The gold standard for the diagnosis of Vitamin B deficiency is a low blood level of Vitamin B. A low level of blood Vitamin B is a finding that normally can and should be treated by injections, supplementation, or dietary or lifestyle advice, but it is not a diagnosis. Hypovitaminosis B can result from a number of mechanisms, including those listed above. For determination of cause, further patient history, testing, and empirical therapy may be clinically indicated. A measurement of methylmalonic acid (methylmalonate) can provide an indirect method for partially differentiating Vitamin B and folate deficiencies. The level of methylmalonic acid is not elevated in folic acid deficiency. Direct measurement of blood cobalamin remains the gold standard because the test for elevated methylmalonic acid is not specific enough. Vitamin B is one necessary prosthetic group to the enzyme methylmalonyl-coenzyme A mutase. Vitamin B deficiency is but one among the conditions that can lead to dysfunction of this enzyme and a buildup of its substrate, methylmalonic acid, the elevated level of which can be detected in the urine and blood. Due to the lack of available radioactive Vitamin B, the Schilling test is now largely a historical artifact. The Schilling test was performed in the past to help determine the nature of the vitamin B deficiency. An advantage of the Schilling test was that it often included Vitamin B with intrinsic factor. Blood findings The blood film can point towards vitamin deficiency: *Decreased red blood cell (RBC) count and hemoglobin levels *Increased mean corpuscular volume (MCV, >100 fL) and mean corpuscular hemoglobin (MCH) *Normal mean corpuscular hemoglobin concentration (MCHC, 32–36 g/dL) *Decreased reticulocyte count due to destruction of fragile and abnormal megaloblastic erythroid precursor. *The platelet count may be reduced. *Neutrophil granulocytes may show multisegmented nuclei ("senile neutrophil"). This is thought to be due to decreased production and a compensatory prolonged lifespan for circulating neutrophils, which increase numbers of nuclear segments with age. *Anisocytosis (increased variation in RBC size) and poikilocytosis (abnormally shaped RBCs). *Macrocytes (larger than normal RBCs) are present. *Ovalocytes (oval-shaped RBCs) are present. *Howell-Jolly bodies (chromosomal remnant) also present. Blood chemistries will also show: *An increased lactic acid dehydrogenase (LDH) level. The isozyme is LDH-2 which is typical of the serum and hematopoietic cells. *Increased homocysteine and methylmalonic acid in Vitamin B deficiency *Increased homocysteine in folate deficiency Normal levels of both methylmalonic acid and total homocysteine rule out clinically significant cobalamin deficiency with virtual certainty. Bone marrow (not normally checked in a patient suspected of megaloblastic anemia) shows megaloblastic hyperplasia.
complications of Lesch–Nyhan syndrome
complications of Myotonic dystrophy
complications of Botulism
complications of Kallmann syndrome
symptom of Lesch–Nyhan syndrome
complications of Hashimoto's thyroiditis
complications of Fabry disease
symptom of Maroteaux–Lamy syndrome