Case histories - Vasovagal syncope

Carotid sinus syndrome (CSS)

History

A 68 year old gentleman presents to you with episodes of recurrent syncope. He describes the episodes as occurring when washing and shaving in the morning. His syncope was briefly preceded by dizziness, and he denies any other warning symptoms. He has a history of anxiety for which he takes sertraline 50 mg once daily. He is an ex smoker of 20 pack years.

Examination

He is normotensive with no postural drop between lying and standing blood pressures. Cardiovascular examination is normal.

Which investigations should be performed in primary care?

The key investigation in this case is an ECG to identify any underlying cardiac abnormality that may be linked to the patient's symptoms. The ECG for this patient is normal.

What would you do next?

This patient has unexplained syncope and you should advise him that he must not drive and that he must notify the DVLA. The next step would be to refer to a specialist for further investigation of this patient's syncope. A referral to a cardiologist or syncope clinic would be most appropriate.

Outcome

This patient is reviewed by a cardiologist. Carotid sinus massage is performed with the patient upright and with beat to beat heart rate and blood pressure monitoring. The patient reports dizziness then faints with an associated ventricular pause of 9 seconds noted on his monitor. He is referred for pacemaker insertion and subsequently has no further episodes.

Learning points

Carotid sinus syndrome (CSS) should be considered in all older patients presenting with syncope with normal examination and normal or near-normal ECG
Triggers for CSS include head rotation or pressure on carotid sinus - which may be caused by tumours, shaving, or tight collars
Carotid sinus massage of 10 seconds causing syncope associated with asystole for over 3 seconds and/or a fall in systolic blood pressure of more than 50 mm Hg is diagnostic of CSS.
If initially negative in the supine position, carotid sinus massage should be performed during passive upright tilting as 30% of cases are missed by testing in the supine position alone.

Convulsive syncope

History

A 58 year old gentleman consults with his GP with a 2 year history of funny turns. He describes episodes of buzzing in his ears associated with feeling dizzy, but no loss of consciousness.

Examination

He is normotensive with no postural drop between lying and standing blood pressures. Cardiovascular and ear, nose and throat examination are normal.

Which investigations were performed in primary care?

A hearing test is organised due to the recent history of tinnitus. In this case the hearing test is normal.

What happened next?

The patent is referred to an ENT specialist for further investigation of the tinnitus and dizziness. An MRI of his internal acoustic meatuses is requested, and this is normal. He is diagnosed with vestibular migraines and treatment with beta-blockers is commenced.

He consults 4 months later after experiencing another episode, which is witnessed by his wife. He reports having felt dizzy, hearing buzzing in his ears, falling down and his wife corroborates that he was unconscious and developed jerking movements of his arms for approximately 10 seconds before stopping. He regained consciousness after approximately 30 seconds and was not confused but reported feeling tired and slow. There was no associated incontinence or tongue biting.

What would you do next?

This history raised the possibility of a seizure. He consults his GP and is advised not to drive and to notify the DVLA. He is referred to a neurologist for further assessment. They organise an EEG which is normal, diagnose epilepsy and commenced treatment with carbamazepine. Over the next 3 months he continues to have similar episodes approximately once a month, despite increases in his carbamazepine dose and monitoring showing therapeutic drug levels.

Frustrated with his continuing symptoms he consults with you for a second opinion.

What could you do next?

You review his medications, stop his beta blocker and organise an ECG which is normal. As he is experiencing recurrent syncopal blackouts, despite escalating anticonvulsant therapy, you refer him to the local syncope clinic for further evaluation.

Outcome

In the syncope clinic, he undergoes further investigations including 24-hour Holter monitoring and carotid sinus massage tests which are normal. Tilt table testing reveals sudden and prolonged bradycardia after 17 minutes, resulting in loss of consciousness associated with asymmetrical mild limb jerking movements. He feels dizzy and experiences buzzing in his ears before fainting. The diagnosis is asystolic vasovagal syncope. He is provided with self-management advice including physical counterpressure manoeuvres to prevent syncope, information about increased fluid and salt intake and avoiding triggers. This fails to improve his symptoms, and he is later successfully treated with a dual chamber pacemaker.

Learning points

Syncope causes transient cerebral ischaemia which may lead to myoclonic jerks. Jerks often begin after several seconds after loss of consciousness and not immediately as in epilepsy
Syncope tends to be associated with a shorter duration of loss of consciousness and rapid recovery with little or no confusion compared with epilepsy
24-hour Holter monitors are an unhelpful investigation unless episodes occur very frequently (ideally daily).
In vasovagal syncope (and also in carotid sinus syndrome) cardiac pacing can be effective if the cardioinhibitory reflex is dominant; there is no role for pacing in the preventing hypotension due to vasodilatation

Differentiating vasovagal syncope epilepsy and epilepsy

Vasovagal Syncope affecting employment

History

A 29 year old security guard consults with you after developing episodes of syncope associated with prolonged standing during guard duties, especially on warm days. These are associated with nausea and sweating prior to syncope. Witnesses report no seizure activity. He has no significant past medical history and takes no medications.

Examination

Cardiovascular examination is normal with no postural drop in blood pressures.

Which investigations should be performed in primary care?

An ECG performed in the surgery is normal.

What would you do next?

There is a clear history of neurocardiogenic (vasovagal) syncope triggered by prolonged standing. He should be provided with advice about preventing syncope by increasing fluids, salt, physical counterpressure manoeuvres and avoiding excessive heat. However, his episodes continued, and he was referred to a syncope service for further assessment. He was advised that he could continue to drive as syncope only occurred after prolonged standing.

Outcome

He undergoes tilt table testing and after 8 minutes of head up tilt he reports feeling nauseated, begins to sweat profusely and develops a bradycardia with a profound drop in blood pressure. He loses consciousness and subsequently regains consciousness when lowered to the supine position.

The patient's symptoms were reproduced exactly during the tilt table test and therefore a diagnosis of vasovagal syncope is confirmed. As his syncopal episodes continue despite lifestyle measures, he commences treatment with fludrocortisone and later midodrine. Although syncope occurred less frequently, ultimately it was necessary to change his employment duties.

Learning points

Vasovagal syncope reproduced on tilt table testing can demonstrate either cardioinhibitory, vasodepressor or mixed responses
Recurrent vasovagal syncope in patients may have consequences for their occupation
Self-management advice, medication and psychosocial support may be helpful
If vasovagal syncope only occurs with prolonged standing, group 1 vehicle drivers may continue to drive, but group 2 vehicle divers (bus and lorry) must cease driving immediately and notify the DVLA.

Post-exercise induced neurally-mediated syncope

History

A 22 year old female university student on the rowing team seeks advice from you after developing episodes of syncope following training on a rowing machine. She also experienced episodes of presyncope after rowing whilst still seated in the rowing boat. She has no significant past medical history and is not taking any regular medications. The syncope episodes were witnessed by her teammates and occurred after completing her exercises with loss of consciousness lasting between 10 and 30 seconds. She complained of feeling generally unwell after the episodes.

Examination

Cardiovascular and neurological examination is normal with no postural drop between lying and standing blood pressures.

Which investigations should be performed in primary care?

An ECG is the most useful initial test to perform and her ECG is normal.

What happened next?

Syncope during exercise is a red flag for a cardiac cause; syncope after exercise is usually associated with less severe outcomes. In view of the episodes while seated and high-risk syncope (alone in a rowing boat on water), she is referred for further specialist assessment via a syncope clinic and is advised not to drive until she had undergone further assessment.

Outcome

At the syncope clinic she undergoes further testing and has a normal echocardiogram. Exercise testing is performed and after exercise she is found to develop a significant drop in blood pressure and heart rate and experiences marked presyncope; blood pressure recovers quickly after lying supine. The test is repeated, but this time she is asked to actively cool down after the test and the symptoms do not recur. She is diagnosed with post-exercise induced vasovagal syncope. She can be advised that she can return to driving after 4 weeks.

Learning points

Syncope after exercise is typically vasovagal in origin and benign in contrast to syncope during exercise, which is most likely to be arrhythmic in origin and not benign
Syncope related to exercise can herald a potentially fatal underlying cardiac condition and requires thorough investigation.