Lymphatic circulation disorders are pathological conditions caused by insufficiency of the lymphatic system, leading to lymph stasis and impaired tissue metabolism. They manifest as edema, dystrophic changes, and, in chronic cases, tissue sclerosis.
Types of insufficiencyMechanical, dynamic, and resorption — frequently occur in combination.
Lymph stasisCessation of lymph flow due to organic or functional obstacles.
Outcome of chronic casesAtrophy, tissue sclerosis, and development of elephantiasis.
Acute consequencesDystrophy, hypoxia, and necrotic changes in tissues.
Classification of Insufficiency
In pathomorphology, three main types of lymphatic system insufficiency are distinguished:
Mechanical: occurs when there are obstacles (organic or functional) along the path of lymph flow.
Dynamic: develops when the volume of tissue fluid exceeds the carrying capacity of lymphatic vessels, often due to high capillary permeability.
Resorption: caused by a decrease in the ability of lymphatic capillaries to absorb fluid or by alterations in the properties of tissue proteins.
Causes and Mechanisms of Lymphedema (Lymph Stasis)
Lymphedema refers to the cessation of lymph flow. The main causes include:
External compression of lymphatic pathways (tumors).
Iatrogenic factors (lymph node dissection).
Spasm of collecting vessels and venous congestion.
In generalized venous congestion, the pressure gradient between lymph and blood in the thoracic duct is disrupted, which impedes lymph drainage from organs and tissues.
Morphological Consequences
Prolonged lymph stasis leads to several severe alterations:
Lymphedema: development of lymphatic tissue edema.
Cavitary disorders: chylosis (chylothorax, chylous ascites) and formation of chylous cysts.
Vascular changes: lymphangioectasia, formation of lymphovenous shunts, and lymph thrombi.
Tissue changes: in chronic processes, fibroblasts are activated, leading to sclerosis and the development of elephantiasis.
What types of parasites cause obstruction of lymphatic vessels?
Obstruction of lymphatic vessels is caused by parasitic roundworms — nematodes.
Filariae are the causative agents of lymphatic filariasis (tropical infection). Adult parasites localize in lymphatic vessels and block lymphatic pathways. This causes reactive inflammation and sclerosis of the lymphatic system, subsequently leading to lymphadenitis, blockade of lymph drainage, and the development of elephantiasis (elephantiasis).
What cellular and biochemical processes underlie the pathogenesis of elephantiasis?
The pathogenesis of elephantiasis (elephantiasis) is based on the accumulation of tissue proteins and the activation of fibroblasts.
Impaired lymph drainage leads to increased interstitial fluid pressure. Water and electrolytes partially return to capillaries, but proteins are trapped in the interstitium. The accumulation of proteins retains water via oncotic pressure, creating a vicious cycle. Chronic lymph stasis stimulates fibroblasts, resulting in massive sclerosis and irreversible fibrous changes in the skin and subcutaneous tissue.
How does chylous fluid in chylothorax differ from venous transudate?
Chylous fluid in chylothorax represents an accumulation of chyle (lymph) and has a milky-white color. Transudate seen on ultrasound is typically anechoic (echo-free).
What is the difference between mechanical and dynamic insufficiency?
Mechanical insufficiency is caused by a physical barrier to lymph flow, whereas dynamic insufficiency is due to a mismatch between an excessive volume of tissue fluid and the rate of its drainage.
Why does venous congestion impair lymphatic circulation?
Elevated pressure in the venous system decreases the pressure gradient between lymph and blood, which is critical for normal lymph drainage from the thoracic duct.
What are the outcomes of chronic lymph stasis?
Chronic lymph stasis activates fibroblasts, causing tissue atrophy and sclerosis, which can ultimately lead to elephantiasis.
Go deeper
Pathogenesis of lymphatic thrombi and their difference from hematogenous ones.
Mechanisms of chylous ascites development during thoracic duct obstruction.
Role of siderophages in the blockade of lymph nodes.
Differential diagnosis of lymphedema and venous edema.
Interrelationship of lymphovenous shunts with compensatory mechanisms of the body.