Cryptococcosis

Christina C. Chang : Department of Infectious Diseases, Alfred Hospital and Monash University, Melbourne VIC
Mark Kelly : Armidale Rural and Referral Hospital, NSW

Cryptococcal disease (cryptococcosis) is caused by Cryptococcus neoformans – Cryptococcus gattii complex, a ubiquitous environmental yeast that is endemic in many countries including Australia. Cryptococcosis is most often associated with human immunodeficiency virus (HIV) infection, but can also occur in immunocompetent individuals. The clinical manifestations of cryptococcosis are protean. Cryptococcal meningoencephalitis (CM) is the most frequent and most severe form with mortality rates of 20-70%;[1] untreated this form is uniformly fatal.[2][3] The most common route of acquisition is via inhalation, yet pulmonary cryptococcosis manifesting as lung infiltrates and cryptococcomas is poorly recognised. Less common again are skin cryptococcomas, ophthalmic, bone and prostatic cryptococcal disease.[4] This chapter will focus on CM and pulmonary cryptococcosis.

Epidemiology

An environmental organism with known clinical latency, the majority of infections are due to reactivation disease rather than acute infection. Risk factors for cryptococcosis include host immunodeficiency (steroids, CD4 depletion, other immunosuppressive host), geographical endemicity (including risk activities) and environmental outbreaks.

Clinical presentation

Cryptococcus spp. have a predilection to invade the central nervous system (CNS) leading to life-threatening meningoencephalitis. [5] Patients present with an acute, subacute or chronic meningitis or meningoencephalitis.[6] Signs and symptoms include headache, nausea, fever, altered consciousness, cranial neuropathy, memory loss, confusion, meningeal irritation signs, nausea and vomiting, seizures, visual and hearing deficits and coma. [7] [8] [9] [10] [11] Signs associated with poor outcome include Glasgow coma scale (GCS) < 15,[12][13] neurological deficit [14], confusion/ abnormal mental state/lethargy/obtundation,[15][16] positive blood culture[17] and high CSF cryptococcal antigen (CrAg).[18][19]

The majority of patients with pulmonary cryptococcosis are asymptomatic or simply report cough, scant sputum production, fever, dyspnoea and chest pain[20], [21], [22], [23] indistinguishable from other causes of pneumonia (reviewed in Chang et al.[24]). Many present with an incidental radiological abnormality, mimicking lung malignancy.

Diagnosis

Patients with cryptococcosis may be asymptomatic. Any patients with HIV infection presenting with subacute/ chronic headache, particularly those who are CD4-deplete, should be investigated for CM. Lumbar puncture should be performed to measure opening pressure, cerebrospinal fluid (CSF) cell counts, biochemistry and culture, CSF CrAg, Gram stain and India ink, along with serum CrAg, blood culture and chest X-ray. CT or MRI brain scans are helpful in assessing cryptococcomas, meningeal inflammation, vasculitis and ventricular compression.

Pulmonary cryptococcosis usually manifests as peripherally distributed lung nodules and masses are most common[25][26][27][28] and more than 60% of patients have multiple nodules on chest X-ray and CT chest scan.[29] Sputum and bronchoalveolar lavage often collected for culture may be negative. Culture and histology from lung biopsies provide a definitive diagnosis. Importantly isolation of the C. neoformans-C. gattii complex in respiratory samples should not be dismissed as contamination. Patients with any form of cryptcoccosis including pulmonary cryptococcosis should be comprehensively assessed with a serum CrAg, blood culture for dissemination, chest X-ray for pulmonary involvement and lumbar puncture for CNS involvement.

Regardless of the presence of symptoms, serum cryptococcal antigen testing should be performed in patients with new diagnosis of HIV - particularly those with advanced HIV and patients from countries where Cryptococcus spp. is endemic. The new lateral flow assay (LFA) for measuring cryptococcal antigen designed as a point-of-care test has performed well (> 95% sensitivity and 100% specificity) when used on serum and CSF, thus is comparable to the previously used latex agglutination test.[30][31] The LFA assay is currently being used in a number of routine laboratories in Australia. A positive serum cryptococcal antigen test should trigger investigations for cryptococcoal dissemination – Chest XRay +/- CT chest, blood culture, a thorough skin examination and a lumbar puncture to diagnose CM.

Management of cryptococcal meningitis / meningoencephalitis

CM is a medical emergency requiring a diagnostic and therapeutic lumbar puncture, fluid resuscitation, airway management and early antifungal therapy. In resource-limited settings, 7.4% of patients die within the first 48 hours of hospital presentation[32] – a reminder of its rapid lethality. The management of CM pivots on two major aspects: antifungal therapy and management of raised intracranial pressure. Antifungal therapy in cryptococcosis has been divided into three phases – induction, consolidation and maintenance. The induction phase is an area of intense research with regards to drug-dose combination and duration, as aggressive antifungal therapy has been shown to improve CSF culture sterility and be associated with improved clinical outcomes.[33][34] The consolidation and maintenance phases are based on fluconazole therapy. Aggressive therapeutic lumbar punctures to relieve raised intracranial pressure are essential in the management of CM.

Antifungal treatment guidelines for cryptococcal meningitis

Current Infectious Diseases Society of America (IDSA) practice guidelines for treatment of CNS cryptococcosis in patients with HIV infection suggest a combination of conventional amphotericin 0.7-1.0 mg/kg/day and flucytosine (5-FC) 100 mg/kg/day as induction therapy for 2 weeks followed by 400 mg/day fluconazole as consolidation for a minimum of 10 weeks before reducing to a maintenance fluconazole dose of 200-400 mg/day.[35] Alternative induction therapy include conventional amphotericin 0.7-1.0 mg/kg/day as a single agent for a prolonged 6-10 weeks duration or fluconazole 400-800 mg/day for 10-12 weeks.[36] The Centre for Disease Control Morbidity and Mortality weekly report (CDC MMWR) 2009 guidelines on management of opportunistic infections endorse the amphotericin–5-FC approach, though they suggest a 0.7 mg/kg/day amphotericin dose, and recommend a minimum of 2 weeks of intensive therapy – prolonging intensive therapy until substantial clinical improvement and a ‘clearance’ culture-negative lumbar puncture is achieved.[37] The 2011 World Health Organization WHO CM guidelines offer recommendations dependent on drug availability, with 2 weeks of 0.7-1.0 mg/kg of amphotericin and 100 mg/kg/day of 5-FC as their first choice, and 0.7-1.0 mg/kg of amphotericin and 800 mg of fluconazole as an alternative for induction therapy.[38]

The IDSA guidelines are currently being rewritten and it is likely that a dose of conventional amphotericin 1.0 mg/kg/day and flucytosine (5-FC) 100 mg/kg/day will be endorsed as induction therapy as this combination has now been shown to have survival benefit over other antifungal combinations.[39] The new Australian guidelines recommend 3 mg/kg/day liposomal amphotericin and 100 mg/kg/day of flucytosine as induction therapy.[40] This recommendation is based on a small study demonstrating similar efficacy and reduced renal impairment when using liposomal amphotericin.[41] Discontinuing maintenance therapy against prior cryptococcal infection is possible in individuals who remain asymptomatic and have a sustained increase in their CD4 T-lymphocyte (CD4) cell counts to > 200 cells/μL for at least 6 months after initiating antiretroviral therapy.[42]

Amphotericin is associated with renal impairment, hypokalaemia and hypomagenesaemia, thus pre-emptive aggressive fluid, potassium and magnesium replacement is recommended. Flucytosine levels should be performed (detailed in Chau et al. ).[43] A short list of possible side effects is in Table 1 (reviewed in Chau et al. ).[44]

Table 1 Side effects of antifungal agents used in Cryptococcosis
Fluconazole Mild to moderate nausea, vomiting, abdominal pain, diarrhoea Rash – may be associated with eosinophilia and pruritus Stevens-Johnson syndrome – rare, but may be fatal Increased liver function tests in 5-7% of patients Hepatic reactions including fulminant hepatic failure – rare Dizziness, headaches, alopecia
Conventional Amphotericin Acute infusion-related reactions – fevers, chills, rigors, nausea and headache – common Anaphylaxis – rare Renal tubular abnormalities including renal tubular acidosis, hypokalaemia and renal impairment in up to 80% of patients Anaemia and cardiac arrhythmias
Liposomal Amphotericin As for conventional amphotericin except less frequent
Flucytosine Gastrointestinal intolerance, dose-related leukopenia and thrombocytopenia, rash, hepatitis, and peripheral neuropathy

Management of raised intracranial pressure for CM

The majority of patients with CM have raised intracranial pressure (ICP).[45] This increased pressure is associated with cognitive impairment, neurological defects and increased short-term mortality.[46] Aggressive management of rapid ICP with therapeutic lumbar punctures is recommended in international CM guidelines[47] based on the dramatic recovery in conscious states reported in early studies.[48][49][50] Current recommendations for the management of raised ICP suggests repeated daily CSF drainage until opening pressure is stable, and drainage until CSF closing pressure is ≤ 20 cmH20 or < 50% of the initial opening pressure.[51][52] Steroids have been used, mostly anecdotally in C. gattii infections, with no consistent result[53][54] while acetazolamide has been clearly harmful in the management of CM.[55]

Management of pulmonary cryptococcosis

There are no prospective studies on pulmonary cryptococcosis, thus treatment guidelines are based on retrospective case series, expert opinion and are inferred from studies of CM. Treatment guidelines from IDSA,[56] the American Thoracic Society (ATS),[57] the Australia and New Zealand Mycoses Interest Group (ANZMIG),[58] World Health Organization (WHO)[59] and other professional societies are summarised in Chang et al.[60]

Overall, asymptomatic or mild-to-moderate pulmonary cryptococcosis may be treated with 400-800 mg fluconazole daily for 6-12 months while those with severe symptoms, diffuse infiltrates on imaging, and those with concomitant CNS disease should be treated as for CNS disease. Patients intolerant of fluconazole may be prescribed itraconazole 200-400 mg/day though there is growing anecdotal experience with the use of posaconazole[61] and voriconazole[62] in CM. Surgical resection should be considered in those with persistent symptoms despite therapy and those with very large pulmonary cryptococcomas (> 5 cm), particularly in the presence of a mass effect.

Adjuvant therapy

There have been two randomised studies of exogenous IFN-gamma as adjuvant therapy in CM but none in pulmonary cryptococcosis.[63][64] Exogenous IFN-gamma showed no impact on mortality but was associated with a faster rate of CSF fungal clearance.[65] Exogenous IGN-gamma is not currently used in routine clinical management of CM.

Primary prophylaxis

There is good randomised controlled trial evidence for the use of fluconazole[66][67] or as second line, itraconazole[68] 200 mg daily, as primary prophylaxis in patients with HIV infection with < 200 cells/μL CD4 cell counts, however uptake of this practice has been poor globally.

Timing of antiretroviral therapy commencement in cryptococcal meningoencephalitis co-infection

The timing of antiretroviral therapy commencement in the setting of any newly diagnosed opportunistic infection has been long debated where the risk of immune reconstitution inflammatory syndrome (IRIS) in early combination antiretroviral therapy (cART) commencement is measured against the ongoing risk of co-infections in late commencement. A number of studies have begun to address the optimal timing of antiretroviral therapy in CM-HIV co-infection with two small and one large randomised controlled trial cautioning against very early antiretroviral therapy initiation. A Zimbabwean randomised study was terminated early at 54 patients, after the early arm (72 hours) showed almost 3 times the risk of mortality of the delayed arm (> 10 weeks), adjusted HR 2.85, 95% CI 1.1-7.2.[69] This study used 800 mg fluconazole as induction therapy and did not perform regular therapeutic lumbar punctures. A smaller, randomised study from Botswana of 27 patients, showed no difference in mortality but not unexpectedly, reported a significantly increased rate of cryptococcosis-associated IRIS (C-IRIS) (p = 0.002) in the early arm (median 7, IQR 5-10 days) compared to the late arm (median 32, IQR 28-36 days).[70] The largest study on optimal antiretroviral commencement in CM (Cryptococcal Optimal ART Timing (COAT) study) was terminated at 35% of enrolment (n = 177), due to significantly increased 6-month mortality in the early arm (7-13 days) compared to the late arm (> 5 weeks) 45% vs. 30% (HR 1.7, 95% CI 1.1-2.8, p = 0.03) (COAT).[71] The rate of C-IRIS was no different between arms 20% early vs. 13% deferred (p = 0.32).[72]

Taken together, current evidence suggests that very early commencement of antiretroviral therapy (in the first 11 days after CM diagnosis) is likely harmful. Equally, deliberate delay of antiretroviral therapy commencement to > 5 or 6 weeks after CM diagnosis risks losses in follow-up. An unexplored time-window between 2-4 weeks of CM diagnosis remains. It is likely that patients could be risk-stratified – patients who demonstrate good clinical improvement, have normalised their CSF opening pressure and have sterilised their CSF are not likely to require a delay of > 5-6 weeks. Patients who have been able to sterilise their CSF (i.e. attain CSF culture negativity) prior to antiretroviral therapy commencement have improved clinical outcomes.[73] The recent International Antiviral Society antiretroviral management guidelines suggest that initiating antiretroviral therapy early during CM treatment should be considered when expert management for both cryptococcal and HIV infection is available.[74]

Neurological deterioration post- antiretroviral therapy commencement

Patients with CM are known to have symptomatic relapse despite being on adequate antifungal therapy and cART[75][76][77] and may re-present with worsening headaches, new seizures or sudden loss of conscious state. The majority of these neurological deterioration episodes are thought to be due to C-IRIS (discussed in detail in Immune reconstitution inflammatory syndromes). Other differential diagnoses include cryptococcal microbiological relapse due to drug non-adherence, a new or undiagnosed second cause of meningitis such as tuberculosis meningitis and non-infective causes such as migraine or malignancy. Determining the cause of neurological deterioration is important as the management of each differs. A thorough history and examination, and a repeat lumbar puncture is recommended to measure opening pressure, and CSF should be sent for biochemistry, cell counts, cryptococcal culture and other molecular tests as necessary. In addition, brain imaging including CT and MRI scans may be necessary to look for focal brain lesions or meningeal enhancement.

Note that while CSF and serum cryptococcal antigen is often performed, this titre can remain high for many months, thus a high titre is not necessarily indicative of relapse disease. Similarly, a positive gram stain or India ink for Cryptococcus spp., is not necessarily indicative of microbiological relapse as dead Cryptococci are often seen for a prolonged period. A repeat positive CSF culture for Cryptococci suggests microbiological relapse, though comparative quantitative cultures[78][79] done in research settings are more helpful – these are yet to be widely accepted in routine clinical work. Antifungal susceptibility testing is not routinely done in hospital laboratories but may be helpful in the setting of neurological deterioration.

1.
Brown GD, Denning DW, Gow NA, et al. Hidden killers: human fungal infections. Sci Transl Med 2012;4:165rv13 
2.
Mwaba P, Mwansa J, Chintu C, et al. Clinical presentation, natural history, and cumulative death rates of 230 adults with primary cryptococcal meningitis in Zambian AIDS patients treated under local conditions. Postgrad Med J 2001;77:769-73 
3.
French N, Gray K, Watera C, et al. Cryptococcal infection in a cohort of HIV-1-infected Ugandan adults. AIDS 2002;16:1031-8 
4.
Chayakulkeeree M, Perfect JR. Cryptococcosis. Infect Dis Clin North Am 2006;20:507-44 
5.
Chayakulkeeree M, Perfect JR. Cryptococcosis. Infect Dis Clin North Am 2006;20:507-44 
6.
Chayakulkeeree M, Perfect JR. Cryptococcosis. Infect Dis Clin North Am 2006;20:507-44 
7.
Chayakulkeeree M, Perfect JR. Cryptococcosis. Infect Dis Clin North Am 2006;20:507-44 
8.
Butler WT, Alling DW, Spickard A, et al. Diagnostic and prognostic value of clinical and laboratory findings in cryptococcal meningitis, a follow-up study of forty patients. N Engl J Med 1964;270:59-67 
9.
Chuck SL, Sande MA. Infections with Cryptococcus neoformans in the acquired immunodeficiency syndrome. N Engl J Med 1989;321:794-9 
10.
Graybill JR, Sobel J, Saag M, et al. Diagnosis and management of increased intracranial pressure in patients with AIDS and cryptococcal meningitis. The NIAID Mycoses Study Group and AIDS Cooperative Treatment Groups. Clin Infect Dis 2000;30:47-54 
11.
McCarthy KM, Morgan J, Wannemuehler KA, et al. Population-based surveillance for cryptococcosis in an antiretroviral-naive South African province with a high HIV seroprevalence. AIDS 2006;20:2199-206 
12.
Bicanic T, Muzoora C, Brouwer AE, et al. Independent association between rate of clearance of infection and clinical outcome of HIV-associated cryptococcal meningitis: analysis of a combined cohort of 262 patients. Clin Infect Dis 2009;49:702-9 
13.
Rothe C, Sloan DJ, Goodson P, et al. A prospective longitudinal study of the clinical outcomes from cryptococcal meningitis following treatment induction with 800 mg oral fluconazole in Blantyre, Malawi. PLoS ONE 2013;8:e67311 
14.
Rothe C, Sloan DJ, Goodson P, et al. A prospective longitudinal study of the clinical outcomes from cryptococcal meningitis following treatment induction with 800 mg oral fluconazole in Blantyre, Malawi. PLoS ONE 2013;8:e67311. 
15.
Saag MS, Powderly WG, Cloud GA, et al. Comparison of amphotericin B with fluconazole in the treatment of acute AIDS-associated cryptococcal meningitis. The NIAID Mycoses Study Group and the AIDS Clinical Trials Group. N Engl J Med 1992;326:83-9 
16.
Dismukes WE, Cloud G, Gallis HA, et al. Treatment of cryptococcal meningitis with combination amphotericin B and flucytosine for four as compared with six weeks. N Engl J Med 1987;317:334-41 
17.
Saag MS, Powderly WG, Cloud GA, et al. Comparison of amphotericin B with fluconazole in the treatment of acute AIDS-associated cryptococcal meningitis. The NIAID Mycoses Study Group and the AIDS Clinical Trials Group. N Engl J Med 1992;326:83-9 
18.
Rothe C, Sloan DJ, Goodson P, et al. A prospective longitudinal study of the clinical outcomes from cryptococcal meningitis following treatment induction with 800 mg oral fluconazole in Blantyre, Malawi. PLoS ONE 2013;8:e67311 
19.
Saag MS, Powderly WG, Cloud GA, et al. Comparison of amphotericin B with fluconazole in the treatment of acute AIDS-associated cryptococcal meningitis. The NIAID Mycoses Study Group and the AIDS Clinical Trials Group. N Engl J Med 1992;326:83-9 
20.
Zhang Y, Li N, Zhang Y, et al. Clinical analysis of 76 patients pathologically diagnosed with pulmonary cryptococcosis. Eur Respir J 2012;40:1191-200 
21.
Ye F, Xie JX, Zeng QS, et al. Retrospective analysis of 76 immunocompetent patients with primary pulmonary cryptococcosis. Lung 2012;190:339-46 
22.
Song KD, Lee KS, Chung MP, et al. Pulmonary cryptococcosis: imaging findings in 23 non-AIDS patients. Korean J Radiol 2010;11:407-16 
23.
Kohno S, Kakeya H, Izumikawa K, et al. Clinical features of pulmonary cryptococcosis in non-HIV patients in Japan. J Infect Chemother 2015;21:23-30 
24.
Chang CC, Sorrell T, Chen SC. Pulmonary cryptococcosis. Semin Respir Crit Care Med 2015;36:681-91 
25.
Zhang Y, Li N, Zhang Y, et al. Clinical analysis of 76 patients pathologically diagnosed with pulmonary cryptococcosis. Eur Respir J 2012;40:1191-200 
26.
Ye F, Xie JX, Zeng QS, et al. Retrospective analysis of 76 immunocompetent patients with primary pulmonary cryptococcosis. Lung 2012;190:339-46 
27.
Song KD, Lee KS, Chung MP, et al. Pulmonary cryptococcosis: imaging findings in 23 non-AIDS patients. Korean J Radiol 2010;11:407-16 
28.
Kohno S, Kakeya H, Izumikawa K, et al. Clinical features of pulmonary cryptococcosis in non-HIV patients in Japan. J Infect Chemother 2015;21:23-30 
29.
Kohno S, Kakeya H, Izumikawa K, et al. Clinical features of pulmonary cryptococcosis in non-HIV patients in Japan. J Infect Chemother 2015;21:23-30 
30.
Kabanda T, Siedner MJ, Klausner JD, et al. Point-of-care diagnosis and prognostication of cryptococcal meningitis with the cryptococcal antigen lateral flow assay on cerebrospinal fluid. Clin Infect Dis 2014;58:113-6 
31.
Rajasingham R, Rolfes MA, Birkenkamp KE,et al. Cryptococcal meningitis treatment strategies in resource-limited settings: a cost-effectiveness analysis. PLoS Med 2012;9:e1001316 
32.
McCarthy KM, Morgan J, Wannemuehler KA, et al. Population-based surveillance for cryptococcosis in an antiretroviral-naive South African province with a high HIV seroprevalence. AIDS 2006;20:2199-206 
33.
Saag MS, Powderly WG, Cloud GA, et al. Comparison of amphotericin B with fluconazole in the treatment of acute AIDS-associated cryptococcal meningitis. The NIAID Mycoses Study Group and the AIDS Clinical Trials Group. N Engl J Med 1992;326:83-9 
34.
Chang CC, Dorasamy AA, Gosnell BI, et al. Clinical and mycological predictors of Cryptococcosis-associated Immune reconstitution inflammatory syndrome (C-IRIS). AIDS 2013;27:2089-99 
35.
Saag MS, Graybill RJ, Larsen RA, et al. Practice guidelines for the management of cryptococcal disease. Infectious Diseases Society of America. Clin Infect Dis 2000;30:710-8 
36.
Perfect JR, Dismukes WE, Dromer F, et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin Infect Dis 2010;50:291-322 
37.
Kaplan JE, Benson C, Holmes KH, et al. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. MMWR Recomm Rep 2009;58(RR-4):1-207 
38.
Rapid advice: Diagnosis, prevention and management of cryptococcal disease in HIV-infected adults, adolescents and children. Geneva: World Health Organization; 2011 Dec 
39.
Day JN, Chau TT, Wolbers M, et al. Combination antifungal therapy for cryptococcal meningitis. N Engl J Med 2013;368:1291-302 
40.
Chen SC, Sorrell TC, Chang CC, et al. Consensus guidelines for the treatment of yeast infections in the haematology, oncology and intensive care setting, 2014. Intern Med J 2014;44:1315-32 
41.
Hamill RJ, Sobel JD, El-Sadr W, et al. Comparison of 2 doses of liposomal amphotericin B and conventional amphotericin B deoxycholate for treatment of AIDS-associated acute cryptococcal meningitis: a randomized, double-blind clinical trial of efficacy and safety. Clin Infect Dis 2010;51:225-32 
42.
Kaplan JE, Benson C, Holmes KH, et al. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. MMWR Recomm Rep 2009;58(RR-4):1-207 
43.
Chau MM, Kong DC, van Hal SJ, et al. Consensus guidelines for optimising antifungal drug delivery and monitoring to avoid toxicity and improve outcomes in patients with haematological malignancy, 2014. Intern Med J 2014;44:1364-88 
44.
Chau MM, Kong DC, van Hal SJ, et al. Consensus guidelines for optimising antifungal drug delivery and monitoring to avoid toxicity and improve outcomes in patients with haematological malignancy, 2014. Intern Med J 2014;44:1364-88 
45.
Graybill JR, Sobel J, Saag M, et al. Diagnosis and management of increased intracranial pressure in patients with AIDS and cryptococcal meningitis. The NIAID Mycoses Study Group and AIDS Cooperative Treatment Groups. Clin Infect Dis 2000;30:47-54 
46.
Jarvis JN, Harrison TS. HIV-associated cryptococcal meningitis. AIDS 2007;21:2119-29 
47.
Perfect JR, Dismukes WE, Dromer F, et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin Infect Dis 2010;50:291-322 
48.
Graybill JR, Sobel J, Saag M, et al. Diagnosis and management of increased intracranial pressure in patients with AIDS and cryptococcal meningitis. The NIAID Mycoses Study Group and AIDS Cooperative Treatment Groups. Clin Infect Dis 2000;30:47-54 
49.
Fessler RD, Sobel J, Guyot L, et al. Management of elevated intracranial pressure in patients with Cryptococcal meningitis. J Acquir Immune Defic Syndr Hum Retrovirol 1998;17:137-42 
50.
van Gemert HM, Vermeulen M. Treatment of impaired consciousness with lumbar punctures in a patient with cryptococcal meningitis and AIDS. Clin Neurol Neurosurg 1991;93:257-8 
51.
Brown GD, Denning DW, Gow NA, et al. Hidden killers: human fungal infections. Sci Transl Med 2012;4:165rv13 
52.
Mwaba P, Mwansa J, Chintu C, et al. Clinical presentation, natural history, and cumulative death rates of 230 adults with primary cryptococcal meningitis in Zambian AIDS patients treated under local conditions. Postgrad Med J 2001;77:769-73 
53.
Lane M, McBride J, Archer J. Steroid responsive late deterioration in Cryptococcus neoformans variety gattii meningitis. Neurology 2004;63:713-4 
54.
Chen SC, Korman TM, Slavin MA, et al. Antifungal therapy and management of complications of cryptococcosis due to Cryptococcus gattii. Clin Infect Dis 2013;57:543-51 
55.
Newton PN, Thai lH, Tip NQ, et al. A randomized, double-blind, placebo-controlled trial of acetazolamide for the treatment of elevated intracranial pressure in cryptococcal meningitis. Clin Infect Dis 2002;35:769-72 
56.
Perfect JR, Dismukes WE, Dromer F, et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin Infect Dis 2010;50:291-322 
57.
Singh N, Huprikar S, Burdette SD, et al. Donor-derived fungal infections in organ transplant recipients: guidelines of the American Society of Transplantation, Infectious Diseases Community of Practice. Am J Transplant 2012;12:2414-28 
58.
Chen SC, Sorrell TC, Chang CC, et al. Consensus guidelines for the treatment of yeast infections in the haematology, oncology and intensive care setting, 2014. Intern Med J 2014;44:1315-32 
59.
Rapid advice: Diagnosis, prevention and management of cryptococcal disease in HIV-infected adults, adolescents and children. Geneva: World Health Organization; 2011 Dec 
60.
Chang CC, Sorrell T, Chen SC. Pulmonary cryptococcosis. Semin Respir Crit Care Med 2015;36:681-91 
61.
Flores VG, Tovar RM, Zaldivar PG, et al. Meningitis due to Cryptococcus neoformans: treatment with posaconazole. Curr HIV Res 2012;10:620-3 
62.
Gamaletsou MN, Sipsas NV, Kontoyiannis DP, et al. Successful salvage therapy of refractory HIV-related cryptococcal meningitis with the combination of liposomal amphotericin B, voriconazole, and recombinant interferon-gamma. Diagn Microbiol Infect Dis 2012;74:409-11 
63.
Pappas PG, Bustamante B, Ticona E, et al. Recombinant interferon- gamma 1b as adjunctive therapy for AIDS-related acute cryptococcal meningitis. J Infect Dis 2004;189:2185-91 
64.
Jarvis JN, Meintjes G, Rebe K, et al. Adjunctive interferon-gamma immunotherapy for the treatment of HIV-associated cryptococcal meningitis: a randomized controlled trial. AIDS 2012;26:1105-13 
65.
Jarvis JN, Meintjes G, Rebe K, et al. Adjunctive interferon-gamma immunotherapy for the treatment of HIV-associated cryptococcal meningitis: a randomized controlled trial. AIDS 2012;26:1105-13 
66.
Powderly WG, Finkelstein D, Feinberg J, et al. A randomized trial comparing fluconazole with clotrimazole troches for the prevention of fungal infections in patients with advanced human immunodeficiency virus infection. NIAID AIDS Clinical Trials Group. N Engl J Med 1995;332:700-5 
67.
Parkes-Ratanshi R, Wakeham K, Levin J, et al. Primary prophylaxis of cryptococcal disease with fluconazole in HIV-positive Ugandan adults: a double-blind, randomised, placebo-controlled trial. Lancet Infect Dis 2011;11:933-41 
68.
McKinsey DS, Wheat LJ, Cloud GA, et al. Itraconazole prophylaxis for fungal infections in patients with advanced human immunodeficiency virus infection: randomized, placebo-controlled, double-blind study. National Institute of Allergy and Infectious Diseases Mycoses Study Group. Clin Infect Dis 1999;28:1049-56 
69.
Makadzange AT, Ndhlovu CE, Takarinda K, et al. Early versus delayed initiation of antiretroviral therapy for concurrent HIV infection and cryptococcal meningitis in sub-saharan Africa. Clin Infect Dis 2010;50:1532-8 
70.
Bisson GP, Molefi M, Bellamy S, et al. Early versus delayed antiretroviral therapy and cerebrospinal fluid fungal clearance in adults with HIV and cryptococcal meningitis. Clin Infect Dis 2013;56:1165-73 
71.
Boulware DR, Meya DB, Muzoora C, et al. Timing of antiretroviral therapy after diagnosis of cryptococcal meningitis. N Engl J Med 2014;370:2487-98 
72.
Boulware DR, Meya DB, Muzoora C, et al. Timing of antiretroviral therapy after diagnosis of cryptococcal meningitis. N Engl J Med 2014;370:2487-98 
73.
Chang CC, Dorasamy AA, Gosnell BI, et al. Clinical and mycological predictors of Cryptococcosis-associated Immune reconstitution inflammatory syndrome (C-IRIS). AIDS 2013;27:2089-99 
74.
Gunthard HF, Aberg JA, Eron JJ, et al. Antiretroviral treatment of adult HIV infection: 2014 recommendations of the International Antiviral Society-USA Panel. JAMA 2014;312:410-25 
75.
McCarthy KM, Morgan J, Wannemuehler KA, et al. Population-based surveillance for cryptococcosis in an antiretroviral-naive South African province with a high HIV seroprevalence. AIDS 2006;20:2199-206 
76.
Chang CC, Dorasamy AA, Gosnell BI, et al. Clinical and mycological predictors of Cryptococcosis-associated Immune reconstitution inflammatory syndrome (C-IRIS). AIDS 2013;27:2089-99 
77.
Bicanic T, Harrison T, Niepieklo A, et al. Symptomatic relapse of HIV-associated cryptococcal meningitis after initial fluconazole monotherapy: the role of fluconazole resistance and immune reconstitution. Clin Infect Dis 2006;43:1069-73 
78.
Chang CC, Dorasamy AA, Gosnell BI, et al. Clinical and mycological predictors of Cryptococcosis-associated Immune reconstitution inflammatory syndrome (C-IRIS). AIDS 2013;27:2089-99 
79.
Bicanic T, Brouwer AE, Meintjes G, et al. Relationship of cerebrospinal fluid pressure, fungal burden and outcome in patients with cryptococcal meningitis undergoing serial lumbar punctures. AIDS 2009;23:701-6