Overview

Imagine a space within your chest, cradled by your lungs. This space houses your heart, the tube carrying air (windpipe), the pathway for food (oesophagus), and other essential organs, it is called the mediastinum. Now, imagine that space becoming inflamed or infected will cause a condition known as mediastinitis. It is a serious condition requiring prompt medical attention.

Mediastinitis is an infection in the chest cavity (this space houses your heart, the tube carrying air (windpipe), the pathway for food (oesophagus), and other essential organs, it is also called mediastinum). It can start abruptly (acute) or gradually (chronic). Acute cases often arise from complications after chest surgery or a tear in the oesophagus.¹

 It's crucial to recognize the signs because early action is key to fighting this infection. This article will explore the different forms of mediastinitis, how it arises, and the surgical procedures used to treat it.

Causes of mediastinitis

Mediastinitis can develop from a variety of factors, and the onset time can vary, as follows:^{1, 2, 3}

Acute mediastinitis

This form starts suddenly, often due to an infection in the chest cavity. The following are some common triggers:

• Surgical complications: bacteria, particularly Staphylococcus aureus, can infect tissues during or after chest surgery, especially those involving the breastbone (after sternotomy)
• Oesophageal problems: a tear in the oesophagus, the tube connecting your mouth to your stomach, can allow food or fluids to leak into the mediastinum, causing infection. This tear can happen due to forceful vomiting, medical procedures like endoscopy, or a condition called Boerhaave syndrome(a rupture in the oesophagus due to forceful vomiting)
• Spread of infection: an existing infection in nearby areas can sometimes travel to the mediastinum. This could be from the lungs, pancreas, or even a severe tooth infection

Chronic mediastinitis

This type develops more slowly and the cause isn't always clear. It includes the following:

• Fungal infection: the most common cause is histoplasmosis( a fungal infection contracted through inhalation). It often resides in the Ohio and Mississippi River valleys in the US but can be found in other parts of the world. While exposure doesn't always lead to illness, in some cases, the immune system can overreact to the fungus much later, causing inflammation in the mediastinum
• Chronic infections: tuberculosis or other long-term infections can also contribute
• Medical procedures or exposure: radiation therapy or exposure to certain materials like silica dust can play a role

Types of mediastinitis

While the causes are diverse, there are different forms of mediastinitis based on their origin:^{2, 3}

• Postoperative mediastinitis: this occurs after chest surgeries, particularly those involving the breastbone
• Descending necrotizing mediastinitis: this arises when an infection from the head or neck, such as a dental abscess, travels down to the chest cavity
• Fibrosing mediastinitis: the exact cause of this type is unknown, but it's believed to be linked to either an immune response to an infection or non-infectious processes like sarcoidosis (an inflammatory disease)

Symptoms of mediastinitis

Mediastinitis can be a serious condition. While uncommon, it's important to be aware of the warning signs so you can seek medical attention.^2,3,4

Unlike some illnesses, mediastinitis symptoms often develop over a few days, not suddenly

• Feeling unwell: you might experience fever, chills, or just a general feeling of being under the weather
• Chest pain: this is a common symptom, often described as a sharp, stabbing pain behind your breastbone (sternum). It may radiate to your neck or back
• Difficulty breathing: shortness of breath or feeling winded can be a sign of mediastinitis
• Neck problems: depending on the cause of the infection, you might experience pain, swelling, or a feeling of congestion in your neck

In severe cases, symptoms can include:

• Confusion or disorientation
• Signs of infection at the chest incision site (if you had recent surgery)
• Shock

Diagnosis

Mediastinitis requires a multifaceted approach to diagnosis. The key steps involved are the following:^2,4,5

Initial evaluation

The priority is ensuring the patient's stability. Doctors check the ABCs: airway, breathing, and circulation. If breathing or blood circulation is affected, resuscitation measures take precedence over any diagnostic tests.

Physical examination

During a physical exam, your doctor will be looking for signs that support a mediastinitis diagnosis. These might include:

• Fever: an elevated body temperature is a sign of infection
• Neck swelling or redness: inflammation in the neck area can be a clue
• Crackling sounds under the skin (Surgical Emphysema): this can occur due to air trapped in the tissues
• Signs of mouth or throat infection: your doctor might check for sources of infection in these areas
• Swollen lymph nodes in the neck: enlarged lymph nodes can indicate your body is fighting an infection
• Nerve problems in the face or neck: mediastinitis can sometimes cause nerve damage
• Abnormal heart sounds: certain heart sounds can indicate complications

Laboratory tests

• Blood tests: these can reveal signs of infection, such as elevated white blood cell count (leukocytosis), increased C-reactive protein (CRP), and procalcitonin levels
• Blood cultures: especially important in suspected postoperative mediastinitis, blood cultures are used to identify bacteria in the bloodstream, a common feature of this condition

Imaging tests

• Chest X-ray: a valuable initial tool, but limitations exist. While it can reveal signs like mediastinal widening or air in the chest cavity (pneumomediastinum), it might not always provide a definitive picture, especially early on
• Computed Tomography(CT) scan and magnetic Resonance Imaging (MRI) scan: these advanced imaging techniques offer a more detailed view of the mediastinum. They can detect inflammation, pus collections, or other abnormalities with greater accuracy

Management

Mediastinitis is a serious infection, and its management requires a swift and coordinated effort. ^{2, 3, 4}

Non-surgical management

This approach is typically used for less severe cases of mediastinitis or as a supportive measure alongside surgery.

Antibiotics: the cornerstone of non-surgical management is the administration of broad-spectrum intravenous antibiotics. These antibiotics target a wide range of bacteria until the specific organism is identified through cultures. Once identified, doctors can refine the antibiotic regimen to target them directly.

Surgical interventions

Surgery plays a critical role in treating most cases of mediastinitis, particularly those that are moderate or severe. The specific surgical approach depends on the severity, location, and cause of the infection.

Surgical drainage and debridement

 It is an approach to the removal of infected and dead tissue.  It is generally necessary for successful treatment, and occurs as follows:

• Superficial infections: for less severe infections near the surface, doctors might perform an incision, drain any pus, pack the wound to promote healing, and administer antibiotics
• Deep infections: for deeper infections, a more extensive debridement procedure is needed. This involves removing infected and dead tissue, irrigating (cleaning) the mediastinal space, and administering antibiotics
• Severe cases: in the most severe cases, the wound might need to be left open for some time before a secondary closure procedure can be performed

Specific considerations

They are:

• Post-operative observation: it is crucial to closely monitor patients after surgery. This includes conducting repeat CT scans to evaluate treatment response, lab tests to monitor progress and consistently assessing the patient's condition through clinical evaluations. Given the seriousness of the illness, patients often require monitoring and care in an intensive care unit
• Fibrosing mediastinitis (chronic mediastinitis): unfortunately there is no treatment for chronic mediastinitis due to the unknown exact cause. While there is evidence supporting medication therapies some treatment approaches may involve the use of immunosuppressants, corticosteroids or antifungals. For patients experiencing symptoms, surgical interventions such as stents or bypasses may be considered to alleviate pressure on affected structures

FAQs

Is mediastinitis contagious?

Mediastinitis itself isn't contagious from person to person. However, the bacteria that cause it can be contagious depending on the source of the infection. For example, if staphylococcus bacteria is the cause of your mediastinitis from a skin infection, someone with close contact might be at risk of catching that specific infection.

What happens during mediastinitis surgery?

Generally, surgeons will make an incision in the skin to access the infected area, drain any pus, and remove infected tissue. This procedure usually needs general anaesthesia.

How long does recovery from mediastinitis take?

Recovery depends on the surgical approach and infection severity. Expect several days in intensive care followed by a hospital stay for continued recovery. Full recovery can take weeks or months, sometimes with physical therapy.

Are there any long-term complications from mediastinitis?

While early and proper treatment can significantly reduce the risk of complications, some potential long-term effects exist including, scarring, chronic pain, and organ damage.

Summary

Mediastinitis, a serious infection behind your breastbone, can cause a sudden onset of fever, chills, and stabbing chest pain. Difficulty breathing and swelling or pain in the neck can also be warning signs. Doctors diagnose mediastinitis through a physical exam, imaging tests like X-rays, and blood work. Early diagnosis is important. 

For milder cases, strong antibiotics might be enough, but most situations require surgery to drain any pus and remove infected tissue. This procedure is often accompanied by antibiotics as well. There's a rarer chronic form where the cause is unknown, but surgery and medications can help manage symptoms in those cases.