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Guo et al. Diagnosis and treatment of cryptococcal meningitis

INTRODUCTION and diagnostic evidence. The CM has a hidden onset
and a slow course, mainly presenting the symptoms
Cryptococcal meningitis (CM) is the most common of increased intracranial pressure (headache,
cause of fungal meningitis worldwide. Globally, there nausea, vomiting, and disturbance of consciousness),
are approximately 957,900 new cases of CM each meningeal irritation sign (neck rigidity, Kernig sign and
year, and about 624,700 of them died. CM occurs Brudzinski sign). Patients with altered mental status
[1]
mainly in the acquired immunodeficiency syndrome have high mortality. [5-7]
(AIDS) crowd abroad. In China, CM is sporadic, mainly
in people without AIDS. In recent years, there is an Patients with typical symptoms of the meningeal
[6]
increasing trend for the incidence of CM as a result irritation are less than 20%. Optic nerve damage is the
of the wide application of antibiotic, hormone and most common among injury of cranial nerves caused
immune inhibitors, organ transplantation in China. In by intracranial hypertension (optic nerve, oculomotor
developing countries, up to 70% of CM lead to death nerve, abducens nerve, facial nerve, vestibulocochlear
eventually. The severity of disease and limited access nerve involvement). Forty percent of the patients with
[2]
to diagnostics and medications results in the high CM have visual involvement, including optic discedema
mortality of CM in resource-limited settings (RLS). and uveitis. [8-10] Second is the vestibulocochlear nerve
[1]
Early diagnosis and treatment is the key to reduce the damage. If there is parenchymal involvement, it would
morbidity and mortality. appear epilepsy seizures, hemiplegia, mental disorder,
ataxia, etc.
No symptoms, hardship to select pathogen or lack
of awareness in the early stages of the disease Imaging examination
make the diagnosis difficult, particularly in RLS. The Computed tomography (CT) and magnetic resonance
clinical manifestations and part of cerebrospinal imaging (MRI) has limited effect on the diagnosis, but it
fluid parameters such as fever, headache, high is necessary to find the complications (intracranial mass
intracranial pressure, high protein and low glucose in and hydrocephalus). Some professors divide the
[11]
[12]
cerebrospinal fluid (CSF) which are easily confused CM course into three periods. Acute phase: cerebral
with tuberculous meningitis. Substantial resources, edema is showed on CT or MRI. Brain parenchyma
such as hospitalization, intravenous antifungal therapy, presents punctate low-density lesions and Long T1,
access to lumbar punctures, and strict monitoring are long T2 signal area, it is similar to cerebral infarction,
required in the process of CM treatment. In this called “soap bubble damage” [12,13] which is caused by
[3]
review, we mainly describe the available diagnostic the expansion of the space (Robin Virchow) around
methods and management of CM without AIDS. the capillary. Subacute stage: Multifocal gelatinous
pseudocysts formed in the deep white matter on both
DIAGNOSE OF CRYPTOCOCCAL MENINGITIS sides of the cerebral hemispheres, basal ganglia,
thalamus and midbrain, etc. Chronic phase: intracranial
The diagnosis of the CM is dependent on the single or multiple rounds, oval and sheet, etc.,
medical history, clinical manifestations, imageological slightly higher or low density massive umbra, lesions
examination, cerebrospinal fluid parameters and surrounded by edema, may have mutual integration.
laboratory tests. Among them, laboratory tests are Enhanced scan shows multiple small nodules ring, it
the main methods to make a definite diagnosis. India is easy to be misdiagnosed as cerebral metastasis.
ink staining and fungal cultures are regarded as the Because of the correlation between CT/MRI and the
diagnostic gold standard. There is not much difference disease progression or cerebrospinal fluid pressure,
in diagnostic criteria of CM between patients with CT and MRI should be reviewed even if it was normal
or without human immunodeficiency virus (HIV). during the acute phase.
Merely for patients with advanced HIV, World Health
Organization (WHO) recomends early cryptococcal CSF parameter
antigen (CrAg) screening and treatment in 2011. [4] The typical characteristic of cerebrospinal fluid for
CM is high intracranial pressure (HICP) which is more
Medical history and clinical manifestation than 350 mmH O or up to more than 900 mmH O. The
2
2
The medical history of CM includes environment (the reason for HICP is that Cryptococcus hinder the CSF
contact history of pigeons) and susceptible population to pass through the arachnoid villi which obstructs
with risk factors including long term treatment of the CSF circulation channel. Furthermore, the
[14]
immunosuppressant, broad-spectrum antibiotics accumulation of capsular polysaccharide in arachnoid
and glucocorticoids, HIV infection and patients with villi and subarachnoid spaces contributes to fluid
immunodeficiency is important for providing initial clues retention by increasing the osmolarity of the CSF and
250 Neuroimmunology and Neuroinflammation ¦ Volume 3 ¦ November 18, 2016