Fungals Flashcards
On his legs and feet it started as scaly, itchy lesions. Following that there were wart like lesions along lymphatics. These wwere tumor like with abscess formation.
What would you do to diagnose, what do you think it is and what is the treatment?
This is description for the subcutaneous mycoses Chromoblastomycosis.
Diagnose the scrapings
Treatment you will surgically remove the infected tissue and use antifungal treatment like itraconazole.
Started on legs or feet. It was a slow progressive infection that started with subsurface nodules and then became ulcerated lesions. He recently had symptoms of a bone infection!
What would you do to diagnose and treatment?
Subcutaneous mycoses Mycetoma! Which is a fungus tumor and is a subcutaneous mass of fungi being surrounded by granulomatous inflammation.
The keyword is spread to bone. Diagnosis would be microscopic examination. Treatment is surgical removal and combination anti-fungal therapy.
Again you never do serology to fungi since they are ubiquitous to environment.
Dimorphic, small painless subcutaneous lump that progresses to an ulcer. Diagnosis is with microscope and culture. On culture the yeast were Cigar shape!
How would you treat?
Sporotrichosis schenckii also known as Rose Gardener’s disease. Commonly caused from cuts of a rose bush.
You will treat with oral itraconazole for 3-6 months
What are common characteristics of systemic mycoses?
They are all dimorphic - yeast at 37 degrees celsius and hyphae in standard culture at 30 degrees celsius. Infection is initially in the lung.
South East US and North to Canada.
Fever, cough, muscle aches, chest pain, fatigue, treatment is itraconazole.
Blastomyces dermatitidis
Soil with high levels of bird droppings or bat guano. Ohio River (midwestern, central, south US) Valley. What is organism and how would you diagnose?
Histoplasma capsulatum:
You would diagnose with antigen detection in urine or serum. Only severe cases do you provide oral antifungals (ketonazole or amphotericin B)
Southwest US, Mexico- flu like symptoms. Diagnosis is actually serological tests which is add for a fungal diagnosis.
Coccidioidomycosis.
Central and South America. Captain’s wheel - buds radiating out from a center vacuole. Treatment is azoles.
Systemic myocses: Paracoccidioidomycosis.
Multidrug resistant, high mortality opportunistic infection. Dimorphic, formation of germ tubes in 37 degrees. Can enter blood stream and spread througout the body.
Presents with thrush and hypahe in lung tissue
Candida auris
Heavily encapsulated yeast. Infection starts in lung and spread to brain or meninges.
Cryptococcus: only heavily encapsulated yeast - sarcophagus.
Acute branching. The treatment was vorconazole followed by caspofungin.
Aspergillosis fumigatus. Form hypahe in tissues and culture. Mostly pulmonary infections caused by inhaled spores.
Right angle branching. Came down with nasopharyngeal and pulmonary infection. He had rapid tissue necrosis, spreading to the brain through the cribiform plate. and can be fatal. How woudl you treat?
Surgical debridement or resection along with amphotericin B.
Not possible to culture in clinical labs. Need to diagnose soley my microscopic examination of lung fluid or tissue.
Treatment is trimethoprim sulfamethoxazole
Pneumocystis jirovecci
Treats:
Opportunistic: candida albicans, cryptococcus neoformans, aspergillus fumigatus, mucormyocses
Systemic: blastomyces dermatitis, histoplasma capsulatum, coccidioides immitis D.
It is the drug of choice for nearly all life threatening systemic infections: often used as initial treatment.
What are we describing and what is the mechanism of action?
Amphotericin B:
nonpolar chain binds tightly to ergosterol in fungal cell membranes. Polar side forms pores for ions to leak out of cell. The mycosamine sugar unit is the crucial link between amphotericin and ergosterol that lets it form the ion channel pores.
What is adverse effect of amphotericin B?
infusion related toxicity: fever, chills, vomiting, headache, hypotension,
Slower toxicity: renal damage is the most common problem - variable anemia and impaired liver functions.
