Approach To Back Pain

 

Red Flags Signs/Symptoms

History Suggestive Diagnosis
New frequent falls, fecal incontinence, urinary urgency, overflow incontinence, bilateral leg symptoms General findings of cord compression/cauda equina
History of weight loss or cancer Epidural tumor/metastasis
Anticoagulation use or recent spinal procedure Epidural hematoma
Fever, immunocompromised, history of IVDU Epidural abscess

Most useful red flags are likely history of cancer, steroid use, abnormal neurologic findings,  difficulty walking, and anticoagulation use.

Patient with no red flags and a normal neurologic examination are at extremely low risk for a serious cause of back pain.

Differential (Serious Causes)

Spinal Pathology

Cancer Related

  • Epidural metastatic disease
  • Intradural metastatic disease
  • Intramedullary tumor

Infectious Related

  • Epidural abscess
  • Vertebral osteomyelitis
  • Infectious discitis

Other

  • Spinal epidural hematoma
  • Central disc herniation with cauda equina

Intrabdominal/Retroperitoneal

  • Aortic dissection
  • AAA
  • Pancreatitis
  • Peptic Ulcer Disease
  • Cholangitis
  • Ureteral colic

Evaluation

Classic presentations are frequently absent making the diagnosis of serious causes of back pain difficult. Many patients with cauda equina syndrome do not have fecal or urinary incontinence or saddle anesthesia on presentation. Only 10% of patients with spinal epidural abscess present with the classic triad of fever, back pain, and neurological deficits. Patients with metastatic epidural cord compression will have no known history of cancer 20% of the time.

Exam

Patients can be difficult to examine. If they can squat and walk on their toes and heels, they most likely have intact motor function. Sensation is likely intact if the patient has sensation to light touch over the anterior thigh (L2-L3), anterior knee (L4), dorsal foot (L5), and posterior leg (S1)

Consider an abdominal exam and/or bedside abdominal ultrasound. In a patient over 50 with risk factors for AAA and a history not consistent with other causes of back pain strongly consider a point of care ultrasound.

Labs

A patient with a normal ESR (less than 20mm/hr) and CRP (less than 1.0) is low risk for an epidural abscess. A normal ESR and CRP cannot exclude other causes of back pain such as central disc herniation or epidural hematoma.

Imaging

  • Plain films have little diagnostic utility and are insensitive. Postive x-rays are likely to need further advanced imaging
  • CT mainly used to assess for fractures
  • MRI is the diagnostic study of choice for serious causes of back pain

Scenarios 

The diagnostic approach should be individualized based on history, exam, and red flags.

Algorithm from Annals of Emergency Medicine

Case Approach
A patient with back pain with no neurologic symptoms and a normal neurologic exam. The patient is likely low risk and can be treated conservatively.
A patient with a history of IVDU whos back pain is worse with movement. Exam is normal, and he is afebrile. An ESR and CRP could likely be used to help assess for an epidural abscess. If negative, the patient can likely be treated conservatively with outpatient follow up.
A patient with a history of anticoagulation use and back pain that is worse when turning to the left. The pain started after moving boxes.  An ESR and CRP would not be helpful as the patient does not have risk factors for an epidural abscess. If the patient has no neurologic findings then discharge for an outpatient MRI is a reasonable approach.
A patient with a history of HIV and fever. A MRI is indicated in a patient who is febrile and immunocompromised. The patient is at risk for epidural abscess, vertebral osteomyelitis, and infectious discitis.
A patient with a history of steroid use and progressive back pain for the last 2 days. There is no history of back pain in the past.

Steroid use places the patient at risk for pathologic fracture and epidural abscess. ESR and CRP can be used to assess the need for MRI. For the evaluation of a possible fracture, a CT scan can be utilized.

 

 

A patient with a history of HIV and back pain radiating down the left leg. Patient afebrile with a normal neurologic exam

Patient is at risk for epidural abscess, but the history is consistent with sciatica. ESR and CRP could be used to determine the need for an MRI.

 

 

Emergency Medicine FOAM

Management of Non-traumatic Back Pain (Annals of Emergency Medicine Review Article)

Podcasts

Episode 26: Low Back Pain Emergencies

Episode 39.0 – Killer Back Pain

References

  1. Edlow JA. Managing nontraumatic acute back pain. Ann Emerg Med 2015;66:
    148–53
  2. Singleton J, Edlow J.A. Acute nontraumatic back pain: Risk stratification, emergency department management, and review of serious pathologies. Emerg Med Clin North Am 2016; 34: pp. 743-757