Elevated Hemidiaphragm

What is Elevated Hemidiaphragm?

The diaphragm, a thin, dome-shaped muscle, is like a pump for your breathing and it’s the chief muscle used when you take a breath. Elevated hemidiaphragm happens if one part of the diaphragm gets weak due to muscle disease or nerve damage, specifically to the phrenic nerve which controls the diaphragm. This can lead to difficulty in breathing but sometimes, this is only identified on body scans and the person doesn’t exhibit any symptoms.

The phrenic nerve runs over a muscle called the anterior scalene muscle, in the neck. When an anesthesiologist gives an interscalene block (regional anesthesia) for a shoulder or arm surgery, sometimes the phrenic nerve can get paralyzed. This complication is reported in many anesthesia and neurosurgery studies.

During inhalation, or drawing in of the breath, the diaphragm flattens which pulls in air to the lungs. When exhaling, or breathing out, the diaphragm relaxes and lets air flow passively out of lungs. This action creates a sort of vacuum which helps to pull air into lungs. Also, as the diaphragm contracts, it moves the lower part of the chest downward and the sides expand. This inflates the lungs and allows for the exchange of gases- oxygen coming in and carbon dioxide going out.

The diaphragm has three points of origin which forms a C-shape ending in a dense, stable tendon in the center. Different groups of muscle fibers originate and attach onto different parts of the body. There are three openings in the diaphragm that lets structures pass between the chest and belly. These include the spots for the esophagus and vagus nerve, the aorta, azygos vein and thoracic duct, and the iron-rich protein, inferior vena cava.

The diaphragm separates the chest cavity from the belly cavity, being the floor of the chest and the top of the belly. The diaphragm is divided into right and left halves, each with its own blood supply.

The diaphragm is controlled by the phrenic nerve that emerges from the neck region (cervical nerve roots of C3-C5) and enters the chest cavity to control the right and left halves of the diaphragm.

Elevated Hemidiaphragm is a condition where one side of the diaphragm is higher than the other. Often, this is found incidentally on body radiological scans like chest X-ray or chest CT. A person normally does not show symptoms because other breathing muscles are used. Also, the healthy half of the diaphragm can adapt to maintain the necessary pressure gradient for proper gas exchange.

However, in severe cases where one half of the diaphragm is paralyzed, a person’s capacity to inhale may be stifled, causing problems with heart function. Under normal conditions, the pressure in the chest and the contracting diaphragm help with blood flow to the heart from the large vein responsible for returning blood back to the heart (inferior vena cava or IVC). When this pressure balance cannot be sustained, blood flow to heart is reduced leading to potential heart problems. Hence, accurate diagnosis and treatment of elevated hemidiaphragm is crucial, especially in patients with difficulty in breathing and multiple organ involvement.

What Causes Elevated Hemidiaphragm?

The causes of a raised hemidiaphragm can be grouped into three categories: above the diaphragm, at the diaphragm, and below the diaphragm.

Above the Diaphragm

The diaphragm, which is the main muscle helping us breathe, is controlled by the phrenic nerve. If this nerve is damaged due to injury, disease, or sometimes for no known reason, it can result in weakened or completely paralyzed diaphragm, also known as diaphragmatic palsy.

The nerve damage can occur in several ways, from brain-related diseases, spine injury, or disorders that damage the nerves and muscles such as Amyotrophic lateral sclerosis (ALS), Multiple Sclerosis (MS), Myasthenia Gravis, or Muscular Dystrophy. These diseases can impair the normal function of the phrenic nerve and the muscles of the diaphragm, resulting in its weakness.

Stroke that affects the middle cerebral artery in the brain can paralyze the opposite side, potentially causing the diaphragm on the other side to rise. Similarly, an injury to the brachial plexus (a bundle of nerves running from the spine, through the neck, to the arm) can affect the function of the phrenic nerve. Neck surgeries, trauma, certain types of spinal fractures, or age-related wear and tear to the neck (cervical spondylosis) can also cause the phrenic nerve to weaken, resulting in an elevated hemidiaphragm.

An unfortunate common consequence of cardiac surgery, specifically on the left side of the heart, is phrenic nerve damage. This often occurs when the heart is cooled during surgery or if the phrenic nerve is stretched, leading to an elevated left hemidiaphragm.

Lung conditions like pneumothorax (collapsed lung), removal of part or all the lung, or birth defects affecting lung development can also cause the hemidiaphragm to rise. In a rare instance, long-term, severe coughing in asthmatics has led to a part of the stomach pushing through the diaphragm (hernia), causing a raised right hemidiaphragm.

At the Diaphragm

In some cases, a birth defect can lead to incomplete muscle development of the diaphragm, causing that area of the diaphragm to have an abnormal shape — this is called diaphragmatic eventration. Penetrating trauma such as a stab wound can also directly injure the diaphragm and lead to it rising.

Below the Diaphragm

Problems with the liver can commonly lead to a raised right hemidiaphragm. If the liver is abnormally large because of a disease process, an abscess or tumor, it can push up the right hemidiaphragm. A distended stomach, tumors in the abdomen, a distended abdomen, abscesses, an enlarged spleen, or a twisted colon can cause the left hemidiaphragm to rise.

In extreme cases, the stomach or colon can rupture, trapping air under the diaphragm and making it rise. There are also rare cases where part of the colon pushes above the liver, which will show up as air under the right diaphragm on imaging — this is called Chilaiditi sign. If the intestine that is looped above the liver gets blocked, it results in Chilaiditi syndrome.

Risk Factors and Frequency for Elevated Hemidiaphragm

Having one elevated part of the diaphragm (hemidiaphragm) is seen more often than having weakness in both sides of the diaphragm. Both conditions can be caused by the same factors, but the rates at which they occur can vary. We don’t know exactly how often disorders of the diaphragm happen because they can be hard to diagnose. They’re often overlooked because their symptoms can be subtle, and because they can be caused by different things. However, we do have an idea about how often many specific causes of these disorders occur.

For example, coronary artery bypass grafting surgery – a type of heart surgery – is known to sometimes cause nerve damage that can lead to postoperative diaphragmatic paralysis. The occurrence of this has been reported to range from as low as 1% to as high as 60%, and certain factors related to the surgery can increase the risk of nerve damage.

Guillain-Barre disease is another condition that can cause diaphragmatic weakness. It has been found that up to 25% of patients with this condition can develop weakness in the diaphragm severe enough to need mechanical ventilation.

Signs and Symptoms of Elevated Hemidiaphragm

In order to figure out why a patient’s diaphragm might be elevated, a detailed medical history and a thorough physical examination are crucial. Several factors may cause this condition, including a recent lung infection, neurological and muscle disorders, autoimmune diseases, birth defects, and injuries. When patients have serious breathing problems and their medical background isn’t readily available, imaging tests can help eliminate other causes. In most cases, people with this problem have no symptoms and only find out when a chest image shows one side of their diaphragm is higher than usual.

• Breathlessness during mild exercise
• General muscle fatigue
• Chest pain
• Difficulty breathing while lying down on the impaired side or when the belly is underwater

People with existing lung diseases may experience more severe symptoms.

In a physical check-up, the doctor might find:

• Lowered breath sounds
• A dull sound when tapping the lower chest on the affected side
• Contracting belly during inhaling
• Low oxygen levels in the blood due to lung collapse
• General or localized neurological problems

Testing for Elevated Hemidiaphragm

An elevated hemidiaphragm usually doesn’t cause any symptoms and around 90% of such cases are discovered by chance when you get unrelated scans or images (like an x-ray or ultrasound) taken for other purposes. In urgent cases, the fastest and most reliable way to check how the diaphragm muscle is working is by conducting an ultrasound, which can be done easily at the patient’s bedside.

1. Ways to Diagnose Elevated Hemidiaphragm with Imaging

Fluoroscopy:

This type of imaging used to be the most commonly used. During a fluoroscopy, patients are asked to perform a “sniff” test: they forcibly inhale (like they would when sniffing) while their diaphragm is examined. In people with an elevated hemidiaphragm, the weakened side of the diaphragm will move in an abnormal way during inhalation. However, fluoroscopy uses a form of radiation, which may raise cancer risk.

Ultrasound:

Nowadays, ultrasound has become a more preferred method of assessment. It’s quick, non-invasive (meaning it doesn’t require incisions or needles), portable, and safe as it does not use radiation. The diaphragm can be visually studied in M-mode and appears as a thick line. When the diaphragm contracts (during inhalation), it should be about 20% thicker compared to when you are breathing normally. If it doesn’t thicken by 20% or if the diaphragm is less than 15mm thick, this could indicate diaphragm weakness.

Chest X-Ray:

To get a clear view of the diaphragm, you may be asked to take a deep breath, and stand upright during an X-Ray. If you have an elevated hemidiaphragm, one side of your diaphragm will be more than 2cm higher than the other side. The Chilaiditi sign can also be spotted in an x-ray, which shows bowel loops above the liver.

Chest and Abdomen Computed Tomography Scan (CT):

If you are suspected to have a diaphragmatic injury, you should have a CT scan of your chest. It is essential to find out, identify, and rule out the reasons for an elevated hemidiaphragm. A CT scan of your chest and abdomen will help spot any masses or abnormalities that might be causing the diaphragm to be elevated.

2. Non-imaging Tests

EKG (Electrocardiogram):

This test helps rule out acute coronary syndrome and checks how well the heart is working.

Echocardiogram:

This is another test to evaluate the pumping function of your heart.

Pulmonary Function Tests (PFT):

The diaphragm is responsible for 80% of the force needed for breathing. If it’s not working properly, the lungs can’t expand as they should, leading to restrictive lung disease. Elevated hemidiaphragm would show a reduced forced vital capacity (a measure of the amount of air you can forcibly exhale) of 30% of the predicted normal value. If both sides of the diaphragm are paralyzed, the forced vital capacity may decrease by 75%.

Electrophysiological studies:

These tests help identify whether the cause of the diaphragm not functioning properly is because of a muscle or a nerve issue.

3. Lab Tests

Arterial blood gas (ABG) analysis:

This kind of test checks if the body is getting enough oxygen and releasing carbon dioxide properly.

Treatment Options for Elevated Hemidiaphragm

The treatment for a raised hemidiaphragm, or when one half of your diaphragm is higher than it should be, is influenced by the severity of your condition and the underlying cause. The severity is determined by your symptoms, imaging tests, and lab results, and your doctor will consider whether you have other long-term conditions like COPD (a type of lung disease), heart failure, or obesity which could potentially make your breathing issues worse. The best way to treat a raised hemidiaphragm is to address the underlining cause.

If you’re experiencing serious breathing difficulties or if your diaphragm is entirely paralyzed, you might need to be intubated—have a tube put down your throat—and put on a ventilator machine to help you breathe. Most people with a raised hemidiaphragm, though, do not show any symptoms. In these cases, especially when the cause is unknown, you might not need any treatment.

A raised hemidiaphragm might be caused by issues with your phrenic nerve, which controls the diaphragm, but this can sometimes get better on its own. Some people find that certain exercises which strengthen their breathing muscles, including the diaphragm can help. If your phrenic nerve is seriously impaired causing weak diaphragm or if you’re experiencing breathing difficulties, using a ventilator machine at bedtime might be beneficial.

If you have a raised hemidiaphragm, your doctor might use imaging, like an ultrasound, to check in on your condition periodically. Although there’s no definitive test for this, getting an ultrasound every 3-6 months could be a good way to monitor your condition while also minimizing your exposure to radiation. Ultrasound is highly valuable as it shows the diaphragm’s movements and size in real-time which can show any changes over time.

In cases where diaphragm paralysis has progressed to a stage of complete inability to move, or if the diaphragm has not healed within a year, or if your breathing has really increased in labor, then a more complex procedure called diaphragmatic plication may be needed. This procedure involves sewing the weaker part of the diaphragm to the core muscle component and peripheral muscles, and several studies have shown that it can reduce breathlessness and improve lung function by between 10% and 30%. The weak part of your diaphragm is then held taut, allowing your lung to inflate better, and reducing the work of the other half of the diaphragm. However, this surgery isn’t recommended for all patients, especially those with weakness on both sides of the diaphragm, a neuromuscular disease, and obesity.

In some cases, a treatment called phrenic nerve pacing may help to significantly improve symptoms. This procedure involves implanting electrodes at certain areas of your diaphragm, that receive electrical impulses sent through the phrenic nerve. This makes the diaphragm contract or tighten, thus helping it to function better. Some patients who required a ventilator for breathing have found this to be a beneficial treatment, and it has helped wean them off the ventilator with a positive long-term outlook. This procedure can be especially helpful for patients who have diaphragm paralysis due to spinal cord injury and neuromuscular disease.

What else can Elevated Hemidiaphragm be?

A raised hemidiaphragm can be caused directly by damage to the phrenic nerve or the hemidiaphragm itself. It can also happen indirectly due to injuries, nervous system diseases, or cancer in the chest or abdomen. Symptoms of diaphragm issues can range from none at all to severe difficulty breathing. It’s important to figure out what’s causing a raised hemidiaphragm to treat and manage it properly. However, several other conditions might look and feel similar, so they’ll need to be ruled out.

Here are some conditions that can look similar to a raised hemidiaphragm :

• Subpulmonic Effusion: This is when fluid builds up at the base of the lung. The fluid can look like a raised hemidiaphragm in X-rays.
• Diaphragmatic Hernia: This condition usually happens in newborns. It’s when the diaphragm muscles don’t close completely, causing a hole in the diaphragm. On an X-ray, a Morgagni hernia (which is in the front part of the diaphragm) can look like a raised hemidiaphragm.
• Diaphragmatic Rupture: The diaphragm can tear or burst because of an injury.
• Diaphragm or Pleural Tumor: A tumor could grow on the surface of the diaphragm or push against it, making it look raised in images.

What to expect with Elevated Hemidiaphragm

The outcome for elevated hemidiaphragm, or when one side of your diaphragm is higher than it should be, depends on how severe it is and what’s causing it. If the issue is due to a problem with an organ below the diaphragm, removing or fixing that organ can often resolve the problem.

A patient who has had a traumatic injury to the phrenic nerve, which controls the diaphragm, usually has a brighter outlook than those who have weakness in both sides of the diaphragm due to nerve and muscle diseases.

The leading cause of death in patients with nerve and muscle disorders like ALS (Amyotrophic Lateral Sclerosis), MS (Multiple Sclerosis), or myasthenia gravis is respiratory failure. This means they can’t breathe properly because their diaphragm, a crucial muscle for breathing, is paralyzed.

Possible Complications When Diagnosed with Elevated Hemidiaphragm

Problems related to a high diaphragm, usually due to nerve or muscle damage, can lead to breathing problems. These can become severe, inducing respiratory failure or even heart failure. Essentially, the diaphragm, a crucial muscle in our body for breathing, struggles to do its job. This also impacts the change in pressure that our heart needs to pump blood around the body effectively.

Potential Complications:

• Respiratory distress or breathing problems
• Respiratory failure, an extreme breathing problem where oxygen levels drop dangerously low or carbon dioxide levels rise dangerously high
• Heart failure, where the heart can’t pump blood as well as it should
• Diaphragm dysfunction, where the main respiration muscle cannot perform its role effectively
• Idequate blood flow impairment, impacting the heart’s normal functioning

Preventing Elevated Hemidiaphragm

Patients who have a high diaphragm should be made aware of any symptoms that might mean they need emergency help, signs that the condition is getting worse, and how necessary it is to stick to regular check-ups and medication. A diaphragm is the muscle at the bottom of your chest, and when it’s ‘high’, it isn’t working as it should. For patients who also have a neuromuscular disease, which affects the nerves controlling your muscles, they may need to receive extra care. This could come from doctors who specialize in the nervous system (neurologists), diseases caused by your body’s immune system (rheumatologists), or lung disorders (pulmonologists).