Lung Cancer & Low Potassium

According to the Centers for Disease Control and Prevention, more
than 200,000 people in the United States were diagnosed with lung cancer in
2007 and more than158,000 people died from the disease that year. Lung cancer
not only affects the function of the lungs, but it can disrupt the balance of
electrolytes such as potassium. Certain cancers of the lung can produce
hormones, which can cause an increase in potassium excretion.

Types of Lung Cancers

Lung cancers can be separated into two groups: cancers that
originate in the lungs and cancers that metastasize, or spread, to the lungs.
The four major cancers that originate in lungs include squamous cell lung
cancer, small cell lung cancer, adenocarcinoma of lungs and large cell lung
cancer; these cancers originate from the main branches of the airways. As lung
cancers get bigger, they cause problems by obstructing the airways. Lung
cancers can cause problems outside the lungs, for example, small-cell lung
cancer can produce ACTH, a hormone that stimulates the release of aldosterone
-- a steroid hormone -- from the adrenal glands.

ACTH, Aldosterone and Balance of Potassium

In normal conditions, potassium levels are maintained by the
adrenal glands, which produce aldosterone, and the pituitary gland, which
produces ACTH. When blood potassium is elevated, the pituitary gland releases
ACTH, which causes the adrenal glands to release aldosterone. The release of
aldosterone results in the increased excretion of potassium into the urine.
Aldosterone secretion decreases when blood potassium level is below normal.
Small-cell lung cancer releases higher than normal levels of ACTH, which
interferes with the body's ability to regulate potassium due to increased
action of aldosterone in the kidneys.

Symptoms of Low Blood Potassium

Potassium is needed for the adequate functioning of the heart and
nerves. When potassium is low, organs most dependent on potassium become
dysfunctional. Arrhythmias, or irregular heart contractions, are the most
worrisome complications associated with low blood potassium, because it can
result in low blood pressure, poor circulation of blood and inadequate oxygen
delivery to organs of the body. Hypokalemia, or low blood potassium, can also
cause weakness of muscles in the arms and legs, tiredness and constipation.
Tiredness can also be attributed to the presence of cancer.

Management of Low Blood Potassium

Before treating a person with hypokalemia, the underlying cause
for hypokalemia must be addressed. In a person with lung cancer-related
hypokalemia the cancer must be initially treated or controlled before pursuing
other methods for correcting hypokalemia. Usually, when lung cancer is
adequately treated, blood potassium levels return to normal. If blood potassium
remains low, the cause is likely temporary but treatment must given to avert
complications associated with low blood potassium. According to
"Davidson's Principles & Practice of Medicine," replacement of
potassium is usually achieved with oral ingestion of slow-release potassium
chloride, or KCl, tablets. Severe cases of hypokalemia are treated with the
infusion of KCl into a large vein.

http://www.livestrong.com/article/486283-lung-cancer-low-potassium/