Thyroid Disease in the Elderly

Thyroid Disease in the Elderly Wayne A. Hale, MD Family Medicine Residency Moses Cone Health System Greensboro AHEC The commonest cause of hyperthyroidism is? 1. Acute thyroiditis 2. Toxic nodule 3. multinodular goiter 4. Graves Disease 5. Excess iodine load Subclinical hypothyroidism 1. 2. 3. 4. Is the “Silent killer” Bears watching if TSH<10 Is treated with high dose levothyroxin Requires a Free T3 to confirm Apathetic hyperthyroidism 1. 2. 3. 4. Decreases voter turn-out Is caused by Cannabis use Results from metabolic burnout Increases with age Thyroid Disease  common, especially in women  subtle and insidious presentation  confounding by medications and nonthyroidal disease  very treatable once identified The Aging Thyroid - Anatomical Change  Anatomic - may have substernal location  Macroscopic- Nodularity  Microscopic  Dilation of follicles  Decreased colloid content  Increase in fibrous tissue  Lymphocytic infiltration Physiological Changes of Thyroid Function with Age       T4 production decreases T4 degradation decreases Serum T4 concentration = Serum T3 concentration decreases Serum TSH = TSH response to TRH: Female =  Male = or decreased CNS Control of Thyroid Function Thyroxin Metabolism Case Finding for Thyroid Disease  Who?  Patients with suggestive symptoms  When?  Low threshold in pregnancy, women over 60  How?  TSH or TSH plus measure of free T4 Prevalence of Hypothyroidism  Known and Unknown  Age <65  Age >65 1% 5-12%  In previously unsuspected over age 60 0.7-2.1% Thyroid Function Testing      TSH - $37 Free T4 - $21 Free T3 - $91 Anti-thyroid antibodies - $83 Old tests  Total T4 - $21  T3 Uptake- $30  T3 Total/RIA - $30 Sensitive TSH  Unselected pop. Sens = 89-95%, Spec = 9096%  Asymptomatic older pop.- only 7% with abnormal TSH had thyroid disease  False positives more common with  Acute illness, pregnancy  Some drugs, especially glucocorticoids  May detect subclinical hypo or hyperthyroidism Subclinical Hypothyroidism  A biochemical abnormality  Elevated TSH with normal T4  Should these patients receive prophylactic therapy? “Thyroid Failure in the Elderly” (Rosenthal et al. JAMA 1987)  26 patients with increased TSH levels, NL T4 levels  Baseline measurements of antimicrosomal antibodies  Annual measurement of T4 , TSH  4 year follow-up “Thyroid Failure in the Elderly”: Results  8/26 patients developed thyroid failure  All patients with TSH >20 U/ml developed hypothyroidism  80% of patients with “high titer” antimicrosomal antibodies developed thyroid failure Sub-clinical Hypothyroidism Sub-clinical Hypothyroidism Management  Consistently increased TSH (above 10) or high titer” antibodies (> 1:1600) - give prophylactic thyroid hormone replacement  TSH < 10 - careful observation for hypothyroid symptoms & periodic TSH & free T4  Treat those where thyroxin may help - CHF  Avoid where it may harm - unstable angina  Ref: Subclinical Thyroid Disease: Scientific Review and Guidelines for Diagnosis and Management JAMA, Jan 2004; 291: 228 - 238. Hypothyroidism - Etiology  Congenital or idiopathic  Autoimmune (Hashimoto’s) thyroiditis  Following therapy for Graves’ Disease  Head and neck surgery or radiation  Iodine deficiency  Drugs (iodine, lithium, amiodarone)  Pituitary or hypothalamic disease (rare) Hypothyroidism in the Elderly Reasons for Missing the Diagnosis     Lower frequency of typical manifestations Disease often has insidious onset Confounding effects of other illnesses Symptoms attributed to “aging” Hypothyroidism - Clinical Clues to the Diagnosis in Elderly Patients      Psychomotor retardation New onset muscle cramps or joint pains Proximal myopathy Carpal tunnel syndrome Unexplained pericardial, pleural, or peritoneal effusion  Unexplained macro- or normocytic anemia  Peri-orbital “puffiness” Hypothyroidism - Therapy  L-thyroxine, “start low, go slow”  Average dose is 10% less in elderly patients  Average replacement 100 to 125 mcg  Less in subclinical hypothyroid  Excessive Tx accelerates osteoporosis?  Periodic monitoring of both patient and laboratory thyroid function  TSH 6 weeks after dose change, When stable, Q yr. Myxedema Coma: Therapy  Support of respiration, avoid sedatives  Identification and treatment of precipitating event  Attention to fluid and electrolyte balance  Steroids in stress doses  Thyroid hormone replacement Thyroiditis Neck pain Self-limited Autoimmune Goiter or neck mass Acute Subacute Silent Hashimoto’s Chronic Infectious Granulomatous Lymphocytic Fibrous Thyroiditis Hyperthyroidism in the Elderly Reasons for Missing the Diagnosis  Presenting symptoms fewer and atypical  Thyroid disorder masked or overshadowed by concurrent illness  Thyroid tests more difficult to interpret  Stereotypism of “aging” Etiology of Hyperthyroidism  Common  Graves’ Disease  Multi-nodular goiter (increased in the elderly)  Toxic adenoma  Rare     Subacute thyroiditis Iodide-induced hyperthyroidism Hashimoto’s thyroiditis (early) Ingestion of thyroid hormone Symptoms in Patients with Thyrotoxicosis Effect of Age (Am J Med, Oct. „86) Number of patients Mean age 25 82 247 40 Symptoms Weight Loss Palpitations Weakness Dizziness % 44 36 32 20 % 85 89 70 -- Nervousness Memory Loss Tremor Pruritis Heat intolerance No symptoms 20 8 8 4 4 8 99 ---89 -- Clinical Clues to Hyperthyroidism in the Elderly  Worsening CHF despite diuretics and digoxin  Change in bowel habits and weight loss  Insidious onset of weakness, fatigue, emotional liability  Acute changes in mental status  Acute mental changes in the elderly warrant investigation of thyroid function Features of Apathetic Hyperthyroidism  Eye signs absent  Minimal thyroid enlargement  The absence of an enlarged or palpable gland does not exclude a diagnosis of hyperthyroidism in the elderly     Weight loss marked Depression, apathy, “senility” No flushing Hyperkinesia absent Laboratory Diagnosis of Hyperthyroidism  TSH  Free T4  Free T3 Subclinical Hyperthyroidism  Low TSH  Normal free T4 and free T3  Up to 12% have only elevation of T3  Repeat in 3 months  If TSH greater than 0.1 , periodic followup  If TSH less than 0.1 consider further follow-up and treatment TSH Response to TRH  To define equivocal test results  Causes of blunted or absent response     Hyperthyroidism Medications (corticosteroids) Severe non-thyroidal illness Advanced age (especially males) Therapeutic Options for the Elderly Patient with Hyperthyroidism  Anti-thyroid drugs  to deplete gland of stored hormone  Beta-blockers to control adrenergic manifestations  Radioactive iodine (131I)  Thyroidectomy Thyroid Disease Summary  Thyroid disease common, but don't screen everyone  Case find in high risk groups  Primary care physicians can manage most conditions  TSH is the best initial test of function, but abnormal must be confirmed