Pneumonia in Immunosuppresion (Fungal) Flashcards
What are the 4 major types of fungal infections?
• what and who do these fungal infections affect?
Superfical and cutaneous mycoses:
• Limited to the skin, hair, and nails
Subcutaneous mycoses:
• involve skin, subcutaneous tissue, lymphatics
Endemic mycoses:
• caused by dimorphic fungi, can cause serious disease in both healthy and immunocompromised patients
Opportunistic mycosis:
• can cause life-threatening disease in immunosuppressed patients
What form do dimorphic fungi take in human tissue (37 degrees) vs. laboratory conditions (25 degrees)?
• which of the dimorphic fungi are capable of causing infection?
- Yeast at 37 in human tissues
- Mold at 25 at Room Temperature
**All dimorphic fungi are capable of causing infection**aka they can all form pneumonia and disseminate
What are the 4 Dimorphic fungi?
• what is the key to telling these appart?
Location is the key to telling these apart:
- Blastomyces dermatitidis - Mississippi and Ohio River Valley + Missouri and Arkansas River basins
- Histoplasma capsulatum - Mississippi and Ohio River valley
- Coccidiodes immitus - southwestern U.S. and Latin America
- Paracoccidiodes brasiliensis - Latin America, Especially Brazil
You have an AIDS patient in memphis who experiences severe symptoms as a result of Histoplasmosis infection.
• From what source did he likely contract this infection?
• What symptoms is he likely experiencing?
• Is there significant risk of him dying from this infection?
Source:
• Soil or Bird Droppings
Symptoms in AIDS:
• Pancytopenia (due to bone marrow infiltration)
• Mouth/GI ulcers
• Skin rash (pustules, nodules)
Risk:
• 10% of AIDS patients that contract Histoplasmosis Die
Contrast Histoplasmosis in an immunocompetent person from someone who is immunocompromised.
Immunocompetent:
• Asymptomatic pulmonary infection
• Respiratory infection characterized by fever, chills, cough, and chest pain (only follows intense exposure)
Immunocompromised (AIDS):
• Pancytopenia (bone marrow infiltration)
• Mouth/GI ulcers
• Skin Rash (nodules and pustules)
• Mortality up to 10%
What visual diagnostic methods can you use to diagnose histoplasmosis capsulatum?
• what are you looking for?
• Chemical methods of Dx?
Tissue Biopsy: Look for macrophages full of oval yeast cells
CXR: infiltrates, Mediastinal LAD, cavitary lesions
Serology and Urinary antigen are two chemical methods to diagnose
You have an AIDS patient in memphis who experiences severe symptoms as a result of Histoplasmosis infection.
• How should you treat him?
• Would you expect to see a skin rash in this patient?
• How would you treat if he was immunocompetent and his symptoms were mild?
Histoplasmosis Capsulatum Tx:
Amphotericin for severe disease or Itraconazole otherwise
Nodular Skin Rash is common in AIDS patients with disseminated infection
You have an AIDS patient in memphis who experiences severe symptoms as a result of Histoplasmosis infection. His CD4+ count is 200.
- Would you expect this patient to have erythema nodosum?
- What causes erythema nodosum/what are they?
Erythema Nodosum are red/tender nodules and are a good prognostic sign because its a delayed type IV hypersensitivity rxn, because its type IV this is an indicator of a adequate CD4+ T-cell count
WOULD NOT EXPECT THIS INDIVIDUAL TO HAVE THESE B/C HE HAS AIDS
How specific is an Erythema Nodosum rash to Histoplasmosis?
• Not that specific - can be seen in TB infections and coccidiomycosis infections too
When comparing the two fugal respiratory diseases that are endemic to the Ohio/Mississippi River Valley, which is most likely to cause disseminated infection?
Blastomyces dermatitidis causes infection in BOTH immunocompetent and immunocompromised people. Disseminated Histo. infections are pretty much limited to immunocompromised.
What are the 2 main clinical manifestations of Blastomyces dermatitidis?
- Asymptomatic Respiratory Illness
- Mild Disease: 50% of infected ppl. develop cough, chest pain, sputum production, fever/night sweats
- Disseminated Disease: seen in BOTH immunocompetent and immunocompromised
What are some of the manifestations of disseminated disease resulting from Blastomyces dermatitidus?
• who gets disseminated blasto infections?
• where does this stuff live?
Disseminated Disease:
• Ulcerated Granulomatous lesions of skin (70%)
• Bone (33%)
• GU tract (25%)
• CNS (10%)
BOTH immunocompetent and immunocompromised people get blasto infections
• Blasto lives in the soil
What do you look for in the CXR and Tissue biopsy of a patient with a suspected Blastomyces infection?
• which is more specific?
• Is serology useful in Dx?
CXR: Lobar consolidation, multilobar infiltrates, multiple nodules - very non-specific
Tissue Biopsy: thick-walled yeast cells with SINGLE BROAD-BASED BUD
• Serology is a method used in diagnosis
A patient from St. Louis presents with granulomatous lesions on his skin and remarks that he has recently broken his wrist. Empirical abx are used to treat the patient but the infection only progresses. CXR shows lobar consolidation and multiple nodules.
• What are some factors to knowing this is fungal and not viral?
• How would you treat this patient?
Key:
• CXR shows lobar consolidation - this is not typical of antiviral pneumonia so that leaves bacterial and fungal, but pt. did not improve on empirical abx so its fungal.
Tx:
• Itraconazole or Amphotericin if sever
Compare treatment methods for Histoplasmosis and Blastomyces.
they are identical: Itraconazole for a non-severe infection, Amphotericin for a severe infection
What is the pathogenesis of Coccidiodes immitus?
Large spherules form and are filled with endospores when the spherule wall ruptures, endospores are released and differentiate to form new spherules
What are the most common clinical manifestations of someone who gets infected with the dimorphic bacteria from the southwest U.S?
• what normal healthy people are most likely to experience a disseminated infection by this pathogen?
Coccidiodes immitus
• ~90% - ASYMPTOMATIC
• ~10% - mild FLU-LIKE illness - valley fever - Erythema Noduosum
Higher Risk of Dissemination:
• 1% disseminated - African Americans, FIlipinos, and women in the 3rd trimester of pregnancy
T or F: TB, Histo, and Coccidiodes immitis can all causes Erythema Nodusum (tender nodular type IV hypersensitivy rxn localized to arms and legs typically).
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