Hyponatremia as the Initial Presentation of Cryptococcal Meningitis After Liver Transplantation

A Conspectus of Euvolemic Hyponatremia, Its Various Etiologies, and Treatment Modalities: A Comprehensive Review of the Literature

Hyponatremia is the most prevalent electrolyte imbalance encountered among hospitalized patients, athletes, the elderly, patients with chronic ailments, postoperative patients, and a few asymptomatic individuals. Clinical manifestations of hyponatremia can be diverse, with characteristic neurological symptoms. Depending on in-depth medical history, physical examination (including volume status assessment), laboratory investigation, and drug history, patients can be classified broadly as undergoing hypervolemic, euvolemic, or hypovolemic hyponatremia. However, patients with hypervolemic hyponatremia often present with distinctive signs such as edema or ascites, and the clinical presentation of hypovolemic and euvolemic hyponatremia poses significant challenges for clinicians. The convolution in clinical manifestations of patients is due to the varied etiologies of euvolemic hyponatremia, such as syndrome of inappropriate antidiuretic hormone secretion (SIADH), adrenocortical insufficiency, hypothyroidism, psychogenic polydipsia, different classes of drugs (chemotherapeutics, antipsychotics, antidepressants), endurance exercise events, and reset osmostat syndrome (ROS). The management of hyponatremia depends on the rate of hyponatremia onset, duration, severity of symptoms, levels of serum sodium, and underlying comorbidities. Over the last decade, the clinical understanding of hyponatremia has been scattered due to the introduction of innovative laboratory markers and new drugs. This article will be a conspectus of all the recent advancements in the field of diagnosis, investigations, management, and associations of hyponatremia, along with traditional clinical practices. Subsequently, a holistic overview has been laid out for the clinicians to better understand and identify knowledge deficiencies on this topic.

Cryptococcus neoformans, a global threat to human health

BACKGROUND

Emerging fungal pathogens pose important threats to global public health. The World Health Organization has responded to the rising threat of traditionally neglected fungal infections by developing a Fungal Priority Pathogens List (FPPL). Taking the highest-ranked fungal pathogen in the FPPL, Cryptococcus neoformans, as a paradigm, we review progress made over the past two decades on its global burden, its clinical manifestation and management of cryptococcal infection, and its antifungal resistance. The purpose of this review is to drive research efforts to improve future diagnoses, therapies, and interventions associated with fungal infections.

METHODS

We first reviewed trends in the global burden of HIV-associated cryptococcal infection, mainly based on a series of systematic studies. We next conducted scoping reviews in accordance with the guidelines described in the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews using PubMed and ScienceDirect with the keyword Cryptococcus neoformans to identify case reports of cryptococcal infections published since 2000. We then reviewed recent updates on the diagnosis and antifungal treatment of cryptococcal infections. Finally, we summarized knowledge regarding the resistance and tolerance of C. neoformans to approved antifungal drugs.

RESULTS

There has been a general reduction in the estimated global burden of HIV-associated cryptococcal meningitis since 2009, probably due to improvements in highly active antiretroviral therapies. However, cryptococcal meningitis still accounts for 19% of AIDS-related deaths annually. The incidences of CM in Europe and North America and the Latin America region have increased by approximately two-fold since 2009, while other regions showed either reduced or stable numbers of cases. Unfortunately, diagnostic and treatment options for cryptococcal infections are limited, and emerging antifungal resistance exacerbates the public health burden.

CONCLUSION

The rising threat of C. neoformans is compounded by accumulating evidence for its ability to infect immunocompetent individuals and the emergence of antifungal-resistant variants. Emphasis should be placed on further understanding the mechanisms of pathogenicity and of antifungal resistance and tolerance. The development of novel management strategies through the identification of new drug targets and the discovery and optimization of new and existing diagnostics and therapeutics are key to reducing the health burden.

Association of Hyponatremia on Mortality in Cryptococcal Meningitis: A Prospective Cohort

Background

Sodium abnormalities are frequent in central nervous system infections and may be caused by cerebral salt wasting, syndrome of inappropriate antidiuretic hormone secretion, or medication adverse events. In cryptococcal meningitis (CM), the prevalence of baseline hyponatremia and whether hyponatremia adversely impacts survival is unknown.

Methods

We conducted a secondary analysis of data from 2 randomized trials of human immunodeficiency virus-infected adult Ugandans with CM. We grouped serum sodium into 3 categories: <125, 125-129, and 130-145 mmol/L. We assessed whether baseline sodium abnormalities were associated with clinical characteristics and survival.

Results

Of 816 participants with CM, 741 (91%) had a baseline sodium measurement available: 121 (16%) had grade 3-4 hyponatremia (<125 mmol/L), 194 (26%) had grade 2 hyponatremia (125-129 mmol/L), and 426 (57%) had a baseline sodium of 130-145 mmol/L. Hyponatremia (<125 mmol/L) was associated with higher initial cerebrospinal fluid (CSF) quantitative culture burden (P < .001), higher initial CSF opening pressure (P < .01), lower baseline Glasgow Coma Scale score (P < .01), and a higher percentage of baseline seizures (P = .03). Serum sodium <125 mmol/L was associated with increased 2-week mortality in unadjusted and adjusted survival analyses (adjusted hazard ratio, 1.87 [95% confidence interval, 1.26-2.79]; P < .01) compared to those with sodium 130-145 mmol/L.

Conclusions

Hyponatremia is common in CM and is associated with excess mortality. A standardized management approach to correctly diagnose and correct hyponatremia in CM needs to be developed and tested.

Severe hyponatremia as the presenting manifestation of primary empty sella syndrome

Severe hyponatremia is associated with neurological impairment and mortality. Furthermore, severe hyponatremia can be the first presentation of several diseases. Therefore, an appropriate investigation for the underlying causes of hyponatremia apart from the proper correction of sodium levels, might lead to a diagnosis of occult diseases.

Orthostatic hypotension as the initial presentation of disseminated cryptococcosis in a kidney transplant recipient

Background

Solid organ transplant recipients are immunocompromised and at risk for invasive viral, fungal, and bacterial pathogens. Cryptococcus neoformans is the third most common invasive fungal infection in transplant recipients, and the clinical presentation of Cryptococcus neoformans infection can vary widely. Cryptococcal disease can affect the brain, lungs, skin, or vasculature, and it is frequently disseminated. Meningitis typically presents with fever, headache, and altered mental status. Solid organ transplant recipients with cryptococcosis tend to have poorer outcomes than HIV patients with cryptococcosis.

Case presentation

In this case report, we describe the case of a 69 year-old man with a past medical history of a deceased donor kidney transplant who presented with severe orthostatic hypotension and was found to have disseminated cryptococcosis.

Conclusions

This case report emphasizes the importance of broadening the differential diagnosis in transplant recipients who present with non-specific chief concerns.

Availability of data and materials

No datasets were used in the preparing of this manuscript. All patient information comes from the electronic health record and authors personal care of this patient.

Fantastic yeasts and where to find them: the discovery of a predominantly clonal Cryptococcus deneoformans population in Saudi Arabian soils

Cryptococcus deneoformans is an opportunist yeast pathogen and causative agent of meningoencephalitis in humans. It is known to be mainly distributed in temperate climates. Most of our current understanding of this species has come from clinical isolates, leaving environmental populations largely unexplored. The Middle East remains one such underexplored area with no published study to date investigating cryptococcal diversity in soil. In this study, we identified 76 C. deneoformans isolates from a survey of 562 soil samples collected from six cities in Saudi Arabia. Multilocus sequence typing revealed the presence of two major sequence types (STs), ST160 (n = 63) and ST294 (n = 9), along with four singleton STs, three of which were novel. One novel ST, ST613, was likely a recombinant product between ST160 and ST294. Among the 76 isolates, 75 belonged to mating type (MAT)α while one isolate was MATa. Our analyses suggest that the Saudi Arabian C. deneoformans population likely reproduces both asexually and sexually in nature. Our study is the first to report the occurrence of C. deneoformans in a desert climate, representing a novel expansion to this species' currently known ecological niche.

Transmission of cryptococcosis by liver transplantation: A case report and review of literature

BACKGROUND

Cryptococcosis is a fungal infection caused by the yeast-like encapsulated basidiomycetous fungus of the Cryptococcus neoformans (C. neoformans) species complex. These fungi are ubiquitous in soil and bird droppings, and infection by them is an important global health concern, particularly in immunosuppressed patients, such as organ transplant recipients and those infected by the human immunodeficiency virus. The fungus usually enters the body through the respiratory tract, but extremely rare cases of infection acquired by transplantation of solid organs have been reported.

CASE SUMMARY

We report a case of disseminated cryptococcosis in a liver transplant recipient, diagnosed 2 wk after the procedure. The patient initially presented with fever, hyponatremia and elevated transaminase levels, manifesting intense headache after a few days. Blood cultures were positive for C. neoformans. Liver biopsy showed numerous fungal elements surrounded by gelatinous matrix and sparse granulomatous formations. Magnetic resonance imaging of the brain showed multiple small lesions with low signal in T2, peripheric enhancement and edematous halo, diffuse through the parenchyma but more concentrated in the subcortical regions. Treatment with amphotericin B for 3 wk, followed by maintenance therapy with fluconazole, led to complete resolution of the symptoms. The recipients of both kidneys from the same donor also developed disseminated cryptococcosis, confirming the transplant as the source of infection. The organ donor lived in a rural area, surrounded by tropical rainforest, and had negative blood cultures prior to organ procurement.

CONCLUSION

This case highlights the risk of transmission of fungal diseases, specifically of C. neoformans, through liver graft during liver transplantation.

Cryptococcal Meningoencephalitis Presenting as a Psychiatric Emergency

BACKGROUND

Organic conditions can often mimic neuropsychiatric disorders, leading to delays in diagnosis and treatment for the most vulnerable populations presenting to the emergency department (ED).

CASE REPORT

Here we discuss a case of cryptococcal meningoencephalitis seemingly consistent with psychosis on initial evaluation, and present strategies to recognize and treat this condition. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to the indolent time course of this disease, initial symptoms of altered mental status and personality changes may be attributed to drug use or psychiatric illness before more overt evidence for increased intracranial pressure and neurologic infection develops. It is important for emergency clinicians to maintain a high level of suspicion for this condition in at-risk patients and reassess them frequently during their ED visit.

Cryptococcemia in an HIV-negative patient with decompensated liver cirrhosis

BACKGROUND

Cryptococcal infections have been mostly associated with immunocompromised individuals, 80-90% of whom have been HIV-positive patients. Increasingly, cryptococcal infections are being reported in cirrhotic patients who are HIV-negative. The underlying immunologic defects in cirrhotic patients seem to play an important role in predisposing them to cryptococcosis and affecting their morbidity and mortality.

CASE PRESENTATION

We present a case of disseminated cryptococcosis in an HIV-negative patient with underlying cirrhosis, who had rapid worsening of his hyponatremia with renal failure and was unable to recover, despite aggressive measures.

CONCLUSION

Cryptococcus is a more common culprit of infections seen in cirrhotic patients than what it was previously known, and a high index of suspicion is required to diagnose these patients. Identification of poor prognostic factors, early diagnosis and intervention is crucial in the management of these patients.