Diagnosis

Diagnosis

DOI: 10.4018/978-1-5225-9655-4.ch007

Abstract

Clinically, a diffuse, firm goiter with pyramidal lobe enlargement, and without signs of thyrotoxicosis, should suggest the diagnosis of Hashimoto's thyroiditis (HT). The association of goiter with hypothyroidism is almost diagnostic. The thyroid stimulating hormone (TSH) is the sensitive marker of hypothyroidism and diagnosis of subclinical hypothyroidism. Thyroid perioxidase antibodies (TPO-Ab) and, less frequently, thyroglobulin antibodies (Tg-Ab) are elevated in the serum of patients with HT. Ultrasound may display an enlarged gland with normal texture, focal, or diffuse glandular enlargement with coarse, heterogenous, and hypo-echoic pattern, or a suggestion of multiple ill-defined micro-nodules. Color Doppler shows extensive hyper-vascularity. Histologically, the thyroid gland shows diffuse lymphocytic and plasma cell infiltration with formation of lymphoid follicles. Atrophy of the thyroid parenchyma is usually evident. It also reveals scant colloid, and a few epithelial cells, which may show Hurthle cell change. This chapter explores the diagnosis of Hashimoto's disease.
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Introduction

Diagnosis of Hashimoto's thyroiditis involves two considerations; (1) differential diagnosis of the thyroid lesion and (2) assessment of the metabolic status.

Clinical Evaluation

A diffuse, firm goiter with pyramidal lobe enlargement, and without signs of thyrotoxicosis, should suggest the diagnosis of Hashimoto's thyroiditis. Most often the gland is bosselated. It is usually symmetrical, although much variation in symmetry (as well as consistency) can occur. The trachea is rarely deviated or compressed. The association of goiter with hypothyroidism is almost diagnostic of Hashimoto's disease, but is also seen in certain syndromes due to defective hormone synthesis or hormone response.

Pain and tenderness are unusual but may be present. A rapid onset is also unusual, but the goiter may rarely grow from normal to several times the normal size in a few weeks. Most commonly the gland is 2-4 times the normal size. Satellite lymph nodes may be present, especially the Delphian node above the isthmus. Multinodular goiter (MNG) occurs in significant incidence in adult women; thus the association of MNG and Hashimoto's thyroiditis is not rare, and may provide the finding of a grossly nodular gland in a patient who is mildly hypothyroid and has positive antibody tests.

Symptoms (History-Taking)

Common, early presenting symptoms of hypothyroidism, such as fatigue, constipation, dry skin, and weight gain, are non-specific. Weight gain due to hypothyroidism is usually no greater than 10% of the baseline euthyroid weight and is mostly attributable to fluid accumulation in interstitial tissues.

Other symptoms of hypothyroidism include the following:

  • Cold intolerance

  • Hoarseness of voice and pressure symptoms in the neck from thyroid enlargement

  • Laziness and loss of energy (chronic fatigue syndrome), and less frequently erectile dysfunction.

  • Decreased sweating

  • Mild nerve deafness

  • Peripheral neuropathy

  • Galactorrhea (may occur because of the increased prolactin levels).

  • Depression, dementia, and other psychiatric disturbances. Hashimoto's when presenting as mania is known as Prasad's syndrome after Ashok Prasad, the psychiatrist who first described it.

  • Memory loss

  • Joint pains and muscle cramps

  • Hair loss from an autoimmune process directed against the hair follicles

  • Menstrual irregularities (typically menorrhagia, infertility, and loss of libido). Increased prolactin secondary to increased thyrotropin-releasing hormone (TRH) leads to decreased luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and to decreased response to gonadotropin-releasing hormone (GnRH), resulting in anovulatory cycles with menstrual irregularities

  • Sleep apnea and daytime somnolence (obstructive sleep apnea in hypothyroidism is thought to be partly caused by hypofunction of upper airway muscles and weakness of the diaphragm).

Physical Examination

Physical findings are variable and depend on the extent of hypothyroidism and other factors such as age of the patient. Findings include the following:

  • Puffy face and peri-orbital edema typical of hypothyroid facies

  • Cold, dry skin, which may be rough and scaly. The skin may appear yellow but does not involve the sclera, which distinguishes it from the yellowing of jaundice due to hypercarotenemia

  • Peripheral edema of hands and feet, typically non-pitting

  • Thickened and brittle nails (may appear ridged)

  • Hair loss involving the scalp, the lateral third of eyebrows, and possibly skin, genital, and facial hair

  • Bradycardia

  • Elevated blood pressure (typically diastolic hypertension); however, most often, blood pressure is normal or even low

  • Diminished deep tendon reflexes and the classic prolonged relaxation phase, most notable and initially described at the Achilles tendon (although it may be present in other deep tendon reflexes as well)

  • Macroglossia

  • The thyroid gland is typically enlarged, firm, and rubbery, without any tenderness or bruit; it may be normal in size or not palpable at all.

  • Hoarseness of voice

  • Slow speech

  • Impairment memory

  • Peripheral neuropathy (either mono-neuropathy as exemplified by carpal tunnel syndrome, or poly-neuropathy due to involvement of several peripheral nerves, manifesting as paresthesia.

  • Cerebellar ataxia.

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