Funicular myelosis

Clemens Gödel is a freelancer for the medical team.

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Funicular myelosis (funicular spinal disease) is a disease of the central nervous system, especially the spinal cord. The cause is usually a vitamin B12 deficiency. The disease usually begins insidiously with sensitive disorders in the legs, which lead to an unsteady gait. Funicular myelosis is treated with vitamin B12. Read more about the symptoms, diagnosis and therapy of funicular myelosis here.

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. E53

Funicular myelosis: description

Funicular myelosis (funicular spinal disease) is a rare condition that mainly affects people between the ages of 50 and 70. (Reversible) damage to the posterior area of ​​the spinal cord (posterior cord) is characteristic. The spinal cord runs protected in the spinal canal from the tailbone to the head and is part of the central nervous system.

In most cases, funicular myelosis is caused by a vitamin B12 deficiency (hypovitaminosis). Vitamin B12 (also called cobalamin) has a variety of functions in the body. It is important for the nerve cells, red blood cells and the protein and nucleic acid metabolism. The nucleic acids are the building blocks of the genetic make-up.

Human beings take in vitamin B12 primarily through dairy products, meat, eggs and whole grain products. The vitamin can be stored in the body in relatively large quantities and for years. The main memory is in the liver. Funicular myelosis usually occurs when these stores are completely exhausted.

Funicular myelosis: symptoms

Funicular myelosis usually develops slowly, only rarely quickly and acutely. First of all, a vitamin B12 deficiency becomes noticeable through anemia (pernicious anemia). In this form of anemia, the red blood cells are enlarged (megaloblastic) and have an increased concentration of the blood pigment hemoglobin (hyperchromic).

Funicular myelosis is a multi-faceted disease. The spinal cord is particularly affected, but also the brain (encephalopathy). Damage to the brain can be seen in cognitive impairments. The mental symptoms range from fatigue to dementia and psychotic symptoms.

Sensory disorders in the legs

In 90 percent of cases, funicular myelosis causes symmetrical and sometimes painful abnormal sensations (paresthesia), which often begin in the legs. Disturbances of the sense of position, vibration and touch such as tingling and pins and needles are characteristic. In addition, funicular myelosis can also be associated with disturbances in the sensation of temperature and pain. These sensory disturbances result in an unsteady gait (sensible ataxia). In addition, those affected tire quickly when walking.

Funicular myelosis rarely leads to motor deficits at an early stage.

Spastic paralysis

Funicular myelosis progresses and over time causes further damage to the spinal cord and brain. As a result, the gait disorders become clearer in the further course. Finally, there is also spastic paralysis of the legs and, later, of the arms.

Disorders of the reflexes

The muscle reflexes can be increased or - in the presence of a polyneuropathy - reduced by the funicular myelosis. Polyneuropathy is a condition that is characterized by damage to a large number of nerves and can also occur with funicular myelosis.

At the same time, normally nonexistent reflexes such as the Babinski reflex on the sole of the foot can be triggered. This is the case when the funicular myelosis also affects the so-called pyramidal tract. This is an important nerve road in the spinal cord that sends signals from the brain to the muscles.

Disorders of the bladder, bowel and sexual function

In around a quarter of all cases, funicular myelosis leads to bladder complaints. This includes an initially increased urge to urinate, which can later develop into incontinence. The function of the rectum can also be disturbed. In some cases there is also a threat of impotence.

Further consequences of the vitamin B12 deficiency

Funicular myelosis and anemia are not the only consequences of vitamin B12 deficiency. In addition, damage to the mucous membranes, which require vitamin B12, also occurs. Inflammatory and painful tissue shrinkage on the tongue (Hunter glossitis) is particularly noticeable.

In addition, homocysteinemia can occur: the amino acid homocysteine ​​cannot be metabolized due to the vitamin B12 deficiency, which increases its concentration in the blood. This disease leads to dangerous vascular damage.

Funicular myelosis: causes and risk factors

Funicular myelosis is usually caused by a vitamin B12 deficiency, more rarely by a folic acid deficiency. In individual cases, a copper deficiency is responsible for the symptoms. With a vitamin B12 deficiency, the blood level of the vitamin is below 150 picograms per milliliter (pg / ml).

Damage in the spinal cord

The funicular myelosis initially affects the rear area (posterior cord) of the spinal cord in particular. As the disease progresses, it can spread, for example to the so-called posterior cords.

The spinal cord consists mainly of the so-called gray matter, the nerve cell bodies and the white matter in which the nerve processes are located. The nerve processes are enclosed in a fat-rich envelope (myelin sheath) to improve the transmission of electrical signals. Funicular myelosis is associated with swelling of these myelin sheaths. The swelling is reversible with early treatment.

However, as with multiple sclerosis, the covering can also be damaged (demyelination). In the course of the process, the nerve lines can be further and irreversibly destroyed.

Creeping start

A vitamin B12 deficiency and thus funicular myelosis usually develop slowly, as the body can store the vitamin in relatively large quantities (up to four milligrams). Since the daily requirement is only a few micrograms, the store can provide sufficient vitamin B12 for years. Cobalamin deficiency can have various causes.

Vitamin B12 deficiency due to insufficient intake

Diet is only to blame for vitamin B12 deficiency in rare cases. A strictly vegetarian or vegan diet can lead to a reduced vitamin B12 level in the blood. In addition, a vitamin B12 deficiency and thus funicular myelosis can occur in the case of chronic alcohol abuse and anorexia nervosa. Diet-related vitamin deficiencies are also possible in old age.

Vitamin B12 deficiency due to a lack of absorption

The lack of vitamin B12 and thus the funicular myelosis are usually caused by insufficient vitamin B12 absorption in the gastrointestinal tract. This so-called resorption disorder arises in 80 percent of cases due to a lack of a transport protein that is required for the absorption of the vitamin. This protein is called intrinsic factor. It binds to vitamin B12 and brings it to special docking points (receptors) in the small intestine, where the vitamin can be absorbed into the blood.

The intrinsic factor is formed and secreted by certain cells in the gastric mucosa. With some gastric diseases (such as chronic atrophic gastritis) or after a part of the stomach has been removed, it is possible that insufficient intrinsic factor is no longer produced. Then there is a risk of funicular myelosis in the long term.

In addition, gastritis often disrupts gastric acid secretion: As a result, cobalamin cannot be released from the animal proteins in the food to which it is bound. Then it cannot be absorbed into blood. This can happen even after years of taking anti-acid medication (such as omeprazole).

In the case of intestinal diseases or partial removal of the small intestine, the absorption of vitamin B12 can also be impaired.Possible causes here are chronic intestinal inflammation (such as ulcerative colitis), tuberculosis infections, gluten intolerance, amyloidosis and also connective tissue diseases.

Vitamin B12 deficiency due to increased consumption

An increased consumption of vitamin B12 is only responsible for funicular myelosis in rare cases. The need and thus the consumption of cobalamin increases during pregnancy and breastfeeding. Infectious diseases caused by fungi, bacteria or fish tapeworms may also have an increased need for vitamins. The same applies to diseases with a high rate of cell regeneration (such as cancer).

Vitamin B12 deficiency due to impaired use

Even with sufficient intake and absorption, a vitamin B12 deficiency can arise, and that is when the use of the vitamin is disturbed. This happens, for example, when antibodies against vitamin B12 are formed, too much nitrous oxide is inhaled (e.g. during anesthesia) or there are congenital disorders of vitamin utilization. For example, a congenital defect in the vitamin B12 transport protein transcobalamin leads to absorption and transport disorders with deficiency symptoms, although the blood concentration of the vitamin is normal in many cases.

Folic Acid Deficiency

In a few cases, funicular myelosis develops as a result of a lack of folic acid. This can (like the lack of cobalamin) result from insufficient intake, disturbed absorption, disturbed use and increased consumption:

An insufficient intake of folic acid can be caused, for example, by chronic alcohol consumption or anorexia. Absorption in the intestine can be impaired by chronic intestinal diseases (such as Crohn's disease, celiac disease), liver cell damage or certain medications (such as oral contraceptives or the pain reliever acetylsalicylic acid). The utilization of folic acid can also be disturbed by certain drugs (such as cancer drugs) or in the case of congenital disorders in the folic acid metabolism. As with vitamin B12, there is an increased consumption of folic acid during pregnancy and breastfeeding as well as in diseases with a high rate of cell formation (such as cancer).

Funicular myelosis: examinations and diagnosis

The symptoms of funicular myelosis cause most people to visit their family doctor or neurologist.

Collection of the medical history (anamnesis)

First, the doctor collects the medical history (anamnesis) in a conversation with the patient. For example, he asks about the start, type and extent of the complaints.

Physical examination

As part of the physical examination, the doctor will check the various qualities of sensitivity (such as position, touch, vibration, pain and temperature sensation). In addition, the reflexes are checked. If funicular myelosis is suspected, the focus of the examination is usually on the legs, as this is where the symptoms are usually most evident.

Blood test

The blood test is of particular importance for the diagnosis of "funicular myelosis". There are often signs of anemia caused by vitamin deficiency. In this context, the following parameters are important:

• Blood cells: number and appearance are analyzed.
• Vitamin B12
• Folic acid
• Holo-transcobalamin: This is an early marker of vitamin B12 deficiency. A lower value indicates that more vitamin B12 is being consumed than is being consumed.
• Methylmalonic acid: an increased level of methylmalonic acid indicates a vitamin B12 deficiency.
• Intrinsic factor antibodies: They make the intrinsic factor unusable and thus hinder the absorption of vitamin B12.
• Parietal cell antibodies: The parietal cells of the gastric mucosa produce the intrinsic factor. Antibodies against these cells therefore hinder the production of the protein.
• Indirect bilirubin
• cholesterol

Magnetic resonance imaging (MRI)

To analyze the damage to the spinal cord more closely, an image is made using magnetic resonance imaging (MRI). Characteristic of a funicular myelosis are abnormalities in the posterior (posterior cord) and laterally posterior (posterior cord) area of ​​the spinal cord.

Neurophysiological examinations

In order to examine nerve damage caused by funicular myelosis in more detail, neurophysiological examinations can be carried out, for example electromyography (EMG, measurement of electrical muscle activity). Funicular myelosis can occur together with polyneuropathy, which these tests can identify.

Schilling test (vitamin B12 absorption test)

If funicular myelosis is suspected, the Schilling test (vitamin B12 absorption test) is sometimes carried out. For this, the patient must take radioactively labeled vitamin B12. Over the next 24 hours, his urine is collected and analyzed to see how much of the radiolabelled vitamin has been excreted. If it is below five percent, this indicates an absorption disorder.

To prevent radioactively labeled cobalamin from being stored in the body, the patient is injected with unlabelled vitamin B12 into a muscle during the test. It saturates the body tissue with cobalamin.

If the test result suggests a vitamin B12 absorption disorder, the examination can be repeated slightly for more precise clarification. In addition to the radioactively labeled cobalamin, the patient also receives intrinsic factor, the vitamin's transport protein. If the excretion of radioactive cobalamin is still reduced, the absorption of the vitamin in the small intestine is disturbed. If the excretion normalizes, a lack of intrinsic factor was the reason for the decreased vitamin intake.

However, the use of the Schilling test in suspected funicular myelosis is controversial and is sometimes viewed as superfluous.

Sternal puncture

To further investigate anemia, the doctor can perform a so-called sternal puncture. To do this, he will take some bone marrow from the patient's sternum with a fine needle to have it analyzed in the laboratory.

Clarification of gastritis

Chronic gastritis can develop in pernicious anemia, such as occurs with a vitamin B12 deficiency. This results in digestive problems and, in turn, vitamin deficiencies, as insufficient hydrochloric acid is secreted in the stomach for digestion ("histamine-refractory anacidity"). Gastritis should therefore be examined by a gastroenterologist.

Exclusion of other diseases

The symptoms of funicular myelosis are similar to a number of other diseases, which must be taken into account when making a diagnosis. The most important alternative diagnosis is multiple sclerosis. Other so-called differential diagnoses are inflammation of the spinal cord (myelitis), lupus erythematosus, sarcoid, muscle diseases (myelopathies) and infectious diseases of the spinal cord.

Funicular myelosis: treatment

Funicular myelosis progresses steadily without therapy and can leave permanent damage. It should therefore be treated as early as possible. In which way depends on the cause of the disease.

Funicular myelosis: therapy for vitamin B12 deficiency

Funicular myelosis is usually characterized by the fact that all body stores for vitamin B12 have been emptied. The treatment therefore begins with the so-called saturation, which means: Initially, not only does the acute daily requirement of cobalamin (two to five micrograms) have to be covered, but the stores also have to be refilled. For this purpose, one milligram of vitamin B12 is usually injected into the muscle daily for the first two weeks of therapy.

Subsequently, as part of the long-term therapy, the vitamin deficiency (and thus the funicular myelosis) is treated with cobalamin injections once or twice a week or even just once a month. As an alternative to the injections, there are also vitamin B12 tablets.

Funicular myelosis: therapy for folic acid deficiency

If the funicular myelosis is caused by folic acid deficiency, 15 milligrams of folic acid per day are acutely injected into the muscle. After three to five days you can switch to tablets, which have to be taken two to three times a day. The folic acid store is usually replenished after around two weeks.

In the further course, a balanced diet is often sufficient to maintain adequate folic acid levels in the body. Otherwise, or in situations with an increased need for folic acid (such as during pregnancy), folic acid can be taken several times a day.

Acute treatment with folic acid and vitamin B12

The combined administration of folic acid and vitamin B12 should only be used in acute cases, as long as the cause of the funicular myelosis is not yet known. The administration of folic acid can improve the symptoms affecting the blood, but in the case of a vitamin B12 deficiency it cannot prevent the neurological symptoms caused by the funicular myelosis. The consequence can be that the administration of folic acid disguises a vitamin B12 deficiency and the funicular myelosis caused by the cobalamin deficiency is not recognized and treated early on.

Funicular myelosis: disease course and prognosis

Starting treatment early is crucial, as the funicular myelosis symptoms can only regress if there is no permanent damage to the nerve cell extensions (axons).

Symptoms may initially worsen immediately after starting treatment. The therapy should still be continued.

The therapy almost always causes at least an improvement in symptoms within days to weeks. If, however, no improvement is noticeable after three months, the diagnosis of "funicular myelosis" must be checked.

Symptoms that have existed for months or even years usually do not resolve completely. In a not inconsiderable number of funicular myelosis patients, residual symptoms - often minor - persist despite successful therapy.

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