Page 121 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-36 Rashes

GRAVES’ DISEASE AND Perspiration Nervousness
PRETIBIAL MYXEDEMA Excitability
Facial flushing Restlessness
Emotional instability
Graves’ disease is the form of hyperthyroidism that is Insomnia
most often seen in the young adult population. It is an
autoimmune disease that causes the thyroid gland to Loss of weight
produce thyroid hormones. This results in the clinical
manifestations.
Clinical Findings: Graves’ disease is seen in females
more frequently than males, in a ratio of approximately Palpable lymph nodes Exophthalmos
7 : 1. Most patients have an insidious onset of symp-
toms. Heat intolerance and nervousness are two of Goiter
the early and more common findings. Anxiety and (may have thrill and bruit)
emotional difficulties can be life altering. Patients Shortness of breath
often complain of difficulty sleeping. Constitutional
symptoms can manifest as weight loss, increased appe-
tite, increased sweating, and profound nervousness. Breast enlargement
Women may suffer from menstrual irregularities. (gynecomastia
Cardiac arrhythmias are common as the disease pro- in male) Palpitation, tachycardia,
gresses. Hypertension and tachycardia can be two of poor response to digitalis
the earliest cardiovascular signs of the disease. As the
disease progresses, exophthalmos becomes prominent, Warm, velvety skin
a goiter can be seen or felt, and patients develop pre-
tibial myxedema. Increased appetite
The exophthalmos may lead to intermittent double
vision and a feeling of posterior ocular pressure. Pho- Muscle wasting
tophobia can be a part of the disease, as can frequent Diarrhea (occasional)
tearing and a feeling of “sand” in the eyes that causes
frequent tearing and pain. Goiter may be noticeable to
the patient, and it may be appreciated initially because Rapid pulse Tremor
of difficulty buttoning one’s collar. The goiter is diffuse
in nature. The thyroid is easily palpable and is firm to
the touch. On occasion, the astute clinician can auscul- Warm and Clubbing of fingers
tate a bruit over the thyroid gland; this represents the moist palms (in some patients with
increased blood flow to the growing gland. severe exophthalmos)
Pretibial myxedema is the most widely recognized
skin finding in Graves’ disease. It begins as small, indu-
rated papules that coalesce into plaques on the anterior
shin. The plaques indent easily when palpated and clini-
cally act like lymphedema, causing a nonpitting edema.
Pretibial myxedema can occur in other areas of the Oligomenorrhea
body, but this is a rare finding. The skin is typically or amenorrhea
warm to the touch and can have a velvety feel. Increased
sweating is noticeable most often as warm, moist palms Muscular weakness,
and soles, similar to what is observed in patients with fatigability
hyperhidrosis. Clubbing of the fingers is seen in a small
proportion of affected individuals. Facial flushing with
an increase in sweating is also seen. Females may
develop breast enlargement, and males may develop
gynecomastia. Pretibial myxedema
Laboratory testing is needed to help define the con-
dition. Radioactive iodine uptake imaging shows a
diffuse, symmetric uptake of iodine in the patient
with Graves’ disease. The pattern of uptake is very dif-
ferent from that seen in patients with a “hot” thyroid
nodule, in which the radioactive signal is dramatically
increased in the nodule. Thyroid antibody testing is
very helpful in differentiating Graves’ disease from
other forms of thyrotoxicosis. Antithyroglobulin, anti-
microsomal, and anti–thyroid-stimulating hormone
(TSH) receptor antibodies can be evaluated. hormones and their effects on target tissues lead to the Treatment: Treatment of Graves’ disease is pre-
Pathogenesis: Graves’ disease is an idiopathic auto- clinical findings. dicated on stopping the excessive thyroid hormone
immune disease that causes autoantibodies against the Histology: Biopsy specimens of the pretibial skin production. Ablation of the thyroid can be achieved
TSH receptor. The antibodies act as agonists to the show large amounts of mucin deposits within the with radiation therapy or surgical removal. Medications
receptor and cause non-stop activation of the TSH middle and lower dermis, between collagen bundles. such as β-blockers are used to lessen the symptoms of
receptor on the thyroid. This leads to increased produc- The mucin is so thick that it causes the dermal collagen the disease until it is rendered under control. Medical
tion of thyroid hormones, both triiodothyronine (T 3) bundles to be splayed apart. Overlying hyperkeratosis management of Graves’ disease can be achieved with
and (T 4), by the thyroid. The increase in metabolic can be appreciated. Biopsy specimens from clinically propylthiouracil or methimazole, both of which act to
functioning of the thyroid leads to diffuse enlargement nonaffected skin may show some of the same histologi- decrease thyroid hormone production.
and goiter. The increased production of thyroid cal findings but on a lesser scale.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 107