Stanley C. Igwe is a Consultant Neuro-psychiatrist, Clinical fellow in Clinical Neurophysiology and Epileptology at the Federal Teaching Hospital (FETHA) and Ebonyi State University, Abakaliki, Nigeria
Epilepsy is a common neurologic condition that affects approximately 50 million people worldwide, of whom 80% reside in developing countries. The World Health Organization (WHO) considers epilepsy to be one of the most cost-effective chronic conditions to treat, since recent studies have shown that up to 70% of newly diagnosed cases can be successfully managed with inexpensive antiepileptic drugs (AEDs). However, of the approximately 40 million people with epilepsy living in developing countries, an estimated 90% do not receive appropriate treatment.[3, 4] Adequate treatment is hindered by cultural attitudes, poor health system infrastructure, inadequate resources, and limited access to AEDs.
Epilepsy care in developing countries usually consists of first-generation AEDs prescribed by nonphysician health care workers, who have limited access to electroencephalography (EEG), neuroimaging, serum drug level monitoring, and specialist referral. Given these practical limitations, we investigated the diagnostic accuracy and therapeutic efficacy of epilepsy management in a tertiary referral center in Nigeria, in order to identify whether limited resources should be directed toward broadening access to diagnostic facilities and/or specialists.
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Epilepsy is one of the most common and serious brain disorders worldwide. The condition has serious physical, psychological, social, and economic consequences for patients and their families. Although epilepsy is a treatable condition for which relatively cheap medication is available, the diagnosis and care of epilepsy in developing countries remains a challenge due to limited resources.
We conducted the present study to assess potential causes of misdiagnosis and mistreatment in a referral center in northeastern Nigeria. Our results capture the difficulties encountered when treating patients with epilepsy in developing countries, where inadequate access to EEG, CT brain scans, and magnetic resonance imaging (MRI) limits definitive diagnosis of epileptic syndromes, and subsequently impacts the appropriateness of therapy. Even at the tertiary-care level, CT scanners are available in only 71% of low-income countries, and MRI capacity is even more limited at 30%. Resources are even more constrained among African nations, with 69% possessing CT scanners and 21% having MRI facilities. The burden imposed by resource limitation is worsened by the guidelines for care of epileptic patients in developing countries explicitly recommending against the use of EEG for routine diagnosis and treatment of epilepsy. Ideally, the choice of AED for each patient should be based on seizure type and/or syndrome as well as the individual person's needs. Unfortunately, in most developing countries, both the choice and supply of drugs are limited. In Nigeria, the range of AEDs/anticonvulsants on the Essential Drug List is limited to the first-generation AEDs, namely carbamazepine, diazepam, clonazepam, ethosuximide, magnesium sulfate, paraldehyde, phenobarbital, phenytoin sodium, and sodium valproate. In our study, only three first-generation AEDs were prescribed: CBZ, PB, and VPA. The newer generation AEDs are very scarce and extremely expensive, if available at all. Because of poor availability of AEDs, some authors have argued that the nonavailability of AEDs is the most important obstacle to the care of people with epilepsy in developing countries.
The majority of patients in our study had no EEG recording and were diagnosed with generalized epilepsy. Conversely, 67.1% who had EEG recording had EEG features indicative of partial epilepsy. Specific diagnoses (juvenile myoclonic epilepsy; rolandic epilepsy) were made only in patients who underwent an EEG recording. It is therefore likely that in a relevant number of our patients who did not have a concomitant EEG recording, the epileptic syndrome may have been erroneously classified. In contrast, a previous study conducted among 1,250 persons with epilepsy in Sri Lanka found that routine EEG confirmed the clinical diagnosis in the majority of cases. However, the seizure classification in patients in our study who had EEG was similar to the studies conducted in Sri Lanka and Nigeria, which employed a more structured data collection.[17, 18] Our study also indicates that in addition to an accurate clinical evaluation, which remains the key instrument for classifying epileptic seizures, EEG represents an extremely important tool for a correct syndromic categorization of epilepsy.
Furthermore, we found that 13% of clinically diagnosed patients had normal EEG readings. Although a normal EEG does not exclude a diagnosis of epilepsy because >40% of patients with epileptic disorders may have one normal interictal EEG, this percentage falls dramatically to 8% with a series of EEG studies and appropriate activating procedures, particularly sleep. This finding may also be an indication that some of the clinically diagnosed epilepsy may well be cases of nonepileptic seizures (NESs). This latter position is supported by the fact that repeated and prolonged recording, in addition to sleep EEG recording, was employed to increase sensitivity in these patients. Where such activation procedures fail to reveal epileptiform discharges in clinically diagnosed cases, the possibility of NESs cannot be ruled out. Moreover, it has been found that 20–30% of those attending tertiary referral centers with refractory epilepsy do not in fact have epilepsy, with the most common differential diagnoses being dissociative seizures and syncope. This could mean that without EEG, a number of clinical epilepsy diagnoses may actually be cases of NES and that these patients are therefore inadvertently exposed to AEDs with concomitant side effects and high rate of treatment failure.
An accurate diagnosis of epilepsy type is essential for selecting the most appropriate AEDs to manage the syndrome. A misdiagnosis may lead to inappropriate treatment that might even induce paradoxical seizure aggravation. In our study, an increase in seizure frequency occurred only in those patients treated with carbamazepine monotherapy, a drug that is known to potentially worsen idiopathic generalized epilepsy. However, when patients on CBZ with seizure remission and those who had their seizures aggravated or unchanged were compared separately in the populations with partial and generalized seizures, the differences were not statistically significant (Table 5). Caution should be applied in interpreting these data, as seizure aggravation in generalized epilepsy was seen in only one patient and the data may not be suitably powered to yield an accurate result. Nevertheless, in cases of epilepsy without a defined syndromic classification, a broad spectrum antiepileptic drug such as valproate or phenobarbital is thought to be more appropriate. In a developing country such as Nigeria, the challenge of appropriately managing epilepsy is further compounded by limited availability of specialist physicians and later-generation AEDs. In the Federal Neuro-Psychiatric Hospital, physicians are limited to first-generation AEDs such as phenobarbital, phenytoin, carbamazepine, and sodium valproate, with phenobarbital being the most cost-effective. Epilepsy surgery is not available. The lack of options for epilepsy care is compounded by the poor socioeconomic status of our study population. Despite the fact that the cost of brain CT scan (<100 US dollars) and EEG recording are subsidized by the hospital, only one patient (0.2%) had a CT brain and 76 (20.4%) received an EEG. The majority of affected individuals are of low socioeconomic status and cannot afford expensive drugs and diagnostic tests that are not listed on the National Essential Drug and Diagnostic Test Lists, and unlikely to be covered by the National Health Insurance Scheme (NHIS).
Table 5. Seizure outcome of patients on carbamazepine with partial or generalized epilepsy
| ||Clinical diagnosis, n (%)|
|Seizure remission||Seizure aggravation|
|EEG diagnosis|| || |
|Partial||44 (80)||3 (75)|
|Generalized||11 (20)||1 (25)|
|p = 0.8|| || |
In conclusion, our study demonstrates that the diagnosis and treatment of epilepsy in Nigeria remains a challenge, mainly due to limited access to diagnostic tests and the narrow range of AEDs available. Resources should be more properly directed toward increasing access to diagnostic facilities and newer generation AEDs. Because the scope of the NHIS is largely determined by the drugs and diagnostic tests covered in the National Essential Drug and Diagnostic Test Lists, widening the range of AEDs and diagnostic tests on these lists to include newer generation AEDs and EEG is key to increasing access to treatment.