Conversion of autoimmune hypothyroidism to hyperthyroidism.

BACKGROUND: Graves' disease and Hashimoto's thyroiditis are the two autoimmune spectrum of thyroid disease. Cases of conversion from hyperthyroidism to hypothyroidism have been reported but conversion from hypothyroidism to hyperthyroidism is very rare. Although such cases have been reported rarely in the past we are now seeing such conversions from hypothyroidism to hyperthyroidism more frequently in clinical practice. CASE PRESENTATION: We are reporting three cases of middle aged Asian females who presented with classical symptoms of hypothyroidism and the investigations showed elevated thyroid stimulating hormone with positive thyroid antibodies. Diagnosis of autoimmune hypothyroidism was made and thyroxine replacement therapy was initiated. Patients became asymptomatic with normalization of thyroid stimulating hormone level. After few years they developed symptoms of hyperthyroidism with suppressed thyroid stimulating hormone level. Over replacement of thyroxine was considered and the dose of thyroxine was decreased, but they remain symptomatic. After gradual decrease in the dose of thyroxine it was stopped finally. Even after few months of stopping thyroxine, the symptoms of hyperthyroidism did not improve and the biochemical and imaging modalities confirmed that the patients have developed hyperthyroidism. Anti-thyroid treatment was then started and the patients became symptom free. CONCLUSION: High index of suspicion should be there for possible conversion of hypothyroidism to hyperthyroidism if a patient with primary hypothyroidism develops persistent symptoms of hyperthyroidism. Otherwise it can be missed easily considering it as an over replacement with thyroid hormone.

Hyponatraemia: etiology, management and outcome.

OBJECTIVE: To determine the etiology of hyponatraemia, the treatment instituted and the outcome of treatment in a tertiary care hospital setting. STUDY DESIGN: Case series. PLACE AND DURATION OF STUDY: The Aga Khan University Hospital, Karachi, between January and June 2004. METHODOLOGY: Case records of 220 patients admitted to the medical service were identified through computerized hospital patients' data. All patients (3) 15 years with a sodium level on admission of (2) 130 mmol/litre were included. The records of those patients were reviewed for relevant demographic, clinical and laboratory data, in addition to the diagnosis, treatment and outcome of hospitalization. The data was analyzed through SPSS software version 11.0. RESULTS: Over a 6-month period, 220 patients were admitted with hyponatraemia (serum sodium (2) 130 mmol/L). Of those 127 females and 93 males, the mean age was 65 + 13.29 years. Neurological symptoms were the presenting feature in 25% patients. The mean serum sodium level on admission was 119.46 mmol/L. The rate of correction was >10 mmol/L/ 24 hours in 17% patients. The average duration of stay was 4 days. The mortality was 6.8%. Medicines accounted for 30% cases of hyponatraemia, of which diuretics, angiotensin converting enzyme inhibitor (ACEI) and angiotensin receptor blockers (ARBs) were top of the list. Other causes were gastrointestinal in 25%, chest infection in 11% patients, depletional hyponatraemia in 10% patients, SIADH (Syndrome of Inappropriate Antidiuretic Hormone) in 6% patients, congestive cardiac failure and malignancy in 5% each and chronic liver disease in 3.6% patients. CONCLUSION: Hyponatraemia was seen more commonly in the elderly, major causes being gastrointestinal losses and use of drugs. Serum sodium correction should be less than 10 mmol/L/24 hours. The treatment plan be directed to correction of the underlying cause. Diagnosis of SIADH should be sought with appropriate investigation.