Various organ systems may be affected with many possible signs and symptoms, including: Metabolic manifestations: Cold intolerance, modest weight gain (due to fluid retention and decreased metabolism), hypothermia Neurologic manifestations: Forgetfulness, paresthesias of the hands and feet (often due to carpal tunnel syndrome caused by deposition of proteinaceous ground substance in the ligaments around the wrist and ankle); slowing of the relaxation phase of deep tendon reflexes Psychiatric manifestations: Personality changes, depression, dull facial expression, dementia or frank psychosis (myxedema madness) Dermatologic manifestations: Facial puffiness; myxedema; sparse, coarse and dry hair; coarse, dry, scaly and thick skin; carotenemia, particularly notable on the palms and soles (caused by deposition of carotene in the lipid-rich epidermal layers); macroglossia due to deposition of proteinaceous ground substance in the tongue Ocular manifestations: Periorbital swelling due to infiltration with the mucopolysaccharides hyaluronic acid and chondroitin sulfate, droopy eyelids because of decreased adrenergic drive Gastrointestinal manifestations: Constipation Gynecologic manifestations: Menorrhagia or secondary amenorrhea Cardiovascular manifestations: Slow heart rate (a decrease in both thyroid hormone and adrenergic stimulation causes bradycardia), enlarged heart on examination and imaging (partly because of dilation but chiefly because of pericardial effusion; pericardial effusions develop slowly and only rarely cause hemodynamic distress) Other manifestations: Pleural or abdominal effusions (pleural effusions develop slowly and only rarely cause respiratory or hemodynamic distress), hoarse voice, and slow speech Symptoms can differ significantly in older patients.