What is new about somatosensory evoked potentials as neurological predictors of comatose survivors after cardiac arrest

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Rickettsia africae infection complicated with painful sacral syndrome in an Italian traveller returning from Zimbabwe

We report a case of Rickettsia africae infection complicated with painful sacral syndrome in an Italian traveller returning from Zimbabwe. The patient presented with fever, a tache noire on the left leg, and a neurological syndrome characterized by severe pain of the left leg, predominantly located in the left dorsal thigh and radiating to the calf; she had urinary retention and faecal incontinence. The diagnosis of R. africae was confirmed by polymerase chain reaction on a skin biopsy. The severe left leg pain persisted despite a complete course of doxycycline. A 4-month course of corticosteroids and the addition of carbamazepine was needed to achieve the control of pain. This case highlights the possibility of severe manifestations of R. africae infection and the possibility of a complex pathogenesis of the neurological syndrome, due perhaps to both the direct damage induced by R. africae and an immune-mediated mechanism

Validation of the peroneal nerve test to diagnose critical illness polyneuropathy and myopathy in the intensive care unit: the multicentre Italian CRIMYNE-2 diagnostic accuracy study

Objectives: To evaluate the accuracy of the peroneal nerve test (PENT) in the diagnosis of critical illness polyneuropathy (CIP) and myopathy (CIM) in the intensive care unit (ICU). We hypothesised that abnormal reduction of peroneal compound muscle action potential (CMAP) amplitude predicts CIP/CIM diagnosed using a complete nerve conduction study and electromyography (NCS-EMG) as a reference diagnostic standard. Design: prospective observational study. Setting: Nine Italian ICUs. Patients: One-hundred and twenty-one adult (≥18 years) neurologic (106) and non-neurologic (15) critically ill patients with an ICU stay of at least 3 days. Interventions: None. Measurements and main results: Patients underwent PENT and NCS-EMG testing on the same day conducted by two independent clinicians who were blind to the results of the other test. Cases were considered as true negative if both NCS-EMG and PENT measurements were normal. Cases were considered as true positive if the PENT result was abnormal and NCS-EMG showed symmetric abnormal findings, independently from the specific diagnosis by NCS-EMG (CIP, CIM, or combined CIP and CIM). All data were centrally reviewed and diagnoses were evaluated for consistency with predefined electrophysiological diagnostic criteria for CIP/CIM. During the study period, 342 patients were evaluated, 124 (36.3%) were enrolled and 121 individuals with no protocol violation were studied. Sensitivity and specificity of PENT were 100% (95% CI 96.1-100.0) and 85.2% (95% CI 66.3-95.8). Of 23 patients with normal results, all presented normal values on both tests with no false negative results. Of 97 patients with abnormal results, 93 had abnormal values on both tests (true positive), whereas four with abnormal findings with PENT had only single peroneal nerve neuropathy at complete NCS-EMG (false positive). Conclusions: PENT has 100% sensitivity and high specificity, and can be used as a screening test to diagnose CIP/CIM in the ICU

Neurophysiological investigations of hepatic encephalopathy: ISHEN practice guidelines

By studying neuronal activity through neuronal electrogenesis, neurophysiological investigations provide a functional assessment of the nervous system and, therefore, has been used for quantitative assessment and follow-up of hepatic encephalopathy (HE). The different clinical neurophysiological approaches can be classified depending on the function to explore and their sensitivity to HE. The reliable techniques are those that reflect cortical function, i.e., cognitive-evoked potentials (EPs) (P300 paradigm), electroencephalogram (EEG), visual EPs (latency > 100 ms) and somatosensory EPs (SEPs) (latency between 25 and 100 ms). Short-latency EPs (brainstem acoustic EPs, SEPs of a latency < 25 ms) are in principle insensitive to HE, but can disclose brainstem conduction deficits due to oedema. SEPs and motor EPs can disclose myelopathies. Because of its parallelism to the clinical examination, clinical neurophysiology can complement the neurological examination: (i) to provide evidence of HE in patients who have normal consciousness; (ii) to rule out, at least under some conditions, disturbances of consciousness due to other causes (e.g. drug-induced disturbances, non-convulsive status epilepticus) with the reservation that the mildest degrees of encephalopathy might be associated with an EEG pattern similar to that induced by drugs; and (iii) to demonstrate the worsening or, conversely improvement, of HE in the follow-up period

Does a combination of ≥2 abnormal tests vs. the ERC-ESICM stepwise algorithm improve prediction of poor neurological outcome after cardiac arrest? A post-hoc analysis of the ProNeCA multicentre study.

BACKGROUND Bilaterally absent pupillary light reflexes (PLR) or N20 waves of short-latency evoked potentials (SSEPs) are recommended by the 2015 ERC-ESICM guidelines as robust, first-line predictors of poor neurological outcome after cardiac arrest. However, recent evidence shows that the false positive rates (FPRs) of these tests may be higher than previously reported. We investigated if testing accuracy is improved when combining PLR/SSEPs with malignant electroencephalogram (EEG), oedema on brain computed tomography (CT), or early status myoclonus (SM). METHODS Post-hoc analysis of ProNeCA multicentre prognostication study. We compared the prognostic accuracy of the ERC-ESICM prognostication strategy vs. that of a new strategy combining ≥2 abnormal results from any of PLR, SSEPs, EEG, CT and SM. We also investigated if using alternative classifications for abnormal SSEPs (absent-pathological vs. bilaterally-absent N20) or malignant EEG (ACNS-defined suppression or burst-suppression vs. unreactive burst-suppression or status epilepticus) improved test sensitivity. RESULTS We assessed 210 adult comatose resuscitated patients of whom 164 (78%) had poor neurological outcome (CPC 3-5) at six months. FPRs and sensitivities of the ≥2 abnormal test strategy vs. the ERC-ESICM algorithm were 0[0-8]% vs. 7 [1-18]% and 49[41-57]% vs. 63[56-71]%, respectively (p < .0001). Using alternative SSEP/EEG definitions increased the number of patients with ≥2 concordant test results and the sensitivity of both strategies (67[59-74]% and 54[46-61]% respectively), with no loss of specificity. CONCLUSIONS In comatose resuscitated patients, a prognostication strategy combining ≥2 among PLR, SSEPs, EEG, CT and SM was more specific than the 2015 ERC-ESICM prognostication algorithm for predicting 6-month poor neurological outcome

The role of early electroclinical assessment in improving the evaluation of patients with disorders of consciousness

We all share the need to optimise the evaluation of patients with disorders of consciousness (DOC), given the high rate of misdiagnosis of vegetative state based on clinical examination. We believe that one way to do this is to optimise assessment from the early stages, in order to reduce discontinuity between the hospital and rehabilitation phases. While clinical observation remains the "gold standard" for the diagnostic assessment of patients with DOC, neurophysiological investigations (electroencephalography, short latency evoked potentials and event-related potentials) could help to further understanding of the pathophysiology underlying the state of unresponsiveness, differentiate coma from other apparently similar conditions (i.e., locked-in and locked-in-like syndromes), and potentially integrate prognostic evaluation with monitoring of the evolution of the clinical state. Moreover, these techniques have the considerable advantage of being available at the bedside. Discontinuity between the hospital and rehabilitation phases is rightly considered to be one of the critical points in the assessment of patients with DOC. In our view, a continuum of expert neurological assessment that begins with monitoring of the acute phase (focusing on evolution of primary brain damage and secondary complications) and follows through to the patient’s discharge from the intensive care unit (focusing on the pathophysiology of brain damage and prognostication based on clinical, neuroimaging and neurophysiological tests) could help to: i) optimise the rehabilitation programme according to the expectations of recovery; ii) provide a basis for comparison with subsequent periodic re-evaluations; iii) ensure uniformity of assessment regardless of the heterogeneity of care facilities; and iv) characterise a subset of patients who, showing discrepancies between neurophysiological tests and clinical status, are more likely to undergo unexpected recovery