Some peculiar symptoms and clinical manifestations in patients with lung cancer arise as a result of exposure to their organs of biologically active products of the metabolism of a malignant tumor. The range of such paraneoplastic disorders can be very pronounced, and some of them with a steadily observed group of symptoms are combined into separate syndromes inherent in lung cancer.
Weakness, increased fatigue, decreased ability to work, and weight loss are the most common and frequent signs of the result of such an effect. They are characteristic not only for the advanced stages of the disease, but can be systematically noted even at its initial manifestations, often in the absence of local clinical signs of a developing tumor in the lung. The combination of these changes was described by A. I. Savitsky in 1951 in the form of the syndrome of “small signs of lung cancer”.
The pathogenesis of paraneoplastic disorders that occur in patients with lung cancer is very diverse and continues to be studied. Its basis is the effect on the patient’s body of the numerous products of the metabolism of a malignant tumor in the lung. Among them, hyperproduction of the parathyroid hormone circulating in the blood, leading to hypercalcemia, is noted. The content of gonadotropic, somatotropic hormones, as well as lipotropin, ACTH metabolic products, insulin-like substances and others, often increases.
The mechanism for the occurrence of endocrine symptoms in patients with lung cancer is still not clear. They can appear with tumors of various histological structures. However, it should be noted that in each of the histological types of lung cancer, cells with neurosecretory granules can be found. Tumors with a double and even triple degree of their differentiation are well known. The hormones secreted by such tumors are unusual, different from those produced by the endocrine glands. Often they are heterogeneous, include precursor forms or fragments. Endocrine symptoms are characterized not only by an increase in the concentration of certain hormones, but also by a violation of control, regulation of their secretion.
A malignant tumor in the lung has a depressing effect on the functional state of the body’s adaptive mechanisms, causing a decrease in the function of the sympathoadrenal, pituitary-adrenal systems and the activity of cholinergic processes.
All this may explain the appearance of some paraneoplastic syndromes in patients with lung cancer. The most common bone-articular syndrome, named after the researchers who described it, is “Pierre Marie – Bamberger” (P. Marie, Bamberger, 1890). It is manifested by pain in the diaphysis of the long tubular bones and the phenomena of periostosis, established by x-ray. Pain also occurs in the joints / ankle, wrist /. Their contours are smoothed out due to swelling of soft tissues in the condyle. The onset of Pierre-Marie-Bamberger syndrome is associated with an increase in serum concentration of somatotropic and gonadotropic hormones.
The ability of some lung cancers, often of a small cell structure, to produce a hormone-like polypeptide that causes severe muscle weakness, hypokalemic alkalosis, hematonemia with unusually high excretion of sodium in the urine with stable normal blood pressure, are combined by Schwartz-Barter syndrome. WBSchwartz described it in 1957, as a nosological syndrome, it has been used in clinical practice since 1967 ode . The syndrome is characterized by a delay in the outside and intracellular fluid, the occurrence of mental disorders in the form of excitement or depression of consciousness, the appearance of various neurological symptoms.
Among the peculiar paraneoplastic syndromes in patients with lung cancer is the one described in 1957 by Lambert and Eaton. Lambert-Eaton syndrome is characterized by muscle weakness, which develops mainly in the proximal regions and is very reminiscent of myasthenic. Such disorders predominate mainly in the legs, are also found in the pelvic organs. A distinctive feature is the so-called “workability” feature. If with myasthenia gravis continuing muscle activity leads to a complete loss of strength, then with Lambert-Eaton syndrome, muscle strength after several repeated movements is completely restored and remains for a rather long time. Due to the appearance of excess cholinesterase and similar substances in such patients, they have an increased sensitivity to the muscle relaxants used during anesthesia. In this case, it is possible earlier and a quick shutdown of the respiratory muscles up to a complete stop of breathing.