Coccidioidomycosis/histo Flashcards
Coccidioidomycosis
general
Reservoir
Also known as San Joaquin Valley fever
Pulmonary or hematogenously spread disseminated disease caused by the fungiCoccidioides immitis and Coccidioides posadasii
Endemic to the southwestern United States:
California, Arizona, Utah, Nevada, New Mexico
Can cause 15%–30% of communitypneumonia in these areas
Reservoir:
Soil in endemic regions
Rodents may serve as animal reservoirs
cocci
Disseminated disease patho
Disseminated disease occurs via hematogenous spread (particularly in immunocompromisedand pregnantpatients)
Cutaneous disease can result from either:
Dissemination
Direct inoculation
cocci
RF
Progressive coccidioidomycosis is uncommon in otherwise healthy people
More likely to occur in the following:
HIV+ patients
Patients taking immunosuppressants/chronic steroid use
Patients of advanced age
Women in the 2nd half of pregnancy or postpartum
Individualswith highsporeexposure:
Construction workers
Farmers
Archaeologists
cocci.
Constitutional Sx
Constitutional symptoms
Low-grade fever
Night sweats
Anorexia
Weight loss
Weakness
Chills
cocci
pulm involvement
Pulmonary involvement – primary site
Chest pain
Dyspnea
Cough
Dry or with sputum
May present withhemoptysis
cocci
cutaneous involvement
Cutaneous involvement
May occur in conjunction with pulmonary involvement, with direct inoculation, or from disseminated disease
Single or multiple granulomatous skinlesions
Abscesses
Draining sinus tracts
cocci
disseminated infection
Disseminated infection
Defined as disease outside the thoracic cavity
Considered an AIDS-defining illness
Patientscan present with:
Meningitis
Myalgias
Arthritis (particularly involving the knee)
Osteomyelitis
cocci
Granulomatous skinlesions
cocci
Dx
Fungal cultures
Microscopy for spherules in body fluid samples (sputum, pleural fluid, cerebrospinal fluid, exudate from draining lesions)
Serologic testing for anti-coccidioidal antibodies includes:
Enzyme immunoassay
Complement fixation (IgGantibodies) - estimate disease severity
Immunodiffusion kit (IgM orIgG antibodies)
Titers≥1:4 in serum → current or recent infection
Titers ≥1:32 in serum → extrapulmonary dissemination
PCRfor lower respiratory tract samples
Urineantigentesting
cocci
chest xray
Chest radiography
Pulmonary infiltrates, nodules, and cavitary lesions
Pleural effusions
Adenopathy
cocci.
Tx
Antimicrobial therapy
Fluconazole(preferred) or itraconazolefor mild-to-moderate disease
Amphotericin B:
Preferred for severe disease or persistentinfections
Switch to oral -azole therapy once stabilized
Patients withHIV- or AIDS-associated coccidioidomycosisrequire maintenance therapy to prevent relapse
Histo
general
Transmission
Pulmonary and hematogenous disease caused by the dimorphic fungusHistoplasma capsulatum
Fungus exists as a mold at low temperatures and as yeast at high temperatures
“Moldin the cold. Yeastin theheat”
Most common endemic fungal infection in the United States
Most prevalent in the midwestern and central states along the Ohio and Mississippi River valleys
Transmission:
By inhalation
Exposure to soils containing bird or bat droppings
Histo
RF
Meds
Immunosuppressive disorders:
HIV infection
Transplant recipients
Immunosuppressive drugs:
Most common fungal infection inpatientson TNF-αinhibitors
Glucocorticoids
Antirejection therapies for solid organ transplants
Extremes of age (infants and adults ≥ 55 years)
Heavy, prolonged inoculation exposure
histo
Clin man
Varies depending on host immune status and underlying risk factors
Most infections are asymptomatic or so mild that patients do not seek medical attention
Pulmonary histoplasmosis
Symptomatic pulmonary histoplasmosis:
Presents several weeks after exposure
Symptoms:
Fever/chills
Cough
Headache
Myalgias
Pleuritic chest pain
Malaise
histo
PE and CXr
Physical examination: rales or signs of consolidation, increased tactile fremitus, decreased lug sounds.
CXR - may show focal infiltrates with/without hilar or mediastinallymphnode involvement
histo
Acute diffuse pulmonary histoplasmosis clin man
Associated with large inoculum
Abrupt onset of symptoms → ARDS can develop within days
Symptoms:
Fever/chills
Cough
Headache
Myalgias
Pleuritic chest pain
Malaise
Dyspnea andfatiguemay persist for months after treatment
CXR - diffuse pulmonary infiltrates
Histo
Chronic pulmonary histoplasmosis
Patients with underlying lung disease are at risk
Symptoms - progressive
Productive cough
Fatigue
Fever
Sweats
Dyspnea
Dissemination does not occur
CXR or CT scan - pulmonary lesions often apical and resemble cavitary tuberculosis
histo
Disseminated histoplasmosis
Mostpatientsexperience asymptomatic dissemination
Can present acutely or years later
Acute:
In infants andimmunocompromisedindividuals
Can be rapidly fatal
Chronic:
Olderpatientswho are immunocompetent
Generalized symptoms:
Fever
Malaise
Weight loss
Systems most commonly affected: CNS, GI, skin (10%), adrenal glands
know
in both cocci and histo there is lung or disseminated and disseminated is pointing towards immunocompromised.
who are at risk?
how do you treat?
histo
Dx
Approach will vary depending on presentation
Multiple tests including:
Culture, direct microscopy, antigen detection, and histopathology
Culture is the most effective when the fungal burden is high
Antigen detection:
ELISAforantigentesting – urine, serum, CSF
Allows for rapid diagnosis, particularly in disseminated disease
Sensitivity increases with disease severity (most sensitive test in disseminated disease)
Imaging
CXR or chest CT
histo
Tx
know this
Treatment varies depending on disease severity
Most cases areself-limiting
Asymptomatic or mild symptoms → no required treatment
Individuals with large inoculum exposure and patients who areimmunocompromisedusually require treatment
Antifungaldrugs are the mainstay of treatment
Itraconazole – acute moderate pulmonary or chronic presentation
Amphotericin B – acute severe pulmonary presentation
Itraconazole and amphotericin B – disseminated disease
Monitor response with chest imaging and monitor forrelapse(several years)
ForpatientswithHIVhaving CD4 counts < 150 cells/µL → long-termitraconazole
