Funicular myelosis

The funicular myelosis or funicular Spinalerkrankung heard how the multiple sclerosis to demyelinating diseases . The English term is S ub a cute c ombined d eGENERATION of the spinal cord ( SACD ). It is caused by a lack of vitamin B ₁₂ and is treated by taking the vitamin. The most prominent symptoms of the disease are loss of motor skills and sensitivity , which can worsen up to paraplegia . The disease is based on damage to the spinal cord . Under certain circumstances, it can precede pernicious anemia , which is also caused by the vitamin deficiency.

Classification according to ICD-10
E53.8 †	Deficiency of other specified vitamins of the vitamin B complex
G32.0 *	Subacute combined degeneration of the spinal cord in a vitamin B 12 deficiency
ICD-10 online (WHO version 2019)

etiology

The disease is caused by a vitamin B ₁₂ deficiency. The most common cause is a lack of intrinsic factors . This glycoprotein is produced in the parietal cells of the stomach and binds vitamin B ₁₂ . Only the bound form of the vitamin is not broken down by digestive enzymes and can be absorbed in the ileum . The parietal cells can be damaged by auto-immune antibodies . Patients after surgical gastric removal cannot produce an intrinsic factor either, or in the case of undetected celiac disease , which is accompanied by destruction of the villi of the small intestine. In alcohol addicts , chronic gastric mucosal inflammation often occurs , which brings the production of the factor to a standstill. Less common causes are absorption disorders in the small intestine and relative vitamin deficiencies in pregnant women. A B ₁₂ deficiency can also be triggered by medication. Phenobarbital , cytostatics or anesthesia with nitrous oxide are described as triggering .

Other possible causes of the deficiency are infestations with the fish tapeworm , which uses up the vitamin for itself. Bacterial colonization of the intestine can also use up the vitamin supplied by food. A vegan diet can also lead to a vitamin B ₁₂ deficiency, as the vitamin that can be used by humans occurs almost exclusively in animal food.

Pathogenesis

Prominent in the disease are demyelinating foci in the spinal cord in the posterior cord tracts , which convey tactile perception and proprioception , the cerebellar lateral cord tracts , which also serve proprioceptive perception, and the pyramidal tracts , which convey movement stimuli. In the foci of demyelinating, the myelin sheaths around the nerve fibers perish first. This is followed by the destruction of the nerve cells themselves. In the final stage, the destroyed tissue is replaced by scar tissue from glial cells . The disease is usually confined to the spinal cord, but it can also affect the myelin sheaths of peripheral nerves. It occurs most often in the neck and chest area of ​​the spinal cord. The mechanism by which the vitamin deficiency damages the medullary sheaths and nerve fibers is not yet known.

Symptoms

The first sign of the disease is a burning sensation that occurs first on the hands and feet. These spread to the respective limbs as the disease progresses. The sensory symptoms are followed by paralysis of the legs and a disturbance of the coordination of movements , which can be traced back to the failure of the sensory pathways. The paralysis can also spread to the arms. Also disorders of bladder function are described. If left untreated, the disease leads to paraplegia . Since the body's vitamin B ₁₂ stores are available for around two years, symptoms appear with a delay.

The neurological examination shows a diffuse weakness of the muscles of the legs and / or arms without a preference for defined muscle groups. The tone of the muscles is reduced. The self-reflexes are first increased in the course, only to decrease in their intensity afterwards. Pathological reflexes can be triggered in many patients with funicular myelosis. Disturbances in sensitivity , position sense and vibration perception are just as common . Failures of the eye muscles and psychiatric symptoms such as psychosis , delirium or depression are less common .

Diagnosis

When the nerve conduction velocity is measured , it is typically shown to be reduced in the motor and sensory nerves. In the laboratory tests , a typical shows up in one third of patients pernicious anemia . It is noteworthy that the myelosis precedes the anemia and can thus be the first symptom of the deficiency state. In 40 to 50 percent of cases, enlarged erythrocytes appear without any signs of anemia. Furthermore, hypersegmented granulocytes can be seen in the blood count . The measurement of the blood level of vitamin B ₁₂ is only of limited diagnostic value. The measurement of the metabolites homocysteine and methylmalonate in the urine , which are increased in the disease (see also: test for vitamin B ₁₂ deficiency ), is evidence of a deficiency . The Schilling test is recommended to differentiate a deficiency of intrinsic factor from a deficiency in the supply of vitamin B ₁₂ . Radiolabelled vitamin with and without intrinsic factor is given. The uptake of the vitamin is determined from the patient's urine.

A gastroscopy is also advisable to rule out gastric cancer or chronic gastritis .

Therapy and prognosis

The disease can be treated by substituting vitamin B ₁₂ . It is given through intravenous or intramuscular injections. In the initial phase, they are carried out daily. Thanks to the high storage capacity in the liver, they can later be reduced to one injection per month or quarter. In early cases, symptoms regress without permanent damage. However, this can take several months. If the anemia is pronounced, iron substitution should be considered, as the body needs large amounts of iron for the increased formation of red blood cells.

The administration of vitamins can definitely stop the symptoms from worsening. If the disease is recognized at an early stage, it regresses completely. If not only the myelin sheaths in the affected areas are destroyed, but also the axon cylinders, the effects are irreversible and residual symptoms remain.

Individual evidence

1. ↑ ^{a b c d e f g} Klaus Poeck, Werner Hacke: Neurology. 12th edition. Heidelberg 2006, p. 585.
2. ↑ Meinhard Classen, Volker Diel, Kurt Kochsiek (ed.): Internal medicine. Munich 2004, p. 712 f.
3. ↑ Meinhard Classen, Volker Diel, Kurt Kochsiek (ed.): Internal medicine. Munich 2004, p. 712.
4. ↑ Timothy Fowler, John Scadding: Clinical Neurology. 3. Edition. London 2003.
5. ^ ^{A b} John Trojanowski, Lawrence Kenyon, Thomas Bouldin: The Nervous System. In: Raphael Rubin, David Strayer: Rubin's Pathology. Philadelphia 2008, p. 1215.
6. ^ Klaus Poeck, Werner Hacke: Neurology. 12th edition. Heidelberg 2006, p. 586.
7. ↑ ^{a b} Meinhard Classen, Volker Diel, Kurt Kochsiek (ed.): Internal medicine. Munich 2004, p. 713.
8. ^ Klaus Poeck, Werner Hacke: Neurology. 12th edition. Heidelberg 2006, p. 586.
9. ↑ Timothy Fowler, John Scadding: Clinical Neurology. 3. Edition. London 2003, p. 492.
10. ↑ Herbert Renz-Polster , Steffen Krautzig (Ed.): Basic textbook internal medicine. Munich 2008, ISBN 978-3-437-41053-6 , p. 290.
11. ^ Klaus Poeck, Werner Hacke: Neurology. 12th edition. Heidelberg 2006, p. 585 f.

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