This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proptosis, Enophthalmos, Developmental Anomalies, Subject name: Ophthalmology
[{'content': 'Pulsatile proptosis is seen in? \nSelect and explain. \nA. Caroticocavemous fistuls, B. Thyroid ophthalmopathy, C. Buphthalmos, D. Orbital cellulitis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Caroticocavernous fistuls o Proptosis is bulging of the eyeball (forward bulging) beyond the orbital margins. Though the word exophthalmos is synonymous with proptosis; some source define exophthalmos as a protrusion of globe greater than 18mm and proptosis as a protrusion equal to or less than 18 mm.o Proptosis may be classified as follows :-1) Unilateral Proptosis Proptosis of one eye.i) Inflammatory lesions Orbital cellulitis, abscess, cavernous sinus thrombosis, etc.ii) Vascular disturbances Haemorrhage, varicose orbital veins, haemangioma, etc.iii) Cysts and tumourDermoid cyst, osteoma, lymphoma, lymphosarcoma, glioma, meningioma of optic nerve, retinoblastoma and metastatic deposits in orbit [Neuroblastoma, breast, prostate, lung, GIT, Kidney, Ewing's tumor, melanoma, wilms tumor (Nephroblastoma)|.iv) Systemic diseases - Leukemias and endocrine disturbances such as Graves' disease and thyrotropic exophthal mos in initial stages.v) Paralysis of extraocular muscles as in complete ophthalmoplegia.vi) Mucocele of PNS9- Frontal (most common), ethmoid, maxillary.2) Bilateral Proptosis Proptosis of both eyes.i) Developmental anomalies of the skull- Oxycephaly (tower skull).ii) Endocrine exophthalmos, both thyrotoxic and thyrotropic.iii) Inflammatory lesions - Cavernous sinus thrombosis.iv) Tumours - lymphosarcoma, lymphoma, pseudotumour, nephroblastoma, Ewing's sarcoma.v) Systemic disease - Histocytosis (Hand - schuller christon disease), amyloidosis, wegner's granulomatosis.3) Intermittent proptosis Proptosis developing intermittently and rapidly in one eye when venous stasis is induced by forward bending or lowering the head, turning the head forcibly, hyperextension of the neek, coughing, forced expiration with or without compression of the nostrils, or pressure on jugular veins. The most important casue is orbital varix (varicocele).4) Pulsatile proptosis : - Pulsatile proptosis is seen in caroticocovernous fistula; saccular aneurysm of ophthalmic artery; and due to transmitted cerebral pulsation as seen in meningocele, neurofibromatosis and traumatic or operative hiatus.", 'role': 'assistant'}]