Brainstem dysfunction in variegate porphyria

Barraza, Gonzalo; Serranová, Tereza; Herrero, Carmen; Casanova‐Mollá, Jordi; To‐Figueras, Jordi; Herranz, Javier Cuesta; Valls‐Solé, Josep

doi:10.1002/mus.23367

Cited by 5 publications

(3 citation statements)

References 40 publications

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“…To establish whether or not unilateral response latency values for R1, R2, R2c and SBR were abnormal, we used reference normative values obtained from our healthy subjects, which did not differ from those previously published elsewhere from our own laboratory [54], [30]. For the TBR, the reference values were 12.8 ms for R1, 38 ms for R2 and 40 ms for R2c.…”

Section: Methodsmentioning

confidence: 99%

Abnormal Control of Orbicularis Oculi Reflex Excitability in Multiple Sclerosis

et al. 2014

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Brain lesions in patients with multiple sclerosis may lead to abnormal excitability of brainstem reflex circuits because of impairment of descending control pathways. We hypothesized that such abnormality should show in the analysis of blink reflex responses in the form of asymmetries in response size. The study was done in 20 patients with relapsing-remitting multiple sclerosis and 12 matched healthy subjects. We identified first patients with latency abnormalities (AbLat). Then, we analyzed response size by calculating the R2c/R2 ratio to stimulation of either side and the mean area of the R2 responses obtained in the same side. Patients with significantly larger response size with respect to healthy subjects in at least one side were considered to have abnormal response excitability (AbEx). We also examined the blink reflex excitability recovery (BRER) and prepulse inhibition (BRIP) of either side in search for additional indices of asymmetry in response excitability. Neurophysiological data were correlated with MRI-determined brain lesion-load and volume. Eight patients were identified as AbLat (median Expanded Disability Status Scale–EDSS = 2.75) and 7 of them had ponto-medullary lesions. Nine patients were identified as AbEx (EDSS = 1.5) and only 2 of them, who also were AbLat, had ponto-medullary lesions. In AbEx patients, the abnormalities in response size were confined to one side, with a similar tendency in most variables (significantly asymmetric R1 amplitude, BRER index and BRIP percentage). AbEx patients had asymmetric distribution of hemispheral lesions, in contrast with the symmetric pattern observed in AbLat. The brainstem lesion load was significantly lower in AbEx than in AbLat patients (p = 0.04). Asymmetric abnormalities in blink reflex response excitability in patients with multiple sclerosis are associated with lesser disability and lower tissue loss than abnormalities in response latency. Testing response excitability could provide a reliable neurophysiological index of dysfunction in early stages of multiple sclerosis.

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Section: Methodsmentioning

confidence: 99%

Abnormal Control of Orbicularis Oculi Reflex Excitability in Multiple Sclerosis

et al. 2014

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“…Sensory involvement is usually less severe and may have a stocking‐glove, a proximal bathing‐suit or a patchy and variable distribution, sometimes leading to suspicion of a conversion disorder (Crimlisk, 1997 ; Pischik & Kauppinen, 2009 ; Simon & Herkes, 2011 ). Cranial nerve involvement (IIIrd, VIIth, Xth nerve) has been reported in up to 75% of patients with porphyric neuropathy (Barraza et al., 2012 ; Pischik & Kauppinen, 2009 ; Simon & Herkes, 2011 ).…”

Section: When To Consider Acute Porphyrias In Neurological Patientsmentioning

confidence: 99%

Acute porphyrias – A neurological perspective

et al. 2021

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Acute hepatic porphyrias (AHP) can cause severe neurological symptoms involving the central, autonomic, and peripheral nervous system. Due to their relative rarity and their chameleon-like presentation, delayed diagnosis and misdiagnosis are common. AHPs are genetically inherited disorders that result from heme biosynthesis enzyme deficiencies and comprise four forms: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA-dehydratase porphyria (ALADP). Depending on the clinical presentation, the main differential diagnoses are Guillain-Barré syndrome and autoimmune encephalitis. Red flags that could raise the suspicion of acute porphyria are neurological symptoms starting after severe (abdominal) pain, in association with reddish urine, hyponatremia or photodermatitis, and the presence of encephalopathy and/or axonal neuropathy. We highlight the diagnostic difficulties by presenting three cases from our neurological intensive care unit and give a comprehensive overview about the diagnostic findings in imaging, electrophysiology, and neuropathology.

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“…[6] Hyponatraemia may result from the syndrome of inappropriate antidiuretic hormone secretion (SIADH), renal tubular dysfunction and the administration of hypotonic intravenous fluids such as dextrose. [7] Rarely, brainstem dysfunction may occur in response to transient ischaemia or hyponatraemia, [8] as may cerebral infarction. [9] Acute psychotic states are occasionally observed.…”

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confidence: 99%