Acute Left Foot Pain and Ecchymosis

Submitted by Geoffrey D. Huntley, Kelly M. Pennington and Emily L. Leasure

Published October 5, 2019

A healthy 47-year old man presented with acute-onset left foot pain. He was running and “felt a pop” in his left shoe followed by severe pain upon flexion. He removed his shoe and found significant bruising and swelling in the arch. His symptoms continued for a few days with severe pain upon weight bearing and toe walking. He had no history of plantar fasciitis, fluoroquinolone use, or plantar steroid injection. Physical exam revealed an ecchymosis over the mid arch of his left foot (Image 1) with swelling and point tenderness over the plantar fascia. An ultrasound (Image 2) demonstrated hypoechoic enlargement around the medial cord. 

 
Image 1

Image 2

Questions:

1. A previously healthy 30-year old woman presents to clinic with an intense tearing sensation on the bottom of her left foot that she sustained during an ultimate Frisbee match earlier in the day. Which of the following is the most important aspect of her history in making a diagnosis?
   

   1. Prior fluoroquinolone use

   2. Prior plantar fasciitis

   3. History of gout

   4. History of malignancy

2. Upon getting further history, the patient in question 1 has had no prior plantar fasciitis or steroid injections and has had no recent antibiotic usage. What is the next best step and what are the associated findings(1)    

   1. Ultrasound: metatarsal articulations with erosions and destruction of bone epiphyses

   2. Ultrasound: disruption of the plantar fascia and hypoechoic enlargement around the medial cord

   3. MRI: mass extending from the plantar fascia with high T2 signal content

   4. MRI: fusiform thickening of the plantar fascia at its origin and edema of the adjacent soft tissues

Answers:

Question 1 - Answer (b)

Question 2 - Answer (b)

Teaching Points:

1. Plantar fascia rupture is usually associated with preexisting plantar fasciitis and/or recent corticosteroid injection (2). Spontaneous rupture, as in this patient, is rare and most commonly occurs in athletes. Treatment entails rest, ice, NSAIDs, and limited weight bearing. 

2. The differential for acute foot pain is vast. Ecchymosis over the mid arch of the foot can indicate tearing or rupture. Imaging can also be helpful to differentiate between diagnoses when a patient’s history and physical exam is equivocal.  Ultrasound is felt to be superior to MRI in differentiating tearing from edema(1). Disruption of the plantar fascia and hypoechoic enlargement surrounding the medial cord are ultrasound features of plantar fascia rupture(1).

References:

1. Jeswani T, Morlese J, McNally EG. Getting to the heel of the problem: plantar fascia lesions. Clin Radiol. [Review]. 2009 Sep;64(9):931-9.

2. Lee HS, Choi YR, Kim SW, Lee JY, Seo JH, Jeong JJ. Risk factors affecting chronic rupture of the plantar fascia. Foot Ankle Int. 2014 Mar;35(3):258-63.

Author:

Mr. Huntley is a fourth-year medical student at Mayo Clinic School of Medicine who hopes to enter an Internal Medicine residency upon graduation. He believes that hand-held ultrasound will soon play an important role in many bedside physical examinations.