B45.3

Clinical Causes: Infection by the Cryptococcus species, typically Cryptococcus neoformans or Cryptococcus gattii Spread from a primary site of infection, such as the lungs or the central nervous system, through the bloodstream to bones Inhalation of spores from environmental sources like bird droppings or decayed vegetation, which can lead to initial lung infection and dissemination Occurs more frequently in individuals with compromised immune systems, such as those with HIV/AIDS, organ transplant recipients, or patients undergoing immunosuppressive therapy Rare cases may result from direct inoculation during trauma or surgery, although this is uncommon

Key Symptoms: Localized bone pain and tenderness Swelling or visible lumps over affected bones Restricted movement in nearby joints if the infection involves bones near joints Fever and chills are less common but may be present in systemic cases Possible signs of bone fractures or weakness in severe cases General symptoms of infection such as fatigue, malaise, and weight loss

Diagnosis Path: Imaging studies such as X-rays, MRI, or CT scans to identify bone lesions, lytic areas, or destruction Laboratory tests including blood work to detect signs of infection and immune status Biopsy of affected bone tissue for histopathological examination Microscopic identification of Cryptococcus using special stains like India ink or PAS stain Culture of bone tissue or cerebrospinal fluid to isolate the fungus Serological tests such as cryptococcal antigen detection in blood or cerebrospinal fluid

Treatment Protocols: Prolonged courses of antifungal medications, commonly including amphotericin B combined with flucytosine Transition to oral azole antifungals like fluconazole or itraconazole after initial therapy, with duration often spanning several months Monitoring of treatment effectiveness through clinical assessment and laboratory tests Supportive care to manage symptoms and prevent complications Addressing underlying immune deficiencies, such as antiretroviral therapy in HIV-positive patients Surgical intervention may be necessary in cases with significant bone destruction or abscess formation