Hello!
Today,
I studied about syncope, which is a common reason for patients to be brought to the emergency room.
こんにちは～
今日は救急外来にもよく運ばれてくる
失神について勉強しました～
Since syncope is also related to symptoms like palpitations and dizziness
that we studied in the previous sessions, let’s learn about them together.
前回、前々回勉強した
動悸やめまいとも関係のある症状なので
絡めて学んでいきましょう
---------------------------------------------------------------------------------------------
Syncope / 失神
Approach to Transient Loss of Consciousness (LOC)
失神（一過性の意識障害）へのアプローチ
When faced with a patient who has experienced a transient LOC,
the first step is to classify the event. Here’s the roadmap:
一過性の意識障害を経験した患者さんを見るときは、
まず何が起こったのかをはっきりさせることが大切です。
以下の3つに大別して考えてみましょう
- Traumatic: Resulting from head injury. / 頭部外傷
- Syncope: Our main focus—transient loss of consciousness due to temporary global cerebral hypoperfusion. / 一過性の脳虚血
- Non-syncopal attacks: Includes conditions like epileptic seizures, psychological pseudosyncope, and others. / てんかん、心因性などの偽性失神
What Causes Syncope? / 失神の原因は？
Etiology: Cerebral Hypoperfusion or Low Blood Pressure?
病因：一過性の脳虚血なのか？低血圧性なのか？
Okay, folks,
here’s one of the most challenging parts: understanding the causes of syncope.
Let’s break down the common causes into three main groups:
では、みなさん
ここが失神を理解していくうえで、肝心要となるところです
原因についても3つに分けて考えていきます
-
I) Low Peripheral Resistance (Reflex Mechanisms) / 末梢血管抵抗の低下
- Reflex Syncope / 反射性
- Vasovagal Syncope : 迷走神経反射
This is the most common type and can happen when someone is stressed, in pain, or stands for too long.
Look for symptoms like nausea, sweating, and pallor before they faint.最も多い原因。ストレス、痛み、長い時間立っているなどが誘因
随伴症状：吐き気、発汗、蒼白など- Situational Syncope : 状況性失神
Ever heard of someone fainting after coughing, swallowing, or even urinating?
These specific triggers can cause it.咳や嚥下、排尿などが誘因となる
- Carotid Sinus Syndrome : 頸動脈洞反射
This happens when pressure on the carotid sinus, like from a tight collar, causes fainting.
頚部に強い圧力、頸椎カラーなどが誘因となる- Orthostatic Syncope / 起立性失神
This occurs when a person stands up quickly and their body fails to adjust blood pressure appropriately.
素早く立ち上がったときに、血圧の調節が上手くいかないことが誘因
- Causes: Volume depletion (dehydration, blood loss), anemia, certain medications (like diuretics), autonomic dysfunction (think Parkinson’s disease), and environmental factors (like a hot day).
- 原因：血管内ボリュームの低下（脱水、失血）、貧血、薬剤（利尿剤）、自立神経障害（パーキンソン病、DM）、環境因子（熱射病）
II) Low Cardiac Output (Cardiac Syncope) / 低心拍出力（心性失神）
This type is related to the heart’s ability to pump blood:
- Structural Heart Diseases:
- Myocardial Infarction (MI): Reduced blood flow to the heart muscle.
- Aortic Stenosis (AS): Narrowing of the aortic valve.
- Cardiac Tamponade: Fluid accumulation around the heart.
- Hypertrophic Cardiomyopathy (HCM): Thickened heart muscle.
- Cardiac Myxoma: A tumor in the heart.
- Pulmonary Embolism (PTE): Blood clot in the lungs.
- Aortic Dissection (AD): Tear in the aorta.
- Pulmonary Arterial Hypertension (PAHtn): High blood pressure in the lungs.
- Arrhythmias:
- Bradycardia: Slow heart rate due to conditions like Sick Sinus Syndrome (SSS) or Atrioventricular Block (AVB).
- Tachycardia: Fast heart rate from Supraventricular Tachycardia (SVT) or Ventricular Tachycardia (VT).
- Electrolyte Imbalance: Abnormal levels of potassium or calcium.
III) Subarachnoid Hemorrhage (SAH) / クモ膜下出血
- SAH can cause a sudden severe headache ("thunderclap headache") followed by fainting. This happens when the pressure in the skull gets too high, cutting off blood supply to the brain.
- SAHは激しい頭痛に失神が伴うことがある。頭蓋内圧が上昇した結果、脳血流を著しく下げることが原因。圧力の関係により、意識が変容する。
How to Examine a Patient with Syncope : 診察方法
Alright,
now that we’ve covered the causes, let’s talk about what to do when a patient presents with syncope.
以上で失神の大きな原因を理解できたので
次は診察で重要となる部分をまとめていきます
Vital Signs:
- Check blood pressure (BP), heart rate (HR), respiratory rate (RR), oxygen saturation (SpO2), and body temperature (BT).
History Taking:
- Onset: Ask about the circumstances of the fainting episode. Did they remember it? What were they doing?
- Symptoms: Look for associated symptoms like palpitations, shortness of breath (SOB), chest pain/discomfort, sweating, nausea, headache, feverish feeling, and general malaise.
- Timing: How long did it last? Is this the first time or has it happened before?
- Past Medical History (PMH): Heart disease, diabetes (DM), medications, hypertension (HTN), dyslipidemia (DL).
- Family History (FHx): Any family history of heart issues, sudden death, or cancers?
- Social History (SHx): Smoking, occupation, diet/drugs, alcohol consumption, exercise habits, and stress levels.
Physical Examination:
- HEENT: Check the eyes and listen for carotid bruits.
- Chest: Perform a thorough heart and lung exam.
- Extremities: Look for signs of dehydration, edema, and assess skin temperature and moisture.
Investigations:
- Electrocardiogram (EKG): To check for arrhythmias or ischemia.
- Laboratory Tests (L/D): Blood count, electrolytes, glucose, and cardiac enzymes.
- Imaging: CT scan if necessary to rule out structural causes.
- Autonomic Function Tests: To assess the autonomic nervous system.
- Transthoracic Echocardiography (TTE): To evaluate heart structure and function.
- Exercise Tolerance Test: For exercise-induced arrhythmias or ischemia.
- Holter Monitor: 24-hour monitoring for intermittent arrhythmias.
Managing Syncope in the Emergency Room (ER) : 救急外来では？
In the ER, your immediate goal is to rule out life-threatening conditions such as arrhythmias, severe anemia, aortic dissection (AD), or acute coronary syndrome (ACS). Quick and efficient assessment is key!
救急外来においては、
喫緊の目標は命に関わってしまう原因を除外していくこと、
不整脈や深刻な貧血、大動脈解離、冠動脈疾患などです
頭の中にこれらを浮かべ、一つ一つ診察していくことが大切です
Additional Notes on Syncope and Stroke : 失神と脳卒中について
- Cerebrovascular Accident (CVA) and Syncope :
Pearls for Junior Doctors
- Always Consider Common Causes First : まずはcommon dsを念頭に
Start with the most likely culprits like vasovagal and orthostatic syncope, especially in younger patients.
まずは頻度の高い原因から探っていくことが大切。
特に若者では、迷走神経反射や起立性失神を考えていく。
- Detailed History is Key : 問診が一番大事
The patient’s history often provides the best clues.
現病歴が診断に至るうえで、重要な情報を与えてくれる
- Use a Systematic Approach : 系統的なアプローチを
Categorize causes as reflex, cardiac, or neurologic.
反射性、心性、神経原性の3つから系統的に
- Know Your Red Flags : Red Flagsも確認を
Symptoms like chest pain, palpitations, and a family history of sudden death require urgent attention.
胸痛、動機、家族歴といったRed Flagsを見逃さないように
- Collaboration : ためらわずコンサルすることも大事
Don’t hesitate to consult with specialists if the cause is unclear or the patient has significant risk factors.
理由がはっきりしないときや、上記のRed Flagsを認めたときにはためらわずにコン
サルしていくことも大切
Understanding syncope and its underlying causes is crucial for providing effective patient care.
By following a systematic approach and keeping key considerations in mind, you can navigate the complexities of this common clinical problem with confidence.
Remember, a calm and thorough evaluation can make all the difference for your patients.
And remember, folks, as Dr. House might say, "Everybody lies," but fainting? That's usually pretty honest. 😄
最後の部分、有名なテレビドラマ「House, M.D」からの一節です
日本では「ドクターG」のようなものになりますが、
ジョークの意味わかりましたか？笑
患者さんが伝えてくる主観的な症状のすべてを信じることはできませんが
失神に関しては、偽ることのできない、唯一信じられる症状
といううことです
Well,
This has gotten quite long, so let's wrap it up here for today.
Good job, folks
さて、
長くなりましたが、今日はこの辺で
お疲れさまでした
American Heart Association (AHA): Offers extensive resources on cardiovascular diseases, including syncope.
National Institute for Health and Care Excellence (NICE): Clinical guidelines on syncope and its management.
Mayo Clinic: Detailed articles on various types of syncope and their causes.
UpToDate: An evidence-based clinical resource with detailed syncope guidelines.
Harrison’s Principles of Internal Medicine: Comprehensive coverage on the pathophysiology, diagnosis, and treatment of syncope.
New England Journal of Medicine (NEJM): Research articles and reviews on syncope.
Journal of the American Medical Association (JAMA): Studies and reviews on the latest findings related to syncope.
American Academy of Neurology (AAN): Guidelines on neurologic causes of syncope, including subarachnoid hemorrhage.
European Society of Cardiology (ESC): Provides guidelines and position papers on the diagnosis and management of syncope.
