診断の困難であった慢性ブロムワレリル尿素中毒—X線微小分析法（EDX）による体液中ブロム測定の臨床的応用

Diagnostic Application of Energy Dispersive Spectroscopy to Chronic Bromvalerylurea Intoxication

　抄録　ブロムワレリル尿素は数10年前より睡眠導入剤として汎用され．中毒症状として幻覚ならびにせん妄状態などの精神症状，および各種神経症状を呈することが既に知られている。今回報告した慢性ブロム中毒の3症例は，入院時ブロムワレリル尿素服用歴を述べず，精神症状ならびに神経症状が多彩であるため，診断が困離であった症例である。

　各症例の血清，尿あるいは髄液について，ブロム検出のためのX線微小分析（エネルギー分散分光法，EDX）を行なった結果，血清と尿では明瞭な，髄液では痕跡程度のブロム元素のピークを認めた。本法のブロム検出感度は，ブロムカリ標準試料を調製し検討したところ，30μg/mlあった。ブロム中毒は数mg/ml以上の血清中濃度で生じるとされているので，EDXが稼働している施設であれば簡便かつ迅速にブロム元素の判定が可能であり，慢性ブロム中毒の有力な補助診断法となり得る。

　Bromvalerylurea has long been used as a hypnotic, and is known to cause complicated neurological symptoms and signs as well as psychiatric ones such as delirium, hallucination, etc. Because patients often hesitate to admit the use of bromvalerylurea, it is usually difficult to reach correct diagnosis of the intoxication. In this study, three cases of chronic bromvalerylurea intoxication were described. All the cases showed nystagmus, gait disturbance and hyperreflexia of the limbs. Dysarthria, double vision, hypotonia and ataxic gait were also observed frequently. As a very rare sign, auditory agnosia was found in one case. Differential diagnosis was necessary to rule out hysterical state, multiple sclerosis, hypoglycemia, porphylia, myasthenia gravis and epilepsy.

　In order to detect bromin, energy dispersive spectroscopy (EDX) was used for analysing serum, urine and cerebrospinal fluid of the three cases. Five micro liter of the specimen was placed on the carboncoated mesh and dehydrated, then using TN-2000 analyzer, characteristic X-ray peaks were examined. Distinct peaks for bromin were obtained from the serum and urine, but peaks from the cerebrospinal fluid were very small. For the purpose of determining the sensitivity of this method, potassium bromide diluted with normal human serum was tested. The study showed that the sensitivity to detect bromin in serum is 30 micro gram per ml. This method is sensitive enough for the diagnosis of bromide intoxication.