Ischemia is the term used in cases of reduced blood flow or complete loss of blood flow to an area of tissue. Ischemia can occur anywhere in the body and can be life-threatening depending on its location, extent, and duration.
What is ischemia?
Ischemia is the insufficient supply of blood to an area of tissue. This may be insufficient blood flow or a complete cessation of blood flow. If ischemia lasts only a short time, the tissue can usually recover quickly after reperfusion. If ischemia persists for a longer period, tissue destruction – which may be irreparable – occurs due to the impaired metabolism. How long ischemia can be tolerated depends primarily on its localization: Certain organ systems, such as the central nervous system, are particularly sensitive to oxygen deficiency; other tissues, such as the skin, can tolerate ischemia for several hours.
Causes
The most common causes of ischemia are internal pathologic changes in the cardiovascular system. Vascular narrowing (stenosis) due to atherosclerosis develops insidiously and causes chronic ischemia. Sudden vascular occlusions due to thrombosis or embolism lead to acute ischemia. Traumatic destruction of a blood vessel also causes a loss of blood flow. Less frequently, ischemia is caused externally, e.g., by ligation of a body part to stop bleeding, by tumors, or by chronic pressure during bedriddenness. The consequences for the metabolism of the affected area are the same in both cases: Because of the insufficient oxygen supply, increased lactate is formed and the ischemic area becomes overacidified (metabolic acidosis). Due to the lack of energy, the cells can no longer maintain their particle and fluid balance: They swell and eventually perish. With the onset of necrosis, one now speaks not only of ischemia but of the clinical picture of infarction.
Symptoms, complaints, and signs
Ischemia is typically manifested by an acute clouding of consciousness. Affected individuals usually experience mild lightheadedness or fatigue; as the condition progresses, unconsciousness and coma may occur. Mild ischemic stroke causes nausea and vomiting. In addition, visual disturbances and visual field loss may develop. Also characteristic of cerebral infarction are pathologic reflexes of the Babinski group and neurologic deficits. When the cranial nerves are involved, dysphagia and a foreign body sensation in the throat occur. Speech may be slurred and indistinct. Many patients experience a blackout and do not remember the incident. Partial or complete memory loss may also occur, depending on the severity of the ischemia. Hemiplegia also often sets in. Many affected persons can no longer move their arms or legs, or can do so only with great effort. However, paralysis of all extremities rarely occurs. In severe cases, the stroke leads to the death of the affected person within a few minutes. Initially, respiratory arrest sets in, which leads to a lack of oxygen to the brain and thus ultimately to brain death. The symptoms of ischemia are usually irreversible. Most affected individuals suffer late effects.
Diagnosis and progression
The course of ischemia depends fundamentally on which organ system is affected. Ischemia of a small area of skin due to pressure damage may not become apparent for many hours. A loss of blood flow to the brain, on the other hand, leads to unconsciousness in only 15-20 seconds and is acutely life-threatening, since irreparable necrosis occurs within 7-10 minutes. The working heart muscle is also very sensitive to oxygen deprivation and can tolerate ischemia for only a few minutes. Pain and shock are typical of major ischemia; however, other clinical symptoms vary widely depending on location. Indications of severe limb ischemia are provided by the 6 P-signs according to Pratt: pain, pallor, pulselessness, paresthesia, paralysis, and shock. A thorough history is important, as vascular occlusions are almost always preceded by pre-existing conditions. The diagnosis of ischemia is confirmed by laboratory findings, functional diagnostics (e.g.B. ECG) and imaging techniques (duplex ultrasonography, catheter angiography, computed sonography, or magnetic resonance imaging) are supported.
Complications
Ischemia can be life-threatening to a patient if it occurs over a prolonged period of time. Poor blood flow to the affected tissue can also cause irreversible secondary damage to the entire body. Patients often suffer from respiratory distress or necrosis due to the lack of oxygen. Furthermore, in the worst case, this can also lead to a heart attack and ultimately to the death of the patient. The affected person may also suffer a brain failure and lose consciousness. If this persists over a longer period of time, it can also lead to consequential damage to the brain, so that the patients suffer from paralysis or spasticity. Pain, sensory disturbances or severe pallor also occur. In the case of ischemia, immediate treatment is required to prevent irreversible consequential damage and complications. Surgical interventions may also be necessary. As a rule, the patient’s life expectancy is significantly reduced and limited by ischemia. However, the further course of the disease depends on the cause of this disease.
When should you see a doctor?
If the affected person notices circulatory disorders, he should consult a doctor in time. If there are cold limbs, numbness on the skin, a sudden pale coloration on the face or sensory disturbances, a visit to the doctor is necessary. If there is pressure pain, a general feeling of pain or discomfort, further investigations should be performed to clarify the cause. If there are cardiac rhythm disturbances, a racing heart, a change in blood pressure, or a clouding of consciousness, a physician is needed. If there is a loss of consciousness, an emergency physician must be called. In these cases, the affected person suffers a life-threatening condition within a few minutes and requires immediate intensive medical care. If there are disturbances in brain activity, interruptions in attention or concentration, and the affected person suffers from a feeling of pressure inside the head, he or she should consult a doctor. If there are signs of paralysis on the body, if no pulse can be felt, and if the affected person feels unexpectedly ill, medical attention must be sought. If there is a drop in performance level, dizziness, unsteadiness of gait, and loss of usual strength, a visit to the doctor is advised. If there is internal weakness, clouding of perceptions, fatigue and lassitude, a doctor should be consulted. If the symptoms increase in extent, a medical examination should take place as soon as possible, since an acute threat to life may develop.
Treatment and therapy
The goal of any ischemia therapy is to restore adequate blood supply to the ischemic area. Acute ischemia with infarction requires rapid action:
Provided there are no contraindications, drug-based systemic or local lysis therapy is first attempted. If this does not work or if the time window for lysis therapy has already expired, vascular surgical revascularization is possible: surgical evacuation of a thrombus, vascular dilatation or bypass surgery. Sometimes these procedures are feasible via catheters; in other cases, they require major surgery. Preventive dilating vascular prostheses (stents) are also used in subacute forms of ischemia. In addition, in patients with ischemia, drug anticoagulation, i.e., a reduction of the blood clotting tendency, is useful to prevent (further) embolisms and thromboses. For this purpose, heparin or vitamin K antagonists are given, for example. In addition, patients at risk of chronic ischemia are often given calcium antagonists, beta blockers, and/ or nitro preparations.
Outlook and prognosis
The prognosis of ischemia is generally unfavorable. Regardless of where it is localized in the body, it results in severe impairment of quality of life or, in severe cases, threat to life. The affected person suffers from various complaints, which have an increasing character. If left untreated, the premature death of the affected person is to be expected, as there is a risk of a heart attack.Depending on the location of the reduced blood flow, life-long impairment or a life-threatening situation may result even if medical care is sought. Early and comprehensive medical evaluation is necessary for a favorable prognosis. The longer treatment is delayed, the greater the likelihood of complications or permanent impairment. In addition to metabolic disorders, there is a risk of damage to the brain. Irreparable tissue damage occurs, which in severe cases leads to functional disorders in addition to organ dysfunction. In acute ischemia, immediate action is necessary to ensure the survival of the affected person. Lifelong impairments as well as a reduced quality of life are to be expected, as secondary symptoms occur. The overall performance is reduced and there may be restrictions in movement or coordination. Everyday life must be restructured, as the performance of familiar tasks can usually no longer be adequately guaranteed after the incident.
Prevention
Ischemia can generally be prevented with measures that keep the cardiovascular system healthy: exercise, a good diet with special attention to healthy fats, and avoiding cigarettes. Patients with pre-existing conditions such as cardiac arrhythmias that predispose to vascular occlusion, as well as those confined to bed after surgery, should be carefully anticoagulated. In addition, ligation of extremities should be performed only in an absolute emergency, because amputation of the affected body part may be necessary after ischemia has persisted too long.
Aftercare
After therapy by the treating physician, it is especially important to pay attention to a healthy and balanced lifestyle in the case of ischemia. Refraining from alcohol and nicotine (in any form) is essential here. Likewise, attention should be paid to cholesterol levels. Excessively high cholesterol levels can lead to further complications in the vascular system. Disturbances in fat metabolism should be avoided at all costs. Attention should also be paid to body weight; excess weight can lead to further problems, which the patient should avoid at all costs. Supportive and in any case beneficial to health is sport and sufficient exercise such as walking, jogging, team sports or cycling. Ongoing monitoring with regard to high blood pressure and diabetes is also recommended. A balanced diet with plenty of fiber is also beneficial in the follow-up of ischemia. Fiber not only lowers cholesterol, but also promotes healthy bowel function. Vitamins help to prevent further vascular diseases. Vitamins E and C should be mentioned here in particular. Carotenoids can also have a positive effect. Patients should avoid eating foods with a high fat content or fried foods. Hardened fats should disappear from the menu. The factor “stress” also plays an important role in the aftercare of ischemia. In the professional as well as private environment, this should be minimized as far as possible.
What you can do yourself
Individuals affected by ischemia should seek medical attention. To determine appropriate self-help measures, the causative condition must first be identified. That is why immediate medical evaluation is the most important action an affected person can take. Mild ischemia can be cured relatively quickly with medication and rest. Even after surgery, bed rest and sparing apply to the affected person. If pain persists, it is best to inform the physician. In consultation with the physician, natural remedies such as St. John’s wort or belladonna can be used to reduce the discomfort. Massages, acupuncture and other alternative treatments are also allowed with the doctor’s consent. After the disease has been cured, the lifestyle must be changed. Measures that strengthen the cardiovascular system are particularly important, for example, exercise, a healthy and balanced diet, and abstaining from stimulants such as alcohol and nicotine. Ischemia patients should also avoid stress and make sure they get a restful night’s sleep. In parallel, regular check-ups in the hospital are indicated, because, depending on the underlying disease, ischemia can occur again and again.
