Pyridoxine deficiency

Infobox_Disease
Name = Vitamin B6 deficiency

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Caption = Pyridoxine
DiseasesDB = 13923
ICD10 = ICD10|E|53|1|e|50
ICD9 = ICD9|266.1
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj = med
eMedicineTopic = 1977
MeshID = D026681

Pyridoxine deficinecy (also known as B6 deficiency) is a paediatric disease due to a lack of pyridoxine (or vitamin B6). The disease presents with several key symptoms including seizures, irritability, cheilitis (inflammation of the lips), conjunctivitis and neurologic symptoms. It ususally becomes noticable within the first 12 months of life in infants with a lack of pyridoxine, a coenzyme responsible for numerous essential metabolic reactions in humans. It is rarely observed, even in undeveloped countries.cite book |title=Textbook of Child Neurology |last=Menkes |first=John H |year=1980 |publisher=Henry Kimpton Publishers |isbn=0-8121-0661-X] Andrews' Diseases of the Skin, 10th Edition, Elsevier.]

igns and symptoms

Familial pyridoxine dependency syndrome causes seizures at birth or shortly afterwards. It has been speculated that the cause of seizures in pyridoxine deficiency lies with abnormalities in the normal ratio of glutamic acid to GABA. Irritiability and other neurologic symptoms, such as confusion, are common place.. Anemia has also been documented as a symptom.

Causes

The main cause of pyridoxine deficiency is a lack of pyridoxine in the diet. Another cause of vitamin B6 deficinecy is the use of the tuberculostatic medication isoniazid, and for this reason, it is ususally replaced with vitamin B6 whilst using this drug.

Pathophysiology

Decarboxylation of glutamic acid to gamma-aminobutyric acid (GABA, a neurotransmitter) and transamination of glutamic acid to alpha-ketoglutaric acid are both impaired in animals when suffering from pyridoxine deficiency. Neurologic symptoms are most likely due to diminished affinity of pyridoxine for the apoenzyme, which can only be overcome by increasing tissue concentrations of the enzyme.

Diagnosis

Pyridoxine deficiency is a very rare condition, even in undeveloped countries. A handful of cases were seen inbetween 1952 and 1953, particularly in the United States, and occurered in a small percentage of infants who were fed a formula lacking in pyridoxine. A positive diagnosis test for pyridoxine deficiency can be assertained by measuring erythrocyte levels of aspartate aminotransferase and transketolase in serum.

Treatment

Treatment of pyridoxine deficiency lies with replacing the missing vitamin. Penicillamine or hydrazides, such as isoniazid, are rarely used due to their ability to provoke deficiency symptoms.

References