Tetralogy of Fallot

Japanese: ファロー四徴症 - ファローしちょうしょう（英語表記）Fallot tetralogy

What kind of disease is it and what causes it?

big Ventricular septal defect ( Evidence-based survey ) There is a right ventricular outlet ( Infundibulum ( Rotten ) ) is a disease in which the gap between the eyes is narrow (Figure 16). Cyanosis (purple color of the skin and mucous membranes) Sexual heart disease ( Mental illness ) This is the most common type of cyanotic syndrome, and occurs during infancy and early childhood, requiring treatment.

In approximately 10% of cases, it occurs in conjunction with chromosomal abnormalities (CATCH22).

How symptoms manifest

The time when cyanosis appears in this disease varies: one third of cases occur within the first month of life, one third occur within the first month or year of life, and the remainder occur after one year of age. In infancy, cyanosis is only seen when crying or exercising, but later it becomes constant.

Approximately 30% of patients with this disease experience characteristic cyanotic attacks (spelling attacks: attacks in which the lips and other parts of the body turn black and the child temporarily loses consciousness) between the ages of 3 months and 3 years. After 6 months or more of cyanosis appears, the tips of the fingers and toes become rounded and deformed, a condition known as drumstick fingering.

When they start walking after the age of one, they squat down when they get out of breath from running or walking, like sumo wrestlers. Crouching ( Respect ) (Stand on your toes, sit deep in the seat, and keep your upper body upright)

Testing and diagnosis

A definitive diagnosis requires cardiac ultrasound (echocardiogram), cardiac catheterization, and cardiac angiography (precise examination). Complete transposition of the great arteries ( Complete grand prize ) , Double outlet right ventricle ( Ryōdai Kōshitsuki Shichō ) , Single ventricle ( Examination room ) , Pulmonary atresia ( Visitor Information Agency ) It is important to distinguish between these and other types of surgery, as this will affect the surgical approach.

Treatment methods

Prevention and treatment of cyanotic attacks are necessary in infants and young children. The first step in treating cyanotic attacks at home is to hold the baby up and Crouching ( Respect ) First, place the child in a neutral position, and secondly, administer oxygen using a home oxygen device. If the attack continues for more than 20 minutes, treatment at a hospital (pediatric cardiology department) is required.

If the cyanotic attacks do not subside with medication, a shunt operation is performed through a chest opening in early infancy. Usually, the baby is about 1 year old and weighs 8-10 kg, and undergoes radical surgery using a heart-lung machine. The risk of surgery is 2-5%, but the risk varies depending on the shape of the pulmonary artery and any associated anomalies.

If the radical surgery is successful, cyanosis will disappear, right ventricular pressure will decrease, and there will be almost no subjective symptoms, but an exercise stress test will show a mild decrease in cardiac function.

Toshiharu Niioka

Figure 16 Tetralogy of Fallot *Numbers indicate blood volume
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Figure 16 Tetralogy of Fallot *The numbers indicate blood volume...

Tetralogy of Fallot
Fallot tetralogy
(Childhood illnesses)

What is the disease?

Tetralogy of Fallot is a congenital heart disease that causes cyanosis (purple discoloration of the skin and mucous membranes). Ventricular septal defect ( Election deadline ) , Right ventricular outflow tract obstruction ( Residents' compensation claim ) , aorta Riding ( Kijo ) , right ventricle Hypertrophy ( Hidai ) There are four characteristics (Figure 7). The symptoms vary depending on the degree of right ventricular outflow tract obstruction, and the method and timing of treatment also vary. It accounts for approximately 5% of congenital heart diseases.

How symptoms manifest

In many cases, it is diagnosed early after birth due to heart murmurs or cyanosis. If the right ventricular outflow tract stenosis is mild, the blood flow will be the same as that of a ventricular septal defect. heart failure ( Shinfuzen ) Symptoms are observed. Cyanosis is relatively mild. If the right ventricular outflow tract stenosis is severe, cyanosis is observed throughout the body from the neonatal period. The right ventricular outflow tract stenosis often becomes stronger as the baby grows, and the cyanosis gradually becomes stronger.

After infancy, the whole body suddenly turns black. Anoxic attacks ( So thin ) This is a serious, life-threatening complication characterized by rapid, loud breathing and cyanosis of the entire body, and seems to occur most often after morning feeding, when crying loudly, or during defecation. In children of walking age, they may crouch down after a certain amount of exercise. This posture is thought to increase the amount of blood flowing to the lungs.

Testing and diagnosis

Diagnosis is by X-ray, cardiac ultrasound, electrocardiogram, etc. Depending on the symptoms and the results of the examinations, further cardiac catheterization will be scheduled and a treatment plan will be decided.

Treatment methods

Treatment plans vary greatly depending on the degree of right ventricular outflow tract obstruction. Medical treatment involves drug therapy according to symptoms. However, the basic treatment is mainly surgical treatment, and medical treatment is only meant as a temporary measure until surgery.

In surgery, the ventricular septal defect is closed and a right ventricular outflow tract is formed. If the child has severe cyanosis, a BT shunt operation (surgery to increase blood flow to the lungs) may be performed before the surgery to improve the cyanosis and wait for the child to grow.

The treatment plan will be determined based on your symptoms and test results.

What to do if you notice an illness

If you have any symptoms that concern you, please visit your local pediatrician.

Hiroshi Suzuki

Figure 7 Tetralogy of Fallot
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Figure 7 Tetralogy of Fallot

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

Japanese:

どんな病気か・原因は何か

　大きい心室中隔欠損(しんしつちゅうかくけっそん)があり、右心室の出口（漏斗部(ろうとぶ)）が狭い病気です（図16）。チアノーゼ（皮膚や粘膜が紫色になること）性心臓病(せいしんぞうびょう)の代表であり、乳児期から幼児期に特有のチアノーゼ発作を起こして治療が必要になります。

　原因として、約10％で染色体異常（CATCH22）に合併して生じます。

症状の現れ方

　本症でのチアノーゼ出現の時期はさまざまで、3分の1は生後1カ月以内に、3分の1は生後1カ月ないし1年に、残りは生後1年以後に現れます。乳児期には泣いた時や運動時にだけみられるチアノーゼが、のちには常時認められるようになります。

　本症の約30％には、特有のチアノーゼ発作（スペル発作：唇などが黒くなり、一時的に意識を失う発作）が3カ月～3歳で生じます。チアノーゼが出現して6カ月以上たつと手足の指先が丸く変形し、これは太鼓バチ指と呼ばれます。

　1歳過ぎに歩行を始めると、走ったり歩いたりして息が切れるとしゃがみ、いわゆる相撲の蹲踞(そんきょ)（つま先立ちで深く腰をおろし、上体を正した姿勢）の姿勢をとります。

検査と診断

　診断の確定には心臓超音波（心エコー）や心臓カテーテル、心血管造影検査（精密検査）が必要です。その他のチアノーゼ性心疾患（完全大血管転位症(かんぜんだいけっかんてんいしょう)、両大血管右室起始症(りょうだいけっかんうしつきししょう)、単心室(たんしんしつ)、肺動脈閉鎖症(はいどうみゃくへいさしょう)など）との区別が重要で、手術の方法に影響します。

治療の方法

　乳幼児期には、チアノーゼ発作に対する予防と治療が必要です。家庭でのチアノーゼ発作に対する処置は、第一に抱き上げて蹲踞(そんきょ)の姿勢をとらせること、第二に家庭用の酸素吸入装置を用いて酸素吸入をすることです。発作が20分以上続く場合は、病院（循環器小児科）での治療が必要です。

　チアノーゼ発作が薬物でおさまらない場合は、乳児期早期に開胸してシャント手術を行います。通常は1歳前後、体重8～10㎏で人工心肺を使用して根治手術を受けます。手術の危険率は2～5％ですが、肺動脈の形態や合併する奇形によって危険率は変わります。

　根治手術が成功すれば、チアノーゼの消失、右心室圧の低下が得られ、自覚症状もほとんどありませんが、運動負荷試験では軽度の心機能の低下が認められます。

新岡　俊治

図16　ファロー四徴症　※数字は血液量を示す
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図16　ファロー四徴症　※数字は血液量…

ファロー四徴症
ファローしちょうしょう
Fallot tetralogy
(子どもの病気)

どんな病気か

　ファロー四徴症はチアノーゼ（皮膚や粘膜が紫色になる）が出る先天性心疾患であり、心室中隔欠損(しんしつちゅうかくけっそん)、右心室流出路狭窄(うしんしつりゅうしゅつろきょうさく)、大動脈騎乗(きじょう)、右心室肥大(ひだい)という4つの特徴があります（図7）。なかでも右心室流出路狭窄の程度により症状の現れ方が違い、治療の方法や時期も違ってきます。先天性心疾患のうち約5％を占めます。

症状の現れ方

　多くの場合、出生後早い時期に心雑音やチアノーゼがきっかけで診断されます。右心室流出路の狭窄が軽い場合は、心室中隔欠損と同じ血液の流れ方になります。ミルクを飲む量が少なく、体重の増えが少なく、汗が多いといった心不全(しんふぜん)症状が認められます。チアノーゼは比較的経度です。右心室流出路の狭窄が強い場合は、新生児期から全身にチアノーゼが認められます。右心室流出路の狭窄は成長とともに強くなっていくことが多く、徐々にチアノーゼが強くなります。

　乳児期以降に、突然全身が黒くなる無酸素発作(むさんそほっさ)が現れることがあります。これは速く大きな呼吸、全身のチアノーゼを特徴とし、生命に関わる重大な合併症で、朝の哺乳後、激しく泣いた時や、排便時に多く起きるようです。歩くことができる年齢では、ある程度の運動のあと、しゃがみこむ動作をみせることがあります。この姿勢により、肺に流れる血液を多くするものと考えられています。