Opportunistic Fungal Infections of the Respiratory Tract medical comic
This comic lines up the fungi that attack the lungs of vulnerable patients. It covers Pneumocystis jirovecii, the aseptate Mucorales, the many faces of Aspergillus, Cryptococcus and Talaromyces marneffei, and shows how septation, branching angle and stains tell them apart and which antifungal fits each one.
For MBBS, NEET-PG, FMGE, NEXT and USMLE revision.
Opportunistic respiratory fungi: what the comic covers
High-yield points
- Opportunistic fungi cause disease mainly in immunocompromised hosts: people with HIV, cancer, transplants, neutropenia or uncontrolled diabetes.
- Pneumocystis jirovecii, once thought to be a protozoan, is a fungus; GMS silver stain shows cysts like 'crushed ping-pong balls', and imaging shows bilateral ground-glass change.
- Mucorales (Rhizopus is the commonest) have broad, ribbon-like, aseptate hyphae, invade blood vessels and strike patients with diabetic ketoacidosis; rhino-orbito-cerebral disease is the classic form.
- Mucormycosis needs urgent surgical debridement plus amphotericin B; posaconazole or isavuconazole are alternatives.
- Aspergillus has narrow, septate hyphae branching at acute (about 45°) angles and causes allergic disease (ABPA), aspergilloma in old cavities and invasive aspergillosis.
- On Sabouraud agar A. fumigatus is smoky green, A. flavus yellow-green and A. niger black.
- Cryptococcus neoformans is an encapsulated yeast inhaled from the environment that spreads to cause meningitis in people with HIV.
- Talaromyces (Penicillium) marneffei is a dimorphic fungus with a red pigment that causes disseminated disease and skin lesions in people with HIV in South-East Asia.
Mnemonics from the comic
- Pneumocystis: Game, set, match: GMS shows the crushed ping-pong balls.
Quick questions
How do you tell Mucor from Aspergillus under the microscope?
Mucorales have broad, ribbon-like hyphae with few or no septa that branch at wide (about 90°) angles. Aspergillus has narrow, septate hyphae branching at acute angles of about 45°.
Which stain shows Pneumocystis jirovecii cysts?
Gomori methenamine silver (GMS) stain, which shows the cysts as dark, crushed ping-pong balls.
What is the treatment of mucormycosis?
Urgent surgical removal of dead tissue together with amphotericin B. Posaconazole or isavuconazole are used as alternatives or step-down therapy.
Is this comic free to read?
The first pages are free to preview. Members read the full comic, and you can sign up free to read one comic in full.
Read next
- Mucormycosis: The Black Fungus medical comic
- Antifungal Agents medical comic
- Mycoses: Skin to Bone medical comic
- Cystic Fibrosis medical comic
From the blog
High-yield flash cards (38 cards)
- Is Pneumocystis jirovecii a fungus or a protozoan?
- A fungus (an ascomycete, confirmed by rRNA sequencing) — but it lacks ergosterol in its membrane, so it does not respond to amphotericin B or azoles
- Who gets Pneumocystis pneumonia?
- People with HIV and CD4 count below 200 cells/µL, organ and stem-cell transplant recipients, patients on high-dose steroids or chemotherapy, and children with primary immunodeficiency
- Clinical and imaging features of Pneumocystis pneumonia
- Subacute dry cough, breathlessness and fever, with hypoxia (especially on exertion); bilateral perihilar ground-glass opacities; pneumatoceles and pneumothorax; raised LDH and β-D-glucan
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