325 Radiculopathy MYOTOMES (CONT’D) Root L5 S1 S2,3,4 Muscles Extensor hallucis longus (big toe extension), tibialis posterior (planterflexion and eversion), gluteus medius (hip abduction) Gluteus maximus (hip extension), gastrocnemius, soleus, peroneus longus (plantar flexors, eversion) Bowel, bladder, sexual organs, anal other pelvic muscles BRACHIAL PLEXUS Nerve Dorsal scapular Long thoracic Suprascapular Lateral anterior thoracic Medial anterior thoracic Subscapular Thoracodorsal Axillary Musculo cutaneous Median Radial Ulnar Root/origin C5/root level C567/root C56 Upper trunk C67 Upper, middle trunk C8 Lower trunk C56 Posterior cord C78 Posterior cord C5 Posterior cord C56 Lateral cord C567T1 Anterior cord C678 Posterior cord C8T1 Lateral cord Muscle function Rhomboids (retracts scapula) Serratus anterior (scapula abduction) Supraspinatus (arm abduction) Infraspinatus (arm external rotation) Pectoralis major (arm adduction, internal rotation) Pectoralis major (arm adduction, int rotation) Pectoralis minor (protracts scapula) Subscapularis (arm adduction) Teres major (arm extension, ext rotation) Latissimus dorsi (arm extension, adduction, internal rotation) Deltoid (arm abduction) Teres minor (arm external rotation) Biceps (forearm flexion) Brachioradialis (supination) See tables below See tables below See tables below MUSCLE NERVE FUNCTION CORRELATION Muscle Tibialis anterior Tibialis posterior Peroneus longus Peroneus brevis Innervation Deep peroneal n (L4L5S1) Tibial n (L4L5) Superficial peroneal n (L5S1) Superficial peroneal n (L5S1) Function Inversion, dorsiflexion Inversion, planterflexion Eversion, planterflexion Eversion, planterflexion DIFFERENTIATING BETWEEN NERVE ROOT AND PERIPHERAL NERVE LESIONS C6 VS MEDIAN NERVE LESION C6 Sensory Palmer surface of 1st 2nd fingers Lateral surface of arm/forearm Motor Biceps, brachioradialis, forearm pronators Wrist extensors Reflex Biceps, brachioradialis Median nerve (C6 T1) Palmer surface of 1st lateral 4th fingers wLOAFw Lateral lumbricals (1st and 2nd), Opponens pollicis (opposition), Abductor pollicis brevis (abduction of thumb), Flexor pollicis brevis (flexion of thumb/fingers) None 326 Radiculopathy DIFFERENTIATING BETWEEN NERVE ROOT AND PERIPHERAL NERVE LESIONS (CONT’D) C7 VS RADIAL NERVE LESION C7 Sensory Palmer surface of 3rd finger Dorsal surface of arm/forearm Motor Triceps Wrist extensors and flexors Finger and thumb extensors Reflex Triceps C8/T1 VS ULNAR NERVE LESION C8/T1 Sensory Palmar and dorsal surface of 4th and 5th fingers Medial surface of arm and forearm Motor Lumbricals (3rd, 4th), interossei 5th finger opposition, abduction, and flexion Thumb adductor LOAF muscles (median n.) Wrist flexion and abduction Triceps (radial n.) Reflex Triceps L3 VS OBTURATOR NERVE LESION L3 Sensory Thigh/knee and medial leg Motor Hip adduction Knee extension Reflex Knee, adductor L4 VS FEMORAL NERVE LESION L4 Sensory Lateral leg to medial malleolus Motor Knee extension Dorsiflexion (deep peroneal n.) Reflex Knee L5 VS PERONEAL NERVE LESION L5 Sensory Lateral leg, dorsal foot including first web space Motor Dorsiflexion and eversion Great toe dorsiflexion Knee flexion Planterflexion and inversion (tibial n.) Hip abduction (sup gluteal n.) Radial nerve (C5 T1) Dorsal surface of 1st lateral 4st fingers Dorsal surface of arm/forearm Triceps (normal if high lesion) Wrist extensors Brachioradialis Fingers and thumb extensors Triceps (normal unless high lesion) Brachioradialis Ulnar nerve (C8T1) Palmar and sometimes dorsal surface of 4th and 5th fingers Lumbricals (3rd, 4th), interossei 5th finger opposition, abduction and flexion Thumb adductor None Obturator nerve (L34) Medial thigh/knee Hip adduction Adductor Femoral nerve (L234) Lateral leg to medial malleolus Knee extension Hip flexion Knee Common peroneal n (L45S1) Lateral leg, dorsal foot including first web space Dorsiflexion (deep peroneal n.) and eversion (superficial peroneal n.) Great toe dorsiflexion 327 Peripheral Neuropathy DIFFERENTIATING BETWEEN NERVE ROOT AND PERIPHERAL NERVE LESIONS (CONT’D) S1 VS SCIATIC NERVE LESION S1 Sciatic nerve (L4 S3) Lower leg and foot Sensory Lateral foot including 5th toe Motor Planterflexion Planterflexion and eversion, dorsiflexion and Toe flexion inversion Hip abduction and extension Knee flexion Reflex Ankle Ankle For the nerve root/peripheral nerve lesions tables above, BOLD=highlights differences between nerve root and peripheral nerve lesions REFLEXES complete peripheral nerve lesions will lead to complete areflexia, while complete nerve root lesions will only lead to partial reduction of reflexes SPECIFIC CONSIDERATIONS DISTINGUISHING FEATURES BETWEEN MEDIAN NERVE LESION, ULNAR NERVE LESION, AND T1 RADICULOPATHY these lesions can be differen tiated by testing two muscles: abductor pollicis brevis is supplied by the median nerve (i.e supinate hand, SPECIFIC CONSIDERATIONS (CONT’D) point thumb toward ceiling, test power by pushing thumb down), while first dorsal interosseous is sup plied by the ulnar nerve (i.e test power of index finger abduction) Lesion Abductor pollicis brevis 1st dorsal interosseous T1 radiculopathy Weak Weak Median nerve Weak Spared Ulnar nerve Spared Weak NOTE: may also test little finger abduction (abductor minimi digiti) to assess ulnar nerve integrity Peripheral Neuropathy DIFFERENTIAL DIAGNOSIS MONONEUROPATHY compression, mononeuritis MONONEURITIS MULTIPLEX vasculitis, diabetes POLYNEUROPATHY AXONAL INJURY carcinoma, lymphoma, MGUS IgA, IgG, IgM INFECTIOUS sepsis, HIV, Lyme METABOLIC diabetes, uremia VITAMIN DEFICIENCY malabsorption DRUGS cisplatin, taxanes, vincristine, isonia zid, nucleoside analogue DEMYELINATING Guillain Barre, neoplastic (car cinoma, lymphoma, MGUS IgM), drugs (taxanes), chronic inflammatory demyelinating polyradi culoneuropathy NEOPLASTIC CLINICAL FEATURES DIFFERENTIATING SITE OF MEDIAN NERVE INJURY if lesion at carpal tunnel, LOAF muscles affected If lesion at or above the elbow, there may be lateral forearm wasting and the index finger held in extension (Benediction sign) CLINICAL FEATURES (CONT’D) DIFFERENTIATING SITE OF ULNAR NERVE INJURY low lesion (below the wrist) characterized by marked hand clawing (because of unopposed flexor digitorum profundus flexion of DIPs) High lesions have subtle clawing, termed ulnar paradox INVESTIGATIONS BASIC CBCD, lytes, urea, Cr, glucose, ESR, serum protein electrophoresis, vitamin B12, ANA, TSH, urinalysis SPECIAL EMG AND NERVE CONDUCTION STUDY LABS / NERVE MUSCLE BIOPSY LUMBAR PUNCTURE MANAGEMENT TREAT UNDERLYING CAUSE diabetic (glucose control), lymphoma/myeloma (chemotherapy) SYMPTOM MANAGEMENT tricyclic antidepres sants (desipramine 10 50 mg qhs), gabapentin (300 mg PO daily Â1 day, then 300 mg PO BID 328 Peripheral Neuropathy MANAGEMENT (CONT’D) SPECIFIC ENTITIES (CONT’D) Â1 day, then 300 mg PO TID, max 1800 mg/day), anticonvulsants (topiramate, carbamazepine) SPECIFIC ENTITIES CARPEL TUNNEL SYNDROME PATHOPHYSIOLOGY median nerve entrapment syndrome ASSOCIATIONS repetitive use, acromegaly, amyloido sis, hypothyroidism, rheumatoid arthritis, diabetes mellitus, pregnancy, and mucopolysaccharidosis Bilateral disease suggests a systemic condition nerve conduction studies (sens 49 84%, spc 95 99%) should be done if inade quate response to conservative therapy (changes in the workplace, nighttime neutral splints), thenar atrophy, or if the diagnosis is unclear TREATMENTS activity modifications, wrist splint ing, NSAIDs, corticosteroid injections (success 49 81%, recurrence 50 86%), carpel tunnel release (success 75 99%) DIAGNOSIS SPECIFIC ENTITIES (CONT’D) RATIONAL CLINICAL EXAMINATION SERIES: DOES THIS PATIENT HAVE CARPEL TUNNEL SYNDROME? KATZ HAND DIAGRAM classic (tingling of at least two of digits The classic pattern permits symptoms in the 4th and 5th digits, wrist pain, and radiation of pain to wrist, but not symptoms on the palm/dorsum of the hand), probable (same symptom pattern as classic, except palmer symptoms are allowed unless confined solely to the ulnar aspect), possible, unlikely LR+ LR History Classic/probable Katz diagram 2.4 0.5 Age >40 1.3 0.5 Nocturnal paresthesia 1.2 0.7 Bilateral symptoms 1.4 0.7 Physical Hypalgesia (# pain sensation) in the median nerve territory 3.1 0.7 Abnormal vibration 1.6 0.8 Weak thumb abduction strength 1.8 0.5 Thenar atrophy 1.6 1.0 Square wrist sign 2.7 0.5 Closed fist sign 7.3 0.4 Flick sign 21.4 0.1 Tinel’s sign 1.4 0.8 Phalen’s sign 1.3 0.7 APPROACH ‘‘Katz hand symptom diagrams, hypalgesia, and thumb abduction strength testing are helpful in establishing diagnosis of carpel tunnel syndrome’’ JAMA 2000 283:23 SPECIFIC ENTITIES (CONT’D) SPECIFIC ENTITIES (CONT’D) AUTONOMIC NEUROPATHY CAUSES autonomic failure may be secondary to peripheral neuropathy associated with diabetes, cancer (paraneoplastic), amyloidosis, cachexia, HIV, Guillain Barre syndrome, Lambert Eaton syn drome, other inflammatory/infectious conditions, or due to primary disorders such as Parkinson’s disease, Shy Drager syndrome (multiple system atrophy with autonomic failure), Lewy body dementia, and multiple sclerosis Vitals Skin Sympathetic dysfunction Orthostatic hypotension Warm and moist Parasympathetic dysfunction Tachycardia Cool and dry H&N Heart Sympathetic dysfunction Horner’s No respiratory variation GI/GU MSK, gait Parasympathetic dysfunction Dry eyes + mouth Dilated pupil Constipation Distended bladder Impotence Postural instability Related Topics Diabetic neuropathy (p 337) Radiculopathy (p 323) 329 Peripheral Neuropathy SPECIFIC ENTITIES GUILLAIN BARRE SYNDROME (GBS) PATHOPHYSIOLOGY precipitants (Campylobacter jejuni, pper respiratory tract infections, possibly flu shots) ! acute inflammatory demyelinating polyradiculoneuropathy weeks later ! reach nadir of symptoms weeks (25% require mechanical ventilation) ! recovery weeks to months CLINICAL FEATURES fine paresthesias in toes and fingertips ! weakness in lower/upper extremities ! potential autonomic dysfunction (50%), cranial nerves, respiratory muscle involvement Areflexia Low/mid back pain common SUBTYPES four subtypes include demyelinating (acute inflammatory demyelinating polyradi culoneuropathy), axonal motor (acute motor axonal SPECIFIC ENTITIES (CONT’D) neuropathy), axonal motor and sensory (acute motor and sensory axonal neuropathy), and Miller Fischer syndrome (ophthalmoplegia, ataxia, areflexia) DIAGNOSIS EMG (demyelinating neuropathy), lumbar puncture (albuminocytologic dissociation, " protein), PFT TREATMENTS IVIG 0.5 g/kg IV daily, plasma exchange ICU admission with respiratory support if FVC