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Ann Saudi MedAnn Saudi MedAnnals of Saudi Medicine0256-49470975-4466King Faisal Specialist Hospital and Research Centre 1768442710.5144/0256-4947.2007.301asm-4-301What's Your Diagnosis?A 40-year old obese female with altered sensorium Ahmed Asrar Asimi Rouf Sharma Amit Nazir Saima From the Department of Neurology, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinigar, IndiaCorrespondence and reprint requests: Asrar Ahmed, Sher-I-Kashmir Institute of Medical Sciences, Soura-Neurology Soura, Srinagar Jammu and Kashmir, India, Srinagar Jammu and Kashmir 190011, T: 9906598681, asrar357@yahoo.co.inJul-Aug 2007 27 4 301 301 01 2 2007 Copyright © 2007, Annals of Saudi Medicine2007This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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A 40-year old obese female was admitted with altered sensorium, a history of vomiting and documented hyponatremia followed by fluctuating encephalopathy and a deep coma state. She was initially managed at a peripheral health center where her serum sodium was 98 mEq/L. She was treated for severe hyponatremia (duration of hyponatremia and rate of correction not known) with a slight improvement noticed by her family members initially. The patient was managed inititally at a primary health center by a primary care physician with slight improvement but soon developed fluctuating encephalopathy and was shifted to our medical center. On admission, the patient was still in a stuperous state with spontaneous guttural vocalization only and no active movement of her limbs. On examination, the patient had asymmetrical extra-pyramidal signs–more on the right side compared to the left. The patient had normal pupillary reflexes and maintained ocular movements. Spastic paralysis of all four limbs was associated with brisk deep tendon reflexes, hypertonia and the Babinski sign (the patient was in a locked-in like state with maintained ocular movements, normal pupillary reaction, brisk deep tendon reflexes and flexor responses to planters). The rest of the systemic examination was normal.

Routine tests were normal except for serum sodium of 115 mEq/L and serum potassium of 1.98 mEq/L. The patient underwent magnetic resonance imaging (MRI) of the brain (Figure 1a).

What are the findings on the MRI scan of the brain?

What is the likely diagnosis in this clinical setting?

Answer on page: 308

Figure 1a A trident-shaped area of T2 hyperintensity (arrow) in the central pontine region in the axial plane on cranial MRI scan.