Tablet-based electroencephalography diagnostics for patients with epilepsy in the West African Republic of Guinea

BACKGROUND AND PURPOSE

Epilepsy is most common in lower-income settings where access to electroencephalography (EEG) is generally poor. A low-cost tablet-based EEG device may be valuable, but the quality and reproducibility of the EEG output are not established.

METHODS

Tablet-based EEG was deployed in a heterogeneous epilepsy cohort in the Republic of Guinea (2018-2019), consisting of a tablet wirelessly connected to a 14-electrode cap. Participants underwent EEG twice (EEG1 and EEG2), separated by a variable time interval. Recordings were scored remotely by experts in clinical neurophysiology as to data quality and clinical utility.

RESULTS

There were 149 participants (41% female; median age 17.9 years; 66.6% ≤21 years of age; mean seizures per month 5.7 ± SD 15.5). The mean duration of EEG1 was 53 ± 12.3 min and that of EEG2 was 29.6 ± 12.8 min. The mean quality scores of EEG1 and EEG2 were 6.4 [range, 1 (low) to 10 (high); both medians 7.0]. A total of 44 (29.5%) participants had epileptiform discharges (EDs) at EEG1 and 25 (16.8%) had EDs at EEG2. EDs were focal/multifocal (rather than generalized) in 70.1% of EEG1 and 72.5% of EEG2 interpretations. A total of 39 (26.2%) were recommended for neuroimaging after EEG1 and 22 (14.8%) after EEG2. Of participants without EDs at EEG1 (n = 53, 55.8%), seven (13.2%) had EDs at EEG2. Of participants with detectable EDs on EEG1 (n = 23, 24.2%), 12 (52.1%) did not have EDs at EEG2.

CONCLUSIONS

Tablet-based EEG had a reproducible quality level on repeat testing and was useful for the detection of EDs. The incremental yield of a second EEG in this setting was ~13%. The need for neuroimaging access was evident.

Intravenous immunoglobulin therapy in the treatment of BK viremia and nephropathy in pediatric renal transplant recipients

Polyoma BKVN is a significant cause of allograft dysfunction and loss in renal transplant recipients. Reduction in immunosuppression is accepted as first-line therapy to decrease viral load and prevent allograft injury and dysfunction. We report our experience with persistent BKV after reduction in immunosuppression followed by successful clearance of BKV in three pediatric renal transplant recipients and histological resolution of BKVN in a fourth patient following therapy with IVIG. Once BKV was detected, immunosuppression was reduced and BKV was monitored until clearance was achieved. All four patients were given IVIG in a dose of 2 g/kg. Allograft function remained stable in all patients. Early routine screening for BKV allows early intervention to prevent the development of BKVN and permanent allograft damage. While immunosuppression reduction is a logical first-line therapy, second-line therapy is not well established. IVIG seems to be an effective treatment for persistent BKV after reduction in immunosuppression and for BKVN and can therefore be considered as a therapeutic option in these patients.

Changes in calcium homoeostasis in patients undergoing liver transplantation: effects of a single infusion of pamidronate administered pre-operatively

Bone turnover, bone loss and fracture risk increase after liver transplantation. It has been postulated that peri-operative administration of a bisphosphonate might prevent bone loss and reduce fracture rate. We studied the effects of a single pre-operative dose of pamidronate on biochemical parameters of skeletal metabolism in the first month after liver transplantation. In a randomized, single-blind study, six of 12 patients with chronic liver disease received 60 mg of pamidronate intravenously on a single occasion 1-30 days before transplantation. Six other patients undergoing transplantation received no pamidronate. We measured serum calcium, phosphate, albumin, bone-specific alkaline phosphatase, plasma parathyroid hormone and tartrate-resistant acid phosphatase before pamidronate infusion and at frequent intervals during the first 30 post-operative days. In treated patients, plasma parathyroid hormone increased 12-fold over baseline values and remained elevated in comparison with baseline at days 26-30; serum calcium and phosphate fell significantly, returning to normal at around day 14 post-operatively. There were no significant changes in any parameter in the untreated group. No changes in bone formation or resorption markers were observed in either group. The large increase in plasma parathyroid hormone concentrations in the treated group is probably secondary to the fall in serum calcium. The magnitude of the increase is much greater than that seen after pamidronate infusion in other patient groups. The lack of change in, or correlation of, serum calcium and plasma parathyroid hormone in the untreated group suggests that additional factors release calcium from bone after liver transplantation, presumably by increasing bone resorption.

Clinical reactogenicity of intradermal bacille Calmette-Guérin vaccination

Clinical, microbiological, and immunologic responses were evaluated in volunteers vaccinated intradermally with bacille Calmette-Guérin (BCG). Most volunteers (98%) developed ulcerative lesions that drained for a mean +/- SE of 4.3 +/- 0.29 weeks. Mycobacterial DNA was detected by a polymerase chain reaction-based amplification technique in biopsy specimens from BCG ulcers 2 weeks after vaccination and in blood specimens 3 days after vaccination. Mycobacteria were cultured from ulcer drainage 2 months after vaccination, demonstrating a prolonged potential risk of contact spread of the vaccine strain. The duration of ulcer drainage was inversely correlated with prevaccination lymphoproliferative (r = -0.515; P < .002) and interferon gamma (r = -0.841; P < .002) responses specific to mycobacteria and directly correlated with postvaccination increases in lymphoproliferative (r = 0.498; P < .002) and interferon gamma (r = 0.688; P < .02) responses specific to mycobacteria. These results demonstrate the clinical reactogenicity of BCG and the potential risk of contact spread of the vaccine strain and suggest that clinical reactogenicity is a trade-off for the induction of protective mycobacterial immunity.

New cell surface marker of the rat floor plate and notochord

Regionally expressed cell surface molecules are thought to mediate contact-dependent interactions that regulate pattern formation and axon pathfinding in the developing vertebrate central nervous system (CNS). We recently isolated monoclonal antibody (mAb) CARO 2 through a screen for positional markers in the developing rat CNS. Between embryonic day (E)11.5 and E13, mAb CARO 2 specifically labels both the floor plate and notochord in the developing spinal cord. In contrast to the distribution of several well-characterized ventral midline markers, mAb CARO 2 labeling is restricted to the apical portion of the floor plate and the outer surface of the notochord. The anterior limit of mAb CARO 2 immunoreactivity corresponds to the midbrain/hindbrain border. Floor plate labeling persists throughout embryogenesis, whereas notochord labeling is not detectable after E13. During later stages of embryonic development (E16-E20) apically restricted floor plate labeling is present only in the rostral spinal cord. In postnatal rats, mAb CARO immunoreactivity is not present in any region of the CNS. Immunoblot analyses show that mAb CARO 2 recognizes an epitope on a 28-kD protein that is enriched in the floor plate, transiently expressed during embryogenesis, and membrane-associated. Consistent with the latter result, mAb CARO 2 labels the surfaces of floor plate cells. These findings suggest that the CARO 2 antigen is a new cell surface marker of the floor plate and notochord which may participate in neural cell patterning and/or axon guidance in the developing rat spinal cord.

Gastrointestinal histoplasmosis presenting as hematochezia in human immunodeficiency virus-infected hemophilic patients

Two hemophiliacs infected with human immunodeficiency virus (HIV) presented with hematochezia secondary to gastrointestinal involvement with Histoplasmosis capsulatum. In one patient who was already receiving fluconazole, the diagnosis was obscured. Both patients responded to amphotericin B followed by intraconazole, with no recurrence of bleeding.

Rapid protein determinations on ultrafiltrates prepared for free phenytoin quantification

Ultrafiltration techniques for the separation of bound and free ligand are dependent on minimal amounts of protein-bound drug leakage through the membrane devices. A dye-impregnated test strip protein assay (Chemstrip-9) provides a rapid, visual assessment of membrane protein leakage. The test strips are sensitive to 200 mg/L of albumin in ultrafiltrates and do not react with as much as 4 mg/L of phenytoin.