Fungi and Mycobacteria

Rocky Mountain Spotted Fever (RMSF - report in 1 week)

A potentially fatal tick borne illness caused by Rickettsia rickettsii that affects both healthy and immunocompromised individuals (children 5-14 at higher risk)

American dog tick (D. variabilis), Rocky Mountain wood tick (D.andersoni), brown dog tick (R. sanguineus - arizona outbreaks) - requires a long attachment time, ticks maintain infection

Vectors for RMSF (no person-to-person)

Rickettsia rickettsii (intracellular gram neg incubates for 2-14 days) spreads via the bloodstream to vascular endothelium

Etiology for RMSF

Doxycycline 🥇, Chloramphenicol 🤰, fluids, O2, antipyretics, organ monitoring, hospitalization for extreme cases

A lumberjack from Arkansas presents to your office for flu like symptoms (fever, HA, malaise, and muscle aches). He also reports N/V and abd pain. On physical exam you note a blanching rash all other even the palms and soles. What is your treatment plan?

thrombocytopenia, hyponatremia, Mild transaminitis (ALT/AST), serology confirms but lags, PCR may work, immunohistochemistry confirms through skin biopsy

RMSF is a clinical diagnosis, but what might the labs look like?

confusion, seizures, ataxia, pneumonitis, myocarditis

Progressive and late stage symptoms for RMSF

multisystem organ failure

Complications of RMSF

avoid tick invested areas, use DEET or permethrin treated clothing, perform full body tick checks, prompt tick removal, control tick exposure in pets

RMSF prevention

mouth, vulvocaginal, intertriginous folds

Common sites for cutaneous candidiasis

erythema, satellite pustules, white scrapable plaques

Classic signs of cutaneous candidiasis

clinical + KOH prep

Diagnosis of cutaneous candidiasis

topical azoles, oral fluconazole

Treatment of cutaneous candidiasis

Invasive Candidiasis

A leading cause of bacteremia for hospitalized patients - especially those with hematologic malignancy, transplant, or uncontrolled DM

Central lines, ICU admission, TPN, neutropenia, recent surgery

RIsk factors for Invasive Candidiasis

Fever

What is often the only early symptom of Invasive Candidiasis?

blood cultures, Beta-D-glucan, ophthalmologic exam (endophthalmitis), imaging to r/o abscesses or organ involvement, call ID

Workup for Invasive Candidiasis

echinocandin → fluconazole (if susceptible, 14 days after 1st negative blood culture), remove central line

Treatment plan for Invasive Candidiasis

Histoplasmosis (not reportable)

An infection endemic to the Ohio/Mississippi river valleys that can cause severe diseases in immunocompromised patients (CD4 under 150)

immunosuppression, construction, farming, cave exposure, old buildings, bird/bat enriched soil

Risk factors for Histoplasmosis

Histoplasma capsulatum (dimorphic fungi - converts to yeast in lungs and spreads through lymphatics to spleen, liver, bone, or CNS); no person-to-person

Etiology and transmission of Histoplasmosis

dry cough, fever, chest pain, malaise, hilar/mediastinal lymphadenopathy

Acute pulmonary symptoms for Histoplasmosis

Cavitary disease, weight loss, hemoptysis (LOOKS LIKE TB)

Chronic pulmonary symptoms for Histoplasmosis

fever, weight loss, hepatosplenomegaly

Progressive disseminated Histoplasmosis (PDH) symptoms

Ulcers, bleeding, diarrhea, meningitis, mass lesion, cutaneous lesions, visual symptoms (POHS)

Other symptoms for histoplasmosis

urine and serum antigen testing, blood cultures (PDH), tissue biopsy with silver stain (definitive), H and M bands (antibody), bone marrow/liver biopsy inadvanced disease, CXR/CT (cavitary or millet seed), CSF (for CNS symptoms)

Diagnostic for histoplasmosis

itraconazole or observation

Management for mild to moderate histoplasmosis

liposomal amp B → itraconazole for up to 12 months (CNS); corticosteroids for mediastinal lymphadenitis or pericarditis

Management for moderate to severe histoplasmosis or PDH

pulmonary fibrosis, disseminated infection to liver, spleen, CNS, or GI tract, bone marrow suppression, pancytopenia, visual impairment, meningitis, mass lesions, mediastinal fibrosis

Complications for histoplasmosis

Avoid soil or dust exposures, use respiratory protection, educate high risk patients, itraconazole prophylaxis if CD4s under 150, screen transplant and TNF inhibitor patients

Prevention of Histoplasmosis

Pneumocystis Jirovecii (PCP - not reportable)

A life-threatening ubiquitous fungal infection that is historically associated with AIDS but is now more common in non-HIV patients

CD4 under 200, TNF inhibitors, chronic glucocorticoids, rituximab, solid organ/stem cell transplant

Risk factors for Pneumocystis Jirovecii

over 60, mechanical ventilation, high LDH

What increases mortality in Pneumocystis Jirovecii

Pneumocystis jirovecii that lives in the alveoli causing foamy exudate and impaired gas exchange; transmitted via airborne route (no person to person)

Etiology and transmission for Pneumocystis Jirovecii

Subacute onset of nonproductive cough, dyspnea (dry rales), and fever, tachypnea, hypoxia especially with exertion, spontaneous pneumo

Signs and Symptoms of Pneumocystis Jirovecii

TMP-SMX (🥇 - atovaquone, dapsone, clindamycin/primaquine, pentamidine) , Corticosteroids (Aa above 35, PaO2 under 70), Check ART regimen, monitor drug toxicities, consider ID

45 y/o male presents to the clinic for cough and fever. His past medical hx is positive for HIV. Chest x-ray has a batwing pattern, ABG reveals a widened A-a gradient of 45. There’s an elevated LDH and 1,3 B-D glucan and BAL with silver stain is positive. What is your treatment plan?

BAL with silver stain or PCR 🏆

Gold standard for Pneumocystis Jirovecii

Acute respiratory failure needing ventilation, pneumothorax, drug reactions (rash, neutropenia, AKI, hyperkalemia), IRIS after ART initiation, superimposed bacterial/fungal, chronic dyspnea or fibrotic lung, DEATH

Complications for Pneumocystis Jirovecii

HIV with CD4 under 200 or 14%, transplant, cancer, or prolonged steroid use

Who’s getting prophylaxis for Pneumocystis Jirovecii (under 3+ months on art or CD4s over 200)

MAC (avium + intracellulare), M. Kansasii 🫁 , M.Marinum, M,abscessus

Most common atypical mycobacterial diseases in the USA

Structural lung disease (bronchiectasis, COPD), older age, low BMI

Risk factors for MAC and M.kansasii pulmonary NTM

Chronic cough, sputum, weight loss, fatigue

Symptoms of pulmonary NTM

tall, thin elderly women (lady windermere syndrome)

MAC is common in who?

positive culture from 2+ sputum samples or 1 bronchial wash + symptoms/imaging; imaging looks similar to TB

Diagnosis for pulmonary NTM

macrolide-based triple therapy (azithromycin, rifampin, ethambutol) for 12+ months after culture conversion

Treatment for pulmonary NTM

M. Marinum

Linked to fish tanks, aquariums, and swimming pools that presents as chronic skin nodule or ulcer after trauma/exposure

M. Abscessus

A rapidly growing species that causes post-traumatic or surgical wound infections that is commonly transmitted in cosmetic procedures

biopsy or aspirates with acid-fast stain and culture

Diagnosis of NTM SSTIs

Macrolides + others (based on susceptibility) for 4-6 months or more

Treatment of NTM SSTIs

Disseminated NTM

Most common in patients with CD4 under 50 that presents with fever, night sweats, weight loss, diarrhea, and anemia often involving liver, spleen, bone marrow, and lymph nodes

azithromycin/clarithromycin + ethambutol + rifabutin → lifelong suppression may be needed

Treatment for Disseminated NTM

Leprosy (Hansen’s Disease)

A mycobacterium disorder that affects the skin, peripheral nerves, eyes, and mucosa that is endemic in parts of Texas, Louisiana, Florida (think Armadillos)

Clinical + biopsy showing acid-fast bacilli

A 23 y/o Texas cowboy presents to the clinic for muscle weakness and sensory changes. He states that he wrangles 9-banded armadillos in his spare time. On physical exam you note a hypopigmented, patch like rash. What are your diagnostic technqiues?

Rifampin + dapsone + clofazimine (6-12 months)

A 23 y/o Texas cowboy presents to the clinic for muscle weakness and sensory changes. He states that he wrangles 9-banded armadillos in his spare time. On physical exam you note a hypopigmented, patch like rash. Your culture comes back with mycobacterium leprae, what is your treatment plan?

Cryptococcus neoformans (bird droppings), C. gattii (eucalyptus trees)

Etiology for Cryptococcosis

antigen testing (serum/CSF), Halo on India Ink stain, fungal culture

Diagnosis for Cryptococcosis

Amp B + flucytosine → fluconazole

Treatment for Cryptococcosis IF BRAIN

HA, fever, neck stiffness (meningitis)

Presentations for Cryptococcosis

Blastomycosis

A condition caused by Blastomyces dermatitidis (dimorphic fungus) that is found in moist soil and decaying organic material especially in Ohio/mississippi river valleys and the Great lakes

Verrucous/ulcerative skin lesions, pulmonary infection resembles TB or bacterial pneumonia, can disseminate to skin, bone, GU tract

Presentation for Blastomycosis

Culture, histopathology with broad-based budding yeast

Diagnosis for Blastomycosis

Itraconazole for mild/moderate, Amp B for severe/dissemination

Treatment for Blastomycosis

Coccidioides immitis, C. posadasii (endemic to the Southwest US)

Valley fever (Coccidioidomycosis) is caused by

Cough, fever, chest pain (can disseminate to skin, bones, or CNS (especially in immunosuppressed, Filipinos, African Americans, pregnant))

Presentation of Valley Fever

serology, culture, spherules on histopathology

Diagnosis of Valley fever

Fluconazole/itraconazole for moderate, Amp B for severe

Treatment of Valley fever

Pott Disease

TB in the skeleton (particular the vertebrae) that causes back pain and deformity

Cutaneous TB

A TB infection of the skin that leads to scrofuloderma, lupus vulgaris (chronic nodules and ulcer)

immunosuppression, endemic exposure, prior TB

Risk factors for extrapulmonary TB

biopsy + AFB stain/culture, PCR, imaging (CXR, MRI, CT)

Diagnosis of extrapulmonary TB

RIPE with public health notification and DOT, HIV testing is recommended

Treatment of extrapulmonary TB