Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 11 3 2026 09 28 149 153 Maryam Maghsoodlo Department of Nursing, Amol School of Nursing and Midwifery, Mazandaran University of Medical Sciences, Sari, Iran. Azam Zare Department of Medical-Surgical Nursing, School of Nursing, Fasa University of Medical Sciences, Fasa, Iran. Serajaddin Arefnia Department of Pediatric Endocrinology, Neonatal and Children’s Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran. Akram Sadat Montazeri Nursing Research Center, Golestan University of Medical Sciences, Gorgan, Iran. 2026 06 25 2026 07 27 Hypothyroidism in children is a prevalent endocrine disorder characterized by insufficient production of thyroid hormones, significantly impacting physical growth, neurodevelopment, and metabolism. This case report presents a child exhibiting atypical manifestations. A 30-month-old (approximately 2.5 years) girl presented with a chief complaint of brown-red particles in her urine. Initial investigations, including repeated urinalyses and abdominal-pelvic ultrasonography, yielded normal results. Importantly, repeated microscopic examinations of the urine samples revealed no crystals or abnormal cellular elements, confirming that the visible particles were purely macroscopic. Despite treatment for a suspected mild urinary tract infection, the symptom persisted. Growth parameters were within normal limits. Following consultation, thyroid function tests revealed elevated thyroid-stimulating hormone (TSH: 9.09 µIU/mL) and low total thyroxine (T4: 6.4 µg/dL), with normal anti-thyroid peroxidase antibodies, confirming a diagnosis of overt hypothyroidism. Upon diagnosis, levothyroxine therapy was initiated, leading to rapid symptom improvement and complete resolution of the urinary particles within days. This case underscores the importance of considering overt hypothyroidism in children with nonspecific urinary symptoms and highlights the value of meticulous clinical follow-up. https://crcp.tums.ac.ir/index.php/crcp/article/view/1211 https://crcp.tums.ac.ir/index.php/crcp/article/download/1211/797