Hamman's syndrome

Hamman's syndrome, also known as Macklin's syndrome, is a syndrome of spontaneous subcutaneous emphysema and pneumomediastinum, sometimes associated with pain and, less commonly, dyspnea, dysphonia, and a low-grade fever.
Hamman's syndrome can cause Hamman's sign, an unusual combination of sounds that can be heard with a stethoscope.

Causes

The cause of Hamman's syndrome is most commonly unknown.
Excessive duration and/or intensity of activities that mimic valsalva manoeuvres, i.e. that increase intrathoracic pressure, can cause barotrauma, and hence pregnancy can be a precipitating cause of Hamman's syndrome. Indeed, it is estimated to occur in approximately 1 in 100,000 live births and is associated with prolonged labour times.
Additionally, vomiting and coughing have also been noted as occasional precipitating factors. Hamman's is thus unsurprisingly occasionally known to be associated with asthma, excessive alcohol use and inhalational illicit substance use.
Despite these associations, often, no precipitating cause is found.

Pathophysiology

Macklin described the pathophysiology of Hamman's syndrome to be barotrauma, whereby rupture of alveolar membranes causes a positive pressure gradient of air from the lungs into the mediastinum.

Treatment

Treatment is supportive. Hamman's syndrome tends to be benign and self-limiting. It is important to differentiate it from far more serious conditions that have similar symptoms, such as Boerhaave's syndrome.

History

It was named after clinician Louis Hamman, M.D.