Low Antigen Titre Disseminated Cryptococcosis in Immunocompromised Hosts: Two Challenging Case Reports

BACKGROUND Cryptococcus is a yeast-like fungus commonly found in soil and typically causes disease in immunocompromised individuals due to impaired cell-mediated immunity. While the central nervous system (CNS) and lungs are most frequently affected, disseminated disease can involve multiple organs, including the skin, liver, spleen, kidneys, and bone marrow. Symptoms such as headache, fever, and altered mental status often require extensive diagnostic evaluation. CASE REPORT We present 2 unusual cases of cryptococcal growth in the blood without meningoencephalitis, with low cryptococcal antigen titres (1: 80 in both cases). The first case involves a post-kidney transplant patient with respiratory symptoms who underwent bronchoalveolar lavage (BAL), revealing Cryptococcus growth. A subsequent positive blood culture confirmed disseminated cryptococcosis, and the patient was treated with antifungal therapy. The second case is of a patient with HIV, non-adherent to treatment, who developed a complicated infection course. The cryptococcal antigen was positive in the serum, prompting treatment with a high-dose antifungal regimen. Despite negative results in BAL and cerebrospinal fluid, the blood culture was positive for Cryptococcus, necessitating intensive antifungal therapy according to protocolized guidelines. CONCLUSIONS These cases highlight the unusual presentation of disseminated cryptococcal infection with low serum antigen titres (1: 80) and positive blood culture, indicating disseminated infection even without CNS involvement. This emphasizes the importance of considering disseminated cryptococcosis in the differential diagnosis of immunocompromised patients, even with low antigen titres in serum. It suggests that clinicians should order blood cultures to alter management strategies, particularly in patients with atypical presentations.