Central sensitization mechanisms in chronic migraine with medication overuse headache: a study of thalamocortical activation and lateral cortical inhibition.

BACKGROUND: It is unclear whether cortical hyperexcitability in chronic migraine with medication overuse headache (CM-MOH) is due to increased thalamocortical drive or aberrant cortical inhibitory mechanisms. METHODS: Somatosensory evoked potentials (SSEP) were performed by electrical stimulation of the median nerve (M), ulnar nerve (U) and simultaneous stimulation of both nerves (MU) in 27 patients with CM-MOH and, for comparison, in 23 healthy volunteers (HVs) of a comparable age distribution. We calculated the degree of cortical lateral inhibition using the formula: 100 - [MU/(M + U) × 100] and the level of thalamocortical activation by analyzing the high frequency oscillations (HFOs) embedded in parietal N20 median SSEPs. RESULTS: Compared to HV, CM-MOH patients showed higher lateral inhibition (CM-MOH 52.2% ± 15.4 vs. HV 40.4% ± 13.3; p = 0.005), which positively correlated with monthly headache days, and greater amplitude of pre-synaptic HFOs (p = 0.010) but normal post-synaptic HFOs (p = 0.122). CONCLUSION: Our findings suggest that central neuronal circuits are highly sensitized in CM-MOH patients, at both thalamocortical and cortical levels. The observed changes could be due to the combination of dysfunctional central pain control mechanisms, hypersensitivity and hyperresponsiveness directly linked to the chronic intake of acute migraine drugs.

A case of renal cell carcinoma with bone and lymph node metastases.

We present a rare case of renal cell carcinoma (RCC) with a metastatic, mainly osteoblastic lesion of the skull and spread to the lymph nodes. Renal tumors are often associated with bone metastases; these are most often of the osteolytic type, while osteoblastic metastases are extremely rare. In the case presented here, the primary metastasis was a large osteoblastic lesion of the skull that spread to the lymph nodes. The patient has undergone treatment for 20 months with interleukin-2: 3 million IU/day (subcutaneous) for six consecutive days once every four weeks, ie a total weekly dose of 18 million IU.