RESUMO
OBJECTIVE: To study the effects of trains of repetitive transcranial magnetic stimulation (rTMS) over the motor cortex in patients with chronic migraine (CM) with or without medication overuse (MOH). SUBJECTS AND METHODS: Thirty-two patients (CM [n = 16]; MOH [n = 16]) and 16 healthy volunteers (HVs) underwent rTMS recording. Ten trains of 10 stimuli each (120% resting motor threshold) were applied over the left motor cortex at 1 Hz or 5 Hz in random order. The amplitude of motor evoked potential (MEP) was evaluated from electromyographic recording in the first dorsal interosseous muscle. The slope of the linear regression line for the 10 stimuli for each participant was calculated using normalized data. RESULTS: rTMS-1 Hz had a normal depressive effect on MEP amplitude in all groups. rTMS-5 Hz depressed instead of potentiating MEP amplitudes in MOH patients, with a significantly different response from that in HVs and CM patients. The slope of the linear regression of MEP amplitudes was negatively correlated with pain intensity in CM patients, and with the duration of overuse headache in MOH patients. CONCLUSIONS: This different plastic behaviour suggests that MOH and CM, despite exhibiting a similar clinical phenotype, have different neurophysiological learning processes, probably related to different pathophysiological mechanisms of migraine chronification.
Assuntos
Transtornos da Cefaleia Secundários/fisiopatologia , Transtornos de Enxaqueca/fisiopatologia , Córtex Motor/fisiopatologia , Plasticidade Neuronal/fisiologia , Adulto , Dor Crônica/fisiopatologia , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Estimulação Magnética TranscranianaRESUMO
OBJECTIVES: To study the effects of a standard acute medication withdrawal program on short-term cortical plasticity mechanisms in patients with medication overuse headache (MOH). METHODS: Thirteen patients with MOH and 16 healthy volunteers underwent repetitive transcranial magnetic stimulation (rTMS) over the left motor cortex; in patients with MOH, recordings were performed before and after a 3-week medication withdrawal program. Ten trains of 10 stimuli each (120% resting motor threshold) were delivered at 1 Hz or 5 Hz in two separate sessions in a randomised order. Motor evoked potential (MEP) amplitudes were measured from the right first dorsal interosseous muscle and the slope of the linear regression line from the first to the tenth stimuli was calculated for each participant. RESULTS: All subjects exhibited MEP amplitude inhibition in response to 1 Hz rTMS. Alternatively, the 5-Hz trains of rTMS inhibited rather than potentiated MEP amplitudes in patients with MOH. The physiological potentiating effect of 5 Hz rTMS on MEP amplitudes was restored after drug withdrawal and in proportion with the percentage reduction in monthly headache days in patients with MOH. CONCLUSIONS: The results suggest that acute medication withdrawal normalises brain responses in patients with MOH. Clinical improvements after medication withdrawal may reflect the reversal of neurophysiological dysfunction. Accordingly, medication withdrawal should be offered to patients with MOH as early as possible in order to prevent the development of more pronounced alterations in brain plasticity.
Assuntos
Transtornos da Cefaleia Secundários/fisiopatologia , Córtex Motor/fisiopatologia , Plasticidade Neuronal/fisiologia , Síndrome de Abstinência a Substâncias/fisiopatologia , Sinapses/fisiologia , Adulto , Potencial Evocado Motor/efeitos dos fármacos , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Córtex Motor/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Plasticidade Neuronal/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Estimulação Magnética TranscranianaRESUMO
Breast imaging screening during lactation poses a real clinical challenge, especially in high-risk patients. We presented the case of a 34-year-old BRCA1-mutated woman showing marked, asymmetric background parenchymal enhancement on the right breast suspicious for malignancy in the context of annual screening magnetic resonance imaging. The patient revealed that she was still occasionally breastfeeding her two-year-old child only from right side. Ultrasound evaluation reported typical benign lactational findings on the right enhancing breast. An in-depth understanding of expected/ physiologic breast changes during lactation and an accurate clinical-radiological correlation are required to appropriately guide patient management and avoid misdiagnosis.