Infectious Disease · Fungal Infections
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Echinocandins (e.g., caspofungin) are the first-line empiric therapy for non-neutropenic patients with suspected invasive candidiasis.
Candida albicans remains the most common species, but Candida glabrata and Candida krusei are increasingly recognized for their intrinsic resistance to fluconazole.
Dilated ophthalmoscopy screens for chorioretinitis or endophthalmitis in candidemia, but guidance conflicts: IDSA (2016) recommends it for all non-neutropenic patients within the first week (deferred until neutrophil recovery in neutropenic patients), whereas AAO (2022) recommends against routine screening of asymptomatic patients and reserves ophthalmology consultation for ocular signs or symptoms.
Central venous catheters are the primary source of infection and should be removed in most patients with documented candidemia.
Beta-D-glucan is a highly sensitive serum biomarker for invasive fungal infections, though it lacks specificity for Candida species.
Neutropenic patients with suspected invasive candidiasis should receive liposomal amphotericin B or an echinocandin as initial therapy.
Fluconazole is generally reserved for patients who are clinically stable and have documented susceptibility to azoles.
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A 62-year-old male in the ICU for 14 days following a bowel resection for perforated diverticulitis develops a persistent fever despite broad-spectrum antibiotic therapy. He has a central venous catheter in place for total parenteral nutrition. Blood cultures return positive for yeast. A dilated funduscopic exam reveals white, fluffy chorioretinal lesions.
What is the most appropriate initial pharmacologic treatment for this patient?
Fluconazole or voriconazole (an azole with good vitreous penetration), given the documented chorioretinitis
The patient has candidemia with evidence of ocular involvement; per IDSA guidelines, once ocular involvement (chorioretinitis) is documented, fluconazole or voriconazole is preferred over an echinocandin because of superior vitreous penetration, even though echinocandins remain first-line empiric therapy before ocular status is known.
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Etiology / Epidemiology
Occurs in immunocompromised patients, ICU admissions, and those with central venous catheters or prolonged broad-spectrum antibiotics.
Clinical Manifestations
Presents as unexplained fever refractory to antibiotics; candidemia may lead to endophthalmitis or hepatosplenic involvement.
Diagnosis
Blood culture is the reference standard; (1,3)-beta-D-glucan assay is a highly sensitive adjunctive screening tool.
Treatment
Echinocandins (e.g., caspofungin) are the first-line therapy; avoid fluconazole in critically ill patients with prior azole exposure.
Prognosis
High mortality rate of 30-40%; ocular seeding is a key complication: IDSA (2016) recommends a dilated ophthalmologic exam for non-neutropenic patients, whereas AAO (2022) recommends against routine screening of asymptomatic patients.
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Epidemiology & Etiology
Primarily affects patients with central venous catheters, total parenteral nutrition, or recent abdominal surgery. It is the most common invasive fungal infection in the ICU. Candida albicans remains the most frequent species, though non-albicans species like Candida glabrata are increasing.
Pertinent Anatomy
The infection typically originates from the gastrointestinal tract or intravascular devices. Hematogenous spread allows for seeding of the eyes, liver, spleen, and kidneys.
Pathophysiology
Disruption of the mucosal barrier or direct inoculation via catheters allows yeast to enter the bloodstream. The organism forms biofilms on prosthetic materials, making eradication difficult. The host immune response, specifically neutrophil function, is critical for containment.
Clinical Manifestations
Suspect in patients with persistent fever despite broad-spectrum antibacterial coverage. Look for candidal endophthalmitis, which presents as white, chorioretinal lesions on funduscopic exam. Red flags include septic shock, multiorgan failure, and skin nodules in neutropenic patients.
Diagnosis
Blood culture remains the reference standard, though sensitivity is only 50%. The (1,3)-beta-D-glucan test is a useful negative predictor due to high sensitivity. Recommendations on ophthalmologic examination in documented candidemia conflict: IDSA (2016) recommends a dilated eye exam for all non-neutropenic patients within the first week (after neutrophil recovery in neutropenic patients), whereas AAO (2022) recommends against routine screening of asymptomatic patients and favors examination when ocular signs or symptoms are present.
Treatment
Initiate Echinocandins (e.g., micafungin, caspofungin) empirically in hemodynamically unstable patients. Fluconazole is reserved for stable patients without prior azole exposure. Transition to oral fluconazole only after clinical stability and negative follow-up cultures; if chorioretinitis is documented, use fluconazole or voriconazole (susceptible isolates) because echinocandins penetrate the eye poorly.
Prognosis
Mortality is significantly higher in patients with delayed initiation of antifungal therapy. Ocular involvement can lead to permanent vision loss if not treated with systemic antifungals and potentially intravitreal injections.
Differential Diagnosis
Bacterial Sepsis: usually responds to initial empiric antibiotics
Aspergillosis: typically presents with pulmonary infiltrates/halo sign
Cryptococcosis: associated with meningitis and HIV/AIDS
Histoplasmosis: associated with bird/bat droppings and endemic geography
Endocarditis: characterized by new murmurs and vegetation on echocardiogram