Hamman's syndrome

Overview

Hamman's syndrome, also known as spontaneous mediastinal emphysema, is a rare condition characterized by the presence of free air in the mediastinum (the central compartment of the thoracic cavity) without an obvious traumatic cause. It is most commonly seen in young adults and can occur suddenly, often during strenuous physical activity, labor, severe coughing, or vomiting. Although the condition may sound alarming, it is generally benign and self-limiting.

Causes

Hamman's syndrome results from alveolar rupture, where air escapes from the lungs into the mediastinum. This occurs due to a sudden increase in intra-alveolar pressure. Common triggers include:

• Forceful coughing or sneezing

• Vomiting (particularly prolonged or forceful)

• Asthma exacerbations

• Intense physical exertion

• Labor and delivery (in women)

• Valsalva maneuver (straining against a closed airway)

In some cases, no clear precipitating event is identified.

Symptoms

Symptoms of Hamman's syndrome typically appear suddenly and may include:

• Chest pain (often sharp and retrosternal)

• Shortness of breath or dyspnea

• Neck pain or swelling

• Voice changes or hoarseness

• Subcutaneous emphysema (air under the skin), often felt as crackling on palpation of the chest or neck

• Hamman’s sign – a crunching or popping sound heard over the heart during systole, best heard with a stethoscope

Diagnosis

Diagnosis is based on clinical presentation and imaging studies. Diagnostic steps include:

• Physical examination: May reveal subcutaneous emphysema or Hamman’s sign.

• Chest X-ray: The most commonly used imaging to confirm the presence of air in the mediastinum.

• CT scan: Offers more detailed visualization, especially if the diagnosis is uncertain or complications are suspected.

• Electrocardiogram (ECG): May be performed to rule out cardiac causes of chest pain.

Treatment

Hamman's syndrome is typically benign and does not require invasive treatment. Management is usually conservative and supportive:

• Rest and observation

• Oxygen therapy – may help absorb mediastinal air more quickly

• Analgesics – to relieve chest pain

• Treatment of underlying cause – such as managing asthma or stopping vomiting

Hospitalization is rarely required unless there is concern for complications or the underlying cause needs further evaluation.

Prognosis

The prognosis for Hamman's syndrome is excellent. Most cases resolve spontaneously within a few days without recurrence or long-term effects. However, identifying and addressing any underlying condition (such as asthma or persistent vomiting) is essential to prevent future episodes. Follow-up may be recommended in some cases to ensure full resolution of symptoms and mediastinal air.