( of )
Correct: 0
Incorrect: 0
You are examining a 6-month old boy whose parents believe that he does not see normally. He does fix and follow your face with either eye occluded, but not quite as well as you expect. Pupils are normal in size for his age and constrict adequately to direct light. Ocular media are clear and ophthalmoscopy of the left eye reveals the picture you see here. A similar abnormality is present in the right eye.
What brain MRI abnormality would be most predictive of hormonal dysfunction?
Incorrect
Incorrect
Correct!
You are looking at a small (hypoplastic) optic disc. In other words, the optic nerve has too few axons, a congenital defect. Hypoplastic optic discs are manifestations of a forebrain dysgenesis, which may include the hypothalamic-pituitary axis. The MRI sign that best predicts hormonal dysfunction, which can be life-threatening, is the displacement of the normal posterior pituitary “bright spot” seen on the pre-contrast T1-weighted sagittal pulse sequence. It should normally be found in the posterior portion of the pituitary gland in the sella turcica. If you find it up in the hypothalamus,
alert the pediatrician to the fact that the patient may not be able to mount an adequate hormonal response in a febrile illness.