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Correspondence: When an article is eligible for submission of Correspondence, a link to the response form is available within the full-text article. You must be a current subscriber who has activated the online portion of your subscription in order to send a Correspondence. Any reader can read published Correspondence.
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Correspondence:Correspondence published:
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Reply to Letter to the Editor
- W Allen Hauser, Arturo Carpio (1 April 2003)
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Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis
- Ambar Chakravarty (1 April 2003)
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Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis
- Jorge Burneo (21 March 2003)
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Reply to Letter to the Editor
- Larry E Davis (20 March 2003)
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Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis
- ALbert C Cuetter (20 March 2003)
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W Allen Hauser Columbia University New York, Arturo Carpio
Send Correspondence to journal:
wahauser{at}optonline.net W Allen Hauser, et al.
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We thank the correspondents for their comments. We addressed two important clinical features of the acute disease. [1] The first was conceptual in that the seizures occurring in the context of acute presentation of NC should be considered "acute symptomatic" and in contrast to other "acute symptomatic seizures" in this condition; the acute brain changes may persist for months. [2] The second related to management: we suggest that anticonvulsant medication be continued in these patients until the inflammatory response disappears from CT scan. In this study as in a previous study of NC, we find that antihelminthic treatment did not influence outcome in seizures. [3] We agree that antihelminthic agents do not prevent seizures, although other authors disagree. [4, 5] We also agree with Dr. Cuetter that there are reasons for using antihelminthic agents and that this treatment is controversial and the efficacy unproven. [6] There may also be unpleasant side effects. [7] Dr. Del Brutto has questioned diagnostic criteria used for the current study. The diagnostic criteria mentioned were based on our previous publication, where we provided criteria to ascertain differential diagnoses. [8] We excluded one patient with tuberculoma and another one with brain metastasis. We are aware of the previously published diagnostic recommendations. [9] Although this criteria is not necessarily discriminating for assessment of an acute case in Ecuador. "Absolute criteria" include: 1) Histologic demonstration of the parasite from biopsy of central nervous system tissue; 2) Visualization of subretinal parasites; or 3) Evidence of cystic lesions with a visible scolix on imaging. Only the latter criterion is appropriate for inclusion in our study. Biopsy for diagnostic purposes would generally not be done in Ecuador and is best discouraged in even more sophisticated medical settings. Ocular cysticercosis is rare. "Major" criteria include: 1) Evidence of lesions suggestive of neurocysticercosis on neuroimaging studies including cystic lesions or enhancing lesions without visualization of scolex; 2) Positive EITB tests for the detection of anticysticercersus antibodies; or 3) Resolution of lesions after treatment with antihelminthic agents. The first of these was an entrance criterion for our study. EITB is not readily available in the diagnostic laboratories in Ecuador, and while sensitivity and specificity are said to be high in individuals with multiple lesions, it is not high (60%) in people with solitary lesions. The relation between treatment and resolution of lesions and treatment is controversial and are not in our opinion a valid criterion. [3] In addition, this logic seems circular. We did not present this as a study of treatment of NC, only of factors that influence seizure recurrence in a longitudinal observational study. Others and we feel there are no definitive studies to date showing effectiveness of antihelminthic agents in human neurocysticercosis. [3, 10] We agree with Dr.Chakravarty that residual calcifications do not necessarily concur with an identified seizure focus. We have also observed edema around calcifications, which warrants further study. As to point 6, we found that 10 of 30 patients treated with antihelminthic agents had residual calcifications compared to 13 of 41 not treated. (Odds Ratio 1.1, 95% Confidence interval 0.4 to 2.9). While not significant, the findings do not support antihelminthic treatment reducing calcification. References: 1. Carpio A, Hauser WA: Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis. Neurology 2002;59:1730-1734. 2. Commission on Epidemiology and Prognosis of the International League against Epilepsy. Guidelines for epidemiological studies on epilepsy. Epilepsia 1993;34:592-596. 3. Carpio A, Santillan F, Leon P, Flores C, Hauser WA. Is the course of neurocysticercosis modified by treatment with antihelminthic agents? Arch Int Med 1995;155:1982-1988. 4. Del Brutto OH, Santibáñez R, Noboa CA, Aguirre R, Diaz E, Alarcón TA. Epilepsy due to neurocysticercosis: análisis of 203 patients. Neurology 1992;42:389-392. 5. Sotelo J, Del Brutto OH. Review of neurocysticercosis. Neurosurg. Focus 2002;12:1-6. 6. Cuetter AC, Andrews RJ: Intraventricular neurocysticercosis: A series of 18 consecutive patients and review of the literature. J. Neurosurg (serial online), 2001;12 page 1-7 Available at www. Neurosurgery.org/focus/jun02/12-6-nsf-toc-htmi 7. Caplan LR, Estanol B, Mitchel WG, Loyo-Varela M. How to manage patients with neurocysticercosis. Eur Neurol 1997;37:124-131. 8. Carpio A, Placencia M, Santillán F, Escobar A. Proposal for a new classification of neurocysticercosis. Can J Neurol Sci 1994;21:43-47. 9. Del Brutto OH, Rajshekhar V, White AC, Tsang VCW, Nash T, Takayanagui OM, et al. Proposed diagnostic criteria for neurocysticercosis. Neurology 2001; 57: 177-183. 10. Salinas R, Prasad K. Drugs for treating neurocysticercosis (tapeworm infection of the brain). Cochrane Database Syst Rev. 2000;(2):CD000215. |
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Ambar Chakravarty Vivekamanda Institute of Medical Sciences Calcutta India
Send Correspondence to journal:
saschakra{at}yahoo.com Ambar Chakravarty
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I read with interest the article by Carpio and Hauser [1] in which they prospectively and critically examine the risk factors for seizure recurrence in patients with neurocysticercosis and evaluate the role of antihelmenthic therapy with albendazole in modifying the seizure recurrence rate. Solitary neuro-cysticercosis (NCC) is a common underlying pathology in patients presenting with localization related epilepsy (acute symptomatic seizures) in India. Based on clinical experience over the past 15 years, a few points need highlighting: 1. I would agree with the observation of Carpio and Hauser [1] that persistence of CT abnormality is the single most important factor contributing to seizure recurrence even while patients are on adequate dosage of anticonvulsants. 2. In a small proportion of cases (10%), the cysts actually increase in size on follow-up CT and this increase in size is almost invariably heralded by the occurrence of breakthrough seizures even while continuing on antiepileptic drugs. [2] 3. Though the vast majority of the single NCC lesions disappear overtime sometime, such lesions (4%) have been found to re-appear at the original site. Such "re-appearance" of the "disappearing" lesion, almost always causes seizures to recur even if anticonvulsants were continued. [2] 4. A proportion of solitary NCC lesions do calcify during the process of healing and solitary calcific nodules (SCN) remain as potential epileptogenic foci. Though not found to be significant as a positional risk factor for seizure recurrence by Carpio and Hauser, [1] these SCN do produce problems in clinical management of patients specially regarding determining the duration of antiepileptic therapy. 5. It is common for patients with first seizure (partial, complex partial and partial with secondary generalization) to have only one or more calcific spots on the CT which purely on epidemiological ground seem to be healed (dead) neurocysticercus lesion. [3] Often focal edema is evident around them if scanned soon after the seizure. Interestingly, these individuals never had seizures when they cysts were active or in a "dying" stage. 6. In India, opinions vary regarding the necessity of giving albendazole therapy to patients with solitary cysticercus lesions. In general, the author prefers not to use albendazole and treats such cases only with anticonvulsants. Albendazole is used only when cysts do not regress after 6 months, in enlarging cysts and in few patients with "disappearing-re-appearing" lesions. However, no controlled trial has been performed. The proponents of routine albendazole therapy believe that such therapy may reduce the chance of calcification in the lesions during healing. Carpio and Hauser should examine if there was any difference in the incidence of calcification of cysts in the patients who received albendazole and those who did not. References: 1. Carpio A, Hauser WA. Prognosis of seizure recurrence in patients with newly diagnosed neurocysticercosis. Neurology 2002;59:1730-1734. 2. Mukherjje A, Chakravarty A. Partial and complex partial seizures. In Singhal B S, Nag D, Ed. Epilepsy in India 2000; Indian Epilepsy Association:P50-75. 3. Murthy J M K, Reddy V S. Clinical characteristics, seizure spread patterns and prognosis of seizure associated with a single small cerebral calcific CT lesion. Seizure 1988;7:153. |
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Jorge Burneo UAB Epilepsy Center Birmingham AL
Send Correspondence to journal:
jburneo{at}uab.edu Jorge Burneo
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I read with interest the article by Carpio & Hauser. [1] The authors attempted to identify potential risk factors for seizure recurrence in patients with neurocysticercosis (NCC) after an initial seizure and also to compare the prognosis of patients with acute symptomatic seizures following treatment, with and without anticysticidal therapy. Based on their findings and methodology, conclusions about risk factors may be amenable, but conclusions regarding prognosis of epilepsy based on different treatments may not. When the authors defined a case of NCC, they did not differentiate between conditions that can imitate parenchymal cystic pattern in neuroimaging studies, especially in an endemic region for other parasitic and fungal conditions. In addition, the usual low-grade gliomas also need to be considered particularly if the abnormality persisted in follow-up studies. The criteria used by the authors' [2] do not appear to be helpful for this study and I would recommend them to base their definitions on recently published criteria for the diagnosis of NCC. [3] The assignment was not random, (as mentioned) and it was completely biased because it was based on the neurologist's judgment, which placed the patient on a particular treatment due to his or her clinical picture when presented to the hospital. Ethical issues need to be considered when a study of this type is conducted, and due to the non-randomized characteristics of this study, conclusions regarding seizure recurrence would not be recommended. The authors contradict themselves when they conclude that persistence of abnormalities in a follow-up CT appear to be predictive of seizure recurrence after mentioning that anticysticidal therapy does not appear to avoid that. It is well known that anticysticidal medication does reduce the lifetime of an active parenchymal cyst. It could be inferred that the abnormalities initially active on neuroimaging studies would degenerate after treatment. Sixty percent of their patients had a single transitional or degenerative cyst, which does not indicate if albendazole was effective, since those cysts may have had degenerated on their own. References: 1. Carpio A, Hauser WA. Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis. Neurology 2002;59:1730-1734. 2. Carpio A, Placencia M, Santillan F, Escobar A. Proposal for a new classification of neurocysticercosis. Can J Neurol Sci 1994;21:43-47. 3. Del Brutto OH, Rajshekhar V, White AC, Tsang VCW, Nash T, Takayanagui OM, et al. Proposed diagnostic criteria for neurocysticercosis. Neurology 2001; 57: 77-183. |
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Larry E Davis New Mexico VA Health Care System Albuquerque NM
Send Correspondence to journal:
LEDavis{at}unm.edu Larry E Davis
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The article by Carpio and Hauser [1] and the accompanying commentary [2] focused on the benefit of treating all patients with seizures from intraparenchymal neurocysticercosis with antihelminthic drugs. This clinical presentation of intraparenchymal cysts and seizures as the symptomatic presentation occurs in the large majority of patients with neurocysticercosis. [3] The Carpio and Hauser study found antihelminthic therapy did not improve seizure control or other outcomes in their patients. Thus, the argument by Dr. Cuetter that treatment with antihelminthic drugs would kill all active, live intraparenchymal cysts and prevent subsequent seizures from future cyst degeneration was not substantiated. I agree with Dr. Cuetter that some patients with neurocysticercosis not discussed in my commentary do require antihelminthic therapy. Occasional patients with neurocysticercosis develop giant parenchymal, spinal, meningeal, intraventricular or ocular cysts and present with other neurologic complaints such as headaches, altered mental status, focal neurologic signs, and visual loss. [3] These patients require treatment with albendazole along with possible surgery to remove the cyst or to place a CSF shunt. [4] References: 1. Carpio A, Hauser WA: Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis. Neurology 2002;59:1730-1734. 2. Davis LE: Neurocysticercosis and seizures: Avoiding the cost of anhelminthic treatment. Neurology 2002:59:1669. 3. White AC Jr. Neurocysticerosis: A major cause of neurologic disease worldwide. Clin Infect Dis 1997;24:101-115. 4. Garcia HH, Evans CAW, Nash TE, et al. Clin Microbiol Rev 2002;15:747-756. |
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ALbert C Cuetter Texas Tech Universite Health Sciences Center El Paso TX
Send Correspondence to journal:
albert.cuetter{at}ttuhsc.edu ALbert C Cuetter
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We read with interest the article on prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis. [1] Carpio and Houser emphasize that the risk of seizure recurrence following and acute episode of neurocysticercosis is not influenced by antihelminthic treatment. The Editorial also suggests that treatment with antihelminthic drugs is expensive and can be avoided. [2] In El Paso, Texas we treat inflammatory (degenerating, involutional, transitional, colloid) cysts with antihelminthic drugs not to "reduce the incidence of recurrent seizures" or to "shorten the duration of provoked seizures" or to "shorten the time to cyst disappearance." We treat patients with symptomatic inflammatory cysts to kill larvae in active, live cysts seen or not seen on neuroimaging. [3,4, 5] If not treated, these active cysts will eventually become inflammatory and symptomatic. In addition antihelminthic treatment will destroy active intraventricular cysts prone to produce obstruction of CSF flow with consequent acute hydrocephalus which requires emergent ventriculostomy. [4,5] Therefore, we believe that treatment with antihelminthic drugs is necessary even if such treatment does not significantly improve seizure outcome. References: 1. Carpio A, Hauser WA: Prognosis for seizure recurrence in patients with newly diagnosed neurocysticercosis. Neurology 2002;59:1730-1734. 2. Davis LE: Neurocysticercosis and seizures: Avoiding the cost of anhelminthic treatment. Neurology 2002:59:1669. 3. Cuetter AC, Garcia-Bobadilla J, Guerra LG, Martinez FM, Kaim B: Neurocysticercosis, focused on Intraventricular Disease. Clin Infect Dis 1997; 24:157-164. 4. Cuetter AC, Andrews RJ: Intraventricular Neurocysticercosis. In Gagandeep S, Prabhakar S: Taenia solium Cysticercosis from Basic to Clinical Science. CAB International (UK) 2001 Chapter 20 pp 199-210. 5. Cuetter AC, Andrews RJ: Intraventricular neurocysticercosis: A series of 18 consecutive patients and review of the literature. J. Neurosurg (serial online) 2001;12:1-7. Available at www. Neurosurgery.org/focus/jun02/12-6-nsf-toc-htmi |
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