When laughter leads to hospital visit: Why 53-year-old Hyderabad man had a medical emergency

After a few minutes, his family felt relief as Shyam opened his eyes, conscious and recognized everyone. He was able to move his arms and legs and hold a conversation with others. However, he had no memory of what had just happened.

By the time Shyam was brought to the emergency room, he had completely recovered and doctors who examined him said he was normal. However, he was referred to Dr Sudhir Kumar, a neurologist at the Apollo Hospital in Hyderabad, for further evaluation.

“I listened to the entire history and clinically examined him. He had no history of any medical illness, and he was not on any medications. The diagnosis was clear to me,” said Dr Sudhir Kumar. The doctor diagnosed him with laughter-induced syncope.

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What is laughter-induced syncope?

Laughter-induced syncope is a rare form of situational syncope (fainting or loss of consciousness) triggered by intense laughter.

Intense laughter can stimulate the vagus nerve, leading to a decrease in heart rate and blood pressure. Laughter increases intrathoracic pressure, which can impede venous return to the heart, reducing cardiac output and cerebral perfusion. Prolonged laughter can cause hyperventilation, which changes the balance of carbon dioxide and oxygen in the blood, potentially leading to vasoconstriction and reduced blood flow to the brain.

“Laughter-induced syncope is a rare entity and is thought to be caused by vasovagal mechanisms. An increase in intrathoracic pressure due to excessive laughter reduces venous return to the heart and stimulates the baroreceptors. This, in turn, causes inappropriate parasympathetic tone with stimulation of the vagus nerve, decreasing heart rate with accompanying vasodilation, causing a sudden transient decline in cerebrovascular perfusion due to low BP and loss of consciousness,” explained Dr Kumar.

Imagine you’re watching a hilarious movie and you start laughing hard. Laughing like this puts a lot of pressure on your chest. This pressure makes it harder for blood to get back to your heart. There’s a nerve called the vagus nerve that gets activated – one can think of it as a switch that controls a person’s heart rate and blood pressure.

The vagus nerve slows down your heart and makes your blood pressure drop. Because of the lower blood pressure, less blood goes to your brain. Without enough blood, your brain doesn’t get enough oxygen for a moment, and you faint. This usually lasts just a few seconds.

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Symptoms

• Sudden loss of consciousness during or after laughing
• A brief period of confusion or disorientation upon regaining consciousness
• Lightheadedness or dizziness

Tests to diagnose a patient

Diagnosis is typically based on the patient’s history and the exclusion of other causes of syncope. Tests that might be conducted include:

• Electrocardiogram (ECG), to check for heart rhythm abnormalities
• Echocardiogram to assess heart function
• Tilt-table test to evaluate how the autonomic nervous system responds to changes in position
• Neurological evaluation to rule out seizures or other neurological conditions

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Treatment and Management

There is no specific treatment for laughter-induced syncope, but management strategies include:

• Avoidance of Triggers – Recognising and avoiding situations that provoke intense laughter
• Physical Countermeasures – Techniques like tensing leg muscles or crossing legs when feeling lightheaded
• Educating patients – Informing patients about the condition to help them understand and manage it better

“I discussed the diagnosis with the patient and attendants and reassured them. I advised Shyam to avoid common triggers for syncope, such as excessive laughter, prolonged standing, and excessive physical exertion. In addition, I asked him to keep well-hydrated. I asked him to lie down if he felt dizzy or if he had a sense of blacking out (symptoms of pre-syncope) so that the blood flow to the brain would not reduce (in case of reduction in blood pressure). No medications are needed to treat this condition. Cardiology evaluation was advised,” said Dr Sudhir Kumar.

Taking to X to post about how he diagnosed and treated Shyam, he explained how even though laughter is considered the “best medicine,” in some cases, it can lead to a visit to the emergency room.

Laughter is the best medicine, however, in case of a 53-year-old, laughter resulted in a visit to emergency department

53-year-old Mr Shyam (name changed) was enjoying a nice evening with his family over a cup of tea. They were watching a popular comedy show on TV. Mr Shyam… pic.twitter.com/TZJAM45QpC

— Dr Sudhir Kumar MD DM (@hyderabaddoctor) May 29, 2024

(Edited by Neena)