Cysticercosis is common in developing countries. Reports from China demonstrate prevalence rates of 0.06%, which may climb to 9.83% in some provinces. It was estimated that around 0.37 million people with cysticercosis live in China[9]. Meanwhile, the relationship between cerebral cysticercosis and stroke is well established previously. The incidence of stroke in neurocysticercosis varies from 2.0 to 11.8% [4, 10]. It has been mostly reported that cerebral cysticercosis is associated with ischemic, hemorrhagic strokes mainly referring to SAH were relatively rare. SAH have been noted in subarachnoid cerebral cysticercosis and have been associated with cerebral aneurysms in some cases[11–15]. The main etiology of SAH is aneurysm, non-aneurysmal SAH associated with cerebral cysticercosis is extremely rare. Only 5 patients have been reported in Table 1.
Table 1
Non-aneurysmal SAH caused by cerebral cysticercosis
Report
|
Sex/
age
|
Clinical symptoms
|
Imaging
finding
|
CSF
Analysis
|
Medication
|
Outcome
|
1.Sawhneyet al.
1998
|
M/10y
|
headache, nausea, vomiting, and partial seizures
|
left parietal SAH
multiple cysts
|
NA
|
Albendazole steroids
|
No
improvement
|
2.Tellez-Zentenoet al.
2003
|
F/32y
|
headache, dysarthria ,hemiparesis, psychomotoragitation
|
SAH
|
WBC: 3/ml
Glucose:55mg/dL
Proteins:33mg/dL
|
Albendazole steroids
|
improvement
|
3.Tellez-Zentenoet al.
2003
|
M/34y
|
headache, nausea, vomiting, diplopia
gait disorder, psychomotor agitation, CNSimpairment
|
SAH
|
WBC: 107/ml (97%L)
Glucose: 19 mg/dL
Proteins: 695 mg/dL
|
Albendazole
steroids
|
improvement
|
4.Violaet al.
2011
|
F/39y
|
severe headache
|
SAH around the left Sylvian fissure
|
RBC:18/ml (78% L, 5% E) WBC:20/ml
Glucose: 88mg/dL protein: 28 mg/dL
|
Dexamethasone
albendazole
|
fully recovered
|
5.Cardenaset al.
|
F/38y
|
headache ,vomiting, blurred vision.
Meningeal signs and papilledema
|
SAH
hydrocephalus
cysts
|
WBC:147/ml ( 86%L)
Glucose: 1 mg/dL
Proteins: 222 mg/dL
|
Prednisone albendazole
|
improvement
|
6.This study
|
M/49y
|
headache, nausea, vomiting, weakness in the limb, hoarseness, dysphagia
|
Hydrocephalus
cysts
|
WBC:592/ml ( 67%L)
RBC:0/ml
Glucose:30 mg/dL
Proteins:178 mg/dL
|
Dexamethasone
Albendazole
|
improvement
|
NA: information not available; CSF: cerebrospinal fluid; L: lymphocytes; E: Eosinophils. |
Among the 5 included case, the ages ranged from 10 to 39 (30.6 ± 11.8). Three patients (60%) were female, two patients (40%) were male, headache predominated in 5 (100%) and blurred vision in 2 (40%) patients. Other symptoms mainly were movement disorder, nausea and vomiting. Most patients presented with epileptic seizures[16, 17], but our case did not. A review showed over 50% of patients with subarachnoid cerebral cysticercosis have imaging evidence of vasculitis[18]. But in our patient, no one finding in neuro-imaging studies was the presence of inflammatory aneurysm. Observation to be seen clearly is that patients with non-aneurysmal SAH associated with cerebral cysticercosis mainly predominates in younger adults having fewer classic cardiovascular risk factors compared to patients with stroke non-associated with cerebral cysticercosis. In clinical practice, aneurysms are considered first in young patients with subarachnoid hemorrhage. That’s indisputable. Because of aneurysmal SAH is a subtype of nontraumatic cerebrovascular disease, which account for 3–5% of strokes and approximately 85% of the subarachnoid hemorrhage[19].
As described previously, in the early stage of cerebral cysticercosis, a large number of larvas enter the systemic circulation of host, causing widespread infection of brain tissue along with high fever, headache, intracranial pressure increased. Nevertheless, at this time the brain CT lack of typical imaging changes. As we all know, two types of cysts are inclined to develop in the brain tissue: cysticercus cellulosae and cysticercus racemosus.
Cysticercus racemosus, varying in size from 4-12cm, tend to grow in the basal subarachnoid spaces and induce inflammatory comprising chronic meningitis. The pathogenesis of inflammatory in neurocysticercosis is not clear. Cysts will shrink in 2–5 years and form calcium deposits which could block third ventricle, the fourth ventricle, and midbrain aqueduct causing hydrocephalus. Cysts in basal subarachnoid space produce dense exudate and eventually form calcification. The density of dense exudate in the intermediate stage is lower than that of calcification, but higher than that of normal brain tissue and cerebrospinal fluid. The authors think that it is likely to be close to the density of acute hemorrhage. Because these exudates are in subarachnoid space, they are likely to be misdiagnosed as subarachnoid hemorrhage.
Strict inclusion criteria were used in the literature review, those did not report sufficient information to categorize them as aneurysmal or non-aneurysmal would be excluded. The literatures indicated that the non-aneurysmal SAH in these five cases was caused by cerebral cysticercosis[12, 14, 20, 21]. Magnetic resonance imaging (MRI) or cerebral angiograms did not show any evidence of aneurysms or vascular malformations. So, we classify them as non-aneurysmal. All cases of SAH were confirmed by CT, the misdiagnosis experience of our case gave us a reflection on whether there were misdiagnoses of SAH in the above five cases. Then, we turned our attention to CSF analysis, CSF examination is a reliable auxiliary method for the diagnosis of SAH, especially for suspected SAH, but only a case showed the number of red blood cells in the CSF increased[12], information of other cases about red blood cells was not available, Therefore, we believe that the four cases of SAH were suspicious[14, 20, 21] and more evidence is needed to further confirm.
There may be several reasons for the misdiagnosis: Firstly, the patient is young without cardiovascular risk factors, accompanied by headache, nausea and vomiting. Combined with the imaging findings of the patient, it is easy to be confused with aneurysmal SAH. Second, when the larva gain easily access to brain, The density of dense exudate in the intermediate stage is lower than that of calcification, but higher than that of normal brain tissue and cerebrospinal fluid, there might be meningitis in initial stage, for example, pandy test in CSF was positive, confirmatory evidence for Cerebral cysticercosis is difficult to find. Finally, comprehensive analysis ability of physician is low, and the medical history is not careful enough to obtain, this patient had a history of cysticercosis 30 years ago, there is no relevant description of medical history in the patient's medical record.
In conclusion, Cerebral cysticercosis is an important cause of neurological diseases that spread in endemic areas. The presentation of the disease is pleomorphic and requires a combination of clinical evaluation, imaging, and laboratory investigation. Furthermore, patients with cysticercosis must be systematically treated to avoid recurrence.