I went to see the ophthalmologist on the 26th of January. I was scared.
the news was mixed, but no one ever told me. . My eyes had improve a
great deal--but I had toget my Blood Pressure down--and keep it down.
it had been that low. But the true test was would it stay that way.
Electrolyte Disorders
Definition
An
electrolyte disorder is an imbalance of certain ionized salts (i.e.,
bicarbonate, calcium, chloride, magnesium, phosphate, potassium, and
sodium) in the blood.
Description
Electrolytes
are ionized molecules found throughout the blood, tissues,
and cells of
the body. These molecules, which are either positive (cations)
or
negative (anions), conduct an electric current and help to balance pH
and acid-base levels in the body. Electrolytes also facilitate the
passage
of fluid between and within cells through a process known as osmosis and
play a part in regulating the function of the neuromuscular, endocrine, and
excretory systems. The serum electrolytes include:
- Sodium (Na). A positively charged electrolyte that helps to balance
- fluid levels in the body and facilitates neuromuscular functioning.
-
- Potassium (K). A main component of cellular fluid, this positive
- electrolyte helps to regulate neuromuscular function and osmotic
- pressure.
-
- Calcium (Ca). A cation, or positive electrolyte, that affects
- neuromuscular performance and contributes to skeletal growth
- and blood
coagulation.
-
- Magnesium (Mg). Influences muscle contractions and intracellular
- activity. A cation.
-
- Chloride (CI). An anion, or negative electrolyte, that regulates blood
- pressure.
-
- Phosphate (HPO4). Negative electrolyte that impacts metabolism
- and regulates acid-base balance and calcium levels
- .
- Bicarbonate (HCO3). A negatively charged electrolyte that assists
- in
the regulation of blood pH levels. Bicarbonate insufficiencies and
- elevations cause acid-base disorders (i.e., acidosis, alkalosis).
Medications, chronic diseases, and trauma (for example,
burns,
or
fractures etc.) may cause the concentration of certain electrolytes
in
the body to become too high (hyper-) or too low (hypo-). When this
happens, an electrolyte imbalance, or disorder, results.
Causes and symptoms
Sodium
HYPERNATREMIA.
Sodium helps the kidneys to regulate the amount of
water the body
retains or excretes. Consequently, individuals with elevated
serum
sodium levels also suffer from a loss of fluids, or dehydration.
Hypernatremia can be caused by inadequate water intake, excessive fluid loss
(i.e., diabetes insipidus,
kidney disease, severe burns, and prolonged vomiting
or
diarrhea),
or sodium retention (caused by excessive sodium intake or
aldosteronism). In addition, certain drugs, including loop diuretics,
corticosteroids,
and antihypertensive medications may cause elevated
sodium levels.
Symptoms of hypernatremia include:
- thirst
- orthostatic hypotension
- dry mouth and mucous membranes
- dark, concentrated urine
- loss of elasticity in the skin
- irregular heartbeat (tachycardia)
- irritability
- fatigue
- lethargy
- heavy, labored breathing
- muscle twitching and/or seizures
HYPONATREMIA.
Up to 1% of all hospitalized patients and as many as
18% of nursing
home patients develop hyponatremia, making it one of the
most common
electrolyte disorders. A 2004 study questioned the routine
make-up of
fluids prescribed for children and delivered intravenously
(through a
needle into a vein) in hospitals today. The authors recommended
only
using IV fluids when necessary and then using isotonic saline.
Diuretics,
certain psychoactive drugs (i.e., fluoxetine, sertraline, haloperidol),
specific antipsychotics (lithium), vasopressin, chlorpropamide, the
illicit drug
"ecstasy," and other pharmaceuticals can cause decreased
sodium levels,
or
hyponatremia.
Low sodium levels may also be triggered by inadequate
dietary intake of
sodium, excessive perspiration, water intoxication, and
impairment of
adrenal gland or kidney function.
Symptoms of hyponatremia include:
- nausea, abdominal cramping, and/or vomiting
- headache
- edema (swelling)
- muscle weakness and/or tremor
- paralysis
- disorientation
- slowed breathing
- seizures
- coma
Potassium
HYPERKALEMIA. Hyperkalemia may be caused by ketoacidosis (diabetic coma),
nervosa, gastrointestinal bleeding, adrenal insufficiency, or
Addison's disease. Diuretic
drugs, cyclosporin, lithium, heparin, ACE
inhibitors,
beta blockers, and trimethoprim
can increase serum potassium levels, as can heavy
exercise. The condition may also
be secondary to hypernatremia (low serum concentrations of sodium). Symptoms
may include:
- weakness
- nausea and/or abdominal pain
- irregular heartbeat (arrhythmia)
- diarrhea
- muscle pain
kidney disease, long-term diuretic therapy, certain penicillins, laxative
abuse,
congestive
heart failure,
and adrenal gland impairments can all cause depletion
of potassium
levels in the bloodstream. A substance known as glycyrrhetinic
acid,
which is found in licorice and chewing tobacco, can also deplete
potassium
- weakness
- paralysis
- increased urination
- irregular heartbeat (arrhythmia)
- orthostatic hypotension
- muscle pain
- tetany
Calcium
HYPERCALCEMIA. Blood calcium levels may be elevated in cases of thyroid
syndrome, and Paget's disease. Excessive use of
calcium-containing supplements
In infants, lesser known causes may include blue diaper syndrome, Williams syndrome,
e deficiency. Symptoms include:
- fatigue
- constipation
- depression
- confusion
- muscle pain
- nausea and vomiting
- dehydration
- increased urination
- irregular heartbeat (arrhythmia)
HYPOCALCEMIA.
Thyroid disorders, kidney failure, severe burns, sepsis,
vitamin D
deficiency, and medications such as heparin and glucogan can deplete
blood calcium levels. Lowered levels cause:
- muscle cramps and spasms
- tetany and/or convulsions
- mood changes (depression, irritability)
- dry skin
- brittle nails
- facial twitching
Magnesium
HYPERMAGNESEMIA.
Excessive magnesium levels may occur with end-stage
renal disease,
Addison's disease, or an overdose of magnesium salts. Hypermagnesemia
is
characterized by:
- lethargy
- hypotension
- decreased heart and respiratory rate
- muscle weakness
- diminished tendon reflexes
HYPOMAGNESEMIA. Inadequate dietary intake of magnesium, often caused
Other causes include malabsorption syndromes,
pancreatitis,
aldosteronism,
burns, hyperparathyroidism, digestive system disorders,
and diuretic use. Symptoms
of low serum magnesium levels include:
- leg and foot cramps
- weight loss
- vomiting
- muscle spasms, twitching, and tremors
- seizures
- muscle weakness
- arrthymia
Chloride
HYPERCHLOREMIA. Severe
dehydration, kidney failure, hemodialysis, traumatic
brain injury, and
aldosteronism can also cause hyperchloremia. Drugs such as boric
acid
and ammonium chloride and the intravenous (IV) infusion of sodium
chloride
Symptoms include:
- weakness
- headache
- nausea
- cardiac arrest
HYPOCHLOREMIA. Hypochloremia usually
occurs as a result of sodium and
potassium depletion (i.e.,
hyponatremia, hypokalemia). Severe depletion of
serum chloride levels
causes metabolic alkalosis. This alkalization of the
bloodstream is characterized by:
- mental confusion
- slowed breathing
- paralysis
- muscle tension or spasm
Phosphate
HYPERPHOSPHATEMIA. Skeletal fractures or disease, kidney failure,
systemic infection,
and intestinal obstruction can all cause phosphate
retention and
build-up in the blood. The disorder occurs concurrently
with
hypocalcemia. Individuals with mild hyperphosphatemia are
typically
asymptomatic, but signs of severe hyperphosphatemia include:
- tingling in hands and fingers
- muscle spasms and cramps
- convulsions
- cardiac arrest
HYPOPHOSPHATEMIA. Serum phosphate levels
of 2 mg/dL or
below may be caused by hypomagnesemia and hypokalemia.
Severe
phosphate
levels. There are typically few physical signs of mild phosphate
depletion.
Symptoms of severe hypophosphatemia include:
- muscle weakness
- weight loss
- bone deformities (osteomalacia)
Diagnosis
Diagnosis is performed
by a physician or other qualified healthcare provider
who will take a
medical history, discuss symptoms, perform a complete
physical
examination, and prescribe appropriate laboratory tests. Because
electrolyte disorders commonly affect the neuromuscular system, the
provider
will test reflexes. If a calcium imbalance is suspected, the
physician will also
check for Chvostek's sign, a reflex test that
triggers an involuntary facial twitch,
and Trousseau's sign, a muscle
spasm that occurs in response to pressure on the
upper arm. Serum
electrolyte imbalances can be detected through blood tests.
Blood is
drawn from a vein on the back of the hand or inside of the elbow by a
medical technician, or phlebotomist, and analyzed at a lab.
Normal levels of electrolytes are:
- Sodium. 135-145 mEq/L (serum)
- Potassium. 3.5-5.5 mEq/L (serum)
- Calcium. 8.8-10.4 mg/dL (total Ca; serum); 4.7-5.2 mg/dL (unbound Ca; serum)
- Magnesium. 1.4-2.1 mEq/L (plasma)
- Chloride. 100-108 mEq/L (serum)
- Phosphate. 2.5-4.5 mg/dL (plasma; adults)
Standard ranges for test results may vary
due to differing laboratory standards and
physiological variances
(gender, age, and other factors). Other blood tests that
determine pH
levels and acid-base balance may also be performed.
Treatment
Treatment
of electrolyte disorders depends on the underlying cause of the
problem
and the type of electrolyte involved. If the disorder is caused by
poor
diet or improper fluid intake, nutritional changes may be prescribed.
If medications such as diuretics triggered the imbalance, discontinuing
or
adjusting the drug therapy may effectively treat the condition. Fluid
and electrolyte replacement therapy, either intravenously or by mouth,
can reverse electrolyte depletion.
Hemodialysis
treatment may be required to reduce serum potassium levels
in
hyperkalemic patients with impaired kidney function. It may also be
ecommended for renal patients suffering from severe hypermagnesemia.
Prognosis
A
patient's long-term prognosis depends upon the root cause of the
electrolyte
disorder. However, when treated quickly and appropriately,
electrolyte imbalances
in and of themselves are usually effectively
reversed.
When they are mild, some electrolyte
imbalances have few to no symptoms and
may pass unnoticed. For example,
transient hyperphosphatemia is usually fairly benign.
However, long-term
elevations of blood phosphate levels can lead to potentially
fatal soft
tissue and vascular calcifications and bone disease, and severe serum
phosphate deficiencies (hypophosphatemia) can cause encephalopathy,
coma, and
death.
Severe
hypernatremia has a mortality rate of 40-60%. Death is commonly due
to
cerebrovascular damage and hemorrhage resulting from dehydration and
shrinkage of the brain cells.
Prevention
Physicians
should use caution when prescribing drugs known to affect electrolyte
levels and acid-base balance. Individuals with kidney disease, thyroid
problems,
and other conditions that may place them at risk for
developing an electrolyte
disorder should be educated on the signs and
symptoms.
Resources
Books
Post, Theodore, and Burton Rose. Clinical Physiology of Acid-Base
and Electrolyte Disorders. 5th ed. New York: McGraw-Hill Professional, 2001.
Periodicals
Cohn,
Jay N., et al. "New Guidelines for Potassium Replacement in
Clinical
Practice: A Contemporary Review by the National Council
on Potassium in
Clinical Practice." Archives of Internal Medicine 160,
no.16 (September 11, 2000): 2429-36.
Goh, Kian Ping. "Management of Hyponatremia." American Family
Physician May 15, 2004: 2387.
Moritz, Michael L., Juan Carlos Ayus. "Hospital-acquired Hyponatremia:
Why are There Still Deaths?" Pediatrics May 2004: 1395-1397.
Springate, James E., Mary F. Carroll. "HAdditional Causes of Hypercalcemia
in Infants." American Family Physician June 15, 2004: 2766.
Key terms
body that keeps the pH level of blood around 7.35-7.45.
hormones due to destruction of the adrenal gland.
Aldosteronism
— A condition defined by high serum levels of aldosterone, a
hormone
secreted by the adrenal gland that is responsible for increasing sodium
reabsorption in the kidneys.
(self-induced vomiting) behaviors.
by excessive
intake of milk and alkalis. Usually occurs in the treatment of peptic
ulcer.
dizziness and
occurs when one rises to a standing position. Also known as
postural
hypotension.
concentrations
are separated by a semipermeable membrane, such as a
cellular wall, and
the lower concentration solute is drawn across the membrane
into the
higher concentration solute (osmosis)
.
Tetany
— A disorder of the nervous system characterized by muscle cramps,
spasms of the arms and legs, and numbness of the extremities.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc.
All rights reserved.
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