Chronic water intoxification leading to blindness
Too much of even very good thing can be bad, even fatal. This is true for water as what this unfortunate Taiwanese lady found out. She drank 7 litres of water a day to detoxify her body and reduce her blood pressure for 3 months. At the end of three months she fainted and when she regained consciousness, she found that she is blind.
The doctor who treated her, Dr. Jiang Shou Shan said that she suffered water intoxification and hyponatremia (lack of sodium or natrium). This lead to excess water being absorbed into her body cells and her brain cells swelled leading to increased pressure in her brain. The increased pressure caused bleeding in her occipital lobe which is the visual processing center of the brain (see drawing below):
Symptoms of water intoxification includes headache, fatigue, nausea, vomiting, frequent urination and mental disorientation.
Newspaper cutting from The New Paper with article "Woman loses sight after drinking too much water" (click to enlarge):