Webster's New World Medical Dictionary

hypochondroplasia
A type of short-limb
dwarfism, with shortening especially of the ends of
the limbs. A child with hypochondroplasia usually
has a prominent forehead, mildly shortened extrem-
ities and digits, limited range of motion at the
elbows, and inward curvature of the lower back.
Diagnosis is made through physical examination
and X-rays. Hypochondroplasia is inherited in an
autosomal dominant manner. Hypochondroplasia
can also occur spontaneously. The gene for
hypochondroplasia is the same gene that causes
achondroplastic dwarfism: the fibroblast growth
factor receptor 3 (FGFR3). However, the two forms
of dwarfism are caused by different mutations in
FGFR3.
hypoglossal nerve
The twelfth cranial nerve,
which supplies the muscles of the tongue.
hypoglossal neuropathy
Disease of the hypo-
glossal nerve. Paralysis of the hypoglossal nerve
affects the tongue, making speech sound thick and
causing the tongue to deviate toward the paralyzed
side. In time, the tongue diminishes in size
(atrophies).
hypoglycemia
Low blood sugar (glucose).
Hypoglycemia may be associated with symptoms
such as anxiety, sweating, tremor, palpitations, nau-
sea, and pallor. Hypoglycemia also starves the brain
of glucose energy, which is essential for proper
brain function. Lack of glucose energy to the brain
can cause symptoms ranging from headache, mild
confusion, abnormal behavior, loss of conscious-
ness, seizure, and coma. Severe hypoglycemia can
cause death. The causes of hypoglycemia include
use of drugs (such as insulin), liver disease, surgi-
cal absence of the stomach, tumors that release
excess amounts of insulin, and pre-diabetes. In
some patients, symptoms of hypoglycemia occur
during fasting (fasting hypoglycemia). In others,
symptoms of hypoglycemia occur after meals (reac-
tive hypoglycemia). Immediate treatment of severe
hypoglycemia consists of administering large
amounts of glucose and repeating this treatment at
intervals if the symptoms persist. Treatment must
also be directed at the underlying cause. Treatment
of reactive hypoglycemia involves changing the diet,
including eating fewer concentrated sweets and
ingesting multiple small meals throughout the day.
hypokalemia
Low potassium in the blood.
Hypokalemia is commonly caused by conditions that
lead to loss of potassium through the gastrointestinal
tract such as vomiting, diarrhea, impaired kidney
function, and use of diuretic medications.
Symptoms may include fatigue, weakness, muscle
cramping, and arrythmias of the heart.
hypomagnesemia
Low magnesium in the blood,
which can occur due to inadequate intake or
impaired intestinal absorption of magnesium.
Hypomagnesemia is often associated with low