Cardiology — MCQs

Question 1221: A 46-year-old woman comes to the physician because of a 2-week history of diplopia and ocular pain when reading the newspaper. She also has a 3-month history of amenorrhea, hot flashes, and increased sweating. She reports that she has been overweight all her adult life and is happy to have lost 6.8-kg (15-lb) of weight in the past 2 months. Her pulse is 110/min, and blood pressure is 148/98 mm Hg. Physical examination shows moist palms and a nontender thyroid gland that is enlarged to two times its normal size. Ophthalmologic examination shows prominence of the globes of the eyes, bilateral lid retraction, conjunctival injection, and an inability to converge the eyes. There is no pain on movement of the extraocular muscles. Visual acuity is 20/20 bilaterally. Neurologic examination shows a fine resting tremor of the hands. Deep tendon reflexes are 3+ with a shortened relaxation phase. Which of the following is the most likely cause of this patient's ocular complaints?

• A. Sympathetic hyperactivity of levator palpebrae superioris
• B. Abnormal communication between the cavernous sinus and the internal carotid artery
• C. Granulomatous inflammation of the cavernous sinus
• D. Glycosaminoglycan accumulation in the orbit (Correct Answer)
• E. Bacterial infection of the orbital contents

Explanation: ***Glycosaminoglycan accumulation in the orbit*** - The patient exhibits classic signs of **Graves' ophthalmopathy (exophthalmos, lid retraction, conjunctival injection, inability to converge)**, which is caused by the accumulation of **glycosaminoglycans** and fibrous tissue in the retro-orbital space due to autoimmune stimulation of fibroblasts. - This accumulation leads to increased orbital pressure, fat and muscle enlargement, causing the described ocular symptoms like **diplopia and ocular pain, especially with eye movement** (though not painful in this case, the other orbital signs are prominent). *Sympathetic hyperactivity of levator palpebrae superioris* - **Sympathetic hyperactivity** can cause **lid retraction (Darlmple's sign)** and a "staring" appearance (lid lag, von Graefe's sign), which are part of Graves' ophthalmopathy. - However, it does not explain the other prominent symptoms like **proptosis (prominence of globes), conjunctival injection, diplopia**, or the more severe orbital changes. *Abnormal communication between the cavernous sinus and the internal carotid artery* - An **arteriovenous fistula** (e.g., carotid-cavernous fistula) can lead to **pulsatile exophthalmos, chemosis, bruits, and visual impairment**. - While it can cause some ocular signs, it typically presents with a **bruit** and often more acute onset or traumatic etiology, which are not described. *Granulomatous inflammation of the cavernous sinus* - **Tolosa-Hunt syndrome**, a form of granulomatous inflammation of the cavernous sinus, typically causes **painful ophthalmoplegia** (paralysis of eye muscles) and can affect specific cranial nerves (III, IV, VI). - This condition does not explain the **proptosis, lid retraction, or systemic features of hyperthyroidism** seen in the patient. *Bacterial infection of the orbital contents* - **Orbital cellulitis** would present with **acute onset, severe pain, fever, erythema, edema, and often vision loss**, along with signs of infection. - The patient's chronic symptoms spanning months, lack of infectious signs, and systemic hyperthyroid features make bacterial infection highly unlikely.