The first symptoms of chronic Minamata disease tend to appear as sensory disturbances like limb numbness, staggering and stumbling. Sensory disturbances are mainly characterized by a decrease in tactile sensitivity and a higher tolerance to pain. Also, some people complain of dysesthesia (abnormal sensation). The numbness is not noticed in the trunk but in the fingertips and those. Some patients, younger than 50 years old, might complain more of movement disorders than numbness.
In addition, painful cramps in the hands, feet and sometimes in the head or trunk are often experienced. Ataxia in the hands is characterized by the dropping of chopsticks and difficulty in buttoning clothes. These motor and sensory symptoms are not always present in milder cases, but become more frequent as the illness becomes more severe and can reach the stage where they are present all the time.
In the worst case scenarios, the senses of smell and taste deteriorate and the range of peripheral vision decreases.
A documented medical history and a medical examination are necessary for the diagnosis of Minamata disease. In the medical history it is important to include records documenting the patient’s history of seafood consumption and proof of residence in a methylmercury polluted area. A general neurological examination is necessary and quantitative sensory tests, such as two-point discrimination, are performed if deemed necessary.
A diagnosis of Minamata disease can be made from having a history of eating methylmercury poisoned seafood and having neurological symptoms such as sensory disturbance or ataxia, to name just two. Also, of particular importance in making a diagnosis is the presence of peripheral dominant sensory disturbance and systemic sensory disturbance.
Accurate information about Minamata disease is very limited, so it is advised that you visit and medical institution with experienced in dealing with the disease. If this is not possible you could recommend your doctor to read the two publications, both of which are in Japanese, “The Common Form of Medical Certificate for Minamata Disease” and, “General Remarks on Minamata Disease Diagnosis”
In medical institutions belonging to the “Japan Federation of Democratic Medical Institutions” there should be quite a few doctors and staff with Minamata disease medical care experience.
For the treatment of Minamata disease we use a variety of medicines, including Chinese medicines, and perform both physiotherapy and acupuncture for the relief of pain and numbness. Although we name some medicines in the section, “For the Medical Profession” we strongly advise you to follow your own doctor’s instructions concerning medication, injections, rehabilitation and so on.
When a patient is certified as having Minamata disease according to the criteria specified by the Japanese law, “Concerning Compensation for Pollution-related Health Damage” the medical care expenses and some form of allowance is paid as a lump sum. However, almost no patients have been certified by the Pollution-related Health Damage Certification Councils in either Kumamoto or Kagoshima prefecture recently.
If you have a medical treatment notebook or a Minamata disease Patient’s Record Book you are entitled to assistance in the payment of medical care expenses. However, if you have not been paying the conventional health insurance contributions you will not be entitled to compensation. On the topic of nursing care insurance, you will be assisted with the individual fees for public nursing care insurance which provides treatment, including rehabilitation at home or at a rehabilitation center and home care. You will receive compensation to cover treatment in all areas of medicine except dental treatment.