Causes of chest pain

The main causes of chest pain are:

• diseases of the musculoskeletal system: costochondritis, rib fracture;
• Cardiovascular diseases: cardiac ischemia caused by atherosclerosis of the heart vessels; unstable/stable angina; cardiac ischemia caused by coronary vasospasm (angina pectoris); mitral valve prolapse syndrome; cardiac arrhythmia; pericarditis.
• gastrointestinal diseases: gastroesophageal reflux, esophageal spasm, gastric ulcer and duodenal ulcer, gallbladder disease;
• anxiety states: vague anxiety or "stress", panic disorders;
• pulmonary diseases: pleurodynia (pleuralgia), acute bronchitis, pneumonia;
• neurological diseases;
• uncharacteristic, specific, or atypical chest pain.

Chest pain is not limited to a particular age group but is more common in adults than in children. The highest percentage is seen in adults over 65 years old, followed by male patients between 45 and 65 years old.

Frequency of diagnosis, by age and gender

Floor	Age group (years)	The most common diagnoses
Men	18-24	1. Gastroesophageal reflux
		2. Muscle pain in the chest wall
	2&44	1. Gastroesophageal reflux
		2. Muscle pain in the chest wall
		3. Costochondritis
	45-64	1. Angina pectoris, unstable angina pectoris, myocardial infarction
		2. Muscle pain in the chest wall
		3. "Atypical" chest pain
	65 and more	1. Chest wall muscle pain
		2. "Atypical" chest pain or coronary artery disease
Women	18-24	1. Costochondritis
		2. Anxiety/stress
	25-44	1. Chest wall muscle pain
		2. Costochondritis
		3. "Atypical" chest pain
		4. Gastroesophageal reflux
	45-64	1. Angina pectoris, unstable angina pectoris, myocardial infarction
		2. "Atypical" chest pain
		3. Chest wall muscle pain
	65 and more	1. Angina pectoris, unstable angina pectoris, myocardial infarction
		2. Muscle pain in the chest wall
		3. "Atypical" chest pain or costochondritis

The position of the doctor in the initial interpretation of pain is no less difficult when he tries to connect it with the pathology of one or another organ. The observation of clinicians of the last century helped them formulate assumptions about the pathogenesis of pain - if an attack of pain occurs without a reason and stops on its own, then the pain is probably functional in nature. Works devoted to a detailed analysis of chest pain are few; the pain groupings proposed in them are far from perfect. These shortcomings are due to the objective difficulties of analyzing the patient's sensations.

The difficulty in interpreting chest pain is also due to the fact that the detected pathology of a particular chest organ or musculoskeletal structure does not mean that it is the source of the pain; in other words, the detection of a disease does not mean that the cause of the pain has been precisely determined.

When evaluating patients with chest pain, the physician must weigh all relevant options for potential causes of the pain, determine when intervention is needed, and choose among a virtually limitless number of diagnostic and therapeutic strategies. All this must be done while simultaneously responding to the distress experienced by patients who are preoccupied with the presence of a life-threatening illness. The diagnostic challenge is further complicated by the fact that chest pain often represents a complex interaction of psychological, pathological, and psychosocial factors. This makes it a common problem in primary care.

When considering chest pain, it is necessary to consider (at a minimum) the following five elements: predisposing factors; characteristics of the pain attack; duration of painful episodes; characteristics of the pain itself; factors that relieve pain.

With all the variety of reasons causing pain in the chest, pain syndromes can be grouped.

Approaches to groupings may vary, but they are mainly based on nosological or organ principles.

Conventionally, the following 6 groups can be distinguished:

1. Pain caused by heart disease (so-called cardiac pain). These painful sensations may be the result of damage or dysfunction of the coronary arteries - coronary pain. The "coronary component" does not participate in the origin of non-coronary pain. In the future, we will use the terms "cardiac pain syndrome", "cardiac pain", understanding their connection with one or another cardiac pathology.
2. Pain caused by pathology of large vessels (aorta, pulmonary artery and its branches).
3. Pain caused by pathology of the bronchopulmonary system and pleura.
4. Pain associated with pathology of the spine, anterior chest wall and shoulder girdle muscles.
5. Pain caused by pathology of the mediastinal organs.
6. Pain associated with diseases of the abdominal organs and pathology of the diaphragm.

Pain is also divided into acute and long-term, with an obvious cause and without an obvious cause, "non-dangerous" and pain that is a manifestation of life-threatening conditions. Naturally, it is necessary to establish first whether the pain is dangerous or not. "Dangerous" pain includes all types of anginal (coronary) pain, pain associated with pulmonary embolism (PE), dissecting aortic aneurysm, spontaneous pneumothorax. "Non-dangerous" pain includes pain associated with pathology of the intercostal muscles, nerves, and bone-cartilaginous formations of the chest. "Dangerous" pain is accompanied by a suddenly developed serious condition or severe disorders of the heart or respiratory function, which immediately allows us to narrow down the range of possible diseases (acute myocardial infarction, PE, dissecting aortic aneurysm, spontaneous pneumothorax).

The main causes of acute chest pain that are life-threatening are:

• cardiological: acute or unstable angina, myocardial infarction, dissecting aortic aneurysm;
• pulmonary: pulmonary embolism; tension pneumothorax.

It should be noted that correct interpretation of chest pain is quite possible during a routine physical examination of the patient using a minimum number of instrumental methods (routine electrocardiographic and X-ray examination). An erroneous initial idea of the source of pain, in addition to increasing the time of examination of the patient, often leads to serious consequences.

History and physical examination findings to determine the cause of chest pain

Anamnesis data	Diagnostic category
	Heart	Gastrointestinal	Musculoskeletal
Predisposing factors	Male. Smoking. High blood pressure. Hyperlipidemia. Family history of myocardial infarction.	Smoking. Drinking alcohol.	Physical activity. New activity. Abuse. Repetitive actions.
Characteristics of a pain attack	When there is a high level of tension or emotional stress	After meals and/or on an empty stomach	During or after activity
Duration of pain	Minutes	From minutes to hours	From hours to days
Characteristics of pain	Pressure or "burning"	Pressure or boring pain	Acute, local, movement-induced
Factors, Shooting Pain	Rest. Sublingual nitro preparations	Eating. Antacids. Antihistamines.	Rest. Analgesics. Nonsteroidal anti-inflammatory drugs
Supporting data	During attacks of angina pectoris, rhythm disturbances or noises are possible	Pain in the epigastric region	Pain on palpation in the paravertebral points, in the places where the intercostal nerves exit, soreness of the periosteum

Cardialgia (non-anginal pain). Cardialgia caused by one or another heart disease is very common. In its origin, meaning and place in the structure of population morbidity, this group of pains is extremely heterogeneous. The causes of such pains and their pathogenesis are very diverse. The diseases or conditions in which cardialgia is observed are the following:

1. Primary or secondary cardiovascular functional disorders - the so-called cardiovascular syndrome of the neurotic type or neurocirculatory dystonia.
2. Diseases of the pericardium.
3. Inflammatory diseases of the myocardium.
4. Cardiac muscle dystrophy (anemia, progressive muscular dystrophy, alcoholism, vitamin deficiency or starvation, hyperthyroidism, hypothyroidism, catecholamine effects).

As a rule, non-anginal pains are benign, as they are not accompanied by coronary insufficiency and do not lead to the development of ischemia or myocardial necrosis. However, in patients with functional disorders leading to an increase (usually short-term) in the level of biologically active substances (catecholamines), the probability of ischemia still exists.

Chest pain of neurotic origin. We are talking about painful sensations in the heart area, as one of the manifestations of neurosis or neurocirculatory dystonia (vegetative-vascular dystonia). Usually these are aching or stabbing pains, of varying intensity, sometimes long-lasting (hours, days) or, conversely, very short-term, instantaneous, piercing. The localization of these pains is very different, not always constant, almost never behind the sternal region. The pains can increase with physical exertion, but usually with psychoemotional stress, fatigue, without a clear effect of nitroglycerin, do not decrease at rest, and sometimes, on the contrary, patients feel better when moving. In diagnostics, the presence of signs of a neurotic state, vegetative dysfunction (sweating, dermographism, subfebrile condition, fluctuations in pulse and blood pressure), as well as young or middle age of patients, mainly female, are taken into account. These patients experience increased fatigue, decreased tolerance to physical activity, anxiety, depression, phobias, fluctuations in pulse and blood pressure. In contrast to the severity of subjective disorders, objective research, including the use of various additional methods, does not reveal a specific pathology.

Sometimes, among these symptoms of neurotic origin, the so-called hyperventilation syndrome is revealed. This syndrome manifests itself as voluntary or involuntary acceleration and deepening of respiratory movements, tachycardia, arising in connection with unfavorable psychoemotional effects. In this case, chest pains, as well as paresthesia and muscle twitching in the limbs due to the emerging respiratory alkalosis, may occur. There are observations (not fully confirmed), indicating that hyperventilation can lead to a decrease in myocardial oxygen consumption and provoke coronary spasm with pain and ECG changes. It is possible that hyperventilation can be the cause of pain in the heart area during a test with physical activity in people with vegetative-vascular dystonia.

To diagnose this syndrome, a provocative test with induced hyperventilation is performed. The patient is asked to breathe more deeply - 30-40 times per minute for 3-5 minutes or until the patient's usual symptoms appear (chest pain, headaches, dizziness, shortness of breath, sometimes a semi-fainting state). The appearance of these symptoms during the test or 3-8 minutes after its completion, with the exclusion of other causes of pain, has a very definite diagnostic value.

In some patients, hyperventilation may be accompanied by aerophagia with the appearance of painful sensations or a feeling of heaviness in the upper part of the epigastric region due to distension of the stomach. These pains may spread upward, behind the sternum, to the neck and the area of the left shoulder blade, simulating angina. Such pains increase with pressure on the epigastric region, in the prone position, with deep breathing, and decrease with belching. Percussion reveals an expansion of the Traube space, including tympanitis over the area of absolute cardiac dullness, and fluoroscopy reveals an enlarged gastric bladder. Similar pains may occur with distension of the left angle of the colon by gases. In this case, the pains are often associated with constipation and are relieved after defecation. A thorough anamnesis usually allows one to determine the true nature of the pains.

The pathogenesis of cardiac pain sensations in neurocirculatory dystonia is unclear, which is due to the impossibility of their experimental reproduction and confirmation in the clinic and experiment, unlike anginal pain. Perhaps, in connection with this circumstance, a number of researchers generally question the presence of pain in the heart in neurocirculatory dystonia. Such tendencies are most common among representatives of the psychosomatic direction in medicine. According to their views, we are talking about the transformation of psychoemotional disorders into pain.

The origin of heart pain in neurotic conditions can also be explained by the cortico-visceral theory, according to which, when the vegetative apparatus of the heart is irritated, a pathological dominant occurs in the central nervous system, creating a vicious circle. There is reason to believe that heart pain in neurocirculatory dystonia occurs as a result of a disturbance in myocardial metabolism due to excessive adrenal stimulation. In this case, a decrease in the content of intracellular potassium, activation of dehydrogenation processes, an increase in the level of lactic acid, and an increase in the myocardium's need for oxygen are observed. Hyperlactatemia is a well-proven fact in neurocirculatory dystonia.

Clinical observations indicating a close connection between pain sensations in the heart area and emotional effects confirm the role of catecholamines as a trigger for pain. This position is supported by the fact that intravenous administration of isadrin to patients with neurocirculatory dystonia causes pain in the heart area of the cardialgia type. Apparently, catecholamine stimulation can also explain the provocation of cardialgia by a hyperventilation test, as well as its occurrence at the height of respiratory disorders in neurocirculatory dystonia. This mechanism can also be confirmed by the positive results of treating cardialgia with breathing exercises aimed at eliminating hyperventilation. A certain role in the formation and maintenance of cardiac pain syndrome in neurocirculatory dystonia is played by the flow of pathological impulses coming from hyperalgesia zones in the area of the muscles of the anterior chest wall to the corresponding segments of the spinal cord, where, according to the "gate" theory, the summation phenomenon occurs. In this case, a reverse flow of impulses is observed, causing irritation of the thoracic sympathetic ganglia. Of course, the low threshold of pain sensitivity in vegetative-vascular dystonia is also important.

Such factors as microcirculation disorders, changes in blood rheological properties, and increased activity of the kinin-kallikrein system may play a role in the development of pain, but are not yet well studied. It is possible that with prolonged existence of severe vegetative-vascular dystonia, it may develop into coronary heart disease with unchanged coronary arteries, in which pain is caused by spasm of the coronary arteries. In a targeted study of a group of patients with proven coronary heart disease with unchanged coronary arteries, it was found that all of them had suffered from severe neurocirculatory dystonia in the past.

In addition to vegetative-vascular dystonia, cardialgia is also observed in other diseases, but the pain is expressed to a lesser degree and usually never comes to the fore in the clinical picture of the disease.

The origin of pain in pericardial lesions is quite clear, since the pericardium contains sensitive nerve endings. Moreover, it has been shown that irritation of one or another area of the pericardium produces different localizations of pain. For example, irritation of the pericardium on the right causes pain along the right midclavicular line, and irritation of the pericardium in the area of the left ventricle is accompanied by pain spreading along the inner surface of the left shoulder.

Pain in myocarditis of various origins is a very common symptom. Their intensity is usually low, but in 20% of cases they have to be differentiated from pain caused by coronary heart disease. Pain in myocarditis is probably associated with irritation of nerve endings located in the epicardium, as well as with inflammatory edema of the myocardium (in the acute phase of the disease).

The origin of pain in myocardial dystrophies of various origins is even more uncertain. Probably, the pain syndrome is caused by a disturbance of myocardial metabolism; the concept of local tissue hormones, convincingly presented by N.R. Paleev et al. (1982), can also shed light on the causes of pain. In some myocardial dystrophies (due to anemia or chronic carbon monoxide poisoning), pain can have a mixed origin, in particular, the ischemic (coronary) component is of significant importance.

It is necessary to dwell on the analysis of the causes of pain in patients with myocardial hypertrophy (due to pulmonary or systemic hypertension, valvular heart defects), as well as in primary cardiomyopathies (hypertrophic and dilated). Formally, these diseases are mentioned in the second heading of anginal pains caused by an increase in the myocardium's need for oxygen with unchanged coronary arteries (the so-called non-coronarogenic forms). However, in these pathological conditions, in a number of cases, unfavorable hemodynamic factors arise, causing relative myocardial ischemia. It is believed that angina-type pain observed in aortic insufficiency depends, first of all, on low diastolic pressure, and, consequently, low coronary perfusion (coronary blood flow is realized during diastole).

In aortic stenosis or idiopathic myocardial hypertrophy, the appearance of pain is associated with impaired coronary circulation in the subendocardial sections due to a significant increase in intramyocardial pressure. All pain sensations in these diseases can be designated as metabolically or hemodynamically conditioned anginal pain. Despite the fact that they are not formally related to coronary heart disease, one should keep in mind the possibility of developing small focal necrosis. At the same time, the characteristics of these pains often do not correspond to classical angina, although typical attacks are possible. In the latter case, differential diagnosis with coronary heart disease is especially difficult.

In all cases of detection of non-coronary causes of chest pain, it is taken into account that their presence does not at all contradict the simultaneous existence of coronary heart disease and, accordingly, requires examination of the patient in order to exclude or confirm it.

Chest pain caused by pathology of the bronchopulmonary apparatus and pleura. Pain quite often accompanies various pulmonary pathologies, occurring in both acute and chronic diseases. However, it is usually not the leading clinical syndrome and is quite easily differentiated.

The source of pain is the parietal pleura. From the pain receptors located in the parietal pleura, afferent fibers go as part of the intercostal nerves, so the pain is clearly localized on the affected half of the chest. Another source of pain is the mucous membrane of large bronchi (which is well proven during bronchoscopy) - afferent fibers from large bronchi and trachea go as part of the vagus nerve. The mucous membrane of small bronchi and pulmonary parenchyma probably does not contain pain receptors, so pain in the primary lesion of these formations appears only when the pathological process (pneumonia or tumor) reaches the parietal pleura or spreads to large bronchi. The most severe pain is noted during the destruction of lung tissue, sometimes acquiring high intensity.

The nature of the pain depends to some extent on its origin. Pain in parietal pleura lesions is usually stabbing, clearly associated with coughing and deep breathing. Dull pain is associated with stretching of the mediastinal pleura. Severe constant pain, increasing with breathing, arm and shoulder girdle movement, may indicate tumor growth into the chest.

The most common causes of pulmonary-pleural pain are pneumonia, lung abscess, tumors of the bronchi and pleura, pleurisy. In case of pain associated with pneumonia, dry or exudative pleurisy, wheezing in the lungs and pleural friction noise may be detected during auscultation.

Severe pneumonia in adults has the following clinical signs:

• moderate or severe respiratory depression;
• temperature of 39.5 °C or higher;
• confusion;
• respiratory rate - 30 per minute or more;
• pulse 120 beats per minute or more;
• systolic blood pressure below 90 mmHg;
• diastolic blood pressure below 60 mmHg;
• cyanosis;
• over 60 years old - features: confluent pneumonia, more severe with concomitant severe diseases (diabetes, heart failure, epilepsy).

NB! All patients with signs of severe pneumonia should be immediately referred to hospital! Referral to hospital:

• severe form of pneumonia;
• patients with pneumonia from socioeconomically disadvantaged backgrounds or who are unlikely to follow doctor's orders at home; who live very far from a medical facility;
• pneumonia in combination with other diseases;
• suspected atypical pneumonia;
• patients who do not respond positively to treatment.

Pneumonia in children is described as follows:

• retraction of the intercostal spaces of the chest, cyanosis and inability to drink in young children (from 2 months to 5 years) also serves as a sign of a severe form of pneumonia, which requires urgent referral to a hospital;
• It is necessary to distinguish pneumonia from bronchitis: the most valuable sign in the case of pneumonia is tachypnea.

Painful sensations in pleural lesions are almost no different from those in acute intercostal myositis or intercostal muscle trauma. In spontaneous pneumothorax, acute unbearable chest pain is observed, associated with damage to the bronchopulmonary apparatus.

Chest pain, difficult to interpret due to its vagueness and isolation, is observed in the initial stages of bronchogenic lung cancer. The most excruciating pain is characteristic of the apical localization of lung cancer, when damage to the common trunk of the CVII and ThI nerves and the brachial plexus almost inevitably and quickly develops. The pain is localized mainly in the brachial plexus and radiates along the outer surface of the arm. Horner's syndrome (narrowing of the pupil, ptosis, enophthalmos) often develops on the affected side.

Pain syndromes also occur with mediastinal localization of cancer, when compression of nerve trunks and plexuses causes acute neuralgic pain in the shoulder girdle, upper limb, chest. This pain gives rise to erroneous diagnosis of angina pectoris, myocardial infarction, neuralgia, plexitis.

The need for differential diagnostics of pain caused by damage to the pleura and bronchopulmonary apparatus with ischemic heart disease arises in cases where the picture of the underlying disease is unclear and pain comes to the fore. In addition, such differentiation (especially in acute unbearable pain) should also be carried out with diseases caused by pathological processes in large vessels - pulmonary embolism, dissecting aneurysm of various parts of the aorta. The difficulties in identifying pneumothorax as a cause of acute pain are associated with the fact that in many cases the clinical picture of this acute situation is erased.

Pain associated with pathology of the mediastinal organs is caused by diseases of the esophagus (spasm, reflux esophagitis, diverticula), tumors of the mediastinum and mediastinitis.

Pain in diseases of the esophagus is usually of a burning nature, localized behind the stomach, occurs after eating, and intensifies in a horizontal position. Such common symptoms as heartburn, belching, and difficulty swallowing may be absent or mild, and retrosternal pains come to the fore, often occurring during physical exertion and giving way to the action of nitroglycerin. The similarity of these pains with angina is complemented by the fact that they can radiate to the left half of the chest, shoulders, and arms. Upon closer examination, however, it turns out that the pains are more often associated with food, especially large meals, rather than with physical exertion, usually occur in a lying position and pass or are relieved by moving to a sitting or standing position, while walking, after taking antacids, such as soda, which is not typical for ischemic heart disease. Often, palpation of the epigastric region intensifies these pains.

Retrosternal pain is also suspicious for gastroesophageal reflux and esophagitis. To confirm the presence of which, 3 types of tests are important: endoscopy and biopsy; intraesophageal infusion of 0.1% hydrochloric acid solution; monitoring of intraesophageal pH. Endoscopy is important for detecting reflux, esophagitis and for excluding other pathologies. X-ray examination of the esophagus with barium reveals anatomical changes, but its diagnostic value is considered relatively low due to the high frequency of false-positive signs of reflux. With perfusion of hydrochloric acid (120 drops per minute through a tube), the appearance of pain usual for the patient is important. The test is considered highly sensitive (80%), but not specific enough, which requires repeated studies in case of unclear results.

If the results of endoscopy and hydrochloric acid perfusion are unclear, intraesophageal pH can be monitored using a radiotelemetry capsule placed in the lower part of the esophagus for 24-72 hours. The coincidence in time of the onset of pain and a decrease in pH is a good diagnostic sign of esophagitis, i.e., a true criterion for the esophageal origin of pain.

Chest pains similar to angina pectoris may also be a consequence of increased motor function of the esophagus in achalasia (spasm) of the cardiac section or diffuse spasm. Clinically, in such cases there are usually signs of dysphagia (especially when taking solid food, cold liquid), which, unlike organic stenosis, is of an inconstant nature. Sometimes, retrosternal pains of varying duration come to the fore. The difficulties of differential diagnosis are also due to the fact that this category of patients is sometimes helped by nitroglycerin, which relieves spasm and pain.

Radiologically, in achalasia of the esophagus, dilation of its lower part and retention of barium mass in it are detected. However, radiological examination of the esophagus in the presence of pain is uninformative, or rather unproven: false-positive results are noted in 75% of cases. Esophageal manometry using a three-lumen probe is more effective. The coincidence in time of pain and increase in intraesophageal pressure has a high diagnostic value. In such cases, a positive effect of nitroglycerin and calcium antagonists, which reduce smooth muscle tone and intraesophageal pressure, may be manifested. Therefore, these drugs can be used in the treatment of such patients, especially in combination with anticholinergics.

Clinical experience shows that in cases of esophageal pathology, ischemic heart disease is often misdiagnosed. In order to make a correct diagnosis, the physician must look for other symptoms of esophageal disorders in the patient and compare clinical manifestations and the results of various diagnostic tests.

Attempts to develop a set of instrumental studies that would help differentiate anginal and esophageal pains have not been successful, since this pathology is often combined with angina, which is confirmed by bicycle ergometry. Thus, despite the use of various instrumental methods, differentiation of pain sensations still presents great difficulties.

Mediastinitis and mediastinal tumors are uncommon causes of chest pain. Usually, the need for differential diagnostics with ischemic heart disease arises at the pronounced stages of tumor development, when, however, there are no pronounced symptoms of compression. The appearance of other signs of the disease significantly facilitates diagnostics.

Chest pain in diseases of the spine. Pain in the chest can also be associated with degenerative changes in the spine. The most common disease of the spine is osteochondrosis (spondylosis) of the cervical and thoracic spine, which causes pain that is sometimes similar to angina. This pathology is widespread, since after 40 years, changes in the spine are often observed. With damage to the cervical and (or) upper thoracic spine, the development of secondary radicular syndrome with the spread of pain in the chest area is often observed. These pains are associated with irritation of sensory nerves by osteophytes and thickened intervertebral discs. Usually, bilateral pains appear in the corresponding intercostal spaces, but patients quite often concentrate their attention on their retrosternal or pericardial localization, referring them to the heart. Such pains may resemble angina pectoris by the following signs: they are perceived as a feeling of pressure, heaviness, sometimes radiating to the left shoulder and arm, neck, can be provoked by physical exertion, accompanied by a feeling of shortness of breath due to the inability to breathe deeply. Given the advanced age of patients, in such cases the diagnosis of coronary heart disease is often made with all the ensuing consequences.

At the same time, degenerative changes in the spine and the pain caused by them can also be observed in patients with undoubted coronary heart disease, which also requires a clear distinction of the pain syndrome. It is possible that in some cases, attacks of angina against the background of atherosclerosis of the coronary arteries in patients with spinal lesions also occur reflexively. Unconditional recognition of this possibility, in turn, shifts the "center of gravity" to the pathology of the spine, reducing the significance of independent damage to the coronary arteries.

How to avoid diagnostic errors and make the correct diagnosis? Of course, it is important to conduct an X-ray of the spine, but the changes detected are completely insufficient for diagnosis, since these changes may only accompany ischemic heart disease and (or) not manifest clinically. Therefore, it is very important to clarify all the features of pain. As a rule, pain depends not so much on physical activity as on a change in body position. Pain often intensifies with coughing, deep breathing, and can decrease in some comfortable position of the patient, after taking analgesics. These pains differ from angina pectoris by a more gradual onset, longer duration, they do not go away at rest and after taking nitroglycerin. Pain irradiates to the left arm along the dorsal surface, to the 1st and 2nd fingers, whereas with angina pectoris - to the 4th and 5th fingers of the left hand. Of certain importance is the detection of local tenderness of the spinous processes of the corresponding vertebrae (trigger zone) when pressing or tapping paravertebrally and along the intercostal spaces. Pain can also be caused by certain techniques: strong pressure on the head towards the back of the head or stretching one arm while turning the head to the other side. During bicycle ergometry, pain in the heart area may appear, but without characteristic ECG changes.

Thus, the diagnosis of radicular pain requires a combination of radiological signs of osteochondrosis and characteristic features of chest pain that do not correspond to coronary heart disease.

The frequency of muscular-fascial (muscular-dystonic, muscular-dystrophic) syndromes in adults is 7-35%, and in certain professional groups reaches 40-90%. In some of them, heart disease is often misdiagnosed, since the pain syndrome in this pathology has some similarities with pain in cardiac pathology.

There are two stages of the disease of muscular-fascial syndromes (Zaslavsky E.S., 1976): functional (reversible) and organic (muscular-dystrophic). There are several etiopathogenetic factors in the development of muscular-fascial syndromes:

1. Soft tissue injuries with the formation of hemorrhages and sero-fibrinous extravasates. As a result, the muscles or individual muscle bundles, ligaments become compacted and shortened, and the elasticity of the fascia decreases. As a manifestation of the aseptic inflammatory process, connective tissue is often formed in excess.
2. Microtraumatization of soft tissues in some types of professional activity. Microtraumas disrupt tissue blood circulation, cause muscle-tonic dysfunction with subsequent morphological and functional changes. This etiological factor is usually combined with others.
3. Pathological impulses in visceral lesions. This impulse, arising in the event of damage to internal organs, is the cause of the formation of various sensory, motor and trophic phenomena in the integumentary tissues innervated by the altered internal organ. Pathological interoceptive impulses, switching through spinal segments, go to the connective tissue and muscle segments corresponding to the affected internal organ. The development of muscular-fascial syndromes accompanying cardiovascular pathology can change the pain syndrome so much that diagnostic difficulties arise.
4. Vertebrogenic factors. When the receptors of the affected motor segment are irritated (receptors of the fibrous ring of the intervertebral disc, posterior longitudinal ligament, joint capsules, autochthonous muscles of the spine), not only local pain and muscle-tonic disorders occur, but also various reflex responses at a distance - in the area of integumentary tissues innervated by the affected vertebral segments. But parallelism between the severity of radiographic changes in the spine and clinical symptoms is not observed in all cases. Therefore, radiographic signs of osteochondrosis cannot yet serve as an explanation for the cause of the development of muscle-fascial syndromes exclusively by vertebrogenic factors.

As a result of the impact of several etiologic factors, muscular-tonic reactions develop in the form of hypertonicity of the affected muscle or muscle group, which is confirmed by electromyographic examination. Muscle spasm is one of the sources of pain. In addition, impaired microcirculation in the muscle leads to local tissue ischemia, tissue edema, accumulation of kinins, histamine, and heparin. All these factors also cause pain. If muscular-fascial syndromes are observed for a long time, fibrous degeneration of muscle tissue occurs.

The greatest difficulties in differential diagnostics of muscular-fascial syndromes and pain of cardiac origin are encountered in the following syndrome variants: scapulohumeral periarthritis, scapular-costal syndrome, anterior chest wall syndrome, interscapular pain syndrome, pectoralis minor syndrome, anterior scalene syndrome. Anterior chest wall syndrome is observed in patients after myocardial infarction, as well as in non-coronary heart lesions. It is assumed that after myocardial infarction, the flow of pathological impulses from the heart spreads along the segments of the autonomic chain and leads to dystrophic changes in the corresponding formations. This syndrome in individuals with an obviously healthy heart can be caused by traumatic myositis.

More rare syndromes accompanied by pain in the anterior chest wall include: Tietze's syndrome, xiphoidia, manubriosternal syndrome, scalenus syndrome.

Tietze's syndrome is characterized by sharp pain at the junction of the sternum with the cartilages of the II-IV ribs, swelling of the costochondral joints. It is observed mainly in middle-aged people. The etiology and pathogenesis are unclear. There is a suggestion of aseptic inflammation of the costal cartilages.

Xiphoidia is manifested by sharp pain in the lower part of the sternum, which intensifies when pressing on the xiphoid process, sometimes accompanied by nausea. The cause of the pain is unclear, perhaps there is a connection with pathology of the gallbladder, duodenum, stomach.

In manubriosternal syndrome, acute pain is noted above the upper part of the sternum or slightly laterally. The syndrome is observed in rheumatoid arthritis, but occurs in isolation and then it becomes necessary to differentiate it from angina.

Scalenus syndrome is a compression of the neurovascular bundle of the upper limb between the anterior and middle scalene muscles, as well as the normal 1st or additional rib. Pain in the anterior chest wall is combined with pain in the neck, shoulder girdle, shoulder joints, sometimes a wide irradiation zone is noted. At the same time, vegetative disorders are observed in the form of chills, paleness of the skin. Difficulty breathing, Raynaud's syndrome are noted.

To summarize the above, it should be noted that the true frequency of pain of this origin is unknown, so it is not possible to determine their specific weight in the differential diagnosis of angina pectoris.

Differentiation is necessary in the initial period of the disease (when angina is the first thing people think about) or if the pain caused by the listed syndromes is not combined with other symptoms that allow one to correctly identify its origin. At the same time, pain of such origin can be combined with true coronary heart disease, and then the doctor must also understand the structure of this complex pain syndrome. The need for this is obvious, since the correct interpretation will affect both the treatment and the prognosis.

Chest pain caused by abdominal diseases and diaphragm pathology. Abdominal diseases are often accompanied by heart pain in the form of typical angina syndrome or cardialgia. Pain in gastric ulcer and duodenal ulcer, chronic cholecystitis can sometimes radiate to the left half of the chest, which creates diagnostic difficulties, especially if the diagnosis of the underlying disease has not yet been established. Such irradiation of pain is quite rare, but its possibility should be taken into account when interpreting pain in the heart and behind the sternum. The occurrence of these pains is explained by reflex effects on the heart in case of damage to internal organs, which occur as follows. Interorgan connections have been discovered in the internal organs, through which axon reflexes are carried out, and, finally, polyvalent receptors have been identified in the vessels and smooth muscles. In addition, it is known that along with the main border sympathetic trunks, there are also paravertebral plexuses connecting both border trunks, as well as sympathetic collaterals located parallel and on the sides of the main sympathetic trunk. Under such conditions, afferent excitation, directed from any organ along a reflex arc, can switch from centripetal to centrifugal paths and thus be transmitted to various organs and systems. At the same time, viscero-visceral reflexes are carried out not only by reflex arcs closing at various levels of the central nervous system, but also through the vegetative nerve nodes on the periphery.

As for the causes of reflex pain in the heart region, it is assumed that a long-existing painful focus disrupts the primary afferent pulsation from the organs due to a change in the reactivity of the receptors located in them and thus becomes a source of pathological afferentation. Pathologically altered impulses lead to the formation of dominant irritation foci in the cortex and subcortical region, in particular in the hypothalamic region and in the reticular formation. Thus, the irradiation of these irritations is accomplished with the help of central mechanisms. From here, pathological impulses are transmitted by efferent pathways through the lower parts of the central nervous system and then along the sympathetic fibers reach the vasomotor receptors of the heart.

Causes of retrosternal pain can also be diaphragmatic hernias. The diaphragm is a richly innervated organ mainly due to the phrenic nerve. It passes along the anterior internal edge of m. scalenus anticus. In the mediastinum, it goes together with the superior vena cava, then, bypassing the mediastinal pleura, reaches the diaphragm, where it branches. Hernias of the esophageal opening of the diaphragm are more common. Symptoms of diaphragmatic hernias are varied: usually it is dysphagia and pain in the lower parts of the chest, belching and a feeling of distension in the epigastrium. When the hernia temporarily penetrates the chest cavity, there is a sharp pain that can be projected to the lower left half of the chest and spreads to the interscapular region. Concomitant spasm of the diaphragm can cause pain in the left scapular region and in the left shoulder, reflected due to irritation of the phrenic nerve, which allows us to assume "heart" pain. Considering the paroxysmal nature of the pain, its occurrence in middle-aged and elderly people (mainly in men), a differential diagnosis should be made with an attack of angina pectoris.

Pain may also be caused by diaphragmatic pleurisy and, much less frequently, by subdiaphragmatic abscess.

In addition, examination of the chest may reveal shingles, and palpation may reveal a rib fracture (local pain, crepitus).

Therefore, to determine the cause of chest pain and make a correct diagnosis, the general practitioner should conduct a thorough examination and interview of the patient and take into account the possibility of the existence of all the above conditions.

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