History

• 55 yo female with 2 day history of atraumatic R foot pain 
• Pain is over the dorsal foot and worse with ambulation, also present at rest
• There is associated parasthesias of the dorsal foot
• She denies swelling, redness, warmth, fevers, or any recent wounds
• She has no prior history of extremity surgeries or pathology

Exam

T 97.6  HR 88  BP 143/63  RR 18

• Well appearing in no acute distress
• Heart sounds normal no mrg
• Lungs clear to auscultation
• Abdomen soft, NTND
• R lower exremity: There is purplish discoloration of the distal dorsal foot and all toes. The dorsal foot is cool to the touch. There is no palpable DP or PT pulse, and a weak Doppler DP signal

Differential Diagnosis - A focus on life&limb threats

• Infection - necrotizing fasciitis, gangrene
• Acute Limb Ischemia 
• Compartment Syndrome
• DVT

Workup

• Vascular surgery consulted
• Patient sent for CTA of lower extremity which demonstrated occlusion of R tibioperoneal trunk 

Management and Outcome

• Pt treated with ASA and a heparin infusion in the ED
• Taken immediately to OR for thrombectomy with successful restoration of perfusion
• Pt recovered well with full function of the exremity

Take Home Points

• Acute Limb Ischemia is a surgical emergency: there is a 20% amputation rate and 25% short term mortality rate
• Pts often present with pain or pain and parasthesias only instead of the classic "6 Ps:" Pain, parasthesias, paralysis, poikilothermia, pallor, pulselessness"
• Patients may have a palpable (though diminished) or Dopplerable pulse and still have acute limb ischemia
• Sx more dramatic for embolic etiology without collateral circulation
• In pts with longstanding disease, collateral circulation may prevent the more dramatic symptoms such as discoloration and severe, intractable pain
• Outcomes completely dependent on time to intervention: beyond 4 hours there is irreversible necrosis of nerves and muscles resulting in poor outcomes such as amputation
• Call vascular surgery early and initiate heparin therapy if there is a suspicion for acute limb ischemia: do not wait for diagnostic studies

Santistevan, Jamie. Acute Limb Ischemia - An Emergency Medicine Approach. Emerg Med Clin N Am 2017;35:889-909.