The Case
CC
Altered mental status
HPI
58yF PMH thoracoabdominal aortic aneurysm s/p stent and HTN p/w AMS. Per husband, the patient was in her USOH, walked home from work and suddenly complained of chest pain and bilateral arm tingling. She sat down and suddenly seemed to fall back into the chair. Per EMS, the patient was unresponsive on arrival and never was able to give any history. They report that the patient had a HR in the 60s, and RR of 15, but could not obtain a BP. FS 120.
PMH / PSH
PMH: Aneurysm (brain – stable, carotid – no intervention indicated on prior evaluation, AAA – ruptured and repaired in 7/2015), Hypertension, Migraines, Chronic low back pain
PSH: Endovascular stent placement for AAA in 7/2015
Medications: Metoprolol 25 mg BiD, Aspirin 81 mg daily, Flexeril 10 mg TID PRN back spasms, Nortriptyline 10 mg qhs
Physical Exam
VS: HR 56 BP 141/78 RR12 SpO2 100% RA FS 122
GEN: Patient is unresponsive, aox0, in distress
HEENT: Atraumatic, normocephalic, airway patent, no stridor, L pupil fixed and dilated, R pupil 3mm-minimally reactive, thready carotid pulses
Cor: +S1, S2, RRR, No m/g/r
Pulm: cta b/l
Abd: soft, nd, no palpable pulsatile masses, +b.s.
Extr: No radial pulses detected b/l—cold and pale, +2 pulses b/l DPs-LE warm b/l
Neuro: aox0, eyes closed, not following commands. Eye exam as above. Not moving any extremity, does not respond to painful stimulus
Labs
POCT Venous Blood Gas: Lactate 6.26
Basic Metabolic Panel: 140/4.3, 106/26, 19/0.9<140, Ca 8.3
CBC: WBC 8.3, Hgb 9.6, Hct 31.8, Plt 172, MCV 90
Coagulation panel: wnl
POCT Troponin: 0.00
Questions
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What is the differential for this patient? What is the most likely diagnosis?
The differential for altered mental status is broad and listing it is unlikely to be very helpful in determining what is going on with our patient. It is easier to think about some of the more unique physical exam findings in this patient and see if we can find a diagnosis that would also explain the remainder of the patient’s clinical presentation. Let’s consider the patient’s most interesting physical exam finding: her loss of pulses in both of her arms. This finding, otherwise known as acute limb ischemia, has a much smaller differential diagnosis and is usually attributed to thrombotic or embolic disease. In rare situations, it can also be caused by trauma or dissection. Given that the symptoms were bilateral and there was no evidence of trauma on exam, dissection becomes the most likely option. Aortic dissection is an interesting disease as the clinical presentation will vary based on the location of the dissection. AMS can occur with dissection, particularly when the dissection affects flow to the carotid arteries.
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What are the next best management steps for this patient?
There are multiple ways to diagnose aortic dissection, with similar sensitivities and specificities noted with CT Angiography (CTA), MRI, and TEE. CTA remains the test of choice used in diagnosing aortic dissection as MRI and TEE are often not available or entail delays.This patient posed a diagnostic challenge as the patient had a known anaphylactoid reaction to IV contrast, making CTA a risky procedure. We also recognized that this patient needed rapid imaging. We initially started with non-contrast CT scans of the head, chest, abdomen and pelvis with the hope of finding pathology explaining the presentation. While obtaining these studies, we called our vascular and CT surgery consults. However, imaging results showed that her previous aneurysmal disease was stable. In retrospect, prophylactic intubation prior to contrast imaging would have likely led to more rapid diagnosis. Early surgical consultation plays an important role in this patient as type A dissections are optimally managed surgically.
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What is the prognosis for this patient?
The patient’s prognosis was poor to start. The dissection caused almost complete loss of blood flow to the carotid arteries bilaterally, meaning by the time the diagnosis became evident, the brain had been hypoperfused for several hours. In consultation with our surgery colleagues, we felt that the patient would unlikely have any meaningful or significant neurologic recovery from surgical intervention. After extensive discussion with the patient’s family with the help with palliative care and our consultants, the patient was admitted to MICU with plan to transfer to hospice.
More Info
The patient was taken immediately to CT scan given patient’s mental status. Cardiovascular and peripheral vascular surgery were called to bedside. Initial imaging obtained was without contrast due to patient’s history of anaphylatoid contrast reaction, which did not elucidate obvious etiology of patient’s presentation. Patient then clinically decompensated, was intubated in the ED and returned for imaging with contrast. The imaging revealed catastrophic type A aortic dissection leading to complete occlusion of one internal carotid artery (ICA) and clinically significant decrease in flow to other ICA.