A familial form of pseudohyperkalemia, a benign condition characterised by increased serum potassium in whole blood stored at cold temperatures, also exists. This is due to increased potassium permeability in red blood cells. Mechanism
Physiology
Potassium is the most abundant intracellular cation and about 98% of the bodys potassium is found inside cells, with the remainder in the extracellular fluid including the blood. Membrane potential is maintained principally by the concentration gradient and membrane permeability to potassium with some contribution from the Na+/K+ pump. The potassium gradient is critically important for many physiological processes, including maintenance of cellular membrane potential, homeostasis of cell volume, and transmission of action potentials in nerve cells.Potassium is eliminated from the body through the gastrointestinal tract, kidney and sweat glands. In the kidneys, elimination of potassium is passive (through the glomeruli), and reabsorption is active in the proximal tubule and the ascending limb of the loop of Henle. There is active excretion of potassium in the distal tubule and the collecting duct; both are controlled by aldosterone. In sweat glands potassium elimination is quite similar to the kidney, its excretion is also controlled by aldosterone.Regulation of serum potassium is a function of intake, appropriate distribution between intracellular and extracellular compartments, and effective bodily excretion. In healthy individuals, homeostasis is maintained when cellular uptake and kidney excretion naturally counterbalance a patients dietary intake of potassium. When kidney function becomes compromised, the ability of the body to effectively regulate serum potassium via the kidney declines.
Dysphagia lusoria (or Bayford-Autenrieth dysphagia) is an abnormal condition characterized by difficulty in swallowing caused by an aberrant right subclavian artery. It was discovered by David Bayford in 1761 and first reported in a paper by the same in 1787. Pathophysiology
During development of aortic arch, if the proximal portion of the right fourth arch disappears instead of distal portion, the right subclavian artery will arise as the last branch of aortic arch. It then courses behind the esophagus (or rarely in front of esophagus, or even in front of trachea) to supply blood to right arm. This causes pressure on esophagus and results in dysphagia. It can sometimes result in upper gastrointestinal tract bleeding. Investigation of choice - CT angiography

Treatment
Surgical repair is performed. Reconstruction or ligation of aberrant right subclavian artery by sternotomy/by neck approach. Eponym
David Bayford called it dysphagia lusoria because in Latin, lusus naturæ means sports of nature or natural anomaly. Bayford-Autenrieth dysphagia is eponym for Bayford and Autenrieth. See also
Aberrant subclavian artery
Ortners syndrome

References


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