Disease mechanism

The basic mechanism why circulatory disorders damage tissue is obvious. Due to the insufficient blood supply, too few nutrients and too little oxygen are transported to the cells. The cells need oxygen for a functioning metabolism and sufficient energy production.Most cells in the body, especially muscle cells, are able to withstand such a state of undersupply for a while.

Sooner or later, however, irreversible damage occurs: the cells have used up their resources and die. This is the process of necrosis. Along with apoptosis, necrosis is one of two ways in which a cell can perish.

While apoptosis is the targeted death of a cell (due to age or dysfunction – mediated by the body or the immune system), necrosis releases toxins because of the involuntary death of cell assemblies. The immune system does not have the possibility to render the toxins harmless. The body is flooded with the toxins and the surrounding tissue is damaged, allowing necrosis to progress.

PAVK

The mechanisms described so far for the development of circulatory disorders caused by smoking describe the development of a clinical picture – that of peripheral arterial occlusive disease (PAVK). This is the progressive narrowing and ultimately the occlusion of arteries in the extremities (arms and legs). The disease, also known as window dressing disease, occurs mainly in people over 50 years of age, with men being affected more often than women.

The main cause of PAVK is arteriosclerosis, which is strongly promoted by smoking. A smoker has a four times higher risk compared to a non-smoker and usually develops the disease 10 years earlier than other patients. The extent of PAVK depends on the level of tobacco consumption.

Localization of the circulatory disorder

The vascular-damaging processes caused by smoking can manifest themselves in the entire vascular system, but are increasingly evident in the extremities. The upper extremities, i.e. arms, hands and fingers in particular, can be affected. It is also possible and more common for the disease to affect the lower extremities – the legs, feet and toes.

Circulatory disorder of the upper extremity: If the changes are limited to small vessels in the fingers, the result can be a relatively unspecific symptomatology. Patients often report having cold hands all the time and feeling pain during long monotonous work with their fingers, such as writing. Subclavian steal syndrome is a narrowing or occlusion of the subclavian artery, which originates in the aorta and supplies the arms with blood.

Blood flows back from the vertebral artery, which originates from the subclavian artery and normally carries blood from it to the brain. This is made possible by the closed blood circulation that exists between the arteries and the brain. If the blood now flows back because the arm at which the subclavian artery is closed also needs to be supplied, the blood in the brain is missing.

This can lead to dizzy spells. Patients also report pain in the affected arm and rapid onset of muscle fatigue. Circulatory disorder of the lower extremity: The classic PAVK in the legs occurs more frequently in the area of the thigh.

Patients feel a strong pain in their legs after a mostly short walking distance and have to take a break. In cases of diabetic causes or circulatory disorders caused by smoking, the tissue on the foot is more likely to be affected. Cold feet can also be a sign of illness in this case with a certain frequency.

The so-called chronic critical limb ischemia (ischemia = reduced blood circulation) occurs mainly in the lower extremities and is manifested by various symptoms. The clinical picture is defined by persistent pain at rest and/or inflammation of the skin in the undersupplied area. Since the skin cells are furthest away from the vessels, these are the first to die in an ischemic condition.

If no treatment is initiated, gangrene forms: the tissue dies, turns black and shrinks. This condition is colloquially known as smoker’s leg. The dead tissue includes not only the skin, but also all underlying layers – the subcutis and the muscles. The border of the necrotized area moves further and further upwards and, if the patient remains alive, may increasingly occupy the entire foot and leg. The last resort to stop this process is usually only to amputate the affected limb.