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Posts Tagged ‘loss of consiouness’

                                                    

                                                             Syncope by definition is a transient loss of consciousness due to cerebral hypo perfusion and loss of muscular tone, and the patient falls but  recovers fully and gets up either assisted or spontaneous.The cardiac and vascular counter response to syncope is most often intact .This makes syncope characteristically transient . If a patient does not recover from syncope it could either be a prolonged loss of consciousness( Stroke etc)  or if he never gets up he will be called a victim of cardiac arrest or  a SCD ! (Sudden cardiac death ) . So technically by defintion ,  all  patients  will  have to  survive  the  syncopal episode.

But the following questions need to be answered   

  1. How prolonged  a syncope can be ?
  2. Can syncope lead onto  sudden cardiac death ?(SCD)  
  3. What are  life  threatening syncope and non life threatening syncope ?                           

What is the link between, syncope and SCD in patients with ventricular arrhythmia’s ?

Some case of long QT syndromes could be life threatening especially in children as they inherit sudden death. A patient with a non sustained VT  may develop syncope  if  the  VT  becomes sustained especially  if there is underlying heart disease and LV dysfunction . Among this  few , may degenerate into ventricular fibrillation and patient may die.  

How common is syncope in acute myocardial infarction ? 
 Syncope is a very  rare presentation of acute myocardial infarction. 
 
Can syncope precipitate  or precede a  cerebro vascular accident  ?   

 

Prolonged syncope , TIA,  stroke in evolution and completed stroke   can be a continuous spectrum in patients with carotid and cerebrovascular  disese . But when a syncope evolves in to a stroke the   patient is not considered to be a victim of syncope but  they enter the stroke protocol.

There is a big list for the causes of syncope

But to put it simply

A.Cardiac

  •    Purely electrical ( Arrhythmic- Brady, Tachycardia)
  •    Mechanical( Valvular obstruction, and other structural heart disease etc)

B. Non cardiac

  • Vasovagal (Commonest 90% of all syncope)

C. Metabolic*

  •  Anemia
  • Hypoglycemia
  • Hypoxia
*Metabolic causes  coupled with simple  vaso vagal(Neuro cardiogenic)  constitute the bulk of causes of syncope .Siezure disorders are very  common and a close  mimicker of syncope and need to be ruled out.

How to work up  a patient with syncope ?

                   First ,  one need to confirm  it is indeed a syncope . If the initial examination is not clearcut   one  need to  go back to the  history and ask for  circumstances under which the syncope occured  and  details of prodromal symptoms  if any . Patient’s  family members who witnessed the event can give useful information . It  is the most  cost effective ( Comes free of cost infact !)  investigative tool available .Cardiac syncopes are usually sudden, vasovagal often have environmental or emotional factor. Apart from routine investigations , ECG, Echocardiography, holter are done generally, head up tilt test, Loop, event recorders may be reuired in few.

Final message

                                          Syncope is one of the common symptoms in cardiology and  general medical practice. Many times the diagnosis is easy . Common syncope is  never fatal but , ruling out dangerous  tachy and bradyarrhythmias is a key aim.  In a significant number (20-30%) identifying the cause could be really  difficult and  may never be made in spite  of the modern diagnostic tools. These syncope of unknown origin is grouped along with the neurocardiogenic category.

The one,  positive thing about syncope is (unlike chest pain) , it is rarely fatal in it’s first episode ,  gives the physicians to  investigate and correct the underlying problem.

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