Template:Lower Limb Pain Neurogenic and Referred DDX

• Systemic Conditions
  • Metabolic Neuropathy
    • Diabetes Mellitus with distal symmetrical polyneuropathy
    • Diabetes Mellitus of other subtypes - proximal diabetes, truncal, cranial, median and ulnar neuropathies
    • Diabetes Mellitus with autonomic neuropathy
    • Diabetic amyotrophy - Probably a vasculitis aetiology with ischaemia followed by axonal degeneration and demyelination. Characterised by unilateral weakness, wasting, and pain, commonly in the quadriceps, then spreading later to the contralateral side asymmetrically.
  • Vasculitic Neuropathy - vasculitis of the small and medium-sized vessels in the peripheral nervous system.
    • Primary vasculitides: Churg-Strauss syndrome, microscopic polyangiitis, classic polyarteritis nodosa and Wegener granulomatosis
    • Secondary vasculitides: A complication of connective tissue disease (systemic lupus erythematosus, rheumatoid arthritis and Sjögren syndrome), infection (hepatitis B and C, human immunodeficiency virus, Lyme disease, cytomegalovirus, Herpes zoster virus and various bacterial infections), medication (sulphonamides, other antibiotics and anti-viral agents) and paraneoplastic vasculitis
  • Paraneoplastic peripheral neuropathy - In addition to local effects and paraneoplastic vasculitis, can also get sensorimotor paraneoplastic neuropathy. May have anti-neuronal antibodies and EMG findings.
• Brain
  • Multiple sclerosis
  • Parkinson’s disease
  • Motor neurone disease
  • Post-stroke pain in lenticulo-capsular haemorrhages
  • Space-occupying lesions.
• Spinal Cord
  • Multiple sclerosis
  • Motor neurone disease
  • Syringomyelia
  • Transverse myelitis
  • Posterior or anterolateral situated space-occupying lesion (e.g. disc herniation, tumour, abscess, haematoma)
• Cervical and Thoracic Spinal Canal
  • Any posterior or anterolateral space-occupying lesion (e.g. abscess, tumour, haematoma)
• Conus Medullaris
  • Disc pathology - parasagittal, as nerve roots are lateral to spinal cord
  • Tumours (soft tissue, intradural, extradural, bone, metastases)
• Lumbar Spine Canal
  • Interspinous bursa (kissing spines, Baastrup's disease)
  • Facet joint (OA, hypertrophy, cyst, rotational instability)
  • Degenerative spondylolisthesis - the vertebral body and inferior facet joints displace anteriorly, compressing the dural sac and nerve roots against the posterior aspect of the caudal vertebral body - May only be appreciated on flexion/extension radiographs
  • Space-occupying lesion (disc pathology, haematoma, tumours)
• Lumbar Nerve Root Canal
  • Intervertebral disc herniation
  • Facet joint - superior articular process moves upwards and forwards impinging nerve root against pedicle or posterior vertebral body in presence of loss of disc height.
  • Osteophytes from superior facet joint or posterior inferior vertebral endplate impinging nerve root
  • Anterior subluxation of vertebra in degenerative spondylolisthesis with hypertrophy of superior facet joint extending into canal.
  • Any nerve root lesion (e.g. cyst, tumour)
  • Isthmic spondylolisthesis, with nerve root narrowing due to combination of disc bulging and pars interarticularis hypertrophy
  • Pedicle moving down compressing nerve root in complete loss of disc height in combination with spondylolisthesis and degenerative scoliosis.
• Lumbar Extraforaminal Area
  • Far lateral disc herniation compression of exiting nerve root
  • Corporotransverse ligament nerve entrapment in rotatory subluxation with complete disc space narrowing - The corporotransverse ligament extends from the vertebral body to the transverse process of the same vertebra.
  • Psoas pathology (abscess, haematoma, tumour)
  • Spondylolisthesis with severe disc space narrowing causing impingement of the L5 nerve root between the L5 transverse process and the ala of the sacrum
  • Degenerative scoliosis with tilting of L5 and depression of the concave L5 transverse process causing impingement of the L5 nerve root
• Pelvis
  • Pelvic malalignment
  • L5 transitional vertebra pseudoarthrosis with a large osteophyte compressing L5 nerve root
  • Lumbosacral ligament ossification in combination with inferior L5 vertebral body osteophytes impinging L5 nerve root
  • Stress fracture of sacrum or pubic rami
  • Degenerative sacroiliitis with an osteophyte extending anteriorly compressing a nerve root
  • Sacroiliitis of any type
  • Tumours of bone and soft tissue
  • Lumbosacral radiculoplexus neuropathy - presents with asymmetrical lower limb pain, weakness, atrophy and paraesthesia. It can be caused by diabetic lumbosacral radiculoplexus neuropathy, non-diabetic lumbosacral radiculoplexus neuropathy, chronic inflammatory demyelinating polyneuropathy, connective tissue disease, Lyme disease, sarcoidosis, HIV and cytomegalovirusrelated polyradiculopathy.
  • Piriformis muscle syndrome with compression of sciatic nerve
  • Superior gluteal nerve entrapment syndrome - The clinical diagnosis triad of buttock pain, weakness of hip, abduction and marked tenderness on deep palpation in the region just lateral to the greater schiadic notch
• Lower Extremity
  • Greater trochanteric pain syndrome (Greater trochanteric bursitis and gluteus medius tendinopathy)
  • Stress fracture of femoral neck, intertrochanteric area, and proximal femur
  • Iliopsoas and iliopectineal bursitis and synovitis
  • Non-traumatic focal mononeuropathies
  • Myositis and myopathy
  • Sports related leg pain
    • Medial tibial stress syndrome
    • Chronic exertional compartment syndrome
    • Tendinopathies
    • Nerve entrapment syndromes
    • Vascular syndromes
    • Myopathies
  • CRPS
  • Restless legs syndrome
  • Painful legs and moving toes syndrome
  • Nerve entrapment syndromes
    • Iliohypogastric (T12, L1), Ilioinguinal (T12, L1), Genitofemoral (L1, L2) - Usually after lower abdominal surgery
    • Lateral femoral cutaneous nerve (L2-4)
    • Femoral nerve (L2-4) entrapment below the inguinal ligament
    • Pelvic procedures with acutely flexed, abducted, and externally rotated positioning
    • Saphenous nerve (L3-4) entrapment as it pierces the roof of the adductor canal, by femoral vessels, pes anserine bursitis, varicose vein operations, and medial knee surgery
    • Common peroneal neuropathy
    • Deep peroneal nerve
    • Superficial peroneal nerve
    • Proximal tibial entrapment neuropathy
    • Distal tibial entrapment
    • Sural nerve
    • Medial plantar nerve neuropathy
    • Inferior calcaneal nerve
    • Interdigital neuropathy
    • Medial plantar proper digital neuropathy (Joplin's neuroma)