Ans is 'c' i.e. Immediate Fasciotomy The child is having Compartment syndrome due to extravasation of contrast. This is a medical emergency and immediate fasciotomy needs to be done to prevent tissue necrosis.Extravasation of contrast and Compartment syndromeExtravasation of contrast is a possible complication of imaging studies performed with contrasts.Most cases of subcutaneous extravasation occur due to small volumes of extravasation of contrast causing pain, minimum swelling and localized erythema that is rapidly resolved. If larger volumes are extravasated, extensive tissue and skin necrosis may occur. Compartment syndrome is a very rare complication.Acute compartment syndrome occurs when the tissue pressure within a closed muscle compartment exceeds the perfusion pressure and results in muscle and nerve ischemia. It typically occurs subsequent to a traumatic event, most commonly a fracture.If left untreated or if inadequately treated, the muscles and nerve within the compartment undergo ischemic necrosis, and a limb contracture, called a Volkmann contracture, results. Severe cases may lead to renal failure and death.The earliest of the 'classic' features are pain (or a 'bursting' sensation), altered sensibility and paresis (or, more usually, weakness in active muscle contraction). Ischaemic muscle is highly sensitive to stretch. If the limb is unduly painful, swollen or tense, the muscles (which may be tender) should be tested by stretching them. When the toes or fingers are passively hyperextended, there is increased pain in the calf or forearm.Confirmation of the diagnosis can be made by measuring the intra compartmental pressures.Treatment is emergent fasciotomy.