Hyperthyroidism

Populations and Risk Factors

• Affects 1–2% of the adult population; occurs 7–10 times more often in women than men
• Graves disease typically presents between ages 20 and 40; toxic nodular goiter is more common in older adults (>50)
• Strong familial predisposition — first-degree relatives of Graves patients have a significantly elevated risk; association with HLA-DR3
• Smoking increases the risk and severity of Graves ophthalmopathy specifically
• Excessive iodine intake (amiodarone, iodine-containing contrast dyes, kelp supplements) can precipitate hyperthyroidism in patients with preexisting nodular thyroid disease
• Postpartum thyroiditis can produce a transient hyperthyroid phase in the first 6 months after delivery before converting to hypothyroidism
• Hyperthyroidism is a primary cause of secondary osteoporosis — particularly relevant in younger women who may not yet be screened for bone density

Causes and Pathophysiology

Graves Disease — Autoimmune TSH Receptor Stimulation

• In Graves disease, the immune system produces thyroid-stimulating immunoglobulins (TSI) — autoantibodies that bind to and activate TSH receptors on thyroid follicular cells. Unlike TSH, these antibodies are not regulated by negative feedback — they stimulate the thyroid continuously, producing uncontrolled T3/T4 secretion.
• The gland hypertrophies diffusely (diffuse toxic goiter) as every follicular cell is stimulated simultaneously. Blood tests show low TSH (suppressed by high T3/T4 feedback) with high free T3 and T4.
• Graves disease is the only form of hyperthyroidism that produces ophthalmopathy (eye disease) and pretibial myxedema (localized dermopathy) — these are caused by TSI cross-reacting with fibroblasts in orbital and pretibial tissues, triggering glycosaminoglycan accumulation and inflammatory infiltration.

Toxic Nodular Goiter

• One or more thyroid nodules develop autonomous function, producing T3/T4 independently of TSH regulation. A single hyperactive nodule is called a toxic adenoma; multiple hyperactive nodules constitute toxic multinodular goiter.
• These nodules function independently of the hypothalamic-pituitary axis — TSH is suppressed by the excess hormone, but the nodules continue secreting. The remaining normal thyroid tissue atrophies from disuse.
• Toxic nodular goiter is more common in older adults and in regions with historical iodine deficiency. It does not produce ophthalmopathy.

The Catecholamine Sensitization Mechanism

• Excess thyroid hormones upregulate beta-adrenergic receptor density and sensitivity on cardiac, smooth muscle, and nervous tissue. This means the body responds to normal circulating catecholamine (epinephrine, norepinephrine) levels as if those levels were markedly elevated — a "pseudo-catecholamine" state.
• This mechanism explains: tachycardia and palpitations (cardiac beta-1 stimulation), fine tremor (beta-2 stimulation of skeletal muscle), anxiety and nervousness (CNS adrenergic activation), heat intolerance and sweating (sympathetic vasodilation and increased metabolic heat production), and hyperreflexia (lowered reflex threshold from increased neural excitability).
• The clinical importance for massage therapy is that these clients are in a physiological state resembling chronic sympathetic overdrive. Their cardiovascular system is already stressed — massage that further increases cardiac demand (vigorous techniques, rapid position changes) or that produces strong sympathetic responses can push the system beyond its compensatory capacity.

Why Proximal Myopathy Develops — Thyrotoxic Muscle Wasting

• Excess T3 shifts muscle protein metabolism toward catabolism — the rate of protein breakdown exceeds synthesis, and the liberated amino acids are diverted to gluconeogenesis and direct oxidation for energy.
• Type II (fast-twitch) muscle fibers are preferentially affected because they have higher protein turnover rates. Proximal muscles (deltoids, quadriceps, hip flexors, iliopsoas) contain a higher proportion of Type II fibers, explaining why proximal weakness predominates.
• The myopathy is painless in most cases — the client notices difficulty climbing stairs, rising from a chair, or lifting overhead before they notice any muscle pain. This distinguishes thyrotoxic myopathy from the painful myalgia of hypothyroidism.
• Creatine kinase (CK) is typically normal or low in thyrotoxic myopathy (protein is being catabolized, not leaking from damaged membranes) — this distinguishes it from inflammatory myopathies where CK is elevated.

Why Bone Density Is Lost — Accelerated Remodeling

• Thyroid hormones directly stimulate osteoclast activity and bone resorption. In hyperthyroidism, the entire bone remodeling cycle is accelerated, but resorption outpaces formation — each remodeling cycle results in a net loss of bone mass.
• The risk is compounded because hyperthyroidism increases urinary calcium excretion and reduces intestinal calcium absorption.
• Bone density loss can be clinically significant even in young patients — hyperthyroidism is one of the most important causes of secondary osteoporosis and should be suspected when osteoporosis is diagnosed in a premenopausal woman or a man under 50.

Why Fine Tremor Develops

• The fine, rapid, postural tremor of hyperthyroidism results from enhanced beta-adrenergic stimulation of skeletal muscle spindles. The tremor is typically 8–12 Hz, regular, and most visible in the outstretched fingers.
• This tremor is postural (present when maintaining a position against gravity) and kinetic (present during movement) but absent at rest — distinguishing it from Parkinson's resting tremor (4–6 Hz, "pill-rolling," present at rest, absent during movement) and essential tremor (variable frequency, postural and kinetic, often familial, improves with alcohol).

Graves Ophthalmopathy

• Autoimmune inflammation targets the retro-orbital fibroblasts and extraocular muscles. GAG accumulation and inflammatory edema increase the volume of orbital contents, pushing the eyeball forward (proptosis/exophthalmos).
• Extraocular muscle swelling restricts eye movement, producing diplopia (double vision). Upper eyelid retraction (from sympathetic stimulation of Mueller's muscle) and lid lag (upper eyelid fails to follow the eye on downgaze) are characteristic signs.
• Ophthalmopathy can be unilateral or bilateral; it can precede, accompany, or follow the onset of hyperthyroidism; and it can worsen paradoxically after radioactive iodine treatment.
• Clinical relevance for MT: clients with significant ophthalmopathy may not tolerate prone positioning (face cradle pressure increases intraorbital pressure) and may require cervical positioning modifications to avoid neck extension that worsens lid retraction and orbital congestion.

Signs and Symptoms

Metabolic and General

• Unintended weight loss (often 5–15 kg) despite normal or increased appetite — the hypermetabolic state burns calories faster than they can be consumed
• Heat intolerance — feeling hot when others are comfortable; excessive sweating; intolerance of warm environments
• Increased appetite but persistent weight loss
• Fatigue despite apparent hyperactivity — the catabolic state eventually depletes energy reserves
• Diarrhea or increased bowel frequency from accelerated GI motility

Cardiovascular

• Tachycardia at rest (heart rate >100 bpm, often 100–130 bpm); palpitations; widened pulse pressure
• Atrial fibrillation in 10–25% of patients (particularly older adults) — this is a significant cardiovascular risk
• Long-term hyperthyroidism can cause high-output cardiac failure from sustained volume overload
• Systolic hypertension with low diastolic pressure (widened pulse pressure)

Neuromuscular — The MT-Relevant Cluster

• Proximal myopathy (thyrotoxic myopathy): painless weakness of shoulder girdle and pelvic girdle muscles — difficulty climbing stairs, rising from a seated position, lifting overhead; wasting visible in severe cases
• Fine tremor: rapid (8–12 Hz), regular, postural tremor most visible in outstretched fingers and hands — distinguish from Parkinson's (resting, slow) and essential tremor (variable, familial)
• Hyperreflexia: deep tendon reflexes are brisk with shortened relaxation time — the opposite of the "hung-up" reflex in hypothyroidism; this reflects increased neural excitability from catecholamine sensitization
• Restlessness, inability to sit still, fidgeting
• Insomnia and anxiety from chronic sympathetic overdrive

Ophthalmopathy (Graves Disease Only)

• Exophthalmos (proptosis) — bulging eyes from retro-orbital GAG accumulation and inflammation
• Lid retraction and lid lag — upper eyelid does not follow the eye on downgaze
• Diplopia from extraocular muscle swelling and restricted motility
• Periorbital edema, conjunctival injection, excessive tearing

Dermatologic

• Warm, moist, smooth skin (the opposite of hypothyroid dry, rough skin)
• Fine, silky hair that may thin diffusely
• Pretibial myxedema (Graves disease only) — raised, waxy, orange-peel-textured plaques on the anterior shins; a localized dermopathy from GAG accumulation in skin fibroblasts
• Onycholysis (nail separation from nail bed) — Plummer's nails

Emergency Presentation — Thyroid Storm

• High fever (>40degC), severe tachycardia (heart rate >140 bpm often with atrial fibrillation), extreme agitation progressing to delirium, nausea, vomiting, diarrhea → this is a medical emergency with 10–30% mortality; do not treat; call emergency services immediately. Thyroid storm is typically triggered by acute stress (surgery, infection, trauma, or abrupt discontinuation of antithyroid medications) in a client with uncontrolled hyperthyroidism.

Assessment Profile

Subjective Presentation

• Chief complaint: Client may present for general relaxation ("I can't slow down; I feel wired all the time"), neck/shoulder tension from anxiety, or muscle weakness ("I've lost strength — I can't carry groceries upstairs"). Many have a known Graves disease diagnosis; some present with unexplained weight loss and anxiety before diagnosis.
• Pain quality: Muscle weakness is more prominent than pain — clients describe heaviness and fatigue in the shoulders and thighs rather than aching. If pain is present, it is typically tension-type (cervical, upper trapezius) from the chronic sympathetic state. No neuropathic quality unless there is a comorbid entrapment.
• Onset: Gradual over weeks to months for Graves disease; may be more acute with thyroiditis (sudden release of stored hormone). Proximal weakness typically develops over 1–3 months.
• Aggravating factors: Heat exposure worsens all symptoms; physical exertion reveals proximal weakness; emotional stress amplifies tachycardia and tremor; caffeine compounds sympathetic symptoms; prone positioning with face cradle worsens ophthalmopathy symptoms.
• Easing factors: Cool environments; rest reduces cardiovascular strain; antithyroid medications (methimazole, propylthiouracil) control hormone levels; beta-blockers (propranolol) provide symptomatic relief of tachycardia and tremor; massage for relaxation is typically welcomed.
• Red flags: Signs of thyroid storm (high fever >40degC, severe tachycardia >140 bpm, extreme agitation or delirium, vomiting) → emergency referral; do not treat. Resting heart rate >120 bpm at the start of the session → defer treatment until medically managed. New-onset atrial fibrillation (irregular pulse, shortness of breath) → medical referral. Radioactive iodine treatment — client must be in radiation isolation; massage is absolutely contraindicated until cleared by physician (typically 1–3 days after treatment).

Observation

• Local inspection: Visible goiter (diffuse anterior neck enlargement in Graves; nodular in toxic goiter); exophthalmos, lid retraction, lid lag (Graves only); fine tremor visible in outstretched hands; warm, moist skin with a flush; possible pretibial myxedema plaques on anterior shins (raised, waxy, orange-peel texture). Client may appear restless, fidgeting, unable to relax on the table initially. Proximal muscle wasting may be visible in severe cases (thinning of deltoid bulk, quadriceps hollowing).
• Posture: No characteristic postural deformity, but restlessness and inability to be still is itself an observation finding. If osteoporosis is developing, early kyphotic changes may be present. Upper crossed pattern from anxiety-driven shoulder elevation.
• Gait: Typically normal unless proximal myopathy is severe (difficulty rising from chair = positive Gower's-like compensation); may show a quick, hurried quality reflecting the hypermetabolic state.

Palpation

• Tone: Proximal muscle groups (deltoids, quadriceps, iliopsoas) feel paradoxically soft and weak rather than hypertonic — this is catabolic muscle wasting, not the stiff hypertonia of hypothyroidism. Cervical and upper trapezius muscles are frequently hypertonic from chronic sympathetic activation and anxiety. Paraspinal muscles may be tense globally from the sustained fight-or-flight state.
• Tenderness: Not prominently tender unless anxiety-driven tension has produced secondary myofascial trigger points (upper trapezius, levator scapulae, suboccipitals). Pretibial myxedema plaques may be tender to pressure — avoid direct pressure over these lesions. No referred path tenderness pattern expected.
• Temperature: Skin is notably warm and moist bilaterally (the opposite of the cool, dry skin in hypothyroidism) — this reflects the hypermetabolic state and peripheral vasodilation. Excessive sweating may be palpable. There should be no focal temperature asymmetry; if present, investigate for other pathology.
• Tissue quality: Proximal muscles feel soft, reduced in bulk, and lacking normal tone — this is the palpatory expression of thyrotoxic myopathy (protein catabolism, not inflammation). Skin is smooth, thin, and moist. Fine tremor may be palpable in the hands when the client is at rest. Pretibial myxedema, if present, feels waxy and indurated.

Motion Assessment

• AROM: Proximal weakness dominates the motion picture — shoulder abduction against gravity may be effortful, hip flexion from seated may be weak, and the client may struggle to rise from supine to seated. Cervical ROM is typically full unless anxiety-driven tension restricts it. No capsular restriction pattern expected.
• PROM / end-feel: PROM is full and pain-free in all joints (the restriction is muscle weakness, not joint pathology). End-feel is normal physiological (tissue stretch) in all directions. PROM significantly exceeding AROM in shoulder abduction confirms that the limitation is muscular weakness rather than joint restriction.
• Resisted testing: Proximal weakness pattern — reduced strength in shoulder abduction, shoulder flexion, hip flexion, and knee extension; grip strength may be mildly reduced. The weakness is non-myotomal (does not follow a nerve root pattern). Pain on resisted testing is not expected — the weakness is painless, which distinguishes it from tendinopathy or inflammatory myopathy.

Special Test Cluster

Conditional cluster — if bone density is a concern (postmenopausal women, long-standing hyperthyroidism, or known osteoporosis): Apply the osteoporosis pressure modification protocol. Assess for thoracic kyphosis, rib tenderness, and height loss. In these clients, the combination of hyperthyroid osteoporosis and proximal myopathy creates a high fall-risk profile — note this for positioning safety during table transfers.

Differential Assessment