Detection and management of hypothyroidism following thyroid lobectomy: evaluation of a clinical algorithm

BACKGROUND

The objectives of this study were to determine: (1) the incidence permanent hypothyroidism after thyroid lobectomy (TL), (2) whether asymptomatic patients with mildly elevated thyrotropin (TSH) levels can be managed without thyroid hormone replacement, and (3) if the degree of lymphocytic infiltration (LI) and germinal center (GC) formation in the resected thyroid lobe correlates with the development of post-TL hypothyroidism.

METHODS

Subjects undergoing TL between January 2006 and January 2008 at 2 centers were enrolled in the study and thyroid function was followed prospectively based on a previously published algorithm. The histology of each resected thyroid lobe was examined, and the degree of LI and GC was quantified.

RESULTS

The study cohort consisted of 117 patients. Early postoperative TSH levels were significantly increased over preoperative levels (P < .001). TSH measured at 6 months to 1 year postoperatively, while still significantly increased over preoperative levels (P < .001), was also significantly reduced (P = .006) compared with early postoperative levels. Of the patients who presented with early postoperative hypothyroidism, 69.2% recovered to normal levels without intervention. The overall incidence of early postoperative hypothyroidism was 21.6%, and permanent hypothyroidism was 7.8%. A high degree of LI and GC correlated with a significantly higher mean TSH level (P = .003).

CONCLUSIONS

The incidence of hypothyroidism following TL is low, and a significant proportion of individuals who become biochemically hypothyroid will demonstrate only a transient elevation in their TSH levels. As well, individuals with LI, or GC formation, within their resected thyroid lobe may be at increased risk for post-TL hypothyroidism.

Detecting and defining hypothyroidism after hemithyroidectomy

BACKGROUND

The incidence of hypothyroidism after hemithyroidectomy for benign thyroid disease remains uncertain. This study examines the incidence, natural history, and the factors contributing to hypothyroidism after hemithyroidectomy.

METHODS

A retrospective review of patients undergoing hemithyroidectomy over 37 months was performed. The incidence of postoperative hypothyroidism was based on thyrotropin values and clinical symptoms. The relationship between hypothyroidism and lymphocytic infiltration of the removed gland was investigated using stepwise logistic regression.

RESULTS

Twelve of 66 patients (18%) became biochemically hypothyroid postoperatively. Four of the 12 patients (33%) subsequently became euthyroid without intervention. Of the remaining 8 patients, 4 (50%) had significant lymphocytic infiltration in the resected gland compared with 10 (19%) of the 54 euthyroid patients. Lymphocytic infiltration was associated with hypothyroidism but was age dependent.

CONCLUSIONS

A minority of patients become hypothyroid after hemithyroidectomy. Some patients with biochemical hypothyroidism will become euthyroid without intervention. The impact of lymphocytic infiltrate on hypothyroidism after hemithyroidectomy is age dependent.