Download Clinical Approach to Thyroid Disease

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Clinical Approach to Thyroid Disease
RV Jayakumar*
Introduction
O
nce diabetes is excluded, thyroid diseases constitute the
main bulk of endocrine problems that the practicing
physician has to sort out during the clinical practice. As with
all endocrine diseases, thyroid diseases mainly presents with
either excess hormonal activity, or with symptoms due to under
production of the hormone or with a swelling due to a neoplastic
process or due to the pressure effects on surrounding structures.
A correct etiological, anatomical and functional diagnosis of the
thyroid problem is absolutely essential for the proper treatment
and well being of the patient (Table 1, 2). As with any branch
of medicine, this can be achieved by careful history, thorough
physical examination and by well-planned investigations.
Table 1 : Classification of hypothyroidism
Type
Primary
hypothyroidism
Secondary
hypothyroidism
Secondary
hypothyroidism
Origin
Thyroid gland
Description
The most common forms
include Hashimoto’s
thyroiditis (an
autoimmune disease) and
radioiodine therapy for
hyperthyroidism. Thyroid
gland itself fails to produce
T3 and T4
Pituitary gland Pituitary gland does not
create enough thyroidstimulating hormone
(TSH) to induce the
thyroid gland to produce
enough thyroxine and
triiodothyronine
Hypothalamus Results when the
hypothalamus fails
to produce sufficient
thyrotropin-releasing
hormone (TRH). TRH
prompts the pituitary
gland to produce thyroidstimulating hormone (TSH).
Table 2 : Some causes of hypothyroidism
Primary
hypothyroidism
Secondary
hypothyroidism
(95% of cases)
Idiopathic
hypothyroidism
(5% of cases)
Pituitary or
hypothalamic
neoplasms
Hashimoto’s
thyroiditis
Other causes
Drug therapy (e.g.,
amiodarone , lithium,
interferon)
Infiltrative diseases
(e.g., sarcoidosis,
amyloidosis,
Pituitary necrosis
scleroderma,
(Sheehan’s
syndrome)
subsequent to Graves’
hemochromatosis)
disease
Irradiation of the
thyroid
Congenital
hypopituitarism
Advances in diagnostic techniques seem to have pushed
physical examination of thyroid to a less significant role and this
may lead some people to conclude that examination of thyroid
may be an unlearned or lost art for many physicians.1 However
all the guidelines regarding thyroid diseases give emphasis on
the clinical assessment of thyroid disease (Table 3).
As with any clinical decision making, the clinical approach to
the thyroid patient begins, from the time he enters the physician’s
chamber. A thyrotoxic patient will be showing signs of tension
and anxiety, with a staring look, while getting to the room and
being seated. As the interview starts the patient’s voice may give
some clues, the hoarseness of hypothyroidism or the hoarseness
due to recurrent nerve compression from the compression from a
benign or malignant goiter.2 Patient complaints which will make
the physician consider a thyroid problem include many, but the
common ones are weight loss , palpitation, tremor, alteration
of bowel problems, sweating disorders, sleep problems and
menstrual irregularities. There are some situations where the
patient may present with only one symptom due to thyroid
disease and the Physician should not miss such ones. The single
symptoms which may be due to a thyroid problem include
growth problems, delays in sexual maturation, infertility, atrial
fibrillation and constipation.
The physical examination for a thyroid related problem
starts with general examination. The weight and height are
important markers, loss of weight recently may be due to
thyrotoxicosis and gain of weight may be due to fluid retention
of hypothyroidism. The height of the growing child can be
defective due to hypothyroidism in which case the extremities
Table 3 : Common Signs and Symptoms of Hypothyroidism
Sign or symptom
Weakness
Skin changes (dry or coarse skin)
Lethargy
Slow speech
Eyelid edema
Cold sensation
Decreased sweating
Cold skin
Thick tongue
Facial edema
Coarse hair
Skin pallor
Forgetfulness
Constipation
Surgical removal of
the thyroid
Late-stage invasive
fibrous
Thyroiditis
Iodine deficiency
Professor of Endocrinology, AIMS School of Medicine, Cochin-682041
*
Fig 1: Grave’s disease
Affected patients (%)
99
97
91
91
90
89
89
83
82
79
76
67
66
61
12
© SUPPLEMENT TO JAPI • JANUARY 2011 • VOL. 59
Table 4 : Laboratory Values in Hypothyroidism
TSH level
High
High (>10μU/
mL [10mU/L])
High (6-10μU/
mL
[6-100mU/L])
Fig 2: Myxedema facies
High
High
Low
Free T4 level Free T3 level
Likely diagnosis
Low
Low
Primary hypothyroidism
Normal
Normal
Subclinical
hypothyroidism with
high risk for future
development of overt
hypothyroidism
Normal
Normal
Subclinical
hypothyroidism with
low risk for future
development of overt
hypothyroidism
High
Low
Congenital absence
of T4-T3–converting
enzyme; amiodarone
(Cordarone) effect on
T4-T3 conversion
High
High
Peripheral thyroid
hormone resistance
Low
Low
Pituitary thyroid
deficiency or recent
withdrawal of thyroxine
after excessive
replacement therapy
TSH = thyroid-stimulating hormone; T4 = thyroxine; T3 =
triiodothyronine.
Fig 3: Palpation of thyroid
will be disproportionately shorter than trunk. Examination
of the skin and appendages will give important clues like the
warm and moist extremities of thyrotoxicosis and the dry, rough
non-sweaty skin of hypothyroidism. Facial appearance will be
very informative as the spot diagnosis of Graves’s disease and
classical Myxoedema are often made by the physician by just a
look at the face (Figs. 1, 2).
The local examination, which is mainly confined to the neck,
starts with inspection. One should look for the scars, asymmetry
and any neck swelling. Erythema overlying a tender swelling
may be due to suppurative thyroiditis or infected thyroglossal
cyst or brachial cleft cyst.3 Slightly extend the neck and inspect
the area from the thyroid cartilage to the sternal notch and
also instruct the patient to do a swallowing act. A thyroid
enlargement is usually made out by its movement on swallowing
which will be lost only by a large impacted goiter or by a rare
case of invasive carcinoma or Riedel’s thyroiditis.4
The term Pseudogoitre is coined to describe apparent
thyroidal enlargement when no true goiter is present.5 Thin
patients may appear to have a prominent appearing thyroid,
especially when the gland is located higher in the neck, overlying
the thyroid cartilage. By palpation and ultrasonography these
glands have been shown to be of normal size. The Modigliani
Syndrome denotes the illusion of a goitre, seen when patients
with long, curved necks have exaggerated cervical spine
lordosis.6 A midline mass visible superior to the isthmus, may be
due to a thyroglossal duct cyst. This is the commonest congenital
neck mass and may present at any age, can be tender due to
infection or due to hemorrhage and can very rarely harbour
a papillary thyroid cancer. The movement upwards as the
tongue is extended is the diagnostic clue for thyroglossal cyst.
There is no consensus as to the best way to examine the thyroid
gland, whether to palpate from the front, facing the patient, or
do the palpation standing from the back of the seated patient.7
The examination from the front begins with the examiner first
identifying the cricoid cartilage and then identifies the isthmus
of the thyroid directly below this. Then from the right, the left
lobe is palpated with two or three fingers of the right hand,
lateral to the trachea and medial to sterno clavicular muscle,
with thumb placed to the right of trachea. The fingers are kept
stationary at various levels of interest and also while the patient
is asked to swallow. The exercise is then repeated for the other
side. While examining from the back, the examiner uses the
fingers of both hands simultaneously (Fig. 3). If a nodule is
identified the upper and lower borders can be trapped between
two examining fingers so as to allow a gross determination of
the size. During palpation vascular thrill may be felt suggesting
increased thyroidal blood flow, which will be confirmed by the
presence of a bruit on auscultation.
Each lobe of the thyroid gland is about the size of distal
phalanx of the individual’s thumb and roughly weighs from
10 to 20gms.8 The consistency of the normal gland is described
as rubbery, while that of Hashimotos is firm and stony hard is
suggestive of infiltrating malignancy. Painful thyroid gland is
usually due to subacute thyroiditis, but very rarely can be due
to hemorrhage in a nodule or due to malignant thyroid lesion.9
Examination of the thyroid gland is not complete without
looking for the cervical lymph nodes, which may give important
clues to the underlying problem. Lastly as thyroid hormone
acts on all the tissues of the body, complete examination of all
systems is a must for making a full diagnosis.
Goitre can be classified as per WHO classification
•
Grade 0 – no goitre presence is found (the thyroid
impalpable and invisible);
•
Grade 1 – neck thickening is present in result of enlarged
thyroid, palpable, however, not visible in normal position
© SUPPLEMENT TO JAPI • JANUARY 2011 • VOL. 59 13
examination include weight loss/weight gain, palpitation,
alteration of bowel habits (diarrhea/constipation), sweating,
sleep problems, menstrual irregularities, growth problems,
delays in sexual maturation, infertility, hoarseness of voice,
exophthalmos, tremors, atrial fibrillation and thyroid gland
enlargement
of the neck; the thickened mass moves upwards during
swallowing. Grade 1 includes also nodular goitre if thyroid
enlargement remains invisible.
•
Grade 2 – neck swelling, visible when the neck is in normal
position, corresponding to enlarged thyroid – found in
palpation.10
Once the physical examination is complete, the physician
must plan the necessary investigations to confirm the diagnosis
and plan treatment. The fact that almost all the investigations
related to thyroid diseases are easily available put an additional
responsibility on the Physician to select the appropriate and
cost effective tests in a given case. The measurement of thyroid
hormones in the blood i.e. serum T3, T4 and TSH, is the most
helpful test in confirming many of the thyroid diseases and for
monitoring therapy of hypo and hyperthyroidism (Table 4).
The isotope scan and uptake of thyroid is seldom needed in
diagnosing and managing hypothyroidsim, where as they are
very useful in diagnosing and managing thyroid malignancy.
Ultrasonography of thyroid has almost become part of clinical
examination in many endocrine centers, but for our patients
it is still an investigation to be ordered, when you want to get
to know more about the nodules, their size, contents and the
pressure effects. So by properly selecting the blood tests and
imaging procedures in a suspected case, the physician will be
able to make a diagnosis in a given case
It is important to remember that endocrine diseases evolve
very slowly and they may often be missed by a person who is
seeing the patient regularly and is picked up by a physician
seeing the patient for the first time. Likewise, endocrine disease
may have a more distant effect than local effects, and don’t expect
the thyroid disease patient to present with neck problem always,
except in subacute thyroiditis. So a combination of right thinking,
good history, thorough physical examination and judicious use
of investigations will sort out majority of thyroid problems in
your practice.
Conclusion
•
A correct etiological, anatomical and functional diagnosis
of the thyroid problem can be achieved by careful history,
thorough physical examination and by well-planned
investigations
•
Pointers to thyroid disease on history and clinical
•
Investigations include serum T3, T4 and TSH for confirming
many of the thyroid diseases and for monitoring therapy
of hypo and hyperthyroidism, ultrasonography of thyroid
and nuclear scan (hyperthyroidism).
•
A combination of right thinking, good history, thorough
physical examination and judicious use of investigations
will sort out majority of thyroid problems in clinical practice.
1.
Daniel GH. Physical Examination of the Thyroid. In Braverman
LE, Utiger RD eds Werner and Ingbar’s the Thyroid: Philadelphia:
Lippincot William’s & Wilkins, 2000: 462-66
2.
Dillman WH. The Thyroid. In Goldman L, Bennett JC, eds Cecil Text
Book of Medicine. Philadelphia: WB Saunders, 2000: 12312-1249.
3.
Leonhardt JM, Heyman WR. Thyroid disease and the skin.
Dermatology Clinics 2002; 20: 471-81.
4.
Larsen PR, Davies TF, Schlumberger MJ et al .Thyroid Physiology
and diagnostic evaluation of patients with thyroid disorders. In:
Larsen PR, Kronberg HM, Melmed S et al. Ed Williams’s text book
of Endocrinology. Philadelphia: WB Saunders, 2003: 364-5
5.
Gwinup G, Morton E. The high lying Thyroid: a cause of
pseudogoiter. J Clin Endocrinol Metab 1975; 40: 37-42
6.
Mercer RD. Pseudogoter: the Modigliani syndrome. Cleve Clin J
Med 1975: 42:319-26.
7.
Siminoski K. The rational clinical examination: does this patient
have a goiter? JAMA 1995; 273: 813-7
8.
Bickley LS, Hoekelman RA. The head and neck. In: Physical
Examination and history taking. Philadelphia: Lippincot, 1999:202206,211, 244
9.
Wartofsky L. Approach to the patient with thyroid disease.
In: Becker KL, Ed Principles and practise of endocrinology.
Philadelphia: Lippincott Williams & Wilkins, 2001: 308
References
10. WHO/UNICEF/ICCIDD. Chapter 2: Selecting target groups and
Chapter 5: Selecting appropriate indicators: Biochemical indicators.
In: Indicators for Assessing Iodine Deficiency Disorders and
their Control Through Salt Iodination. Geneva. World Health
Organization, WHO/NUT/94.6, 1994.