Post Traumatic Carotid Cavernous Fistula Presenting as Parathyroid Crisis

Abstract

This is a case of two rare entities causing non-specific symptoms. Carotid-cavernous sinus fistula (CCF) arises from miscommunication of carotid arterial flow and the cavernous sinus. Post traumatic CCF presents bilaterally are uncommon, only 1-2% of patients. While already a rare diagnosis, our patient presented in an acute parathyroid crisis defined by symptomatology caused by markedly elevated calcium and parathyroid hormone, which may have masked our diagnosis of CCF.CASE PRESENTATION: A 57-year-old Colombian female presented with dizziness, anorexia, nausea, and vomiting. She also endorsed intermittent diplopia in the left eye. Physical exam revealed left sided ptosis. She reports a remote history of head trauma a month prior. Serum calcium on presentation was 13.6 mg/dL, ionized calcium of 6.8 mg/dL, and parathyroid hormone (PTH) was 219.8 pg/mL. Subsequently, a Technetium 99m sestamibi scan showed increased radioisotope along the right lower pole of the thyroid gland confirming primary hyperparathyroidism. She was resuscitated with normal saline fluid and started on Cinacalcet for hypercalcemia. Attempts to lower serum calcium can be achieved using bisphosphonates and may be effective within the first 24 hours. In our patient, Cinacalcet did not achieve sufficient calcium lowering thus, Zoledronic acid was used due to its potency with small doses. Nausea, vomiting, and positional dizziness resolved. Despite resolution of symptoms, she continued with ptosis; thus prompting further work up. Magnetic resonance angiography and venography revealed extensive time of flight enhancement throughout the bilateral cavernous sinuses. A cervical and cerebral angiography revealed bilateral carotid cavernous fistulas with ophthalmic vein arterialization. The next day, she underwent left cavernous sinus embolization with coiling. Parathyroidectomy was delayed due to recurrence of ptosis and need for a second embolization for persistent diplopia that resulted in resolution of symptoms.DISCUSSION: Each of these diagnoses are rare and both require timely evaluation and treatment. The patient's symptoms are classically seen in a parathyroid crisis, with nausea, vomiting, and anorexia being the most common symptoms in up to 48% of parathyroid crises. Like the aforementioned, CCF symptomatology also includes non-specific symptoms; however, may pose more of a challenge during diagnosis as symptoms wax and wane depending on the hemodynamic flow within the fistula.CONCLUSIONS: This case highlights the necessity of a thorough physical exam and further as a reminder that a clinician must be vigilant in ruling out alternative pathologies supported by the objective findings no matter how rare or unlikely.