Referred Pain: Identifying Causes and Effective Treatments

Referred Pain vs Local Pain

Local pain is pain that occurs at the site of injury. For example, chronic musculoskeletal pains around injured body parts are called local pains. If you have injured your neck and the pain perceived is in your neck, this chronic musculoskeletal pain is a local neck pain. 

In contrast, referred pain is pain arising in a different part of the body, away from the source of injury or illness. If you have a pinched nerve in your spine and the pain experienced is in the leg instead of low back pain, this is called referred pain.

What Causes Pain To Be Referred?

The transmission of pain signals in the nervous system through an interconnected network of nerves causes pain to be referred.

In other words, referred pain occurs because all the sensory nerves in the central nervous system are part of one big network of nerves. As a result, when the nervous system transmits signals from painful stimuli to the brain, the brain sometimes sends pain signals to a different part of the body. This results in the pain being felt in referred pain areas. 

Simply put, you experience referred pain when your brain receives signals from one part of the body and transmits pain signals to a location other than where the pain originates.

What Are Some Examples of Referred Pain?

Brain Freeze

Brain freeze is a classic example of referred pain. It is a short-lived, intense pain in the head region that occurs after eating something very cold. In this case, extreme cold in the mouth and throat is the origin of the pain, but the pain is felt in the forehead and temples. 

The exact mechanism of brain freeze is unclear, but scientists believe the sudden drop in temperature in the mouth and throat causes blood vessels in this region to rapidly become narrower. This triggers arteries in the head region to dilate (widen) in an effort to warm the area. The expanding pressure exerted by the arteries irritates the trigeminal nerve, which relays pain symptoms to the head region.

Kehr's Sign

Kehr's sign is left shoulder blade pain experienced by people with a ruptured spleen. This shoulder pain is a referred muscle pain caused by irritation of the undersurface of the diaphragm from bleeding as a result of splenic rupture. You can feel pain in your shoulder when you’re lying down with your legs elevated. 

Kehr’s sign can be explained by the irritation of the diaphragm being transmitted as pain signals in the phrenic nerve. The phrenic nerve shares cervical nerve roots C3 and C4 with the supraclavicular nerves, which supply the area of the collarbone. As a result, pain signals in the phrenic nerve get transmitted to the supraclavicular nerves, causing left shoulder pain. This is called Kehr's sign and is a diagnostic symptom in people with a splenic rupture. In contrast, right shoulder pain can signal problems in the liver or gallbladder.

Jaw Pain

Another common example of referred pain is jaw pain. This can be from a variety of causes, including cluster headache, dental abscess, gum disease, sinus problems, and even something serious such as a heart attack. 

A person having a heart attack can feel pain in their jaw and left arm due to the distribution of nerves in the spinal cord. The nerves in the spine that detect pain signals from the heart muscle are located in roughly the same area of the spinal cord as the nerves that detect pain in the jaw and left arm. As a result, some people with an impending heart attack feel pain in the jaw for a few days before the heart attack or develop left arm pain during a heart attack.

Chronic Low Back Pain

In people with peptic ulcer disease, the pain caused by a stomach ulcer can travel from the stomach upwards, causing neck pain, or downwards, causing low back pain. Similarly, pancreatitis (an inflammation of the pancreas) can also cause referred pain in the back or below the shoulder blade.

Learn about “Sciatic Nerve Pain Relief: Best Methods and Solutions.”

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Causes of Referred Pain

Neurological Pathways

Research findings suggest that referred muscle pain occurs when nerve cells in the spinal cord and brainstem receive signals from different parts of the body but cannot pinpoint the exact source of pain. 

Local pain occurs due to activity in the nerve pathways going towards the spinal cord. At the same time, it initiates a process of releasing substances that make the nerves more sensitive. This causes latent synaptic connections (inactive nerve connections) in the referred area to open up (to become active), causing referred pain. 

Note: Phantom limb pain is a sensation of pain in a limb that has been amputated. It is different from referred pain.

Common Sources and Triggers

The most common sources and triggers for referred pain are pain radiating from a spinal segment or sacroiliac joint (spinal referred pain), internal organs (visceral referred pain), tumors (referred bone pain or nerve pain), or infections. 

Referred pain can occur anywhere in the body, but the pain location is frequently in the jaw, neck, shoulders, and back.

Examples include:

• Nerve compression in the spine, causing pain in referred areas such as the buttocks or legs

• A pinched nerve in the neck causing pain in the shoulder or elbow 

• Pain from gallbladder inflammation, causing referred pain in the right shoulder

• Pain from a heart attack resulting in left arm or left shoulder blade pain

• Chronic musculoskeletal pains from joint disorders, muscle spasms, or injuries causing referred muscle pain in distant areas

Conditions Associated with Referred Pain 

A wide range of conditions can be associated with referred pain, including heart, lung, liver, gallbladder, pancreas, spleen, stomach, intestinal, and kidney problems.

Certain medical treatments can also cause referred pain. For example, intramuscular electrical stimulation (IMES) for myofascial pain syndrome involves inserting needles into trigger points. This can cause referred pain by causing an expansion of the receptive fields and referred areas.

Affected Areas and Pain Location of Referred Pain

• Referred pain in the upper back or shoulder can be from a ruptured spleen. This is called the Kehr sign (the pain is between the shoulder blades).

• Referred pain in the lower back muscles or oblique muscles (flanks) may be from colon issues, kidney problems, or pancreatitis.

• Referred pain in the shoulder could indicate problems in the heart, lungs, or liver.

• Referred pain in the upper limb could be a sign of chest pain (angina), heart attack, shingles, or fibromyalgia. 

• Referred pain in the jaw and teeth could be from trigeminal neuralgia or a heart attack.

Clinical Diagnosis of Referred Pain

How to Recognize Referred Pain?

• Referred muscle pain can feel like a dull ache. It can also be a deep, burning, gnawing, tightening, or pressure-like pain that may spread over larger areas. Referred pain feels different from neuropathic (nerve) or cutaneous (skin) pain.

• Referred pain can last anywhere from a few seconds to a few hours, days, weeks, or longer.

• Other symptoms accompanying referred muscle pain can include numbness, tingling, a sensation of coldness, stiffness, weakness, and fatigue. 

• Muscle and joint referred pain can have a similar distribution.

• Referred pain can spread in a cranial/caudal direction (up and down) or ventral/dorsal direction (front and back).

Referred Pain vs Radiating Pain or Radicular Pain

As mentioned, referred pain is pain perceived in a part of the body that is distant from the origin of the pain. In contrast, radiating pain, also called radicular pain, is a pain that begins in one part of the body and spreads to a larger surrounding area. 

Like referred pain, radiating pain also involves the nerves. For example, a pinched nerve or herniated disk in the spine can cause pain radiating down the leg accompanied by other symptoms such as weakness, numbness, and tingling. Radiating pain or radicular pain can also stem from nerve irritation in the neck causing neck pain that spreads to the arms and hands. 

A key difference between radiating pain and referred pain is that radiating pain follows specific nerve pathways to surrounding areas, whereas referred pain can occur in many places in the body located at a distance from the injured tissue.

Diagnostic Measures and Tools

If you are experiencing pain without any injury in the area, your healthcare provider may suspect referred pain. They will perform a physical examination and try to find the source of your pain by asking you questions about:

• A history of injuries or accidents.

• Timing (when the pain started).

• Duration (how long the pain has been occurring).

• Pain location.

• Nature (whether the pain is constant or comes and goes).

Your doctor may order blood tests and imaging studies such as X-rays, ultrasounds, CT (computed tomography) scans, MRI (magnetic resonance imaging) to find the origin of the pain stimulus. 

Treatment and Management of Referred Pain

The pain felt in referred areas should be evaluated by a healthcare provider. It is important to treat the source of the pain. Simply treating referred pain itself will not solve the problem.

Multidisciplinary Approach

A team of healthcare professionals from different specialties may need to work together to treat referred pain by treating the underlying cause. If referred pain continues after the underlying condition has been diagnosed and treated, your healthcare provider may offer pain management with pain relievers, acupuncture, physical therapy, and TENS (transcutaneous electrical nerve stimulation).

Home Remedies: Tips for Managing Referred Pain

Home remedies for short-term pain management include: 

• Taking over-the-counter pain relievers and anti-inflammatory drugs such as acetaminophen (Tylenol) and ibuprofen (Advil, Motrin). Check with your doctor or pharmacist to make sure it’s safe for you to take these OTC pain medications and follow the instructions for the recommended dosage.

• Resting the affected area to allow healing.

• Applying heat and/or ice to the painful areas.

• Taking Epsom salt baths to ease muscle pain and tension.

When to See a Healthcare Provider

Call 911 or go to the nearest emergency room if you have symptoms such as unexplained shoulder pain, arm pain, jaw pain, or teeth pain—these can be heart attack symptoms.

Contact your healthcare provider immediately if you have unexplained pain that does not get better with over-the-counter pain medications or keeps coming back.