Can intramedullary spinal injury at T4 and 5 can cause hot flashes , dizziness and nausea ? I can provide a copy of my MRI.

A present in tumor spinal cord itself is a true "intramedullary spinal cord tumor," and is unlikely to cause the symptoms you described without also cause leg weakness, sensory loss and pain in the legs. However, it may affect the cells of the sympathetic nervous system in this region of the spinal cord, which can cause some of the symptoms you describe, and in the rare cases of tumors in the spinal cord fluid accumulation can occur in the brain ("hydrocephalus") which may cause dizziness and nausea. If the tumor is present in the bone of the spine at the T4 and T5, is even less likely that these symptoms come from this area.