0:00 Cryptococcus neiformans is a fungus commonly found in the environment and 0:09 usually infects 0:09 the lungs or the central nervous system in more advanced age. 0:13 People become infected after inhaling the microscopic fungus, although most 0:17 healthy 0:18 individuals who are exposed to see neiformans never become ill from it. 0:23 Most cases occur in people who are immunocompromised, particularly those with 0:27 advanced HIV and 0:28 AIDS. 0:31 Since cryptococcus neiformans enters the body through the respiratory tract, 0:35 infection 0:35 can present as a pneumonia-like illness before moving to the central nervous 0:41 system and causing 0:42 meningio encephalitis. 0:44 It is fatal if left untreated. 0:48 Cryptococcus neiformans is a fungus found worldwide. 0:51 It was estimated that 223,000 cases of cryptococcal meningitis occurs globally 0:58 each year 0:58 and 181,000 deaths, a decrease since the widespread availability of antiretrov 1:04 iral drugs. 1:05 90% of cryptococcal meningitis cases are seen among patients with AIDS and a CD 1:10 4 cell 1:11 count less than 100 cells per microliter. 1:14 Approximately 15% of age-related mortality is caused by cryptococcal disease. 1:23 Also, the risk factors for cryptococcus infections in descending order includes 1:31 AIDS, prolonged 1:32 treatment with glucocorticoids, person who's had an organ transplant, certain 1:40 malignancies, 1:42 liver disease, and sarcoidosis. 1:44 Most of these conditions, as you know, reduces the immune system, suppresses 1:49 the immune system, 1:50 and thus increases the risk of opportunistic infections, such as cryptococcus 1:58 infections. 1:59 Let's talk about the pathogen in the life cycle itself. 2:03 Cryptococcus neiformans is a species of the genus Cryptococcus, a group of path 2:08 ogenic 2:09 encapsulated yeasts that can live in both plants and animals. 2:14 Cryptococcus species are distinguished based on antigen antibody reaction, 2:19 termed capsular 2:19 agglutination, and are designated A, B, C, or D, serotypes. 2:27 Serotype A is known as cryptococcus grooby. 2:32 Serotypes B and C is cryptococcus gary, and serotype D is the cryptococcus ne 2:39 iformans 2:40 that we know, which worldwide is pathogenic. 2:46 The cryptococcus neiformans life cycle involves both asexual and sexual forms. 2:52 The asexual form exists as yeast and reproduced by budding. 2:57 Cryptococcus neiformans first grows as a budding yeast and switches to high 3:02 full growth during 3:03 sexual cycle. 3:07 Cryptococcus neiformans is a fungus found in the environment throughout the 3:11 world. 3:12 It is typically found in soil, decaying wood, tree hollows, or in-bird dro 3:19 ppings. 3:20 Most people who inhale the microscopic fungus never become ill, as mentioned. 3:26 But cryptococcus neiformans can lie dormant in the body and cause infection 3:32 later in those 3:33 with a weakened immune system. 3:35 Cryptococcus neiforman infection is not contagious. 3:40 Upon inhalation of cryptococcus neiformans, the spores can colonize the lung, 3:46 where it 3:47 will typically cause an asymptomatic pneumonia. 3:52 And from here, in an immunosuppressed person, the fungus can then spread hemat 3:58 ogenously 3:59 across the blood-brain barrier and infect the brain tissue. 4:03 The central nervous system is the most common secondary side of infection. 4:09 Cryptococcus has a thick capsule consisting of negatively charged polysacchar 4:14 ides that 4:15 are immunosuppressive, blocking both cell-mediated immune responses and leuk 4:20 ocyte migration. 4:22 These effects explain the minimal inflammatory response elicited by invading 4:27 cryptococci. 4:28 Cryptococcus also produces manatol, a product that may induce cerebral edema 4:33 and inhibit 4:34 phagoside function. As the infection advances and intracranial pressure 4:39 increases, encephalopathy, 4:43 cranial neuropathies and papillodema can develop. 4:49 Cryptococcus neiformans can cause symptomatic pneumonia, especially in immunos 4:54 uppressed 4:54 patients. And this manifests as a cough, shortness of breath, chest pain and fe 5:01 vers. 5:01 In cryptococcal meningitis, it is usually slowly progressive with a waxing and 5:06 waning 5:06 cause, characterized by severe intermittent headaches, fever, followed by mild 5:12 confusion, 5:12 maybe some personality changes that can progress to stupor and coma. 5:20 Important differential diagnoses to consider for pulmonary cryptococcus include 5:25 pneumonia, 5:25 tuberculosis and other conditions or diseases, infections that cause problems 5:32 in immunosuppressed 5:33 people, including pneumocystis, toxoplasma, histoplasma, coccidioides, Candida, 5:41 cytomegalovirus 5:43 and myobacterium avium complex. The differential diagnosis of crypto, meningo, 5:49 encephalitis 5:50 is broad and will not be discussed. Investigations to order with someone 5:56 suspected 5:56 of cryptococcus infections include a cryptococcal antigen test in the blood, 6:01 HIV antibody 6:03 testing, if the patient's HIV status is unknown, a chest x-ray and even a CT 6:09 chest that may 6:10 show nodules, consolidation, infiltration. If meningo encephalitis is suspected 6:17 , an MRI 6:18 brain is important and a lumbar puncture, with the lumbar puncture sending for 6:23 cryptococcal 6:24 antigen and also microscopic culture sensitivity, so culturing basically, and 6:29 agar culture is 6:30 a gold standard. There's also india ink preparation of the cerebrospinal fluid, 6:36 which can help 6:37 visualise the capsule surrounding cryptococcus neiformans. 6:44 In terms of treatment, cryptococcus neiformans pneumonia is treated with antif 6:52 ungals. For 6:53 asymptomatic mild to moderate infection, this is fluconazole. With more severe 6:58 cases, 6:58 we were treated as cryptococcus meningitis. With cryptococcus meningitis, which 7:04 is quite 7:04 serious because of the risk of increased intracranial pressure, induction with 7:10 IV amphotericin 7:11 B, plus flu cytosine, which is an oral antifungal, is important, and this is 7:17 followed by maintenance 7:19 therapy such as oral fluconazole until symptoms resolve. Serial therapeutic l 7:25 umbar punctures 7:26 are also used for patients with increased intracranial pressure, and this is 7:30 done to 7:30 reduce the pressure in the brain. Complications of cryptococcal infections, 7:38 mainly meningitis, 7:40 with that of permanent neurological damage, as well as cryptococcoma, which is 7:45 granulomas 7:46 within the brain. To summarise, cryptococcal neiformans infection typically 7:55 causes problems 7:56 in immunosuppressed people. Typically, they cause either a lung problem or a 8:03 brain problem. 8:06 It is with antifungals.
