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Back pain is a relatively benign presentation that can portend a very sinister diagnosis… occasionally. The real question is who gets further imaging and investigations – CT scanning everyone will cause more cancer than actually finding a surgical/ID diagnosis, and conditions that require MRIs are generally not emergencies (and are impractical to organize in the ED timeframe). This article is written in the negative to exclude back pain red flags for patients presenting with a gestalt for boring benign lumbago (does not apply to everyone with back pain!). It is designed to be interpreted with common sense (f*#! AI) and is a little bit more in-depth than the Med School TUNA FISH mnemonic.

Step 1: Exclude an actual cord emergency
There is no evidence of cord compromise on assessment:
– Spinal stenosis is unlikely as there is no progressive weakness on standing, and pain/weakness is not exacerbated by extension.
– Dorsal column intact (prioprioception to ankles/toes tested)
– Corticospinal tract intact (equal power on L2 HE / L3 KE / L4 ADF / L5 GTE / S1 APF)
– Spinothalamic tract intact (no spinal level to cold sensation tested with ice)
– Excluding Cauda Equina and Conus Medullaris syndromes: No hyper/hyporeflexia to the lower limbs (knee/ankle reflexes tested). No ankle clonus. No bowel/bladder dysfucntion (incontinence or new retention). Normal voluntary anal contraction (note DRE not performed as there is no other neurology). No loss of sacral dermatomes / saddle analgesia.

Tested with ice, sensation is present to:
– perianal area (S3-S5)
– back of thigh (S2) and Leg (S1)
– medial (L4) and lateral (L5) leg
– anterior groin / thigh (L1-L3)
There is equal power on:
– Hip Flexion (L2)
– Knee Extensors (L3)
– Ankle Dorxiflesion (L4)
– Great toe extensors (L5)
– Ankle plantar flexion (S1)
– Plantars downgoing. (S1)
Reflexes Intact:
– Normal ankle deep tendon reflex. (sciatic/tibial S1/S2)
– Normal patella reflex (femoral n. L2/L3/L4)
– Normal voluntary anal contraction (S2-4)
^if any of the above is abnormal, perform a DRE for anal tone.

Step 2: Focused History and Assessment
– There is no suspicion of occult infection or malignancy. Patient is afebrile, with a WCC and CRP that is not significantly elevated. There is no history of immunosuppression or active chemotherapy. There is no history of malignancy. There are no features of new malignancy such as weight loss / anorexia / night sweats / night pain waking patient up from sleep.
– Patient is stable without any recorded episodes of hypotension to suggest a sinister acute vascular syndrome (aortic dissection). The pain is also not described as tearing. The pain was not sudden and unprovoked at rest (ddx ACS / dissection / AAA rupture). There is no history of vascular repair or known AAA.
– There is no high risk of bleeding to raise suspicion of an epidural/retroperitoneal haematoma. Patient reports no history of haemophilia, and is not on any antiplatelets or anticoagulants.
– The pain is not localized to the thoracic spine
– The back pain did not start after an episode of high energy trauma.
– There is no pint tenderness to suggest a focal lesion (occult fracture / epidural abscess / OM / acute disc bulge)

Step 3: Education and Safety Netting
– The duration of the pain (<6 weeks) also does not warrant further imaging at present (may require in future). Patient has been advised the low back pain exacerbated by lifting/bending will likely improve over the coming weeks. If it is constant and increasing despite simple analgesia, a workup of occult malignancy/infection may be indicated.
– Should patient represent to a healthcare provider, a repeat WCC CRP and CT Scan (+/- MRI) should be considered. Patient has been advised of the above and will also seek urgent review if a fever develops or the pain worsens.

Addendum: Consider focused assessments / statement in specific situations.

Under 20yo
– patient is not pregnant (ddx placental abruption).
– No atypical kyphosis to suggest Scheuermann’s Disease
– No features of juvenile ankylosing spondylosis on assessment: other joints (toes/ankles/knees/ribs/upper spine/shoulders/neck) not involved. Back pain not worse at night/early morning. No stiffness after inactivity. No SOB. No anorexia / fever / fatigue.

Over 55yo
– Out of an abundance of caution, an ECG and troponin (performed over 4 hours from onset of pain) has been performed to exclude a myocardial infarct.
– A CT Scan to exclude occult fracture (risk factor: age) was performed given the history of minor trauma.

Useful for re-presenting patients:
Screening for risk factors to recovery from musculoskeletal back pain.
– No reason for having poor coping skills (eg intellectual disability / chronic brain failure).
– No hx depression / anxiety / MH dx.
– No acute social/emotional stressors
– No hx occupational risks/strain
– No current illicit drug use and or alcohol misuse
– No current insurance claim in progress (includes Workcover / TAC – Consider MRI.)

Patient has benign sciatica (radicular nerve pain), evidenced by:
– Pain shooting down the thigh/leg following the PLACEHOLDER dermatome.
– Trigger point to the gluteal region
– Positive straight leg raise test
– Note no evidence of cauda equina (see assessment above)
– Emergent neurosurgical referral is not indicated as:
— patient is ambulant (can heel walk / no foot drop) without significant weakness.
— There is no bilateral weakness or numbness to suggest acute cord compression