MOBILE CAROTID THROMBUS ON BEDSIDE POCUS AS THE KEY CLUE TO EXTENSIVE CAROTID AND AORTIC DISSECTION

Case Presentation: A 58‑year‑old man with alcohol and cannabis use was found unresponsive at home, last known well the prior evening. EMS documented severe hypoglycemia (32 mg/dL), corrected with D50. On arrival he was minimally responsive and required intubation. Initial labs showed creatinine 1.6 mg/dL, lactate 7.8 mmol/L, WBC 21K/µL, and a rising troponin (0.089→0.374 ng/mL). UDS was positive for cannabinoids and methamphetamines. Arterial blood gas revealed pH 7.17, pCO2 52 mmHg, pO2 109 mmHg. CT head demonstrated no acute pathology. CTA chest with PE protocol showed patchy basilar opacities and a 4.2‑cm ascending aortic aneurysm without pulmonary embolism. He was hypertensive at admission but then developed shock with tachycardia of 120–140 bpm and hypotension requiring high‑dose norepinephrine.At approximately 1 PM, during ultrasound guidance for internal jugular central venous access, a mobile intraluminal thrombus was incidentally visualized in the right carotid artery. This unexpected bedside finding prompted urgent reconsideration of the differentials. MRI brain revealed numerous acute and subacute infarcts throughout bilateral cerebral and cerebellar hemispheres. He was transferred to a tertiary care center. CTA following transfer demonstrated right carotid artery dissection and type 1 aortic dissection involving both ascending and descending aorta. An hour post CTA he deteriorated and then died that night.

Discussion: This vignette illustrates the diagnostic complexity of multisite arterial dissection presenting as unexplained coma and shock. Initial metabolic disturbances and nondiagnostic imaging obscured the vascular etiology. The key diagnostic clue—a mobile carotid thrombus detected during routine ultrasound for line placement—shifted clinical reasoning and prompted urgent vascular imaging. The presence of multiterritory infarction further supported a proximal arterial process. The rapid extension of dissection into the carotid artery and abdominal aorta highlights the aggressive nature of this pathology and the narrow therapeutic window.

Conclusions: Hospitalists frequently manage patients with undifferentiated coma or shock, and this case emphasizes the importance of considering arterial dissection when findings are atypical or imaging reveals multiterritory ischemia. Bedside procedural ultrasound can provide critical, unexpected diagnostic information. Early vascular imaging is essential to identify catastrophic arterial dissections and guide timely disposition decisions in hospital medicine.