CHAPTER 11 Fluids and Electrolytes^435
PROGNOSIS
Correction of the magnesium level is necessary to return normal electrolyte bal-
ance to the patient. Correction or management of the underlying condition may be
necessary to correct the magnesium level. Nerve impulse transmission is increased
in patients with hypomagnesemia. As the magnesium level drops, the patient may
develop seizures or cardiac arrhythmias.
HALLMARK SIGNS AND SYMPTOMS
- Painful paresthesia (numbness and tingling)
- Hyperactive deep tendon reflexes—using a reflex hammer, strike tendon
at specific site to elicit response (patellar tendon, Achilles tendon, brachio-
radialis, bicep, or tricep) - Muscle twitching
- Seizures due to irritability of nervous tissue in brain
- Confusion due to Central Nervous System (CNS) irritability
- Headaches
- Mood changes or irritability
- Decreased appetite, nausea, and constipation due to decreased gastrointestinal
motility - Decreased bowel sounds and abdominal distention
- Arrhythmia, ectopic beats, ventricular arrhythmias
- Contraction of facial muscle after tapping facial nerve anterior to ear
(Chvostek’s sign) due to increased excitation of nerve and muscle cells if
concurrent hypocalcemia - Carpal spasm after inflation of blood pressure cuff to upper arm—occludes
brachial artery and applies pressure to nerves (Trousseau’s sign) if concurrent
hypocalcemia
INTERPRETING TEST RESULTS
- Blood serum magnesium level < 1.5 mEq/L.
- EKG shows depressed ST segments, tall T-waves.