L23 - Chronic Pneumonias - mycobacteria & endemic fungi Flashcards
(38 cards)
Which is not a common Feature of Mycobacterial & Fungal Pneumonias?
A. Lung inflammation days to weeks
B. Symptoms: fatigue, weight loss, fever, cough & dyspnea
C. Common pathophysiology: intracellular pathogens of macrophages
D. Histopathologic hallmark: granuloma (necrotizing or non-necrotizing)
E. Diagnosis often delayed & High index of suspicion required
A. Days to weeks is more typical of community acquired pneumonia. Myocobacterial and fungal pneumonias last weeks to months
These are the differential diagnoses of what kind of findings? • Lung Cancer • Mycobacterial disease (look similar radiographically) ○ Tuberculosis (TB) ○ Nontuberculous Mycobacteria • Fungi ○ Histoplasmosis ○ Blastomycosis ○ Coccidiodomycosis • Sarcoidosis
Upper Lobe Infiltrate & Adjacent Adenopathy
These labs are done to diagnose what fungi? • Serology
- Complement Fixation – Yeast & Mycelial antigens
- Immunodiffusion – H band shows up earlier (~2 months) than; M band
○ Serum in well with antigens.
Both CF and ID peak @ ~3 months and remain +ve> 2 years
Lung, right, transbronchial biopsy (not shown):
- Granuloma & necrosis with fungal organisms morphologically consistent with this fungi.
- Fungal Cultures negative since this fungi is hard to grow
Histoplasmosis
Acute vs convalescent - acute has low titer in yeast & mycelial antigens but convalescent shows 3x titer rise
What are endemic mycoses mean fungi linked to location. Where are these commonly located? 1. Cocci 2. Blasto 3. Histo
- Arizona (desert southwest) - Snow birds (people traveling to warm places for the winter then returning)
- Wisconsin (midwest states bordering the great lakes)
- SE, mid Atlantic and central US (Mississippi/Ohio river valley)
Histo, blasto or cocci?
- Dimorphic process (fungi –> yeast in human host)
- Infectious particle is the microconidia which gets inhaled and lodged into the alveoli (yeast then accessible to macrophages)
- Incubation period 2 weeks
- Histo: multi-uclear giant cell with cytoplasmic shrinking/white spaces
- fever in compromised host
Histoplasma capsulatum - cytoplasmic shrinking/white spaces (capsulatum - not a real capsule)
T/F Histoplasmosis has a narrow clinical spectrum
False - Broad
- Acute pulmonary histoplasmosis (localized and diffuse)
- Chronic pulm histo
- disseminated histo
- Others (e.g. pericarditis, fibrosing mediastinitis)
What kind of histo?
- CXR may show localized pulmonary infiltrate and adjacent hilar adenopathy
- most resolve spontaneously
- most common manifestation of histo
Localized pulmonary histo/acute pulmonary histo
What kind of histo?
• Indolent process
• Pre-existing lung disease (eg, COPD)
• Upper lobe predominant (sarcoid is like this too)
• Appears cavitary (mimics TB & non-tb mycobacteria)
• Organism can be isolated in sputum, unlike acute pulmonary Histo
Chronic pulmonary histo
What kind of histo?
• Immunosuppressed patients (eg, steroids, HIV)
• Chest x-ray changes subtle or absent
• Like TB, TNF essential to defense against H. capsulatum
○ Endemic region (midwest), ⇑ Histo risk a/w TNF inhibitor Rx (eg, Infliximab)…greater than risk for TB
○ Fever on anti-TNF Rx
• (Progressive) Disseminated Histoplasmosis
What kind of histo?
• Relentless/excessive inflammatory response to Histo antigen
○ B-cell mediated reaction
• Compresses vital structures such as pulmonary arteries (arrow), SVC, main bronchi, esophagus
• Doesn’t respond to antifungal or other immunosupression
• Intervene with catheters.
Fibrosing mediastinitis
Diagnosis of what kind of histoplasmosis is best done (has highest sensitivity) by urine antigen testing?
Disseminated histo mostly - acute pulmonary histo may also be sensitive, but NOT helpful for sub-acute or chronic pulmonary histo
Antigen testing has highest sensitivity for diagnosing which type(s) of histo?
Disseminated histo
Serology testing has highest sensitivity for diagnosing which type(s) of histo?
Chronic and acute pulmonary histo
Fungal stain testing has highest sensitivity for diagnosing which type(s) of histo?
Not very helpful in general (additive test for diagnosing disseminated)
Culture testing has highest sensitivity for diagnosing which type(s) of histo?
Chronic pulmonary histo (additive test for diagnosing disseminated as well)
Is antifungal treatment indicated here?
- Acute pulmonary disease with hypoxia
- acute pulmonary symptoms >1 month
- Chronic pulmonary disease
- Esophageal compression/ulceration
- mediastinal granuloma w/obstruction or tissue invasion
- disseminated disease
Treatment IS indicated
Is antifungal treatment indicated here?
- Acute self-limited syndromes
- Acute pulmonary disease, mildly ill
- Joint complaints
- pericarditis
- histoplasmoma
- fibrosing mediastinitis
- broncolithiasis
- Sarcoidosis-like syndrome
Treatment IS NOT indicated
T/F Acute/Chronic Histo: ID & CF Serology not helpful bc…
○ possible false-negatives
○ Cross reactions
○ Index of suspicion
False - it is helpful, but be aware of these possibilities of false neg, cross reactions and have an index of suspicion
T/F Histopath/culture & urine antigen for diagnosis of acute cases of histo
False - severe cases
- disseminated
- diffuse pulm histo
Histo, blasto, or cocci treatment?
- severe: lipo-AmphoB
- Other: Itraconazole
Histo
Histo, blasto, or cocci treatment?
- severe: AmphoB
- Other: Itraconazole
Blasto
Histo, blasto, or cocci treatment?
- severe: AmphoB
- Other: Itraconazole and fluconazole
Cocci
Which is false regarding TB?
A. This is a leading cause of death and disability with 8 million new cases each year.
B. 1/3 of the world’s population is actively infected with M tuberculosis
C. Co-infection with HIV increases rate of progression
D. Resistance to standard TB drugs are rising
E. M tb is transmitted by aerosol route (person-to-person) ONLY due to sustained, close contact w/infected person
B. Latently infected - and at risk of developing active TB
Isoniazid and rifampin are among the first line drugs that are classified as ______ in treating TB
Multi-drug resistant (MDR TB)
