Metabolic cause of shoulder impingement syndrome

514 JOURNAL of CHINESE CLINICAL MEDICINE VOLUME 2|NUMBER 9|September2007 formation) under the greater tuberosity of the humeral
head and sclerosis of the undersurface of the acromion
( Sourcil sign) and /or the cortex of the greater tuberos唱
ity were not seen in this patient.Laboratory studies,
which were done routinely,showed an elevated TSH of
160 U /ml, the rest of the studies were within normal
ranges.The patient was managed with 100 mg of thy唱
roxine per day during the week and 150 mg of thyrox唱
ine during the weekend.The patient was not referred to
physiotherapy.After one year of treatment, TSH levels
returned to within normal range,the patient reported to唱
tal alleviation of the shoulder pain and discomfort, ex唱
amination revealed a negative Neer摧s and Hawkin摧s
sign.During the treatment period,the patient reported
occasional use of NSAIDS for pain relief.
DISCUSSION
In the last two decades,subacromial impingement syn唱
drome has become an increasingly common diagnosis
for patients who have a painful shoulder.Many causes
have been proposed for subacromial impingement syn唱
drome.These factors can be broadly classified as intrin唱
sic( intratendinous) or extrinsic ( extratendinous).To
understand the etiology of subacromial impingement, it
is important to understand the unique anatomical char唱
acteristics of the subacromial space.Within this space,
a number of soft唱tissue structures are situated between
two rigid structures.The superior border( the roof) of
the space is the coracoacromial arch,which consists of
the acromion,the coracoacromial ligament,and the cor唱
acoid process.The acromioclavicular joint is directly
superior and posterior to the coracoacromial ligament.
The inferior border( the floor) consists of the greater
tuberosity of the humerus and the superior aspect of the
humeral head.However, interposed between these two
osseous structures are the rotator cuff tendons,the long
head of the biceps tendon, the bursa, and the cora唱
coacromial ligament.Normally,the bursa facilitates the
motion of the rotator cuff beneath the arch.Any abnor唱
mality that disturbs the relationship of these subacromi唱
al structures may lead to impingement.
Normal function of the thyroid gland is directed to
the secretion of the active thyroid hormones that influ唱
ence a diversity of metabolic processes.Hypothyroidism
refers to a metabolic state resulting from a deficiency in
thyroid hormone function, in which decreased caloric
expenditure ( hypometabolism ) is a principal fea唱
ture [1]
.Hypothyroidism can result from any of a variety
of abnormalities that leads to insufficient synthesis of
thyroid hormone.Theprevalenceis3% ~5% of the a唱
dult population.Hypothyroidism usually arises from pri唱
mary thyroid disease(95%),but in rare cases it is due
to hypothalamic唱pituitary disease or generalized tissue
resistance to thyroid hormone [1]
.Hypothyroidism may
manifest in different ways and can affect almost every
organ system in the body.Hypothyroidism can first
present with an assertion of different symptoms.These
symptoms may include fatigue,myalgia,arthralgia,mus唱
cle weakness, stiffness and cramps, dry skin, head唱
aches, and menorrhagia.Brittle nails, thinning of hair,
pallor,and symptoms of carpal tunnel syndrome may al唱
so be seen [1]
.
Clinical connection between hypothyroidism and
musculoskeletal manifestations is well documented in
the literature [5]
such as carpal tunnel syndrome and
Dequervain disease.In clinical observations, we have
had the impression that the prevalence of thyroid dys唱
function in patients with shoulder impingement syn唱
drome is higher than in the normal population.In a re唱
view of the literature, we did not find a study that ex唱
amined the association between rotator cuff impinge唱
ment and hypothyroidism.One possible explanation for
impingement syndrome,in hypothyroid patients,is infil唱
tration of tendon sheaths with glycosaminoglycans; no
studytodatehasevaluatedthishypothesis.
The early recognition of hypothyroidism remains a
challenge,especially when the decline in thyroid func唱
tion is gradual.TSH levels in the blood remains the
most reliable and accessible tool for diagnosing hypot唱
hyroidism.
In the case presented, impingement syndrome
presented in a patient without an overt presentation of
hypothyroidism, and after thyroid function was correc唱
ted,the patient returned to playing tennis without any
further discomfort or need for any adjuvant therapy.Al唱
though the patient has reported intermittent use of
NSAIDS during the treatment period,the amount taken
by the patient,for general pain relief has been well be唱