Post-traumatic Intercostal Neurlagia (A hidden cause of chest pain) / July 2012

         Chest pain has numerous causes and most of them are not cardiac.  Nevertheless, expensive cardiac investigations are often performed on patients with chest pain-partly because patients and physicians harbor fears of missing heart attacks and partly because it is legally safer to rule out heart disease before dismissing the patient.  This tendency for disproportionate chest pain investigation has been compounded by overwhelming advances in technology, which have eroded the clinical confidence of physicians, thus rendering most of them less comfortable in diagnosing and treating chest pain without resorting to a certain amount of cardiac testing.  The cost to society of such fear-generated, cardiac evaluations is high and the harms that arise from them are substantial.

         Among the many non-cardiac causes of chest pain is the Post-traumatic Intercostal Neuralgia Syndrome.  This syndrome, which is thought to be rare, is actually common.  However, it is rarely diagnosed because the diagnosis cannot be established with laboratory tests, x-rays, endoscopies, MRIs, etc.  It remains a stubbornly clinical diagnosis, which means that the examining physician must make the diagnosis solely with the history and physical examination, unaided by tests.

         There are 12 thoracic nerves; they arise from the spinal cord and travel around the ribcage in the grooves located underneath each rib.  Whereas the upper intercostal nerves wrap around the rib cage, the lower nerves drop towards the abdominal wall as they reach the front.  Of the 12 nerves, the 7th terminates at the bottom of the sternum, the 10th at the umbilicus, and the 12th at the lower abdominal wall and groin.  Even though the upper 11 nerves are intercostal because they travel between ribs while the 12th nerve is not because there is no rib beneath it, the term Intercostal Neuralgia is used to indicate pain along any of the 12 thoracic nerves.  

         There are many causes of Post-traumatic Intercostal Neuralgia such as a) falls, b) athletic activities, c) prolonged, violent coughing d) surgical operations which pin the patient in certain positions for prolonged periods, and e) chest and back traumas.  The trauma may be minor and not always obvious but a detailed history will usually elicit the required evidence.  Non-traumatic causes, which include a) osteoporosis with vertebral collapse, b) degenerative thoracic disks, c) painful neuropathies, d) rib-joint arthritis, e) spine deformities such as scoliosis, f) infections such as shingles, g) certain intra-thoracic tumors, and h) etc. are not part of this discussion.  Nevertheless, all conditions that cause the Intercostal Neuralgia Syndrome do so by compressing, irritating, or damaging the thoracic nerves.  There is a paucity of published research on the Post-traumatic Intercostal Neuralgia Syndrome because it is primarily subjective (cannot be measured with tests), is often self-limited, and is not usually life threatening.

         The diagnosis should be suspected when chest movements (such as bending, rotating, coughing, or breathing) increase the pain and when different positions reduce or worsen it.  The character of the pain varies; it may be constant or episodic, acute or chronic, and it commonly traces the involved thoracic nerves from back to front.  The upper thoracic nerves may cause neck, shoulder, axillary, and chest pains whereas the lower nerves may cause abdominal or groin pains.  The pain may be bilateral if the nerves on both sides are involved (such as after prolonged, violent coughing or a bad fall) but more commonly, it tends to be unilateral and localized to well-defined nerve zones.  Occasionally, the pain is referred only to the front of the trunk-entirely skipping the back and sides-thus rendering the diagnosis less obvious.

         Physical examination is crucial and rests on finding each tender nerve by palpating the tender zone beneath each related rib.  Confirming the diagnosis of Post-traumatic Intercostal Neuralgia involves blocking these tender nerves at their most tender points and seeing if the referred pains disappear.  Frequently, one has to block several nerves in sequence before totally obliterating the pain.  The skills involved in thoracic nerve blocks depend on the physicians’ experiences, who utilize a combination of local anesthetics with or without a steroid.  Non-traumatic Intercostal Neuralgias such as shingles, neuropathies, tumors, spinal deformities, etc. do not usually respond to blocks.

         Treatments include anti-inflammatory medicines, nerve-silencing medicines, physical therapy, anesthetic patches, and pain pills.  When these simple treatments fail, nerve blocks should be tried because they commonly provide dramatic relief.  Many a long lasting, undiagnosed, chest or abdominal pain has been cured with thoracic nerve blocks.

         Thinking of the Post-traumatic Intercostal Neuralgia Syndrome is the first step in unraveling the cause of mysterious chest or abdominal pains.  Most patients will have had numerous workups and treatments without benefit.  Detailed pain and trauma histories plus careful palpation of the spaces beneath the ribs usually provide the necessary clues for diagnosis and effective therapy.  

This information is not intended to replace the personal physician, who should always be consulted before any treatment or action are taken.