Pyruvate carboxylase deficiency is an inherited disorder that causes lactic acid to accumulate in the blood. High levels of these substances can damage the bodys organs and tissues, particularly in the nervous system. Pyruvate carboxylase deficiency is a rare condition, with an estimated incidence of 1 in 250,000 births worldwide. Type A of the disease appears to be much more common in some Algonkian Indian tribes in eastern Canada, while the type B disease is more present in European populations. Signs and symptoms
Pyruvate carboxylase deficiency causes lactic acidosis and hyperammonaemia. Lactic acidosis may then lead to liver failure, hepatomegaly, reduced ketone body synthesis, and demyelination of neurons. Genetics
Pyruvate carboxylase deficiency is caused by mutations in the PC gene. The PC gene provides instructions for making an enzyme called pyruvate carboxylase. This condition is inherited in an autosomal recessive pattern, which means two copies of the gene must be inherited for the disorder to be present. The parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene, but do not show signs and symptoms of the disorder. Mechanism
Pyruvate carboxylase is active in mitochondria in cells. It is involved in the generation of glucose through gluconeogenesis. By generating oxaloacetate, it catalyses an important anaplerotic reaction that maintains the citric acid cycle to generate energy by aerobic respiration. Pyruvate carboxylase also plays a role in the formation of the myelin sheath that surrounds certain nerve cells, and the production of neurotransmitters for communication between neurons.
There is some evidence that immobilization with the wrist in dorsiflexion as opposed to palmarflexion results in less redisplacement and better functional status. Significant angulation and deformity may require an open reduction and internal fixation or external fixation. The volar forearm splint is best for temporary immobilization of forearm, wrist and hand fractures, including Colles fracture. There are several established instability criteria:
dorsal tilt >20°,
comminuted fracture,
abruption of the ulnar styloid process,
intraarticular displacement >1mm,
loss of radial height >2mm. A higher amount of instability criteria increases the likelihood of operative treatment. Treatment modalities differ in the elderly.Repeat Xrays are recommended at one, two, and six weeks to verify proper healing. Prognosis
Recovery time depends on the degree of bone displacement, the number of bone fragments, whether or not the break is "intra-articular" (involves the wrist joint), as well as the persons age, gender, and medical history, and may range from two months to a year or more for complete recovery. Epidemiology
Colles fractures occur in all age groups, although certain patterns follow an age distribution. In the elderly, because of the weaker cortex, the fracture is more often extra-articular. Younger individuals tend to require a higher energy force to cause the fracture and tend to have more complex intra-articular fractures. In children with open epiphyses, an equivalent fracture is the "epiphyseal slip", as can be seen in other joints, such as a slipped capital femoral epiphysis in the hip. This is a Salter I or II fracture with the deforming forces directed through the weaker epiphyseal plate.