EPISODE 26 - EMERGENCY CAUSES OF LOW - EMERGENCYMEDICINECASES.COM

EPISODE 26: EMERGENCY CAUSES OF LOW BACK PAIN WITH DR. BRIAN STEINHART & DR. WALTER HIMMEL General approach to low back pain / clinical history: Main categories of patients with 5) vascular - leaking/ruptured AAA, 5) History of trauma or coagulopathy, acute back pain are nonspecific retroperitoneal bleed, and spinal 6) Cauda equina/cord compression lumbosacral pain/strain, radicular pain or epidural hematoma. symptoms (bowel, bladder or erectile , and emergent pathologies. Red flags for serious pathology: dysfunction, saddle paresthesia, The 5 emergent pathologies are: 1) Age <18 or >60, progressive bilateral leg weakness) 1) infection such as , or 2) Symptoms or history of cancer, Pearls: *Constant, unrelenting, severe spinal epidural abscess, pain, especially if it is worse lying down 2) fracture (trauma or pathologic), 3) Immunodeficiency (including is a red flag for infection or cancer.* diabetes, IVDU), previous spinal 3) disk herniation & cord compression, Discogenic pain is worse with flexion, interventions, or recent infections, and spain from spondylolysis is worse 4) cancer in spine causing cord 4) Pain not resolved by analgesia, with extension. compression,

A challenge in the ED? SPINAL EPIDURAL ABSCESS: PEARLS AND PITFALLS Upwards of 90% of low back pain Spinal epidural abscess is rare (1–2/10,000 of hospitalized presentations in the ED are due patients). The classic triad of fever, back pain, and neurologic to benign causes. However there deficit is present in only 15% of patients, depending on stage of are several important life/limb- disease. Spinal epidural abscess is often missed on first ED visit. threatening diagnoses we must consider in the low Fever is present in only 50% of patients, and neuro deficits start back pain patient, and most of these diagnoses are very subtly. Risk Factors: Diabetes, IVDU, indwelling easy to miss. Furthermore, lumbosacral sprain is catheters, spinal interventions, infections elsewhere (especially often associated with significant morbidity, and ED skin), immune suppression (i.e. HIV), and “repeat ED visits.” docs should provide specific education and evidence based treatments (see page 3). Physical exam, imaging tests, & pearls for diagnosis

Physical Exam Maneuvers: EPIDURAL ABSCESS surgical decompression as quickly as possible. 1) Percuss the spinous processes Suspect epidural abscess in a for tenderness, a red flag for patient with: Start antibiotics while awaiting infection and fracture, definitive diagnosis: include a) back pain or neurologic deficits appropriate coverage for MSSA and 2) Test for saddle anesthesia and fever, or (sensation changes may be subtle MRSA, and cover gram negatives. b) back pain in an immune- and subjective), (1) compromised patient, or 3) DRE looking for tone/sensation, c) patient with a recent spinal CAUDA EQUINA 4) Look for fever, or signs of procedure and either of the above. SYNDROME infection, CRP and ESR may help, Definition: 5) Check carefully for bilateral, or depending on the clinical suspicion 1) urinary retention multi-level neurologic findings in for epidural abscess. If suspicion is or rectal lower extremities, and assess for low after the history and physical, dysfunction or gait disturbances. low ESR and CRP levels support not sexual dysfunction Straight leg raise (SLR): doing an MRI, and discharging the (or all of the above) patient home with close follow up. If Non-specific test, only positive pain PLUS is produced distal to the knee there is a high index of suspicion, an 2) saddle or anal anesthesia and/or between 30–70°. Pain with MRI is indicated *regardless of CRP hypoesthesia (1). contralateral SLR is more specific and ESR*. for siatica. Remember the normal ESR Urinary retention is non-specific for compression, but Slump test: Helps discriminate cutoff is: (age+10)/2. sensitive. Post void residual <100cc radicular pain from hamstring pain. In one study of epidural abscesses, has a very high NPV to rule out With thoracic and cervical flexion, 98% had ESR >20, and most were . and knee in extension, dorsiflex the much higher (>60) (2). foot and flex the neck to determine When are steroids indicated: Is there any role for CT if pain is produced, with release of Evidence supports dexamethasone scan? CT cannot rule out epidural cervical flexion to see if symptoms for metastasis to spine causing abscess because it does not show improve (image below). cauda equina. There is no indication the epidural space, spinal cord, or for IV steroids for patients with spinal nerves. CT can lead to the cord compression by other causes. pitfall diagnosis of osteomyelitis, missing coexistent abscess (and the urgent indication for surgery). COGNITIVE FORCING Remember if the suspicion is STRATEGY TO REMEMBER epidural abscess, the entire SERIOUS PATHOLOGIES: spine must be imaged by Considering renal colic? MRI. Spinal cord obstruction and think about AAA! paralysis can happen very quickly Abdomen exam and ED Considering pyelonephritis? from epidural abscess, so there ultrasound: look for AAA and think about spinal infection! bladder distention post-void. needs to be definitive imaging and SPINAL VASCULAR LUMBOSACRAL / METASTASES EMERGENCIES MECHANICAL PAIN Known cancer + new back pain = spinal Spinal Epidural Hematoma Making the Diagnosis: metastases until proven otherwise! Spinal epidural hematoma may present Lumbosacral sprain or mechanical Time is Limbs: Spinal metastases are after spinal procedures (epidural back pain is a diagnosis of exclusion, one of the most common causes of cord anesthesia), but can be spontaneous, made only after carefully ruling out compression. Pre-treatment neuro status especially in anti-coagulated patients. serious causes of low back pain. predicts outcome for this emergency. Neurologic findings depend on the Management: extent of — Workup: from isolated pain to flaccid paralysis. 1) Education This is a mechanical 1)X-ray to look for compression #, soft Suspect this emergency in patients with problem requiring a mechanical tissue changes, blastic/lytic lesions, a history of trauma and neurologic solution - and pain medications pedicle erosion (see image below) findings who are coagulopathic. alone will not fix the problem. 2)Consider testing ESR and CRP, and Patients need to play an active role calcium profile if signs are consistent in their recovery, and prolonged with hypercalcemia (e.g. polyurea) Abdominal Aortic Aneurysm bed rest will worsen the problem. 2) Reassurance 90% get better 3)Give dexamethasone as soon as Typical manifestations of rupture of a mets are suspected (at least 10mg IV) AAA is abdominal or back pain, with a with time (over weeks) if the patient has neurologic pulsatile mass in a patient with a history 3) Symptom Management symptoms. Consider bisphosphonate* of HTN. However, symptoms may range Evidence from the Cochrane and calcitonin if patient is from dizziness, syncope, groin pain, or collaboration (4) supports heat, hypercalcemic, or if you suspect flank mass to presentation with NSAIDs, acetaminophen, massage compression # or bony metastasis. paralysis. Look for livedo reticularis and physical therapy. Muscle (atheroemboli to feet) and signs of poor 4)Get an urgent MRI if there are relaxants may be as effective as circulation in the lower extremities. symptoms of cord compression. NSAIDs, but they have significant If there are hard neurologic findings, Transient hypotension or syncope after side effects, especially in combination with opioids. MRI is needed within 24 hours. If the onset of pain is an important clue for x-ray findings are consistent with bleeding from a ruptured AAA. Patients mets, but there are no neuro findings, may present in shock, and quickly an MRI should be done within 7 days. decline. Do an ED ultrasound right away References: as an extension of the physical exam to 1) Lavy, C et al. BMJ. 2009;338:b926. *Bisphosphonates may decrease bone rule out AAA in patients with low back 2) Davis, D et al. J Neurosurg Spine. resorption in patients with metastatic pain and hypotension. disease to the bone, and relieve pain better 2011;14:765–70 than placebo. (3) 3) Armingeat, T et al. Osteoporos Int. 2006;17:1659–65. Retroperitoneal Bleed (RPB) 4) http://back.cochrane.org/our-reviews Hematogenous Patients with coagulopathies, as well as spread from patients with retroperitoneal masses or metastatic tumors, or abdominal/pelvic trauma are disease often at risk. Blood may dissect anteriorly, settles in end causing abdominal pain, or may cause arterioles in the pain to the hip, groin, or anterior thigh. pedicles. Lytic lesions there On the physical exam, look for psoas present with sign caused by retroperitoneal irritation, pedicle femoral neuropathy and hip pain, as well destruction, as Cullen’s/Turner’s signs, or bruising or visible on the swelling in the groin caused by extension lumbar spine x- of bleeding into the skin. ray as a winking owl sign (arrow) where the pedicle, or “owl eye,” is lost. SUBSCRIBE TO EMCASES