Liver pain is a common clinical occurrence, but it is often poorly diagnosed and treated. The liver can serve as a source of pain in and of itself through the sympathetic nervous system and via referred pain secondary to peritoneal irritation through the intercostal and subcostal nerves. Pain that emanates from the liver itself tends to be ill defined and may be referred primarily to the epigastrium. It is dull and aching, and is mild to moderate in severity. The pain can be related to swelling of the liver and concomitant stretching of the liver capsule or distention of the veins, as is seen with portal obstruction. This pain is carried via sympathetic fibers from the celiac ganglion that enter the liver along with the hepatic artery and vein. This type of liver pain responds poorly to adjuvant analgesics. Occasionally, hepatic enlargement causes diaphragmatic irritation, which produces pain that is referred to the ipsilateral supraclavicular and shoulder region. This referred pain is known as the Kehr sign , and is transmitted via the phrenic nerve and often misdiagnosed.
Referred liver pain is caused by mechanical irritation and inflammation of the inferior pleura and peritoneum. This pain is somatic and carried primarily by the lower intercostal and subcostal nerves. This somatic pain is sharp and pleuritic and is moderate to severe in intensity. It responds more favorably to nonsteroidal antiinflammatory drugs (NSAIDs) and opioid analgesics in contrast to sympathetically mediated liver pain.
Signs and Symptoms
The clinical presentation of liver pain is directly related to whether the pain is mediated via the sympathetic or somatic nervous system or both. In patients with sympathetically mediated pain, the abdominal examination may reveal hepatomegaly with tenderness to palpation of the liver. Primary tumor or metastatic disease may also be identified. The remainder of the abdominal examination is nondescript. Auscultation over the liver fails to reveal a friction rub in most cases. As mentioned, the patient may report ill-defined pain in the supraclavicular region
Patients with somatically mediated liver pain present in an entirely different manner. The patient often splints the right lower chest wall and abdomen and takes small, short breaths to avoid exacerbating the pain. The patient may avoid coughing because of the pain and accumulated upper airway secretions, and atelectasis may be a problem.
The abdominal examination may reveal signs of peritoneal irritation over the right upper quadrant. A friction rub is often present with auscultation over the liver. The liver may be extremely tender to palpation. Primary tumor or metastatic disease or both may be present.
How is liver pain investigated?
Testing for patients with liver pain should be aimed at identifying the primary source of liver disease responsible for the pain and ruling out other pathological processes that may be responsible for the pain. Plain radiographs of the chest and abdomen, including an upright abdominal film, are indicated in all patients with pain thought to be emanating from the liver. Radiographs of the ribs are indicated to rule out occult bony pathological conditions, including tumors. Based on the patient’s clinical presentation, additional tests, including complete blood cell count, automated chemistries, liver function test, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated. Computed tomography (CT) and magnetic resonance imaging (MRI) of the lower thoracic contents and abdomen are indicated in most patients with liver pain to rule out occult pulmonary and intra-abdominal pathological processes, including cancer of the gallbladder and pancreas. Positron emission tomography may help identify occult lesions both above and below the diaphragm. Differential neural blockade on an anatomical basis can serve as a diagnostic and therapeutic maneuver.
Pain of hepatic origin must be taken seriously. It is often the result of an underlying serious disease, such as biliary malignancy, portal hypertension, or hepatic metastatic disease. Pain emanating from the liver is often mistaken for pain of cardiac or gallbladder origin and can lead to visits to the emergency department and unnecessary cardiac and gastrointestinal workups. If trauma has occurred, liver pain may coexist with rib fractures or fractures of the sternum itself that can be missed on plain radiographs and may require radionucleotide bone scanning for proper identification.
Neuropathic pain involving the chest wall may be confused or coexist with liver pain. Examples of neuropathic pain include diabetic polyneuropathies and acute herpes zoster involving the lower thoracic and upper lumbar nerves. The possibility of diseases of the structures of the inferior mediastinum and retroperitoneum is ever present, and these diseases sometimes can be difficult to diagnose. Pathological processes that inflame the pleura, such as pulmonary embolus, infection, and Bornholm disease, may mimic or coexist with pain of hepatic origin.
Initial treatment of liver pain should include a combination of simple analgesics and NSAIDs or cyclooxygenase-2 (COX-2) inhibitors. If these medications do not control the patient’s symptoms adequately, an opioid analgesic may be added. Local application of heat and cold may be beneficial to provide symptomatic relief of liver pain. The use of an elastic rib belt over the liver may help provide symptomatic relief.
For patients who do not respond to these treatment modalities, an intercostal nerve block using a local anesthetic and steroid may be a reasonable next step. If the pain is thought to be sympathetically mediated, a celiac plexus block is a reasonable next step. This technique provides diagnostic and therapeutic benefit. If the pain is thought to be somatic, intercostal nerve blocks should be the next step. Pain of hepatic origin may be somatic and sympathetic, and require celiac plexus and intercostal nerve block for complete control. The use of ultrasound guidance may improve the accuracy of needle placement and decrease the incidence of needle-related complications.
The major problem in the care of patients thought to have liver pain is the failure to identify potentially serious pathological processes of the thorax or upper abdomen. Given the proximity of the pleural space, pneumothorax after intercostal nerve block is a possibility. The incidence of the complication is less than 1%, but it occurs with greater frequency in patients with chronic obstructive pulmonary disease. Although uncommon, infection, including liver abscess, remains an ever-present possibility, especially in an immunocompromised patient with cancer. Early detection of infection is crucial to avoid potentially life-threatening sequelae.
Liver pain is often poorly diagnosed and treated. Correct diagnosis of the cause of liver pain and the nerves subserving the pain is necessary to treat this painful condition properly and to avoid overlooking serious intrathoracic or intra-abdominal pathological processes.
Intercostal nerve block is a simple technique that can produce dramatic relief for patients with liver pain thought to be somatically mediated. Celiac plexus block is technically more demanding and should be performed only by clinicians well versed in the technique and potential complications.