Adams–Stokes syndrome

Stokes–Adams syndrome (alternative eponyms include Adams–Stokes syndrome, Gerbezius-Morgagni-Adams–Stokes syndrome and Gerbec-Morgagni-Adams–Stokes syndrome)^[1] is a periodic fainting spell in which there is a periodic onset and offset of blockage of heart due to disorder of heart rhythm that may last for seconds, hours, days, or even weeks before the conduction returns. Named after two Irish physicians, Robert Adams (1791–1875)^[2] and William Stokes (1804–1877),^[3] the first description of the syndrome was published in 1717 by the Carniolan physician of Slovene descent Marko Gerbec, which was 44 years after its publication quoted by Giovanni Battista Morgagni. It is characterised by decrease in cardiac output and loss of consciousness due to a transient arrhythmia. For example, bradycardia due to complete heart block.

Signs and symptoms

Typically an attack occurs without warning leading to sudden loss of consciousness.^[4] Prior to an attack, a patient may be pale with hypoperfusion. Normal periods of unconsciousness last approximately thirty seconds; if seizures are present, they will consist of twitching after 15–20 seconds (seizures occur because of brainstem hypoxia and not due to cortical discharge as evident by EEG findings which show no epileptiform activities). Breathing continues normally throughout the attack, and so on recovery the patient becomes flushed as the heart rapidly pumps the oxygenated blood from the pulmonary beds into a systemic circulation which has become dilated due to hypoxia.^[5]

As with any syncopal episode that results from a cardiac dysrhythmia, the faints do not depend on the patient's position. If they occur during sleep, the presenting symptom may simply be feeling hot and flushed on waking.^{[5] [6]}

Diagnosis

Stokes-Adams attacks may be diagnosed from the history, with paleness prior to the attack and flushing after it particularly characteristic. The ECG will show asystole, an AV block, or ventricular fibrillation during the attacks.

Causes

The attacks are caused by any temporary lack of cardiac output. This in turn could be due to any number of causes, including antimony poisoning, cardiac asystole, heart block, Lev's disease or ventricular fibrillation. Paroxysmal supraventricular tachycardia or atrial fibrillation is the underlying cause in up to 5% of patients [4]. The resulting lack of blood flow to the brain is responsible for the faint.

Treatment

Initial treatment can be medical, involving the use of drugs like isoprenaline (Isuprel) and epinephrine (adrenaline). Definitive treatment is surgical, involving the insertion of a pacemaker – most likely one with sequential pacing such as a DDI mode as opposed to the older VVI mechanisms,^[5] and the doctor may arrange the patient to undergo electrocardiography to confirm this type of treatment.^[7]

Prognosis

If undiagnosed (or untreated), Stokes–Adams attacks have a 50% mortality within a year of the first episode. The prognosis following treatment is very good.

References