Extreme tiredness, high fever, hypoglycemia or low blood sugar, high blood sugar, kidney problems causing brain fog, liver problems causing brain fog, low electrolytes, brain lesions, very high blood pressure, alcohol or drug intoxication, etc can all cause slurred
speech with tiredness. Basilar migraine, complicated migraine, Parkinson’s disease, transient ischemic attacks, hyperthyroid states, and seizures should all be investigated for.