Thanks for asking your question. Although I am an internal medicine
physician, please see your primary care physician for specific
questions regarding any individual cases please do not use Google
Answers as a substitute for medical advice. I will be happy to answer
factual medical questions.
You asked the following question:
"What are diseases that can cause a hand tremor in a 20 year old
Basic types of tremor include physiologic, essential, and resting
tremor. All of these tremor types may affect a young adult male.
Further discussion of this is addressed below. I will be happy to
discuss the evaluation and approach to these tremors in a seperate
Tremor is defined as a rhythmic and oscillatory movement of a body
part with a relatively constant frequency and variable amplitude. It
is caused by either alternating or synchronous contractions of
antagonistic muscles. Tremor is the most common of all movement
disorders, occurring from time to time in most normal individuals in
the form of exaggerated physiological tremor (1).
Normal individuals have a very low amplitude, high frequency
physiologic tremor of approximately 10 to 12 Hz that is not visible
under ordinary circumstances. Many factors may enhance the tremor to
the point of detection, most often by increasing sympathomimetic
Common drugs that increase adrenergic activity include beta-adrenergic
agonists such as terbutaline, isoproterenol, epinephrine,
amphetamines, tricyclic antidepressants, levodopa, nicotine, and
xanthines such as theophylline and caffeine.
Anxiety, excitement, fright, muscle fatigue, hypoglycemia, alcohol and
narcotic withdrawal, thyrotoxicosis, fever, and pheochromocytoma also
enhance adrenergic activity.
Miscellaneous drugs and toxins that increase physiological tremor by
other uncertain means include lithium, corticosteroids, sodium
valproate, bromides, mercury, lead, and arsenic.
Enhancement of physiological tremor is the most common cause of
postural and action tremors.
"Essential tremor is the most common neurologic cause of postural or
action tremor, affecting approximately one million individuals in the
United States (2). The incidence increases with age, although it often
affects young individuals, especially when it is familial. By
definition, tremor should be the only neurologic manifestation of
essential tremor." (3)
Some patients with essential tremor also develop enhanced
physiological tremor due to anxiety or other adrenergic mechanisms,
thereby aggravating the underlying tremor. Essential tremor is
typically relieved by small amounts of alcohol; physiologic tremor is
aggravated by caffeine.
Of note, essential tremor has a bimodal distribution (i.e. peak age of
incidence) during the 2nd and 6th decade of life.
Parkinson's disease is the most common cause of resting tremor. The
tremor is evident with the affected body part supported and completely
at rest and temporarily dampens or disappears during voluntary
activity. Resting tremors usually fluctuate in amplitude and may
appear and disappear depending upon the degree of patient repose,
whether the patient feels he is under observation, or other unknown
The resting tremor in idiopathic Parkinson's disease usually appears
first in one upper extremity. It later spreads to involve the
ipsilateral lower limb followed by the contralateral side; leg or foot
tremor is more commonly due to Parkinson's disease than to essential
tremor. The face, lips, and jaw may be involved but, unlike essential
tremor or cerebellar disease, Parkinson's disease usually does not
produce head tremor.
"Parkinson's Disease typically presents in middle and late life.
However, early-onset disease can occur before age 40 years, and a
juvenile form presents before age 20. Most affected children have a
rigid, akinetic disorder, although many have a typical resting
Wilson's disease can also present as a resting tremor:
"Clinical manifestations of Wilson's Disease are rare before age 6 and
almost always present before the age of 30 . . . The most common
neurologic findings at first evaluation were dysarthria (97 percent),
dystonia (65 percent), dysdiadochokinesia (58 percent), rigidity (52
percent), gait and postural abnormalities (42 percent), tremor (32
percent), abnormal eye movements (32 percent), hyperreflexia (29
percent), drooling (23 percent), and bradykinesia (19 percent)." (5)
I will be happy to discuss the diagnostic approach to tremor in a
seperate question. However, I stress that this answer is not
inteneded as and does not substitute for medical advice - please see
your primary care physician for further evaluation of your individual
Please use any answer clarification before rating this answer. I will
be happy to explain or expand on any issue you may have.
Internet search strategy:
No internet search engine was used in this research. All sources were
from objective physician-written and peer reviewed sources.
1) Jankovic, J, Fahn, S. Physiologic and pathologic tremors.
Diagnosis, mechanism, and management. Ann Intern Med 1980; 93:460.
2) Epidemiology and genetics of essential tremor. Neurology 2000;
3) Tarsy, D. Tremor. UptoDate, 2002.
4) Lucking, CB, Durr, A, Bonifati, V, et al. Association between
early-onset Parkinson's disease and mutations in the parkin gene.
French Parkinson's Disease Genetics Study Group. N Engl J Med 2000;
5) Jankovic, J. Bradykinetic movement disorders. UptoDate, 2002.