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Brain hypoperfusion
定義 : 沒有處置
自己 Fully recover and back to baseline conscious level
 
Brief loss of consciousness associated with an inability to maintain postural tone
that spontaneously resolves without medical intervention
with the person returning to their baseline neurologic condition.
 
 先排除 Seizure + Stroke ! 
 排除頭部外傷 , 問目擊者經過 ! 
 
Over a lifetime, the prevalence of syncope ranges from 10.5% to 19%
 
Near syncope, a premonition of fainting without loss of consciousness,
shares the same basic pathophysiologic
 

 
* 暫時性大腦灌流不足, 導致意識喪失, 且會很快完全的恢復
   Brain hypoperfusion
   Transient conscious loss, fully reversible  
 
* 短暫的意識喪失, 醒過來之後沒有不舒服
  → 若產生不舒服, 就不是單純的syncope而已, 一定要 Survey
 
* 醒過來後若有不舒服就不太像 syncope
 
要區分 syncope vs seizur : Convulsion, Tongue biting, Incontinence
Seizure 時間較長, 抽動, 尿失禁, 眼睛上吊, 醒過來後會有一段 confusion
Syncope 痙攣是非常短暫的, because brief tonic-clonic movements are often associated with syncope
而且病人的意識隨後就恢復正常
Recovery is usually rapid, with no postictal-like symptoms
 
   - Syncope 後通常肌張力低
   - Seizure 後通常肌張力還是 spasm 
 
 

 
要排除中風 → 會有 Irreversible focal neurological deficit 
 
 

 

 
暈厥的常見原因有數十種
其中可能立即致命的診斷則有
Dissection/AAA, PE, Myocarditis, SAH, IVH, ICH, CO, Arrhythmia 共 7 種
可利用「病史身體檢查」+「EKG」+「超音波」三個「組塊」
​​​​​​​從暈厥的眾多原因中篩選出必須立即決定的情況
GI bleeding, Ectopic
 

- Vasovagal (reflex mediated, 21%)
- Cardiac (10%)
- Orthostatic (9%)
- Medication related (7%)
- Neurologic (4%)
- Unknown (37%)
 
- Rule out : Seizure, Stroke, Head trauma, GIB, Ectopic
 
- Lethal Diagnosis :
  Dissection/AAA, PE, Myocarditis, SAH, IVH, ICH, CO, Arrhythmia
 
- PE : Conjunctiva, Murmur, Abdomen, DRE, NE, Orthostatic BP 
 

 

 

Cardiac (Structural disease and dysrhythmias)
the heart is unable to provide adequate cardiac output to maintain cerebral perfusion
Syncope from dysrhythmias is typically sudden without prodromal symptoms
 
Structural cardiac :
Valvular heart, AS (chest pain, dyspnea on exertion, syncope)
Tamponade,
Hypertrophic cardiomyopathy
Cardiac masses (atrial myxoma, tumors), 
Prosthetic valve dysfunction
 
Cardiopulmonary and great vessels : 
PE, Dissection/AAA, pHTN
 
PE, Myocarditis change in ECG
 
Brugada syndrome, long or short QT syndromes
Exertional syncope, Family hx of sudden death
 
-->  EKG, Holter, Cardiac echo, Carotid echo 
 

 

 

 

Vasovagal, Reflex mediated
 
inappropriate vagal or sympathetic tone result in vasodilatation, bradycardia
 
Prodrome of lightheadedness, with or without nausea, pallor, and/or sweating,
and an associated feeling of warmth may accompany vasovagal syncope. Abdominal pain
 
A slow, progressive onset with associated prodrome suggests vasovagal syncope.
 
誘發事件 : 壓力, 情緒, (Triggered by pain, anxiety, distress)
May occur after exposure to an unexpected or unpleasant sight, sound, or smell;
fear; severe pain; emotional distress; or instrumentation.
 
Situational syncope occurs during or immediately
after coughing, micturition, defecation, or swallowing.
 
Carotid sinus syndrome (Carotid sinus hypersensitivity)
Men, the elderly, and those with ischemic heart disease,
hypertension, or head and neck malignancies.
inciting event, such as shaving or turning of the head
男生刮鬍子, 衣領太緊, 轉頭動作太猛
 
Consider carotid sinus hypersensitivity in older patients
with recurrent syncope and negative cardiac evaluations.
 
 

Orthostatic hypotension
 
If the autonomic response is insufficient
to counter the drop in cardiac output upon standing,
decreased cerebral perfusion and syncope may follow.
 
藥物 : Alpha-blocker, Vasodilators, diuretics, phenothiazine, antidepressants 
自主神經失調 : DM neuropathy, Parkinsonism 
Hypovolemia : Hemorrhage, Diarrhea, Vomiting​​​​​​​
 
< BP meds, dehydration, alcohol, & ANS dysfunction >
 
Postural hypotension (drop in SBP of 20 mm Hg or DBP of 10 mm Hg)
姿勢改變 : 躺 -> 站
SBP 下降 20 mmHg or DBP 下降 10 mmHg
 
Many serious causes of syncope may be associated with orthostatic changes,
so consider other life-threatening causes
before attributing syncope to orthostasis and autonomic dysfunction,
especially in the elderly.
 

Psychiatric disorders

Medications
 
β-Blockers or CCB : blunted heart rate response after orthostatic stress
nitrates can cause venous pooling and vascular dilation.
Diuretics may produce volume depletion

 

Neurogenic
 
Rare
Patients with loss of consciousness with persistent neurologic deficits
or altered mental status do not have true syncope
Transient brainstem ischemia, vertebrobasilar atherosclerotic disease,
or basilar artery migraine :
not only rare but also typically preceded by other signs or symptoms,
such as diplopia, vertigo, focal neurologic deficits, or nausea.
 
Subclavian steal (during arm exercises) : Brainstem ischemia
stolen from the vertebrobasilar system
to the subclavian artery supplying the arm muscles.
 

PDF) Subclavian steal syndrome: a review

 
Spontaneous SAH may present as a cause of syncope,
but is usually accompanied by other symptoms
such as focal neurologic deficits, headache, or persistent altered mental status,
 
removing it from the true definition of syncope.
(increase in ICP with a decrease in cerebral perfusion pressure)
 
 
 

L
Q  昏倒多久, 目擊者, 有沒有 seizure,      
     醒來後任何不舒服     
     發作前預兆 (噁心、流冷汗、心跳變快、臉色蒼白、感覺暈眩感)
O  何時發生, 之前有沒有過, 發作頻率, 每一次發生細節
P   誘發因子 
E  
R  
A :
心悸 頭暈 胸悶胸痛?
發燒畏寒 頭痛 噁心嘔吐
失眠
藥物 : 血壓藥、促排尿藥物 (alpha-blocker)
排除中風 癲癇 外傷
 
PE :
頸動脈聽診, Heart EKG, Holter, Cardiac echo, Carotid echo 躺坐站血壓 !!
聽心音 : Any outflow murmur that increases with valsalva in syncope
is hypertrophic cardiomyopathy (HCM) until proven otherwise !
 
排除解黑便 GI bleeding 
合併腹痛要小心 AAA, Ectopic pregnancy 
 
NE
 
 
 
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