An unusual case of anisocoria in a child with bleeding aneurysm of posterior communicating artery and idiopathic thrombocytopenic purpura (ITP).

BACKGROUND ITP can give rise to bleeding episodes in different parts of the body including the central nervous system with various systemic manifestations. CASE An eight-year old female child, diagnosed as a case of chronic ITP for last two years, developed intense headache and vomiting for a few days before admission. This was associated with right sided mid dilated pupil with brisk reaction to light. MRI-angiography showed a bleeding aneurysm of posterior communicating artery. The features of raised intra cranial tension subsided with conservative management but the anisocoria persisted. CONCLUSION A bleeding aneurysm can manifest with anisocoria as a sign of partial third cranial nerve palsy.