Clinical Manifestations of Hypothyroidism
Hypothyroidism presents with a wide range of clinical manifestations including hoarseness, joint pain, sleep disturbances, fatigue, weight gain, cold intolerance, constipation, dry skin, and cognitive impairment. 1
Common Clinical Manifestations
Thyroid hormone deficiency affects virtually every organ system in the body, resulting in the following manifestations:
Neurological/Cognitive
- Brain fog and mental slowing
- Poor concentration
- Lethargy and fatigue
- Memory impairment
- Slowed speech
- Rarely aphasia (not a typical primary symptom)
Musculoskeletal
- Joint pain and stiffness
- Muscle weakness
- Muscle cramps
- Delayed relaxation of deep tendon reflexes
Voice and Speech
- Hoarseness
- Thick tongue
- Slow speech
Dermatological
- Dry, coarse skin (xeroderma)
- Hair thinning
- Brittle nails
- Myxedema (non-pitting edema)
Cardiovascular
- Bradycardia
- Mild hypertension (often diastolic)
- Narrowed pulse pressure
- Pericardial effusions (in severe cases)
- Increased risk of atherosclerosis
Gastrointestinal
- Constipation
- Decreased appetite
- Abdominal distention
Metabolic
- Weight gain
- Cold intolerance
- Decreased sweating
- Elevated lipid levels
Sleep
- Sleep disturbances
- Sleep apnea
- Excessive daytime sleepiness
- Poor sleep quality
Special Considerations
Severity and Presentation
The clinical features of hypothyroidism depend on:
- Patient's age
- Presence of other diseases
- Rate at which hypothyroidism develops 2
Elderly Patients
- Atypical presentation is common
- Diagnosis may be easily missed
- Symptoms may be attributed to aging 2
Subclinical Hypothyroidism
- Characterized by elevated TSH with normal free T4
- May have minimal or no symptoms
- Affects up to 5% of women and 3% of men 3
Diagnostic Approach
When hypothyroidism is suspected based on symptoms like hoarseness, joint pain, and sleep disturbances:
- Initial laboratory evaluation should include serum TSH with reflex testing of free T4 1, 4
- In primary hypothyroidism (most common form), TSH is elevated and free T4 is low
- Thyroid antibodies (TPO and TGA) may help confirm autoimmune etiology 1
Treatment Considerations
- Levothyroxine replacement therapy is the standard treatment, typically started at 1.5-1.8 mcg/kg/day 1, 5
- Elderly patients or those with heart disease should start at lower doses (12.5-50 mcg/day) 5
- TSH levels should be monitored to guide dosage adjustments
- Treatment goal is to normalize TSH and relieve symptoms
Potential Complications of Untreated Hypothyroidism
If left untreated, hypothyroidism can lead to:
- Cardiovascular disease
- Infertility and menstrual irregularities
- Neurocognitive impairment
- Myxedema coma (rare but life-threatening)
- In infants: mental retardation and delayed developmental milestones 1, 6
Common Pitfalls in Management
- Inadequate monitoring of thyroid function
- Medication interactions affecting levothyroxine absorption
- Incorrect timing of medication
- Inconsistent brand use
- Overlooking subclinical disease 1
The American College of Radiology notes that imaging studies have no role in the initial workup of hypothyroidism in adults, as the diagnosis is primarily biochemical 3, 1.