Etiology and Clinical Manifestations of Obesity
Based on the etiological factor, obesity is classified into primary (idiopathic) and secondary forms. Secondary obesity has well-defined causes and is subdivided into several types:
- Alimentary — develops due to unbalanced nutrition and physical inactivity (sedentary lifestyle).
- Cerebral — associated with brain damage, particularly hypothalamic tumors or following neurotropic infections.
- Endocrine — occurs in pathologies of the endocrine glands (e.g., Cushing syndrome, hypothyroidism, hypogonadism, or adiposogenital dystrophy).
- Hereditary — genetically determined forms, a prominent example being von Gierke disease (glycogen storage disease type I).
Based on external manifestations and the distribution of adipose tissue, symmetrical, upper body, intermediate, and lower body types of obesity are distinguished.
Morphological Variants and Severity Grades
The severity of the pathology is assessed by the percentage by which the patient's actual body weight exceeds the normal weight. There are four grades:
| Grade | Weight Excess |
|---|---|
| Grade I | 20–29% |
| Grade II | 30–49% |
| Grade III | 50–59% |
| Grade IV | > 100% |
At the microscopic level, depending on the state of fat cells (adipocytes), two morphological variants are distinguished:
- Hypertrophic variant — typical of generalized obesity. The total number of fat cells is unchanged, but their size is significantly increased due to the excessive accumulation of triglycerides.
- Hyperplastic variant — characterized by a true increase in the number of adipocytes. Clinically, the course of the disease in this variant is considered more favorable.
Cardiac Obesity (Lipomatosis cordis)
In generalized obesity, the most formidable complication is cardiac involvement. The macroscopic picture is highly specific: the dimensions of the organ are significantly increased, and a thick layer of fat is visualized beneath the epicardium, enveloping the heart like a "case."
The pathological process is not limited to the surface. Adipose tissue begins to actively infiltrate the myocardial stroma. This leads to mechanical compression of the muscle fibers, resulting in cardiomyocyte atrophy.
Morphological changes are distributed unevenly: they are always more pronounced in the right side of the heart. Clinically, this condition manifests as progressive heart failure. In extremely rare and severe cases, wall thinning can lead to a fatal complication—rupture of the right ventricle.
Antipode of Obesity and Cholesterol Metabolism
The direct opposite of the excessive accumulation of neutral fats is cachexia (wasting). This condition represents a generalized atrophy of all organs and tissues of the body, accompanied by a critical depletion of fat stores in adipose depots.
In addition to neutral fats, disturbances in cholesterol and cholesterol ester metabolism play a crucial role in pathological anatomy. This imbalance is the fundamental basis for the development of atherosclerosis—a systemic vascular disease.