minocycline and Trigeminal-Neuralgia

Trigeminal neuropathic pain attacks can be excruciating for patients, even after being lightly touched. Although there are rodent trigeminal nerve research models to study orofacial pain, few models have been applied to studies in mice. A mouse trigeminal inflammatory compression (TIC) model is introduced here which successfully and reliably promotes vibrissal whisker pad hypersensitivity.. The chronic orofacial neuropathic pain model is induced after surgical placement of chromic gut suture in the infraorbital nerve fissure in the maxillary bone. Slight compression and chemical effects of the chromic gut suture on the portion of the infraorbital nerve contacted cause mild nerve trauma. Nerve edema is observed in the contacting infraorbital nerve bundle as well as macrophage infiltration in the trigeminal ganglia. Centrally in the spinal trigeminal nucleus, increased immunoreactivity for an activated microglial marker is evident (OX42, postoperative day 70). Mechanical thresholds of the affected whisker pad are significantly decreased on day 3 after chromic gut suture placement, persisting at least 10 weeks. The mechanical allodynia is reversed by suppression of microglial activation. Cold allodynia was detected at 4 weeks.. A simple, effective, and reproducible chronic mouse model mimicking clinical orofacial neuropathic pain (Type 2) is induced by placing chromic gut suture between the infraorbital nerve and the maxillary bone. The method produces mild inflammatory compression with significant continuous mechanical allodynia persisting at least 10 weeks and cold allodynia measureable at 4 weeks.

Topics: Animals; Behavior, Animal; Disease Models, Animal; Facial Pain; Hyperalgesia; Imidazoles; Inflammation; Male; Mice; Mice, Inbred C57BL; Microglia; Minocycline; Nerve Compression Syndromes; Neuralgia; Neurons; Orbit; p38 Mitogen-Activated Protein Kinases; Purinergic P2X Receptor Antagonists; Pyridines; Tetrazoles; Trigeminal Ganglion; Trigeminal Nerve; Trigeminal Neuralgia; Trigeminal Nucleus, Spinal

Topics: Aged; Anti-Bacterial Agents; Carbamazepine; Drug Hypersensitivity; Female; Humans; Immunosuppressive Agents; Isoxazoles; Minocycline; Pemphigoid, Bullous; Pharyngitis; Syndrome; Time Factors; Treatment Outcome; Trigeminal Neuralgia; Zonisamide

A 64-year-old man visited our clinic with a 9-day history of headache and fever. He had frequent, severe, electric shock-like pain in his left eye, forehead, and scalp. The body temperature was 37.1 degrees. Cranial nerve functions were intact. Limb weakness and stiff neck were absent. There were injection of the conjunctiva, a red rash on the trunk, and an eschar in the axilla. Abnormal laboratory findings included AST 40 IU, ALT 44 IU, CRP 16.0 mg/dl, WBC 11,090/microl, and proteinuria. CT scan was unremarkable. The cerebrospinal fluid (CSF) showed 2 polymorphs/microl, 6 lymphocytes/microl, 65 mg/dl of glucose, and 42 mg/dl of protein. A diagnosis of scrub typhus was made. Treatment with minocycline brought about prompt disappearance of the fever and dramatic clinical improvement. Increased antibody titers confirmed the diagnosis. Although almost all patients present with high fever and severe headache, only a small number of patients have CSF pleocytosis. The present case illustrates that pain in scrub typhus is, on rare occasions, indistinguishable from trigeminal neuralgia. Neurologists should have a high index of suspicion in patients with fever and headache during the epidemic season and should be familiar with the systemic symptoms and signs.

Topics: Anti-Bacterial Agents; Diagnosis, Differential; Fever; Headache; Humans; Male; Middle Aged; Minocycline; Scrub Typhus; Treatment Outcome; Trigeminal Neuralgia