慢性硬膜下血腫に伴うパーキンソニスムの1例

Parkinsonism Secondary to Chronic Subdural Hematoma. A Case Report.

　要旨　症例は83歳男性。約1年前より歩行障害が緩徐に進行し，全身の動作緩慢も伴っていたが，転倒を契機にこれらの症状が亜急性に増悪したため入院した。神経学的には，短期記憶障害および注意力障害と開脚性の小刻み歩行，姿勢反射障害に加え右上下肢優位の歯車様筋強剛を呈したが，安静時振戦は認めなかった。頭部CTにて右前頭葉から側頭葉にかけて慢性硬膜下血腫の形成を認めたが，SPECTでは左基底核を中心とした左大脳半球に血流低下がみられた。入院後，血腫の自然吸収に伴い臨床症状が改善したため，慢性硬膜下血腫に伴うパーキンソニスムと考えた。これまで，本症に類似した報告例が散見されるが，本症例では血腫存在側と同側肢に優位なパーキンソニスムを認め，これに対応して血腫と対側の基底核を含んだ大脳半球に広範な血流低下を認めた点が特徴的であった。高齢化の社会変化に伴い，パーキンソニスムの鑑別において本疾患は重要であると考えられた。

　We described a case of secondary parkinsonism due to chronic subdural hematoma （CSH）. An 83-year-old man developed memory impairment and gait disturbance gradually since one year ago, and these symptoms subacutely deteriorated after he fell down and hit his head. On admission he had moderate cognitive impairment, gait disturbance （wide-based, small steps and initial freezing）, postual instability, akinesia and right-sided rigidity. He did not have resting tremor. A CT scan showed a right-sided CSH with marked compression on the left hemisphere, and remarkable decrease of the blood flow in the left cerebral hemisphere was revealed by single photon emission computed tomography. His neurological condition improved gradually through the decrease of the CSH, which suggested the diagnosis of secondary parkinsonism due to CSH.

　We thought that the CSH in the right hemisphere caused right-sided parkinsonism through mechanical compression to the left hemisphere, which was shown in the SPECT image, in this case. Elderly people suffering from subacute progressive parkinsonism, should undergo CT studies be to differentiate the parkinsonism secondary to CSH.