An unusual presentation of longstanding atrophic Hashimoto's thyroiditis: challenges in a resource-limited setting.

Summary: Hypothyroidism, affecting approximately 5% of the population, often remains undiagnosed, more so in developing countries. We report a 12-year-old girl with longstanding, untreated hypothyroidism who initially presented with proteinuria. History revealed recurrent vomiting, poor appetite, lethargy, and neurodevelopmental delays. Examination showed short stature, ptosis, outer eyebrow hair loss, myxedematous facies, dry skin, and hypertrophied calves. Investigations confirmed severe primary hypothyroidism, Hashimoto's thyroiditis, which most commonly presents between the ages of 45 and 55 years, with elevated thyroid autoantibodies and an atrophic thyroid gland. Additional findings were dyslipidemia and moderate proteinuria, both of which resolved with levothyroxine, which also improved growth. However, weight fluctuations persisted due to treatment non-adherence from financial challenges. This case illustrates a broad and atypical spectrum of complications arising from longstanding, untreated primary hypothyroidism. Awareness of such varied clinical manifestations is essential for timely diagnosis and appropriate management. Learning points: Undiagnosed cases of hypothyroidism are more prevalent in poor-resource setups. Longstanding hypothyroidism can lead to varied presentations involving different organs, including the kidneys and gastrointestinal system, besides its profound negative effect on growth and brain development. Dyslipidemia and ptosis have been reported as well. Calf muscle hypertrophy, Kocher-Debré-Semelaigne syndrome, has been reported in longstanding hypothyroidism.