The Kocher Debre Semelaigne Syndrome (KDSS) is also known as cretinism muscular hypertrophy. It is an unusual presentation in intellectually deficit children, commonly associated with congenital or iatrogenic hypothyroidism. The incidence of KDSS is less than 10%. It is more common in males, consanguineous marriage and age range from 18 months to 10 years [4]. The creatinine phosphokinase (CPK) is usually elevated [5]. It might be misdiagnosed particularly when other classical features of hypothyroidism are not dominant at first presentation. We present a case of 15-year-old intellectually deficit female. Her epilepsy had been managed on phenytoin for a decade. She had rigidity, leg cramps, malaise, oliguria, fever, myxedema, delayed deep tendon reflexes, calf muscle hypertrophy and agitation. Her agitation was controlled by haloperidol, which worsened the condition by altering her mental status. The patient was initially managed on line of Neuroleptic Malignant Syndrome due to raised CPK of 40,680 IU/L and mixed presentation. Nevertheless, no significant change was noticed until thyroid profile was done to exclude alternative resources. Thyroid stimulating hormone (TSH) was 74.5 IU, free T3 1.22 ng/dL, and free T4 0.43 ng/dL. Thyroxine was started along with change in anti-epileptic and recovery was observed within five days. This case report highlights the inconsistent finding from previously reported cases of KDSS. The female gender, non-consanguineous marriage, slightly delayed onset with primarily neuromuscular symptoms, and raised CPK is not the frequent demonstration in KDSS. On parallel, thyroid work-up is not routinely done, which can lead to misdiagnosis and mismanagement.

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