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Infectious Disease - Cryptococcal Infections
Basics: Cryptococcus is a type of yeast that has a special polysaccharide capsule surrounding its membrane.
• Although Cryptococcus has more than 50 species, the two most significant for medicine are Cryptococcus neoformans, which mainly infects immunocompromised patients, and Cryptococcus gattii, which also infects immunocompetent hosts.
• Cryptococcus infections can spread to any part of the body, including the bones, skin, prostate, and eyes, although they usually affect the lung or central nervous system in patients with compromised cell-mediated immunity (such as those with AIDS or organ transplantation).
• Inhalation is the main way that infections are spread. It has a preference for the central nervous system and can spread throughout the body.
The study of epidemiology
• Pigeon feces are linked to C. neoformans, which is more prevalent in the US, but direct there is no evidence of transfer from pigeons to people.
• C. gattii is typically found in the vegetation surrounding eucalyptus trees in tropical and subtropical areas. More recently, it has been observed in North America, particularly in British Columbia and the Pacific Northwest.
• There have been no reports of respiratory transmission between people or between humans and other animals. Rare situations, such transplanting an infected organ into a recipient who is not infected, can result in human-to-human transmission.
• Since the widespread use of antiretroviral medication, cryptococcal infection has significantly decreased in patients with HIV.
• For instance, following extensive antiretroviral therapy, a research assessing the incidence of cryptococcal infection in AIDS patients per 1000 people found that it had decreased from 66 to 7 in Atlanta and from 24 to 2 in Houston (1,2).
• 20–60% of cryptococcal infections in individuals without HIV in the United States are caused by Cryptococcus, the third most prevalent invasive fungal infection in solid-organ transplant recipients (3).
AIDS is a risk factor.
• Haematologic cancers.
• Transplanting solid organs
• Immunosuppressive drugs, such as tacrolimus, cyclosporine, and glucocorticoids.
• Other: Chronic obstructive pulmonary disease, diabetes mellitus, lupus, rheumatoid arthritis, splenectomy, and sarcoidosis
OVERALL PREVENTION
• HIV patients: Use antiretroviral medication to rebuild the immune system.
• Individuals with AIDS: Antiretroviral therapy can help rebuild the immune system, and fluconazole and itraconazole can help prevent cryptococcal infection in people with a CD4 cell count below 50 cells/μL. However, few HIV providers put patients on primary prophylactic regimens because of drug interactions and the lack of survival benefits with this approach.
• Secondary prophylaxis: Fluconazole (200 mg/d PO) should be administered to AIDS patients who have finished therapy for cryptococcal meningitis for the rest of their lives, or until their CD4 count is higher than 200 cells/μL for more than six months.
Pathophysiology
Spores of yeast are inhaled into the alveoli. Individuals with T cell
Deficits increase the risk of infection spreading. Primary infections are represented by pneumonia, while disseminated diseases are represented by meningitis, skin lesions, or involvement of other organs (such as the prostate, bone, etc.).
Ethiology
Among the species that are clinically significant are C. gattii and C. neoformans.
History of Diagnosis
The symptoms of a lung infection can include fever, hemoptysis, coughing, pleuritic chest discomfort, dyspnea, and acute respiratory distress syndrome.
• CNS infection: Usually manifests as headache, fever, and irritability with a subacute onset that lasts 1-3 weeks. It can then develop to disorientation, nausea, somnolence, and seizures. Just 25% of patients exhibit the typical meningitis symptoms, which include fever, photophonophobia, nausea, vomiting, and stiff neck.
MEDICAL EXAMINATION
• CNS: Usually, nuchal stiffness is not the main symptom. Rarely, cryptococcomas can cause focal neurologic impairments.
• Nearly one-third of patients have papilledema.
• Skin: Papules, ulcers, or painless sores. Skin findings could feature a molluscum contagiosum-like central umbilication.
Diagnostic Examination and Interpretation Laboratory
For cryptococcal antigen, send blood. Cryptococcus can also develop in blood cultures, and if cultures are taken in fungal isolator tubes, the test's yield will be higher.
•
• Lung infection: culture of sputum or lung nodule biopsy. If there is no growth, lung biopsy histopathology may be useful.
India ink staining, culture, and the identification of cryptococcal antigen in CSF are all crucial diagnostic tools for CNS infections.
• Usually, the CSF opening pressure is higher than 200 mm H2O.
• A CSF investigation reveals lymphocytic pleocytosis, low glucose, and high protein.
• When individuals have similar symptoms, a serum test for cryptococcal antigen can frequently be used to diagnose meningitis or pneumonia.
• Skin biopsy for cultures and fungus staining.
Imagining
• Lung infection: If there are pulmonary symptoms, a CT scan and CXR are useful. Infiltrates of interstitial
are frequently seen in patients with impaired immune systems. Both immunocompetent and immunocompromised hosts may exhibit one or more pulmonary nodules. Cavitation is uncommon. It is also possible to see a cryptococcoma, hilar or mediastinal lymphadenopathy, and pleural effusions (5).
• CNS infection: When focal neurologic impairments are apparent, a CT or MRI scan can be useful. Check for hydrocephalus, cryptococcomas, or nodules.
Pneumonia, Pneumocystis Carinii Pneumonia, TB, Sarcoidosis, Histoplasmosis, Coccidiomycosis, Meningoencephalitis, and CNS metastases are examples of differential diagnoses.
MEDICATION FOR TREATMENT
First Phrase
• Lung infection: Fluconazole 400 mg/d for 6–12 months is recommended for mild-to-moderate infections.
• CNS infection: Amphotericin B (using a lipid formulation in patients at risk of nephrotoxicity) and flucytosine 100 mg/kg/d, divided into 4 doses daily, are administered for 14 (or more) days during the first "induction phase." A "consolidation phase" of 400 mg/d of fluconazole is administered for 8 weeks, followed by "maintenance" therapy with 200 mg/d of fluconazole if patients exhibit a clinical response.
Line Two
• Itraconazole, voriconazole, and posaconazole are substitute active medicines for pneumonia.
• For those who are unable to tolerate amphotericin B plus flucytosine during the consolidation phase, fluconazole plus flucytosine is an option for CNS disease;
But this is not a good enough treatment.
ADDITIONAL MEDICATION
Overall Actions
Patients with cryptococcal infections are frequently treated by infectious disease specialists.
OTHER PROCEDURES AND SURGERY
During lumbar puncture, patients may experience opening pressures that are consistently elevated. To alleviate elevated intracranial pressures, patients with persistent neurologic symptoms (such as papilledema or lower limb clonus) should have repeated lumbar punctures. In severe cases that do not respond to serial lumbar punctures, neurosurgeon services should be consulted in order to consider ventriculoperitoneal shunting.
Continuing Care Follow-Up Suggestions
• Tracking creatinine and BUN while taking flucytosine and amphotericin.
• Keeping an eye on liver function tests when using fluconazole.
COMPLICATIONS
• Visual impairment • Dementia • Death • Hydrocephalus
Basics: Cryptococcus is a type of yeast that has a special polysaccharide capsule surrounding its membrane.
• Although Cryptococcus has more than 50 species, the two most significant for medicine are Cryptococcus neoformans, which mainly infects immunocompromised patients, and Cryptococcus gattii, which also infects immunocompetent hosts.
• Cryptococcus infections can spread to any part of the body, including the bones, skin, prostate, and eyes, although they usually affect the lung or central nervous system in patients with compromised cell-mediated immunity (such as those with AIDS or organ transplantation).
• Inhalation is the main way that infections are spread. It has a preference for the central nervous system and can spread throughout the body.
The study of epidemiology
• Pigeon feces are linked to C. neoformans, which is more prevalent in the US, but direct there is no evidence of transfer from pigeons to people.
• C. gattii is typically found in the vegetation surrounding eucalyptus trees in tropical and subtropical areas. More recently, it has been observed in North America, particularly in British Columbia and the Pacific Northwest.
• There have been no reports of respiratory transmission between people or between humans and other animals. Rare situations, such transplanting an infected organ into a recipient who is not infected, can result in human-to-human transmission.
• Since the widespread use of antiretroviral medication, cryptococcal infection has significantly decreased in patients with HIV.
• For instance, following extensive antiretroviral therapy, a research assessing the incidence of cryptococcal infection in AIDS patients per 1000 people found that it had decreased from 66 to 7 in Atlanta and from 24 to 2 in Houston (1,2).
• 20–60% of cryptococcal infections in individuals without HIV in the United States are caused by Cryptococcus, the third most prevalent invasive fungal infection in solid-organ transplant recipients (3).
AIDS is a risk factor.
• Haematologic cancers.
• Transplanting solid organs
• Immunosuppressive drugs, such as tacrolimus, cyclosporine, and glucocorticoids.
• Other: Chronic obstructive pulmonary disease, diabetes mellitus, lupus, rheumatoid arthritis, splenectomy, and sarcoidosis
OVERALL PREVENTION
• HIV patients: Use antiretroviral medication to rebuild the immune system.
• Individuals with AIDS: Antiretroviral therapy can help rebuild the immune system, and fluconazole and itraconazole can help prevent cryptococcal infection in people with a CD4 cell count below 50 cells/μL. However, few HIV providers put patients on primary prophylactic regimens because of drug interactions and the lack of survival benefits with this approach.
• Secondary prophylaxis: Fluconazole (200 mg/d PO) should be administered to AIDS patients who have finished therapy for cryptococcal meningitis for the rest of their lives, or until their CD4 count is higher than 200 cells/μL for more than six months.
Pathophysiology
Spores of yeast are inhaled into the alveoli. Individuals with T cell
Deficits increase the risk of infection spreading. Primary infections are represented by pneumonia, while disseminated diseases are represented by meningitis, skin lesions, or involvement of other organs (such as the prostate, bone, etc.).
Ethiology
Among the species that are clinically significant are C. gattii and C. neoformans.
History of Diagnosis
The symptoms of a lung infection can include fever, hemoptysis, coughing, pleuritic chest discomfort, dyspnea, and acute respiratory distress syndrome.
• CNS infection: Usually manifests as headache, fever, and irritability with a subacute onset that lasts 1-3 weeks. It can then develop to disorientation, nausea, somnolence, and seizures. Just 25% of patients exhibit the typical meningitis symptoms, which include fever, photophonophobia, nausea, vomiting, and stiff neck.
MEDICAL EXAMINATION
• CNS: Usually, nuchal stiffness is not the main symptom. Rarely, cryptococcomas can cause focal neurologic impairments.
• Nearly one-third of patients have papilledema.
• Skin: Papules, ulcers, or painless sores. Skin findings could feature a molluscum contagiosum-like central umbilication.
Diagnostic Examination and Interpretation Laboratory
For cryptococcal antigen, send blood. Cryptococcus can also develop in blood cultures, and if cultures are taken in fungal isolator tubes, the test's yield will be higher.
•
• Lung infection: culture of sputum or lung nodule biopsy. If there is no growth, lung biopsy histopathology may be useful.
India ink staining, culture, and the identification of cryptococcal antigen in CSF are all crucial diagnostic tools for CNS infections.
• Usually, the CSF opening pressure is higher than 200 mm H2O.
• A CSF investigation reveals lymphocytic pleocytosis, low glucose, and high protein.
• When individuals have similar symptoms, a serum test for cryptococcal antigen can frequently be used to diagnose meningitis or pneumonia.
• Skin biopsy for cultures and fungus staining.
Imagining
• Lung infection: If there are pulmonary symptoms, a CT scan and CXR are useful. Infiltrates of interstitial
are frequently seen in patients with impaired immune systems. Both immunocompetent and immunocompromised hosts may exhibit one or more pulmonary nodules. Cavitation is uncommon. It is also possible to see a cryptococcoma, hilar or mediastinal lymphadenopathy, and pleural effusions (5).
• CNS infection: When focal neurologic impairments are apparent, a CT or MRI scan can be useful. Check for hydrocephalus, cryptococcomas, or nodules.
Pneumonia, Pneumocystis Carinii Pneumonia, TB, Sarcoidosis, Histoplasmosis, Coccidiomycosis, Meningoencephalitis, and CNS metastases are examples of differential diagnoses.
MEDICATION FOR TREATMENT
First Phrase
• Lung infection: Fluconazole 400 mg/d for 6–12 months is recommended for mild-to-moderate infections.
• CNS infection: Amphotericin B (using a lipid formulation in patients at risk of nephrotoxicity) and flucytosine 100 mg/kg/d, divided into 4 doses daily, are administered for 14 (or more) days during the first "induction phase." A "consolidation phase" of 400 mg/d of fluconazole is administered for 8 weeks, followed by "maintenance" therapy with 200 mg/d of fluconazole if patients exhibit a clinical response.
Line Two
• Itraconazole, voriconazole, and posaconazole are substitute active medicines for pneumonia.
• For those who are unable to tolerate amphotericin B plus flucytosine during the consolidation phase, fluconazole plus flucytosine is an option for CNS disease;
But this is not a good enough treatment.
ADDITIONAL MEDICATION
Overall Actions
Patients with cryptococcal infections are frequently treated by infectious disease specialists.
OTHER PROCEDURES AND SURGERY
During lumbar puncture, patients may experience opening pressures that are consistently elevated. To alleviate elevated intracranial pressures, patients with persistent neurologic symptoms (such as papilledema or lower limb clonus) should have repeated lumbar punctures. In severe cases that do not respond to serial lumbar punctures, neurosurgeon services should be consulted in order to consider ventriculoperitoneal shunting.
Continuing Care Follow-Up Suggestions
• Tracking creatinine and BUN while taking flucytosine and amphotericin.
• Keeping an eye on liver function tests when using fluconazole.
COMPLICATIONS
• Visual impairment • Dementia • Death • Hydrocephalus
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