What is a pain stimulus for one person does not necessarily have to be for another. A particularly pronounced sensation of pain does not automatically mean illness. If, in turn, there is hardly any pain sensation, hypoalgesia may be present. In this case, it is a nociceptor disorder.
What is hypalgesia?
According to abbreviationfinder, the first instance of human pain perception are the sensory cells of the skin. These sensory cells correspond to nociceptors. These are free nerve endings of sensitive neurons in the spinal cord. Nociceptors are located in all pain-sensitive body tissues and give the central nervous system feedback about tissue damage.
In addition to surface pain on the skin, nociceptors report deep pain in the muscles and bones and pain in the organs. The sensitivity of the receptors is related to the pain threshold. Nociception is to some extent individual.
An exaggerated or reduced pain sensitivity does not therefore have to be automatically associated with an illness. Above a certain limit, however, abnormal pain perception is associated with illness. One such phenomenon is hypalgesia. With this phenomenon, the perception of pain is greatly reduced.
This is to be distinguished from allodynia, in which the perception of pain is exaggerated due to over-reactive nociceptors. Both phenomena are referred to as sensory disturbances and as such are often associated with neurogenic diseases.
Causes
The cause of hypalgesia and thus reduced pain perception is often a neurological disease. If the perception of pain is reduced due to nerve damage in the peripheral nervous system, the nociceptors react to pain stimuli with the formation of an action potential. However, due to a peripherally disturbed pathway, the excitement does not reach the central nervous system and thus does not become conscious.
Peripheral nerve damage includes polyneuropathies, in which nerves of the peripheral nervous system demyelinate. Myelin insulates nerve conduction, protecting it from loss of excitation. In polyneuropathies, the myelin around peripheral nerves is broken down. The primary cause of this phenomenon can be infections, metabolic disorders such as diabetes mellitus, previous trauma, inflammation, poisoning or malnutrition.
If hypalgesia is caused by damage to the central nervous system, this damage can be caused by inflammation, tumors or degenerative phenomena. For example, inflammation in the spinal cord or the areas of the brain that process pain are often caused by the autoimmune disease multiple sclerosis.
Spinal cord infarctions, strokes or herniated discs can also cause centrally mediated sensory disturbances. There doesn’t necessarily have to be a physical cause. Psychoneuroses can also cause hypalgesia.
Symptoms, Ailments & Signs
A patient with hypoalgesia does not perceive pain stimuli as painful up to an unusually high intensity. With this phenomenon, the affected person suffers from the symptom of a higher-level disease. All other symptoms depend on the primary cause of the sensory disturbance.
If the disturbed perception of pain is associated with lesions in the brain or spinal cord, those affected often complain of more or less severe headaches or back pain, especially with inflammation in the central nervous system.
Depending on the cause, hypalgesia can be associated with other sensory disorders in the sense of reduced perception of other sensory qualities. For example, the general temperature sensitivity or touch sensitivity can be limited at the same time.
Symptoms such as general numbness in certain areas of the body can also accompany hypalgesia. Contrary to what many people assume, deafness does not have to be automatically associated with hypoalgesia and can only affect touch or temperature sensitivity, for example.
If there are no other neurological symptoms other than hypalgesia, the most likely cause is psychoneurosis due to a “crippling” event. In this context, the hypalgesia can be an expression of mental insensibility. A psychologically induced loss of pain sensitivity is often caused by an extreme pain experience.
Diagnosis & disease progression
The diagnosis of hypoalgesia is usually made by a neurologist. As part of sensitivity tests, the neurologist examines all qualities of the skin’s senses. Diagnosed hypoalgesia should not be taken as an actual diagnosis. The diagnosis is only made when the primary cause of the hypoalgesia has been identified and the sensory disturbance can thus be traced back to a primary disease.
For example, a centrally mediated hypoalgesia is traced back to diseases or pathological processes in the central nervous system within the scope of diagnostics. In order to classify the cause of hypoalgesia, the doctor resorts to imaging methods and nerve conduction tests. If there is no lesion in either the central or peripheral nervous system, the sensory disturbance is a psychosomatic phenomenon.
Complications
The hypalgesia leads to significant sensory disturbances in the patient. These disorders lead to an incorrect or insufficient perception of the feeling of pain. As a rule, the hypalgesia means that the person concerned does not recognize certain symptoms and the diseases are only treated with a delay.
Various complaints and complications can develop from this if various diseases or infections are only discovered and treated at a late stage. Different areas can be numb or completely paralyzed. In some cases, this leads to restricted mobility in the patient. It is not uncommon for those affected to suffer from pain in the head and back. This pain can also spread to other regions of the body and cause discomfort there.
In some cases, the patient’s temperature sensitivity is severely limited by the hypoalgesia, which can result in burns. There are no further complications in the treatment of hypoalgesia. It runs with the help of antibiotics or surgical interventions. In some cases, therapies are also necessary to restore the affected person’s sensitivity. Life expectancy is usually not affected by hypoalgesia.
When should you go to the doctor?
If strong pain stimuli and abnormal sensations occur again and again that cannot be attributed to a specific cause, hypoalgesia may be the cause. A doctor must be consulted if the symptoms do not go away on their own or if they rapidly increase in intensity. If there are other symptoms such as abnormal sensations or numbness, it is best to see a doctor immediately. The same applies to a disturbed sense of temperature up to fever.
At the latest when serious complications develop, medical advice is required. Pronounced movement restrictions, chronic headaches or back pain and persistent numbness must be clarified. Individuals suffering from nerve damage are particularly susceptible to the symptoms of hypoalgesia. Likewise people with tumors, degenerative phenomena or autoimmune diseases such as multiple sclerosis. Anyone who belongs to one of these risk groups should see a doctor immediately if they experience the symptoms mentioned. The right contact person is the general practitioner or a neurologist. If the symptoms are severe, the emergency doctor should be called or the patient must go to a hospital immediately.
Treatment & Therapy
Therapy for hypoalgesia depends on the primary cause. In the case of diabetic polyneuropathy, for example, the optimal blood sugar control of the patient is of central importance in the treatment. Infectious polyneuropathy requires drug treatment of the causative infection, such as antibiotics.
Patients with peripheral nerve damage can often recover almost completely once the cause has been eliminated. In the case of causative lesions in the central nervous system, complete regeneration often does not occur. An exception to this may be tumor-related hypoalgesia. In this case, removal of the tumor can lead to the restoration of pain sensation.
In the case of degenerative causes, recovery is not possible. In the case of causative inflammatory lesions of the central nervous system, the inflammation must first be brought under control by administering medication. Injuries to the central nervous system leave scars. The affected nerve tissue is permanently impaired in its function and cannot fully recover due to the high level of specialization.
However, the functions of the defective tissue can under certain circumstances be transferred to the neighboring nerve cells as part of a sensitivity therapy. In the case of psychologically caused hypoalgesia, the triggering event is processed in psychotherapeutic care .
Outlook & Forecast
Depending on the type and severity of the hypalgesia, persistent symptoms can also occur, which severely limit the quality of life. The prognosis for mild sensory disturbances is positive. Drug treatment is then often enough to reduce the symptoms to such an extent that a normal life is possible.
In the case of severe hypalgesia with severe headache and back pain, full recovery is unlikely. Patients are often impaired throughout their lives and need support in everyday life later in life. In the worst case, serious illnesses are not recognized in time as a result of the disturbed perception of pain. Any infections or internal diseases are then sometimes well advanced and potentially fatal. If the sense of temperature is also disturbed, burns and frostbite and the associated consequences can also occur.
These significant limitations often lead to the development of psychological complaints, which in turn reduce the quality of life. However, life expectancy is not normally reduced by hypoalgesia. Nevertheless, early and comprehensive treatment is necessary in any case. A positive prognosis can be made with drug therapy combined with physiotherapy and behavioral therapy.
Prevention
Physically caused hypoalgesia can only be prevented insofar as degenerative, infectious and autoimmune diseases, cancerous diseases, hypoxia and trauma of the nervous tissue can be prevented: in other words, hardly. Psychologically caused hypoalgesia, on the other hand, can be prevented by processing stressful events.
Aftercare
In the case of hypoalgesia, aftercare focuses on regular consultations with the specialist. The doctor will ask the patient about the current pain sensation and adjust the medication if necessary. In most cases, this is not necessary, as the hypoalgesia can usually be treated and will go away on its own once treatment of the causative disease has been completed.
The follow-up checks therefore only have to take place monthly and later every six months. If no further pain insensitivity is noted, doctor visits can be discontinued. Because the disease often causes psychological symptoms, psychological treatment makes sense after the therapy.
The same applies if the reduced pain sensation is due to a mental illness. Then the person concerned should consult a therapist and, if necessary, visit a self-help group. Which measures make sense in detail always depends on the intensity of the disease and requires initial consultation with a specialist.
In the case of chronic complaints, such as those that can occur with neurological diseases, comprehensive therapeutic support is required in any case. The patient must also take medication and have the medication regularly adjusted to the current state of health. Unlike allodynia, hypalgesia usually has physical causes that need to be identified. Depending on the nature of the condition, this can sometimes take several months or even years.
You can do that yourself
In the case of hypoalgesia, the causative disease must first be determined. Various self-help measures can be taken depending on which condition triggers the limited pain sensitivity.
If it is a diabetic polyneuropathy, the focus is on adjusting the blood sugar level. The affected person must pay attention to the body’s own signals and possibly also keep a complaints diary in order to quickly reach an optimal value that no longer causes symptoms. Infectious polyneuropathy must always be treated with medication. Natural remedies with antibiotic effects support the medical administration of antibiotics.
In the case of degenerative causes, full restoration of pain sensitivity is not possible. The focus is on reducing the symptoms as much as possible. This can be achieved, for example, through sensitivity therapy and alternative measures such as acupuncture, massages or cold and heat therapy. Since diseases and injuries in the affected area can only be perceived to a limited extent, regular visits to the doctor are also indicated.
In the case of psychologically related hypoalgesia, the person concerned should also seek psychotherapeutic care. In a conversation with a therapist, the triggering event can be processed, which normally also reduces the symptoms.