The term microangiopathy is used to describe a pathological change and reduction in function of the small blood vessels where the exchange of substances with the surrounding cells of the body takes place. The disease primarily affects the capillaries of certain organs such as the eyes, kidneys and heart with serious health consequences. Metabolic disorders, hypertension, and autoimmune diseases are considered the main causes of microangiopathy.
What is microangiopathy?
The vascular system is composed of arteries that branch progressively into small arterioles. The arterioles branch further into capillaries that are not visible to the naked eye. As the capillaries continue, they join to form alveoli, which in turn join to form macroscopic veins. Microangiopathy is the term used to describe disease and diminished function of blood vessels with microscopic thin cross-sections such as arterioles, capillaries and alveoli. There is no precisely defined distinction from macroangiopathy, which affects blood vessels with larger cross-sections (arteries and veins). Microangiopathy can affect all body tissues. Preferably, the pathological changes of the vessels occur in the back of the eye, kidneys, heart, brain and extremities, depending on the cause. The walls of the capillaries can be altered in such a way that the necessary diffusion processes, i.e. a bilateral exchange of substances, through the walls with the surrounding tissue cells is only possible to a limited extent or is completely absent. The functional limitations are often due to deposits in the capillary walls, which – comparable to arteriosclerosis – make the capillary walls inelastic and unfit for gas and substance exchange. In rare cases, microangiopathies may also be caused by locally occurring occlusions of the upstream arterioles and arteries, resulting in a lack of mass transfer in the capillaries due to the absence of blood flow.
Causes
Microangiopathies are usually long-term sequelae of other preexisting conditions. Arterial hypertension, metabolic diseases such as diabetes mellitus, and systemic autoimmune diseases are considered the most important triggers. Arterial hypertension is usually itself caused by pre-existing conditions that also affect the vascular system in different ways. In primary arterial hypertension, where there is no pre-existing organic disease, chronic stress is probably the most common culprit. Chronic stress leads to a sympathetic switch of the metabolism to short-term retrieval of peak physical performance such as flight or attack, without the physical potential ultimately being retrieved. The stress hormones adrenaline and noradrenaline released by the sympathetic nervous system cause constant vasoconstriction resulting in increased blood pressure with corresponding effects on the capillaries of the vascular system. Metabolic diseases can change the composition of the capillary membranes in the long term and impair their function. In diabetes mellitus, the retina in the area of the macula, the site of sharpest vision, is usually affected.
Symptoms, complaints, and signs
The symptoms and complaints of microangiopathy depend primarily on the organs and tissues affected and the resulting limitations on their functions. In metabolic disorders caused by diabetes mellitus, if the sugar balance is not artificially stabilized, the retina of the eye is often the first to be affected. There is an initially mostly unnoticed disturbance of the metabolism at the retina. As the disease progresses, first the macula and later the entire retina are affected. In Europe and North America, diabetic retinopathy, which is based on microangiopathy, is the most common cause of blindness.
Diagnosis and disease progression
Possible diagnostic methods always refer to the organ tissue in which microangiopathy is suspected. Whereas in the case of retinopathy, the fundus of the eye can be examined optically noninvasively, in the case of kidneys and liver, a biopsy and microscopic examination of the tissue samples taken are necessary for proper clarification. Microangiopathy of the kidneys and heart can lead to renal failure and heart failure, respectively, in advanced stages.Subcortical arteriosclerotic encephalopathy (SAE) also ultimately arises from microangiopathy, which initially leads to the degradation of myelin, the myelin sheaths of the neurons in the CNS. In the advanced stage, motor disorders, urinary incontinence and neuropsychological disorders up to dementia set in. Only in the skin, blood circulation in the end-stream pathway (arterioles, capillaries, venules) can be directly observed microscopically by using laser Doppler fluxmetry and staining with Na-fluorescein.
Complications
In general, the symptoms of microangiopathy depend on the particular organ affected and can vary widely. However, this disease has a very negative effect on the organ and tissue that is affected by it. It is not uncommon for diabetes to affect the eyes and the retina, so that in the worst case the affected person can go completely blind. Especially in young people, complete blindness can lead to severe psychological discomfort or depression, thus severely limiting the quality of life. It is not uncommon for microangiopathy to develop into renal insufficiency. In the worst case, the affected person can die and is dependent on dialysis or a donor kidney. Heart failure can also occur and, in the worst case, lead to the death of the patient. The treatment of microangiopathy is usually always based on the underlying disease and attempts to treat it. However, it cannot be generally predicted whether this will be successful and whether the course of the disease will be positive. In many cases, life expectancy is significantly reduced by microangiopathy.
When should you see a doctor?
Microangiopathy must always be examined and treated by a physician. It does not result in self-healing. If left untreated, the disease can also lead to the death of the patient in the worst case. The symptoms of microangiopathy depend greatly on the organ affected. As a rule, however, patients suffer from diabetes and continue to have eye complaints. The vision decreases and there are visual complaints or veil vision. If these complaints occur without a particular reason and especially permanently, a doctor should be consulted. Microangiopathy can lead to blindness if the symptoms are ignored. Also, complaints of the kidneys or heart indicate this disease. The disease can be diagnosed by a general practitioner. For further treatment, however, it is necessary to visit other specialists. Whether this will result in a positive course of the disease cannot generally be predicted. In some circumstances, the patient’s life expectancy may be limited and reduced by the microangiopathy.
Treatment and therapy
Efficient treatment always depends on the underlying disease because microangiopathy is usually a consequence and not a cause of the underlying disease. First and foremost are diabetes mellitus and primary arterial hypertension (high blood pressure). Before or in parallel with treatment of retinopathy or renal insufficiency, it should be ensured that the sugar balance is adjusted as well as possible and that the arterial blood pressure corresponds to the normal values. In some cases, microangiopathy is caused by a change in the composition of the blood and, consequently, a change in its flow properties. Here, too, it is advisable to first treat the causes of the change in blood composition. Normally, when the flow properties of the blood normalize, the microangiopathy also recedes. In the case of disease from one of the numerous autoimmune diseases, treatment is very difficult because the autoimmune reactions must be contained by medication and the body should not come into contact with the triggering substances if possible.
Outlook and prognosis
In general, early initiation of therapy leads to a favorable prognosis. Physicians can thereby not only relieve the acute symptoms, but also prevent chronic renal failure. Furthermore, the following aspects favor the outlook: a young age, no significant concomitant diseases, and a reduced level of lesions. If these aspects are not present, no complications are usually to be expected. If a microangiopathy has already developed, however, the chances of recovery are unfavorable.Doctors can only try to inhibit or decelerate the progression. This is done primarily by adjusting the blood glucose level with suitable therapies. Microangiopathy can be fatal if it progresses unfavorably. Sometimes people also go blind, which can lead to psychological problems. A disease always leads to restrictions in everyday life. Patients must be closely monitored. The reduction in the function of the blood vessels must be counteracted. All in all, the overall picture is mixed. Patients often have to cope with a reduced life expectancy. If treatment is started too late, the life expectancy is reduced even further. However, today’s medical possibilities allow a largely symptom-free everyday life. Those who adhere to agreed rules significantly reduce their risk.
Prevention
Preventive measures as protection against microangiopathy essentially consist of avoiding triggering underlying diseases such as diabetes mellitus and arterial hypertension. If other metabolic diseases are known to trigger microangiopathy, preventive measures consist of adjusting the affected metabolic values to normal values, if possible. In the presence of an inherited or acquired gene mutation that may be a trigger for autoimmune reactions, there are no direct preventive measures. Usually, such abnormalities of the immune system are discovered only after the onset of symptoms.
Follow-up
Microangiopathy leads to various complaints and complications, all of which usually have a very negative impact on the quality of life and also on the life expectancy of the affected person. A doctor should be consulted at the first signs and symptoms to avert further complications. In this clinical picture, no independent healing can occur. In most cases, microangiopathy leads to various complaints of the internal organs. It mainly leads to metabolic disturbances and furthermore to diabetes. It is also not uncommon for those affected to suffer from a need for fluids and also weight loss. Likewise, in the worst case, if left untreated, it can lead to complete blindness, which can no longer be treated. Likewise, the kidneys and the heart are affected by the microangiopathy, so that it can come to an insufficiency at the heart or at the kidneys, which also leads to death. The further treatment depends very much on the cause of the disease, so that a general prediction can usually not be made. In many cases, the life expectancy of the affected person is also reduced in this case.
What you can do yourself
What measures affected persons can take in the case of a microangiopathy always depends on the underlying disease. If the condition is based on diabetes mellitus, the most important step is a change in lifestyle habits. If this has not already been done, the affected person must adapt his or her diet to the disease, accompanied by moderate exercise. Overweight individuals should strive to lose weight, as this is the only way to counteract diabetes mellitus and thus also microangiopathy in the long term. A physician must optimally adjust the sugar balance and also check the arterial blood pressure. If the microangiopathy is due to an autoimmune disease, treatment with medication is necessary. In this case, patients should first and foremost take it easy and completely cure the underlying disease. Lifestyle changes are also recommended, as a strengthened immune system is less susceptible to serious complications. Persons suffering from microangiopathy require close monitoring by their family doctor. If secondary diseases or serious complications have already developed, a specialist must be consulted. The most important self-help measure is to have the reduced function of the small blood vessels checked regularly by a medical professional and to ensure that the medication is optimally adjusted.
