Cause:
Nontoxic: iodine deficiency; lithium, or iodides rx; genetic and/or autoimmune silent subacute thyroiditis (nonstimulating)?
Toxic: progession from nontoxic
Pathophys:
Nontoxic: unknown for most common type
Toxic: autonomous function of 1 or more nodules
Nontoxic: iodine deficiency, esp in Equador (Nejm 1969;280:296)
Toxic: associated with elderly, CHF, AF, and angina
Sx:
Nontoxic: goiter
Toxic: CHF sx, angina, palpitations
Si:
Nontoxic: goiter
Toxic: CHF, Afib, apathetic hyperthyroidism of elderly with ptosis
Both: tracheal compression (Ann IM 1994;121:757); vague head and neck sx due to thoracic inlet compression manifest by positive Pemberton si = facial and head redness and suffusion w elevations of arms up to ears (Ann IM 1996;125:568)
Both: r/o autoimmune thyroid disease
Lab:
Chem:Nontoxic: thyroid function tests normal
Toxic: T 4 increased or normal, r/o benign increase in 15% sick or psychotic patients; RAIU elevated; TRH/TSH test positive, better than T 3 suppression test; normal = TSH of 2-3 rises to 15+; abnormal = no increase in TSH with TRH stimulation
Xray:Thyroid131I,123I, or technetium scan; in nontoxic, shows large gland w diffuse patchy uptake; in toxic, shows hot nodule(s), rest of gland atrophic and cool
Ultrasound of gland shows nodules.
Rx:
(Nejm 1998;338:1438) Nontoxic: thyroid replacement? (Hypothyroidism/Myxedema/Cretinism), but if any autonomous production, can lead to toxicity, esp in the elderly; 131I or surgery, esp if compressive sx (Ann IM 1994;1221:757)
Toxic: 131I rx; surgery