Interictal autonomic changes in persons with epilepsy (PWE) on carbamazepine (CBZ) versus other anti-seizure drug monotherapy: A cross-sectional study

OBJECTIVE

Epilepsy is one of the most prevalent neurological conditions and carbamazepine is a commonly used anti-seizure drug (ASD), especially in developing nations. There are reports of carbamazepine causing atrioventricular conduction defects and autonomic dysfunctions and its implication in Sudden Unexpected Death in Epilepsy (SUDEP) is controversial. We planned this study to assess the effect of carbamazepine (CBZ) on autonomic function compared to other ASDs in persons with epilepsy.

METHODS

In this cross-sectional study, we assessed the sympathetic and parasympathetic autonomic functions in persons with epilepsy (PWE) on CBZ versus other anti-seizure monotherapy using tests of heart rate variability including its time-, frequency- and non-linear domains, heart rate response to deep breathing, valsalva maneuver, and blood pressure response to isometric handgrip.

RESULTS

Persons with epilepsy on CBZ monotherapy did not show a significant reduction in the time domain parameter SDRR compared to other ASDs used as monotherapy (mean ± SD, 38.04 ± 18.75 ms vs 44.37 ± 20.35 ms; p = 0.125). However, PWE on CBZ had significantly lower time-domain measurements including RMSSD (mean ± SD 31.95 ± 17.29 ms vs 42.02 ± 22.29 ms; p = 0.018), SDSD (mean ± SD 31.91 ± 17.26 ms vs 41.96 ± 22.27 ms; p 0.018), and pNN50 [median (IQR) 05.45(0.69-25.37) vs 16.38(2.32-36.83); p = 0.030]. Frequency domain measures of HRV, heart rate responses to deep breathing, valsalva maneuver and tilt-testing and BP responses to valsalva and tilt-testing were not significantly different between the groups.

CONCLUSION

The findings of our study indicate reduced parasympathetic activity in persons on CBZ monotherapy compared to other ASDs, which may pose risk of SUDEP. Carbamazepine may thus be avoided in those at risk of autonomic dysfunction and SUDEP.

Effectiveness of 3 months of rifampicin and isoniazid chemoprophylaxis for the treatment of latent tuberculosis infection in children

BACKGROUND/SETTING: Treatment for 3 months with rifampicin (R) and isoniazid (H) (3RH) for latent tuberculosis infection (LTBI), defined as an inappropriately positive tuberculin skin test with no clinical or x-ray evidence of disease, has been used locally since 1989. The efficacy of this regimen in children in the UK has only been studied indirectly. The long-term outcome of those children treated with 3RH, in the Chest Clinic of this high tuberculosis (TB) incidence district, has been studied to derive a more direct assessment of effectiveness.

METHODS

All children treated with 3RH for LTBI from 1989 to 2004 inclusive were matched with the local patient administration system (PAS), GP registration and local TB notification databases. Only those persons still registered locally on PAS, or locally GP registered were then checked for subsequent TB notification.

RESULTS

A total of 334 patients were identified, of whom 252 remained locally, with 82 lost to follow-up; 3 cases of clinical TB developed in the 252 (1.19%), with 3113 years observation (mean 12.35 years) giving 0.964/1000 person years (95% CI 0.199 to 2.816). Sensitivity analyses showed a 'best case' scenario of 0.727/1000 person years (95% CI 0.15 to 2.12), and if 10% of those lost to follow-up developed clinical TB of 2.66/1000 person years (95% CI 1.33 to 4.77).

CONCLUSIONS

Follow-up of those cases treated with 3RH, for a mean of 12.35 years, and over 3100 patient years observation, shows a rate of active TB of under 1/1000 patient years. This suggests that 3RH has very high efficacy when used to treat LTBI in children in the UK and compares favourably with the expected untreated TB rate.

Evaluation of the polymerase chain reaction analysis for diagnosis of falciparum malaria in Delhi, India

Plasmodium falciparum infections are frequently fatal if untreated and hence need to be diagnosed and treated early. Malaria diagnosis, with conventional Giemsa staining as a gold standard, has had several limitations. New rapid and accurate methods are needed for diagnosis. In this study, polymerase chain reaction (PCR) analysis specific for diagnosis of P. falciparum was evaluated. For the study, blood samples were collected from 310 patients suspected of having malaria. PCR analysis for P. falciparum from venous blood and at the same time Giemsa staining of thick and thin blood smears was done. A total of 160 (51.6 %) samples were positive for malarial parasite of which 63 (39.4 %) were positive for P. falciparum by Giemsa staining while 61 (38.1 %) were positive for P. falciparum by PCR analysis. Giemsa staining was time consuming, laborious and may give poor results in cases with low parasitaemia. The PCR analysis for P. falciparum was able to detect 3 cases of low parasitaemia missed initially on Giemsa staining, was 96.8 % sensitive, 100% specific but was very costly, needed a lot of practice and standardization and was time consuming. PCR analysis can be used to supplement the conventional Giemsa staining for reliable diagnosis of falciparum malaria especially in cases with low parasitaemia.

Evaluation of the direct acridine orange staining method and Q.B.C. test for diagnosis of malaria in Delhi, India

Conventional Giemsa stained peripheral blood smear examination for demonstration of malarial parasites remains the gold standard for diagnosis of malaria in developing endemic countries. However this technique is time consuming, requires training and may give poor results in cases with low parasitaemia. To overcome these problems and improve diagnostic accuracy two newer tests have been studied and compared with standard Giemsa staining. These are the wet mount fluorescence microscopy of Acridine Orange stained thin blood films (A.O.) and the Quantitative Buffy Coat technique (Q.B.C) for diagnosis of malaria. A.O. staining was found to be 97.5% sensitive and 100% specific for detection of all stages and species of malarial parasite. The Q.B.C assay was found to be 100% sensitive and 97.5% specific for diagnosis of malaria. A.O. staining was very fast and the species identification was easy once the staining was optimised. The Q.B.C. test required considerable amount of practice, costly equipment, however it was fast and in our study was found to be highly sensitive.