhering to the hair shaft. Two types:
- Black Piedra (Piedraia hortae): infections occurring on scalp hair producing hard, dark brown to black gritty nodules firmly attached to the hair shaft, consisting of asci and ascospores.
- White Piedra ( Trichophyton spp.): characterized by soft mycelial mats surrounding the hair of the scalp, face, and pubic regions. Caused by Trichosporon beigelii (Trichosporon cutaneum)
Identification methods include KOH preparation and microscopic examination.
Treatment typically involves removal of the infected hair shafts and application of topical fungicides.

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Description

This quiz covers various aspects of mycoses, including superficial infections and mycotic keratitis. Explore the factors influencing fungal disease identification and learn about specific types of fungal infections affecting the skin, hair, and nails. Test your knowledge on the characteristics and implications of mycotic diseases.