**Question:** A 16 years old female presents with recurrent abdominal pain but biochemical assays and ultrasound abdomen is normal. After waking up from sleep, she suddenly complains of loss of vision of bilateral eyes. Ophthalmologist finds nothing on examination. This condition is most probably due to

A. Hyperthyroidism
B. Krabbe disease
C. Multiple Sclerosis
D. Migraine

**Correct Answer:** C. Multiple Sclerosis

**Core Concept:** Multiple Sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS), characterized by inflammation and demyelination of the white matter. It is the most common cause of non-traumatic neurological disability in young adults.

**Why the Correct Answer is Right:** In this case, the patient presents with a combination of symptoms: recurrent abdominal pain, normal biochemical assays and ultrasound abdomen, and sudden bilateral visual loss after waking up from sleep, with normal ophthalmological examination. This combination of symptoms leads to the suspicion of CNS involvement and demyelination.

**Why Each Wrong Option is Incorrect:**

A. Hyperthyroidism (Option A): Hyperthyroidism is an endocrine disorder characterized by elevated thyroid hormone levels, causing symptoms like weight loss, palpitations, and irregular menstrual periods. The symptoms described in the question do not align with hyperthyroidism.

B. Krabbe disease (Option B): Krabbe disease is a rare lysosomal storage disorder affecting the CNS, causing neurological symptoms like seizures, developmental delay, and hypotonia. The described symptoms in this question are not consistent with Krabbe disease.

D. Migraine (Option D): Migraine is a primary headache disorder characterized by severe headache, nausea, and photophobia. The described symptoms are not consistent with migraine.

**Clinical Pearl:** Multiple Sclerosis (Option C) is a chronic inflammatory disease affecting the CNS, characterized by demyelination and immune-mediated inflammation. The combination of symptoms in this question aligns with the clinical presentation of MS, leading to the correct diagnosis.