Kernicterus

Japanese: 核黄疸 - かくおうだん（英語表記）Kernicterus

What is the disease?

This is a disease in which the bilirubin level in the blood rises and is deposited in the brain, affecting brain cells. It causes specific central nervous system symptoms and can leave aftereffects.

Currently, the incidence of this disease has decreased significantly in Japan through phototherapy and exchange transfusion. However, in the United States, kernicterus has reappeared and become a problem due to early discharge from hospitals and revisions to jaundice management standards.

What is the cause?

Newborns Hemolytic ( Lifestyle ) Disease (blood type incompatibility, etc.), obstructive bleeding ( Galea ( Defense ) Subarachnoid hematoma, adrenal hemorrhage, etc.), pathological jaundice such as polycythemia, which causes an increase in the bilirubin level in the blood, resulting in cerebral Basal ganglia ( Foreign exchange ) This is because it is deposited in these areas.

How symptoms manifest

In the first stage (2-3 days after onset), muscle tone decreases. Lethargy ( Citizen ) Symptoms include impaired consciousness (asleep-like state), decreased ability to breastfeed, etc. At this stage, there is a possibility of improvement with appropriate treatment.

However, in the second stage (approximately 3 days to 1 week after onset), muscle tension Increased ( Public health ) , Backbow Rebound ( Chief of police ) Symptoms include bowing backwards, fever, high-pitched crying, convulsions, etc., and in the third stage (one week after onset), the increased muscle tone weakens or disappears. Some children die during this stage, while others survive and develop cerebral palsy, intellectual disability, hearing loss, etc., as symptoms of the chronic stage (one to one and a half years after birth).

As such, prompt treatment is necessary at least during the first stage of symptoms. However, in low birth weight infants (premature infants), these typical symptoms of kernicterus are rarely observed, making diagnosis difficult.

Testing and diagnosis

While searching for the cause of pathological jaundice, it is necessary to frequently measure the bilirubin level in the blood. At the same time, it is important to closely observe the child's condition. Tests to check the effect of bilirubin on the nervous system include a hearing test called the auditory brainstem response and an MRI of the head.

Treatment methods

We will try to treat hyperbilirubinemia by using phototherapy and exchange transfusion.

What to do if you notice an illness

If early onset jaundice is detected, it is important to transport the child to a facility where diagnosis and treatment can be performed as soon as possible. At the very least, immediate treatment is required during the first stage of symptoms.

Hajime Yamazaki

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

Japanese:

どんな病気か

　血液中のビリルビン値が上昇し脳内に沈着した結果、脳細胞が侵される病気です。特有な中枢神経症状を示し、後遺症を残すことがあります。

　現在、この病気は日本では光線療法や交換輸血によって著しく減っています。一方、米国では、早期退院、黄疸管理基準の見直しなどにより核黄疸が再び現れ、問題になっています。

原因は何か

　新生児溶血性(ようけつせい)疾患（血液型不適合など）、閉鎖性出血（帽状腱(ぼうじょうけん)膜下血腫、副腎出血など）、多血症などの病的黄疸によって血液中のビリルビン値が上昇した結果、大脳基底核(きていかく)というところに沈着することが原因です。

症状の現れ方

　第1期（発病2～3日）に筋緊張低下、嗜眠(しみん)（眠っているような状態の意識障害）、哺乳力の低下などがみられます。この段階では適切な治療で改善する可能性があります。

　しかし、第2期（発病約3日～1週間）には筋緊張の亢進(こうしん)、後弓反張(こうきゅうはんちょう)（後ろに弓なりに反る）、発熱、甲高い泣き声、けいれんなどを示し、第3期（発病1週間以降）には筋緊張の亢進は弱まりあるいは消えていきます。この時期に死亡したり、生存しても慢性期（生後1年～1年半）の症状として脳性麻痺、知的障害、難聴などが認められます。

　このように、少なくとも第1期症状のうちに早急な処置が必要です。しかし、低出生体重児（未熟児）ではこのような典型的な核黄疸症状が認められることは少なく、診断は困難です。