PEREHHRAL NERVOUS SYSTEM Dr Sadik AL-Ghazzawi MRCP,FRCP UK

Concepts 1• Peripheral nerve diseases are diseases of the lower motor neuron system and sensory afferents. 2• The lower motor neuron system starts at the anterior horn cells in the spinal cord, or the cranial nerve nuclei in the brain stem, and includes whatever is distal to that.

Concepts cont 3-Diseases of peripheral nervous system share common symptoms and signs, but with different distributions depending on which area are involved. 4-• Symptoms can be motor, sensory or autonomic (one or a combination). 5• Signs include some of the above, along with the known signs of lower motor neuron disease: reduced reflexes, atrophy, fasciculation, and flaccidity.

Concepts cont 6-Not every patient with a peripheral nerve disease should have all the symptoms and signs. 7-• The combination of which symptoms patient has depends on the disease and its distribution, for example some have more sensory than motor symptoms, others have the opposite.

1• Spinal nerve roots – Radiculopathy 2• Plexus – Plexopathy Anatomical Areas Involved 1• Spinal nerve roots – Radiculopathy 2• Plexus – Plexopathy 3• Peripheral nerves: a– Single nerve - Mononeuropathy b– Multiple nerves – Polyneuropathy c– Multiple nerves (patchy) – Mononeuropathy multiplex

Types of Peripheral Nerve Disease 1• Radiculopathy 2• Plexopathy 3• Mononeuropathy 4• Polyneuropathy ( or sometimes referred to as peripheral neuropathy) 5• Mononeuropathy multiplex

Radiculopathy • Usually cervical or lumbosacral • Symptoms: 1– Pain, radicular. Starts in the neck radiating to the upper extremity if cervical radiculopathy (Brachialgia). Or starts in the lower back and radiates to the lower extremity if lumbosacral (Sciatica). 2– Other sensory symptoms in the involved distribution. 3– Motor symptoms: Weakness, possibly atrophy in the involved distribution.

Radiculopathy • Causes can be compressive or non compressive. 1– Compressive: Disc disease (most common) 2– Non compressive: Diabetes, Herpes Zoster 3-• Diagnosis: Clinical, MRI of the involved area, electromyography and nerve conduction studies (EMG/NCS). 4-• Treatment according to etiology

Plexopathy 1• Usually the brachial plexus or the lumbosacral plexus. 2• Symptoms and signs of lower motor neuron disease in the distribution of the involved plexus (similar to radiculopathy). 3• Causes: compressive or non compressive

Plexopathy • Compressive causes: – a-usually tumor invasion, breast and lung in brachial plexus cases, gynecological and colorectal tumors in lumbosacral plexus cases. b– Compression by abscess, aneurysm, hematoma. c– Trauma. • Non compressive: – Diabetes, Infections, radiation induced plexopathy. • Diagnosis: Clinical, MRI, EMG/NCS • Treatment according to etiology

Mononeuropathy 1• Single nerve involved, with signs and symptoms depending on which nerve is involved. 2• Most common: a– Upper extremity: median nerve (carpal tunnel syndrome), ulnar nerve, radial nerve. b– Lower extremity: Peroneal nerve

Mononeuropathy • Carpal tunnel syndrome 1– Median nerve compression at the wrist 2– Risk factors: Thyroid dysfunction, Rheumatoid arthritis, Pregnancy, Diabetes, Occupation. 3– Symptoms: mostly and initially sensory: palmar pain, numbness and tingling in 3.5 lateral fingers, but also weakness in median innervated muscle is possible (FP, AP, OP), and possibly atrophy. – Diagnosis: clinical, EMG/NCS – Treatment: conservative, surgical

Mononeuropathy • Ulnar neuropathy 1– Usually compression at the elbow (ulnar groove behind the medial epicondyle). 2– Sensory symptoms in the medial 1.5 fingers. 3– Motor symptoms in ulnar innervated muscles in the hand. – Diagnosis: clinical, EMG/NCS. – Treatment: conservative, surgical

Mononeuropathy • Radial Neuropathy 1– Usually secondary to compression at the spiral groove of the humerous (Saturday night palsy). 2– Symptoms are more motor than sensory: weakness of wrist dorsiflexors resulting in wrist drop. – Diagnosis: clinical, EMG/NCS. – Treatment: usually self limiting, with improvement within two months, helped by physiotherapy. 3– If the compression is caused by a mass, it has to be removed.

Mononeuropathy Peroneal Neuropathy 1– Compression, usually at the fibular head. 2– Symptoms are mostly motor, with weakness of foot dorsiflexors (foot drop). 3– Sensory changes in peroneal distribution. 3– Sudden severe loss of weight is a risk factor, frequent leg crossing especially in very thin people. 4– Can be caused by a mass like a tumor. – Diagnosis is clinical, EMG/NCS, sometimes imaging if a mass is suspected. – Treatment: usually self limiting with physiotherapy and AFO’s. If mass, it has to be removed.

Polyneuropathy The classical polyneuropathy or peripheral neuropathy: 1–Length dependent peripheral nerve involvement, starts distally and progresses proximally, bilaterally. 2– Symptoms: sensory and motor, sometimes autonomic. – Causes: 3• Systemic diseases like DM (most common), chronic hepatic or renal failure, thyroid disease, infections..etc. Autoimmune. 3• Medications like chemotherapy. 4• Toxins like alcohol. 5• Nutritional deficiencies like B12, folate. 5• Hereditary causes: CMT – Diagnosis: clinical, EMG/NCS. – Treatment: according to etiology, treat neuropathic pain

DPolyneuropathy Acute Inflammatory emyelinating Polyradiculoneuropathy (AIDP) = G.B.S. 1– Prodrome of URTI or GI infection. 2– Progressive weakness in the lower and upper extremities (usually peaks at two weeks, and by definition in less than 4 weeks). Reduced or absent reflexes. 3– Could involve cranial and respiratory muscles. 4– Admit to ICU, follow up respiratory status by PFT’s (FVC), not by ABG’s. – Diagnosis: clinical, EMG/NCS, CSF. – Treatment: Plasma exchange, IVIg.

Polyneuropathy • Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP). 1– Similar to AIDP, but progression of symptoms is by definition more than 8 weeks. 2– Motor and sensory symptoms with reduced reflexes. 3– Chronic monophasic or relapsing patterns. – Diagnosis: clinical, EMG/NCS – Treatment: IVIg, Steroids, Steroid sparing agents.

Mononeuropathy Multiplex 1• More than one nerve is involved, but not necessarily contiguous. (Patchy). 2• Different nerves involved at different times. 3• Most common etiology is Vasculitis, but can also be caused by diabetes and other etiologies. 3• Symptoms are sensory and motor, pain can be a prominent feature. • Treat the etiology, treat neuropathic pain

Clinical Pearl 1• beware, different types of peripheral nerve disease are in the differential diagnosis of each other, particularly mononeuropathy and radiculopathy because both are common, and some times plexopathy. 2• So, in the differential diagnosis of mononeuropathy is radiculopathy involving the nerve roots supplying that particular nerve, examples: a– Peroneal neuropathy and L5 radiculopathy b– CTS and cervical radiculopathy (C6,7,8) c– Radial neuropathy and cervical radiculopathy (C6,7) d– Ulnar neuropathy and cervical radiculopathy (C8)