# Presentation: 015754

## Spotlight Case March 2008

**Back Again**

## Source and Credits

- This presentation is based on the March 2008 AHRQ WebM&M Spotlight Case
- See the full article at _[http://webmm.ahrq.gov](http://webmm.ahrq.gov/)_
- CME credit is available
- Commentary by: **Jon D. Lurie**, **MD, MS**Dartmouth Medical School
- Editor, AHRQ WebM&M: Robert Wachter, MD
- Spotlight Editor: Tracy Minichiello, MD
- Managing Editor: Erin Hartman, MS

## Objectives

*	**At the conclusion of this educational activity, participants should be able to:*
- Understand the evidence-based evaluation for patients presenting with low back pain
- Identify important “red flags” for serious systemic illness presenting with low back pain
- Recognize potential pitfalls in caring for patients with low back pain

## Case: Back Again

*	**A 34-year-old man came to the emergency department for evaluation of low back pain. He stated that the pain had been present for about one week and that he had an isolated episode of fever, which resolved with acetaminophen. Past medical history was significant for use of heroin and cocaine until one year earlier. Medications included methadone and ibuprofen. He had no allergies. *

## 	Physical examination revealed tachycardia and tenderness in the lumbosacral region; straight leg raising test was negative. X-ray of the lumbar spine was normal. The patient was discharged home on ibuprofen and advised to follow up with his primary physician the next day.

**Case: Back Again**

## Low Back Pain (LBP)

- Common problem
- Typically benign and self-limited
- Occasionally is presenting symptom of serious illness (e.g., cancer, infection, surgical emergency)
- Key to history is looking for “red flags”

*Lurie JD. Best Pract Res Clin Rheumatol. 2005;19:557-575.*

## Evaluation of Low Back Pain

- Assess likelihood of serious underlying systemic disease without over-testing those with benign musculoskeletal pain
- History is usually key to early detection of serious causes of low back pain

*Jarvik JG, Deyo RA. Ann Intern Med. 2002;137:586-597. *

## Causes of Low Back Pain

- Regional mechanical low back pain (≥ 90%)
- Mechanical low back pain with neurogenic leg pain (7%-10%)
- Non-mechanical spine disorders (≤1%)
- Other conditions: usually present with accompanying symptoms

*Lurie JD. Best Pract Res Clin Rheumatol. 2005;19:557-575.*

## Non-specific mechanical low back pain (sprain, strain, lumbago, etc.)	
Degenerative changes in discs and/or facet joints
Osteoporotic compression fractures
Traumatic fractures
Deformity (severe scoliosis, kyphosis, spondylolisthesis)

- Degenerative changes in discs and/or facet joints
- Osteoporotic compression fractures
- Traumatic fractures
- Deformity (severe scoliosis, kyphosis, spondylolisthesis)

**Causes of Low Back Pain**** ****1. Regional mechanical low back pain**

*Lurie JD. Best Pract Res Clin Rheumatol. 2005;19:557-575.*

## Intervertebral disc herniation
Spinal stenosis
Spinal stenosis associated with degenerative spondylolisthesis

- Spinal stenosis
- Spinal stenosis associated with degenerative spondylolisthesis

**Causes of Low Back Pain ****2.**** ****Mechanical LBP with neurogenic leg pain**

*Lurie JD. Best Pract Res Clin Rheumatol. 2005;19:557-575.*

## Causes of Low Back Pain 3. Non-mechanical spine disorders 

- Neoplasia (metastases, lymphoid tumors, spinal cord tumors, etc.)
- Infection (infective spondylitis, epidural abscess, endocarditis, herpes zoster, lyme)
- Seronegative spondyloarthritides (ankylosing spondylitis, psoriatic arthritis, reactive arthritis, Reiter’s syndrome, inflammatory bowel disease)

*Lurie JD. Best Pract Res Clin Rheumatol. 2005;19:557-575.*

## Causes of Low Back Pain 4. Other causes...usually have accompanying symptoms

- Pelvic (prostatitis, endometriosis, pelvic inflammatory disease)
- Renal (nephrolithiasis, pyelonephritis, renal papillary necrosis)
- Aortic aneurysm
- Gastrointestinal (pancreatitis, cholecystitis, peptic ulcer disease)
- Paget’s disease
- Parathyroid disease
- Hemoglobinopathies

*Lurie JD. Best Pract Res Clin Rheumatol. 2005;19:557-575.*

## Important “Red Flags” for Serious Illness

- General red flags on history:
- Pain worse at night or with recumbency (particularly when patients sleep in a chair to avoid pain) is very worrisome for malignancy or infection
- Suspicion should be particularly high in patients whose pain is unrelieved in any position
- Other red flags can be disease specific

*See Notes for References.*

## Causes of Low Back Pain:“Don’t miss these diagnoses”

- Malignancy
- Infection
- Compression Fractures
- Other Acute Neurological Entities

## 1. Malignancy

- Malignancy accounts for less than 1% of patients seeking care for low back pain
- Risk factors or red flags include:
- Age > 50
- Previous history of cancer
- Unexplained weight loss (> 4.5 kg over 6 months)
- Failure to improve after 1 month of therapy
- No relief with bedrest
- In patients with none of these red flags, probability of malignancy approaches zero

*See Notes for References.*

## 2. Infection

- Risk factors or red flags include:
- Fever
- Intravenous drug use
- Urinary tract infection
- Indwelling urinary catheters
- Skin infections
- Note that fever is a suggestive but insensitive symptom, particularly if patient is taking acetaminophen

*See Notes for References.*

## 3. Compression Fractures

- Make up about 4% of low back pain cases
- Risk factors or red flags include:
- Age > 70
- Corticosteroid use (very specific to this diagnosis)
- History of trauma is not predictive

*See Notes for References.*

## 4. Important Neurological Entities

- Cauda equina and spinal cord compression syndromes are surgical emergencies
- Quite rare—an estimated 0.04% of low back pain cases
- Symptoms/signs include:
- Unilateral or bilateral leg pain
- Numbness and/or weakness
- Urinary retention

*Deyo RA, et al. JAMA. 1992;268:760-765. *

## Issues in Present Case

- Patient is young with little or no concerning features for malignancy
- Report of fever is worrisome
- Lack of elevated temperature on examination is not reassuring, since patient reports taking acetaminophen
- Significant red flag is history of probable injection drug use
- Might be misinterpreted as a red flag for “drug-seeking behavior” rather than a clue to serious systemic illness

## Case (cont.): Back Again

*	**The patient did not see his primary physician the next day. Instead, the day after that, he went to another  ED with complaints of back pain and was again advised to use ibuprofen and follow up with his primary physician. The patient returned to the hospital again after 4 days with complaints of worsening back pain and new shortness of breath. Examination revealed bilateral rales, a systolic murmur in the mitral area, and track marks over flexor aspects of both upper extremities.*

## Work-up of Patients with “Red Flags”

- Standard work-up
- Complete blood count
- Erythrocyte sedimentation rate (ESR)
- Urinalysis
- Plain radiography of the spine
- In patients with one or more red flags, with either a worrisome X-ray or an ESR greater than 50, advanced imaging (MRI or bone scan) may be warranted
- In patients with a personal history of cancer, directly obtaining an MRI is warranted

*See Notes for References.*

## Summary of Test Characteristics

*See Notes for definitions and references.*

## Case (cont.): Back Again

*	**Shortly after admission, the patient developed acute respiratory failure requiring intubation. He became hypotensive and laboratory results were significant for the presence of bandemia, thrombocytopenia, coagulopathy, acute renal insufficiency, and micro- and macro-hematuria. He was treated with fluid resuscitation, antibiotics, fresh frozen plasma, and platelets. Despite these efforts, the patient developed bleeding from his venipuncture sites, oral cavity, and rectum, along with refractory hypotension. *

## Case (cont.): Back Again

*	**Aggressive resuscitation efforts, including red cell transfusion and vasopressor therapy, were initiated, but the patient died of overwhelming shock. The patient’s cultures subsequently grew methicillin-resistant staphylococcus aureus. Autopsy revealed a 2x1 inch tricuspid valve vegetation, bilateral patchy pneumonias, and multiple bilateral cortical infarcts in the kidneys. The final cause of death was “complications of infective endocarditis.”*

## What Happened?

- In this case, the patient rapidly progressed to severe systemic infection, which may or may not have started as infective spondylitis
- Increased attention (or concern) to his history of fever and injection drug use at the first two visits might have led to a more timely diagnosis with further diagnostic evaluation

## Back Pain With Infective Endocarditis

- Pathogenesis often not known but can include
- Septic embolization
- Renal or splenic infarction
- Myalgias/arthralgias related to the inflammatory response
- Infective spondylitis with or without epidural abscess
- Frank infective spondylitis reported to be rare in endocarditis
- However, was present in 15% of cases in one recent study

*See Notes for References.*

## Care of Patients with Substance Abuse

- Injection drug users are at high risk for serious infections
- Extra care in the evaluation of their complaints is often warranted
- Respectful approach
- Understanding the medical and behavioral sequelae of addiction
- Use of multidisciplinary teams
- Refraining from moralistic judgments

*Edlin BR, et al. Clin Infect Dis. 2005;40(suppl 5):S276-S285. *

## Pitfalls in Back Pain Care

- Many patients seek health care for simple back pain
- Important to maintain proper vigilance for potentially “dangerous” causes of low back pain without performing unnecessary diagnostic work-ups
- Physicians faced with decisions of diagnostic triage of low back pain in the acute setting can follow useful, highly relevant algorithms available in the Clinical Practice Guideline on “Acute Low Back Problems in Adults”

*See Notes for References.*

## Take-Home Points

- Patients with mechanical low back pain and without red flags do not require extensive diagnostic work-up
- Patients with a personal history of cancer, noted red flags on history, an ESR > 50, or with a worrisome lesion on lumbar radiographs should receive further evaluation, typically MRI
- Fever, injection drug use, urinary tract infection, or recent skin infection are red flags for infection in patients presenting with low back pain

## Take-Home Points (2)

- Back pain is a common complaint in infective endocarditis, occurring in up to 43% of cases
- Presenting a myriad of challenges for health care providers, injection drug users are at high risk for serious infections; therefore, extra care in the evaluation of their complaints is often warranted