<s>[INST] What could be the cause of a numbness and tingling as though the area had fallen asleep to last 12hrs now? Started out only in my left shin under the knee cap all down to my ankel. At onset I was grocery shopping, felt an urge of nausea and light headed with an instant severe headache like between my eyes/forehead (different than how my migraines usually begin) I also noticed red hue splotch in my vision which kinda went from transparent to solid over the 3 or 4 different times i seen it. [/INST] Hi, You may be having what is sometimes referred to as complicated migraine or "stroke equivalent".  This translates usually into a TIA or other forms of temporary of blood flow to the brain due to either a clot that quickly breaks up or some change in hemodynamics such that pressure is lost to an area of the brain subserving the sensory function of the left leg.  Hope I have answered your query. Let me know if I can assist you further. </s>