CEREBRAL CYSTICERCOSIS IN CHILDREN
Prof. Dr. Allie Moosa SOUTH AFRICA

O YE WHO BLIEVE EAT OF THE GOOD THINGS WHEREWITH WE HAVE PROVIDED YOU, AND RENDER THANKS TO ALLAH IF IT IS HE WHOM YE WORSHIP. HE HATH FORBIDDEN YOU ONLY CARRION AND BLOOD AND SWINE FLESH AND THAT WHICH HATH BEEN IMMOLATED TO (THE NAME OF ) ANY OTHER THAN ALLAH. BUT HE WHO IS DRIVEN BY NECESSITY, NEITHER CRAVING NOR TRANSGRESSING, IT IS NO SIN FOR HIM. LO!ALLAH IS FORGIVING, MERCIFUL. S 2:V 172, 173) FORBIDDEN UNTO YOU (FOR FOOD) ARE CARRION AND BLOOD AND SWINE FLESH.. (S5:V4)

HE HATH FORBIDDEN FOR YOU ONLY CARRION, AND BLOOD AND SWINE FLESH AND THAT WHICH HATH BEEN IMMOLATED IN THE NAME OF ANY OTHER THAN ALLAH, BUT HE WHO IS DRIVEN THERETO, NEITHER CRAVING NOR TRANSGRESSING, LO!THEN ALLAH IS FORGIVING, MERCIFUL. (S16:V115)

INTRODUCTION

Cysticercosis is the most common parasitic disease in the world affecting the central nervous system. It is caused by the larval stage of Taenia solium, the pork tape worm. Man is normally the definitive host of Taenia solium and becomes infected by eating inadequately cooked pork containing embryos. These embryos develop into the adult tape worm in the intestine. The gravid proglotticls are passed in the stool liberating viable eggs which are usually eaten by pigs as the intermediate host. The ova develop into embryos or oncospheres in the pig's stomach and penetrate the intestinal mucosa to lodge in muscle, brain, eye and other tissues. The cycle is complete when man eats pork containing the embryos.

Cysticercosis is a systemic infestation which occurs when man becomes the intermediate host. This results from ingesting food or soil containing tape worm eggs or from auto-infestation via the fecal-oral route. The egg shell is digested in the stomach and releases the oncospheres which then lodge in various tissues of the body, but especially the brain. The parenchymal cysts in the brain elicit an intense inflammatory reaction that subsides when the organism dies at about 18 months after infection.

Cerebral cysticercosis (CC) is prevalent throughout the world but is especially common in Mexico, central and southern Asia, eastern Europe, the Far East and southern Africa. There are several reports in the literature of cerebral cysticercosis but most of these deal mainly with adults in whom epilepsy, encephalopathy and onbstructive hydrocephalus are the main clinical manifestations1,2. This report describes our experience of children with cerebral cysticercosis.

PATIENTS

Between January 1979 and January 1982, 28 children with CC were seen at King Edward VIII Hospital, Durban, RSA. There were 12 males and 16 females. The ages ranged from 3 - 14 years with a mean of 9 years. Twenty-seven of the children were African and 1 'Coloured'.

DIAGNOSIS

The diagnosis of CC was made in any child who had unexplained fits and/or unexplained encephalopathy or meningoencephalitis, together with either a positive indirect haemagglutination test against cysticercal antigen (IHA) in blood and/or cerebrospinal fluid (CSF) or a characteristic computed tomographic scan (CT) of the brain, or both. The CT scan was considered to be positive for cerebral cysticercosis if any of the following occurred singly or in combination2,3.

1. Multiple small intra-paranchymal calcified lesions with or without a vicinity reaction detected by contrast.
2. Focal low density areas with peripheral enhancement with contrast.
3. Large cystic lesions which enhance in a ring-fashion with the administration of contrast.

CLINICAL FEATURES

The symptoms at presentation are listed in Table 1. Twenty-one (74%) children presented with convulsions, 11 (41%) with headache, 4 (15%) with vomiting and 6 (19%) with focal signs (mainly hemiplegia). One child had paraplegia from spinal cysticercosis.

The patients were classified into 4 separate clinical categories (Table 2). Of the 28 patients, 13 (48%) presented with epilepsy, 7 (26%) with the syndrome of raised intracranial pressure (as judged clinically); 4 (15%) with meningo-encephalitis, 1 (4%) with paraplegia due to spinal cysticercosis (who had CC as well, defined by CT scan); and 3 (7%) were non-classifiable. Patients in the non-classifiable group included one who had severe headache only; 1 loss of consciousness and 1 progressive dementia, spasticity and myoclonic jerks which was shown to be due to subacute sclerosing paraencephalitis (SSPE) (high CSF and blood measles titres). At autopsy he was found to have both SSPE and CC.

INVESTIGAT1ONS

The investigations included routine CSF examination, CSF and serum IHA, blood eosinophil count, skull radiograph. and CT scan.

Blood eosinophilia (absolute count of > 400/cumm) occured in 8 of 11 patients in whom this documented. The mean eosinophil count was 783/cumm with a range of 420-1245.

Cerebrospinal fluid pleocytosis (Table 3) (range 8-5121cumm) was present in 7 patients who presented with either meaningo-encephalitis or the syndrome of raised intracranial pressure. In 4 patients there was a predominant lymphocytosis (range 8-3481cumm), in 2 a predominant polymorpholeucocytosis (106-156/cumm) and in 1 an initial polymorph predominance was replaced by a lymphocytosis. The CSF protein was elevated in 4 patients (0.53 - 1.28 g/L) and normal in the other 3 (0.32 - 0.40 g/L). The CSF glucose was normal in all cases with a mean of 3.2 mmol/L.

Skull radiographs were available in 27 cases; of these 9 showed calcification and 4 evidence raised intracranial pressure.

The IHA (Table 4) was done in blood and CSF in 23 children. Of these, the test was positive in both blood and CSF in 12 cases. Both tests were negative in 3 cases. In 3 cases the blood was positive and the CSF not done, and in one blood was positive and CSF negative, and in another the CSF was positive and blood negative. Thus the blood and/or CSF was positive in 87% of the children.

CT scans (Table 5) were performed in 22 of the cases, and of these 11 showed calcification only 4 focal areas of low density and 7 both. There was a good correlation between the clinical presentation and the CT findings. Of the 11 patients who had calcification only, 6 had epilepsy, one headache only, 1 paraplegia from spinal cysticercosis, one had loss of recent memory and one SSPE and cysticercosis. Only 1 patient had evidence of raised intracranial pressure. On the other hand, 8 of those with evidence of active or dying lesions (as judged by focal areas of decreased density) had meningo-encephalitis or the syndrome of raised intracranial pressure; the other 3 had epilepsy (these had calcified lesions as well). CT scan and the IHA test (Table 6) were both available in 16 patients. Of these 10 children had a positive CT scan and a positive blood and CSF IHA tests. One had a positive blood IHA test and positive CT scan; another a positive CSF IHA test and positive CT scan. In 3 children the CT scan was positive, but both the CSF and blood IHA test were negative. All of these 3 children had calcified lesions only; one of these had concomitant SSPE and died. However, autopsy revealed active cysticercosis as well as calcified lesions. In only 1 child was the CT scan negative when the blood IHA was strongly positive with a titre of 1/2560. This child had meningo-encephalitis with papilloedema and CSF pleocytosis. It is possible that he may have had another reason for his meningo-encephalitis.

TREATMENT AND OUTCOME

None of our patients had any surgical intervention. Patients who presented with epilepsy were well-controlled on anticonvulsant drugs. Five of the 7 patients who presented with the syndrome of raised intracranial pressure were given dexamethasone. The other 2 had no treatment. All 7 patients improved over a pariod of 2-3 weeks. Four patients with meningo-encephalitis all improved spontaneously. Only 1 child died, he had SSPE as well..The mortality was thus 3%. In contrast the morbidity amongst our patients was 60%, which was due to epilepsy in 48% and motor deficit in 19% of patients (4 children had hemiplegia and 1 had paraplegia). The long-term outcome is unknown in this group of patients because prolonged follow-up was not possible.

COMMENT

This report describes our experience of cerebral cysticercosis in 28 children and demonstrates the value of CT scanning and serology in the diagnosis of cysticercosis. Cerebral cysticercosis is probably much more common in our environment than is appreciated. Between 1971 and 1978 only 7 cases of cysticercosis were recorded amongst children admitted to King Edward VIll Hospital. However, over a period of 3 years between 1979 and 1981 we saw 28 children with CC. This apparent increase in incidence is largley due to the introduction of CT scanning and to increased medical awareness of this condition.

The most common mode of presentation was epilepsy (48%), followed by the syndrome of raised intracranial pressure (26%) and meningo-encephalitis (15%). The high frequency of epilepsy in cysticercosis has been reported by others 1,5-7. No case of hydrocephalus due to obstruction to the flow of CSF by cysticerci was seen amongst our patients. Racemose meningitis. which is a grave complication of cysticercosis and associated with a poor outcome was also not encountered in our series.

Before the introduction of CT scanning the diagnosis of cysticercosis was difficult. Our results show the value of CT scanning in the diagnosis of cysticercosis. Serology is also of considerable value although it is less sensitive and less specific than CT scanning. The CT scan was positive in 95% of our patients and the IHA test for cysticercosis in 87% of the cases. The CT scan and IHA test were both positive in 80% of the patients. Two of the 3 patients with false-negative serology had calcified lesions only on CT scan. Negative or weakly positive titres have been reported in patients with chronic or inactive disease as reflected by the presence of calcified lesions only8,9. Other workers have also found serology of value and serum IHA has been reported to be positive in 87.5% of cases11.

The disadvantage of the IHA test is that a tape worm infestation confined to the intestine can give a false-positive reaction. Cross-reactions also occur with antibodies against Echinococcus and other cestodes'o. False-positive reactions occur in the CSF when the VIDRL is positive. In practice, cross-reactions with hydatid disease is not a practical problem amongst our patients since echinococcal infections are rare in our environment. A study by Proctor et al9 found that 2% of asymptomatic African blood donors had a positive IHA test. This rate rose to 5% when the subjects were selected from a hospital population with no evidence of intestinal or systemic cysticercal infection. The serum 1HA was positive in 17% of subjects who had intestinal taeniasis. The aforementioned data is of particular relevance to our study since their subjects were drawn from the same geographical area as our patients.

A complement fixation test (CFT) is also available and is widely used in South America. It has been reported to be positive in 64-89% of cases8-11. This test also cross-reacts with cestodes and treponemal antigens. Attempts have been made to compare the sensitivities of the 1HA and CFT 8-12, but the results are not conclusive since the number of patients in the studies were too small. Further purification and concentration of the antigenic fractions should provide a more sensitive and specific test that can be used for routine diagnostic purposes.

Peripheral eosinophilia occured in 74% of cases in whom it was measured. We did not find it of much diagnostic value because patients often had other parasitic infestations. The CSF was not examined for the presence of eosinophils in our study but other studies have shown it to be the only helpful finding in the CSF 13-15. In these studies eosinophilic pleocytosis was reported in 16% to 40% of cases of cysticercosis. The differential diagnosis of CSF eosinophilia is limited and includes other CNS parasites, CNS lymphoma, carcinomatosis, cocciodal meningitis and lymphocytic chorio-meningitis16. In areas of the world where cysticercosis is endemic and CT scan not readily available, the presence of CSF eosinophilic pleocytosis would be quite helpful in the diagnosis of cysticercosis.

The skull radiographs were positive in 50% of the cases with 33% showing calcification suggestive of cysticercosis. The other 17% showed non-specific signs of raised intracranial pressure only.

The mortality amongst our patients was only 3%, in contrast to the much higher morbidity of 60%. The morbidity was mainly due to epilepsy (48%) and motor handicaps (19%). The finding is confirmed by other studies2,13.17,18. Earlier reports indicated a bad prognosis for patients with cysticercosis with mortality being as high as 40%14. This was largely due to the frequent use of surgery to extirpate the cysts in the 3rd and the 4th ventricles19,20. Recently the use of surgery has been restricted mainly to the insertion of shunts for obstructive hydrocephalus and the outcome in these cases is quite good2. Our data also show that surgery is very rarely needed.

The long term outcome of our patients is unknown, but nonetheless some authors have found that epilepsy improves over a period of years and may stop completely even without treatment2-19.

Medical treatment has a limited role in the management of cerebral cysticercosis. Dexamethasone may be used for the relief of cerebral oedma in encephalitic cases 20. The treatment of intestinal worms has no effects on cysticercosis. Recently praziquantel has been found to be cysticercidal in experimental animals21. There has been as yet no systematic double-blind study to show the effectiveness of this drug. Ultimately the most important method of combating this disease is prevention. Improved sanitation and careful meat inspection can reduce the incidence of cysticercosis. Human taeniasis must be reduced if cysticercosis is to be prevented.

REFERENCES

1. DIXON HBF, LIPSCOMB FIVI. "Cysticercosis: An analysis and Follow-up of 450 cases." Med Res Council Spec. Rep. 1961: 299: 1-58.
2. McCORMICK GF, ZEE CHI-SINGH, HEIDEN T. "Cysticercosis Cerebri Review of 127 cases." Arch Neurol 1982; 39: 534-539.
3. SANTIN G, VARGUS J. "Roentgen study of cysticercosis of the central nervous system." Radiology 1966; 86: 520-528.
4. CARBAJAL JR, PALACIOS, E, AZAR-KIA B, et al. "Radiology of cysticercosis of the central nervous system including computed tomography" Radiology 1975; 125: 127-131.
5. LOMBARDO L, MATEOS JH. "Cerebral cysticercosis in Mexico." Neurology 1961; 11: 824-828.
6. GARBUTT GA, COURVILLE CB. "Cerebral cysticercosis." Bull Los Angeles Neurol Soc. 1967; 32: 6-16.
7. ZEE CS, SEGALL HD, MILLER C, et al. "Unusual neuroradiological features of intracranial cysticercosis." Radiology 1980; 137: 397-407.
8. MAHAJAN RC, CHOPRA JS, CHITHARA NC. "Comparative evaluation of indirect hemagglutination and complement fixation tests in serodiagnosis of cysticercosis." Indian J Med. Red. Res. 1975; 63: 121-125.
9. PROCTOR EM, POWELL ST, ELSDON-DEW R. "Theserological diagnosis of cysticercosis." Ann Trop Med. Parasitol 1966; 60: 146-151.
10. RY1DZEWSKI A, CHISHOLM ES, KAGAN IG. '"Comparison of serological tests for human cysticercosis by indirect hemagglutination, indirect immunofluorescent antibody and agar gel precipitin tests." J Parasitol 1978; 28: 832-842.
11. BELTRAN P. "Cysticercosis of the nervous system: 111. Clinical findings and treatment." J Neurosurg 1962; 19: 641-643.
12. BIAGI FF, NAVARRETE F, AZELIA P, et al. "Estudio de tres reacciones serologicas en el diagnostico de la cisticercosis." Rev Med Hosp Gen Mex City 1961; 24: 501-508.
13. PUPO PP. "Cysticercosis of the nervous system: clinical manifestations." Rev. Neuropsychiatry 1964; 27: 70-82.
14. STEPPIEN L. "Cerebral cysticercosis in Poland: clinical symptoms and operative results in 132 cases." J Neurosurg 1962; 19: 505-513.
15. ARSENI C, SAMITCA DC. "Cysticercosis of the brain." Br Med J 1957; 1: 494-497.
16. KLIBERSKI T. "Eosinophils in the CSF" Ann Intern Med 1979; 91: 70-76.
17. GRISOLIA JS, WIEDERHOLT WC. "CNS cysticercosis." Arch Neurol 1982; 39: 440-544.
18. ARSENI C, CRISTENSEN A. "Epilepsy due to cerebral cysticercosis," Epilepsy 1972; 13: 253-258.
19. DIXON I-IBF, HARGREAVES WH. "Cysticercosis (Tsolium): A further ten years clinical study covering 284 cases." 0 J Med 1944; 13: 107.212.
20. CABIESES F. "Cysticercosis of the nervous system: 111. Clinical findings and treatment." J Neurosurg 1962; 19: 643-649.
21. THOMAS H, GONNERT R. "Theefficacy of praziquantel against experimental cysticercosis and hydatidosis." Z Parasitenkcl 1978; 55: 165-179.

TABLE 1
CEREBRAL CYSTICERCOSIS IN CHILDREN

TABLE 2
CEREBRAL CYSTICERCOSIS IN CHILDREN

TABLE 3
CEREBRAL CYSTICERCOSIS IN CHILDREN

TABLE 4
CEREBRAL CYSTICERCOSIS IN CHILDREN

TABLE 5
CEREBRAL CYSTICERCOSIS IN CHILDREN

TABLE 6
CEREBRAL CYSTICERCOSIS IN CHILDREN