Back pain Emergencies

🖥️ Watch teaching video

---

Back pain Emergencies

• Back pain is a common complaint, with 90% of cases being benign. However, it is crucial to identify the 10% of cases that are dangerous, as they can be easily missed.
  
• This lecture will discuss the five back pain emergencies, their causes, diagnosis, and management.
  
• The five back pain emergencies include: Aortic syndrome or retroperitoneal bleed, spinal epidural abscess, cauda equina syndrome, spinal metastases, and spinal fractures.

 
Aortic syndrome or retroperitoneal bleeding

• Aortic syndrome and retroperitoneal bleeding are life-threatening conditions that require immediate attention.
• Patients may present with sudden, severe back pain, along with other symptoms like abdominal pain, hypotension, or syncope.
• Point-of-care ultrasound is a valuable diagnostic tool for quickly identifying abdominal aortic aneurysms.
• Diagnosis of retroperitoneal bleeding may require a CT scan.

 
Spinal epidural abscess (SEA)

• Spinal epidural abscess can cause severe back pain and neurologic deficits.
  
• The classic triad of fever, back pain, and neurologic deficit is present in only 15% of cases, and these infections are often missed on the first ED visit. 
• Elevated C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are useful markers for the diagnosis of spinal epidural abscess (SEA), and MRI is the imaging modality of choice.

 
Cauda equina syndrome

• Cauda equina syndrome is a surgical emergency, usually caused by lumbar disc herniation (HIVD).
  
• The symptoms include bilateral sciatica, urinary retention, saddle anesthesia, reduced sphincter tone, and lower limb weakness.
  
• The straight leg raise test (SLRT) and slump test can help diagnose sciatica, but they are not specific for cauda equina syndrome. MRI is the imaging modality of choice.

 
Straight Leg Raise Test (SLRT)

• The straight leg raise test is used to assess for lower back and leg conditions like nerve root irritation, disc herniation, and disc degeneration.
• It involves slowly raising the patient's leg while keeping the knee extended, and pain below the knee that occurs between 30 to 70 degrees of flexion may indicate lumbar disc herniation.
• The test is performed with the patient lying flat, and the examiner gently raises the patient's leg by flexing the hip with the knee extended.
• A positive test is indicated by pain along the lower limb.

 
The slump test

• A positive slump test indicates the presence of a herniated lumbar disc.
• The slump test is performed as follows:
• 1. The patient sits with their hands behind their back to achieve a neutral spine position.
• 2. The patient then slumps forward at the thoracic and lumbar spine.
• 3. If this does not cause pain, the patient is asked to flex their neck by placing their chin on their chest.
• 4. The patient is then asked to extend one knee as much as possible. If this causes pain, the patient extends their neck back to neutral.
• 5. If the patient is still unable to extend the knee due to pain, the test is considered positive for nerve root irritation or HIVD.
• 6. The patient may also be asked to actively dorsiflex the ankle, which can further reproduce symptoms if the test is positive.

 
Spinal Metastases

• Cancer is a common cause of back pain. 
• Spinal metastases can cause neurologic deficits and require urgent management. 
• Hypercalcemia is a common complication of cancer and can cause general weakness, constipation, and confusion

 
Spinal Fractures

• Spinal fractures that require urgent management include burst fractures, Chance fractures, and spondylolysis.
• Burst fracture is a result of compression injury which causes vertebral fragments to be retropulsed into the spinal canal. 
• Chance fracture is a horizontal fracture through the posterior elements due to flexion-distraction injury caused by a seatbelt.
• Spondylolysis is a stress fracture of pars interarticularis, and is commonly seen in young athletes.

 
Red Flags for Back Pain

• The following red flags should raise suspicion for a serious underlying condition:
• Age below 18 or above 60.
• Immunodeficiency.
• Previous spinal interventions.
• Recent infections.
• Cancer history.
• Trauma history.
• Acute urine retention (AUR) or saddle anesthesia.
• Coagulopathy.
• Pain not resolved by analgesia.

 
Important Physical Findings of patients with back pain

• Physical findings of back pain can vary depending on the underlying cause. 
• For retroperitoneal bleeding, one may observe bruising in the groin, umbilicus (Cullen's sign), or flank (Grey-Turner's sign).
• An abdominal aortic aneurysm may be palpable as a pulsatile abdominal mass.
• In cases of spinal epidural abscess, symptoms may include fever and percussion tenderness over the spinous processes.
• Herniated intervertebral disc or cauda equina syndrome can present with acute urinary retention, saddle anesthesia, decreased anal tone, gait disturbance, paraparesis, and positive straight leg raise test and slump test. 
• Spinal metastases may exhibit physical findings that mimic those of HIVD.
• Lastly, spinal fractures can also have percussion tenderness over the spinous processes.

 
Diagnostic Tests for Back Pain

• Point-of-care ultrasound (POCUS) is utilized to assess for conditions like abdominal aortic aneurysm (AAA) and aortic dissection, particularly focusing on the presence of an intimal flap. 
• CT or MRI scans are commonly employed to investigate spinal epidural abscess, osteomyelitis, spinal metastases, and retroperitoneal bleeding, providing detailed anatomical information. 
• In cases where infection is suspected, such as SEA and osteomyelitis, ESR and CRP levels are measured. 
• A calcium profile may be ordered to evaluate for hypercalcemia secondary to spinal metastases. 
• X-rays play a crucial role in detecting spinal metastases, fractures, osteoblastic or osteolytic lesions, and pedicle erosion, providing valuable insights into the structural integrity of the spine.

 
Management of Back Pain Emergencies

• The management of back pain emergencies depends on the underlying condition. 
• Aortic syndrome and retroperitoneal bleeding require immediate surgical intervention. 
• SEA and osteomyelitis require antibiotics and surgical intervention. 
• Cauda equina syndrome requires urgent surgical intervention. 
• Spinal metastases require urgent radiation therapy and medical management. 
• Spinal fractures require immobilization and surgical intervention.

 
Take Home Message

• Back pain is a common complaint, and it is crucial to identify the 10% of cases that are dangerous. 
• The five back pain emergencies are vascular aortic syndrome, infection, disk herniation, cancer, and fracture. 
• Red flags, physical exam maneuvers, and diagnostic tests can help diagnose serious underlying conditions. 

• The management of back pain emergencies depends on the underlying condition and requires urgent intervention.