=====Neuropathies and entrapments===== ====Cranial Nerves==== ^Olfactory I |smell from mucosa of roof of nasal cavity | ^Optic II |sight - retina | ^Oculomotor III |motor to sup, inf, med recti, inf oblique, levator palpebrae superioris\\ parasymp to sphincter pupillae and ciliary M's - constriction and accommodation | ^Trochlear IV |sup oblique - inf gaze | ^Trigeminal V\\ [[wiki:neurology:trigeminalneuralgia|Trigeminal Neuralgia]] | | ^Ophthalmic Va |sensation - eyelids, scalp, nose and nasal cavity, paranasal sinuses| ^Maxillary Vb |sensation - maxillary face, upper lip, upper teeth, maxillary sinuses and palate | ^Mandibular Vc |sensation - mandibular face, lower teeth, ant 2/3 tongue\\ motor - mastication | ^Abducens VI |motor - lat rectus - lat gaze | ^Facial VII\\ [[wiki:neurology:nentrapments#bells_palsy_cn_vii|Bells palsy]]\\ [[wiki:neurology:nentrapments#ramsay_hunt_syndrome_cn_vii|Ramsay Hunt]] |motor - facial M's and middle ear\\ parasymp - salivary and lacrimal glands, glands of nose and palate\\ sensory - **taste** ant 2/3 tongue and palate | ^Vestibulocochlear VIII |Vestibular - semicircular canal sensation, saccules - position\\ Cochlear - hearing | ^Glossopharyngeal IX |Sensory - ext ear\\ Motor - stylopharyngeus (swallowing)\\ parasymp - parotid\\ Taste - post 1/3 tongue\\ sensory - parotid, carotid body/sinus | ^Vagus X |Motor - pharynx, larynx, upper 2/3 oesophagus\\ Parasymp - cardioresp, gut\\ Visceral sensory - thorax, abdomen\\ taste - epiglottis and palate\\ Sensation - ext auricle, ext auditory meatus, dura of post cranial fossa | ^Accessory XI |Motor - SCM and trapezius | ^Hypoglossal XII |Motor - tongue | ^|{{:wiki:neurology:cns.png?200|}}| ====Bells Palsy (CN VII)==== {{:wiki:neurology:bellsvstroke.jpg?300|}} *rapid (<72/24) onset of facial paralysis - may be preceded by a slight fever, pain behind the ear on the affected side, a stiff neck, and weakness and/or stiffness on one side of the face. *//**unilateral paralysis is complete vs stroke which does NOT include forehead paralysis due to crossing of innervation**// *may have loss of taste on one side of mouth, drooling, and an increased sensitivity to sound (hyperacusis) *usually results from ischemia and/or compression of CN VII *exact cause not known - viral and auto-immune frequently implicated. There appears to be an inherited tendency *usually resolves - 2/52 ***//Prednisolone//** if presents ≤72/24. No consensus on dosage but 2 possible regimens: *50 mg daily for 10/7 or *60 mg daily for 5/7 followed by a daily reduction in dose of 10 mg (for a total treatment time of 10/7) if a reducing dose is preferred. *Differential: *acoustic neuroma - due to associated compression of the neuroma on VII *Myasthenia Gravis *Ramsay-Hunt syndrome - due to Varicella zoster. Look for associated rash ===House-Brackmann score for the Facial nerve=== ^I. Normal |Normal facial function in all areas | ^II. Mild dysfunction |**Gross**\\ Slight weakness noticeable on close inspection\\ May have slight synkinesis\\ At rest, normal symmetry and tone\\ **Motion**\\ Forehead - Moderate to good function\\ Eye - Complete closure with minimal effort\\ Mouth - Slight asymmetry | ^III. Moderate dysfunction |**Gross**\\ Obvious but not disfiguring difference between sides\\ Noticeable (but not severe) synkinesis, contracture, or hemifacial spasm\\ At rest, normal symmetry and tone\\ **Motion**\\ Forehead - Slight to moderate movement\\ Eye - Complete closure with effort\\ Mouth - Slightly weak with maximum effort | ^IV. Moderately severe dysfunction |**Gross**\\ Obvious weakness and/or disfiguring asymmetry\\ At rest, normal symmetry and tone\\ **Motion**\\ Forehead - None\\ Eye - Incomplete closure\\ Mouth - Asymmetrical with maximum effort | ^V. Severe dysfunction |**Gross**\\ Only barely perceptible motion\\ At rest, asymmetry\\ **Motion**\\ Forehead - None\\ Eye - Incomplete closure\\ Mouth - Slight movement | ^VI. Total paralysis |No movement | ====Ramsay Hunt syndrome (CN VII)==== rare neurological disorder caused by varicella zoster characterized by paralysis of CN-VII with variable presentation of other findings: *erythematous & vesicular rash affecting the pinna and sometimes external auditory canal and occasionally the soft palate and pharynx. *may be associated with tinnitus and hearing loss. *Treatment with antivirals ≤72/24 + other symptomatic Rx ====Thoracic outlet Syndrome==== *Compression of the brachial plexus which can occur between the anterior and middle scalene muscles, underneath a cervical rib, beneath the pectoralis minor tendon, or by fibrous bands anywhere along the course of the plexus. *scalenus anticus syndrome: abnormal insertion of scalenus anterior onto 1st rib (commonest cause) *congenital cervical rib *bony abnormality of 1st rib or clavicle (congenital anomaly, malunited fracture, callus, Paget disease, tumour) *elongated C7 transverse process *muscle hypertrophy *fibrous bands *supraclavicular tumour or lymphadenopathy *//**Differentials**// - other causes of brachial plexopathy including trauma, mass lesions, vascular lesions, brachial plexitis, and cervical spinal cord or foraminal stenosis **subtypes:** *arterial thoracic outlet syndrome (ATOS) *neurogenic thoracic outlet syndrome (NTOS) *venous thoracic outlet syndrome (VTOS) *//neurogenic pectoralis minor Syndrome (NPMS)// *//venous pectoralis minor syndrome (VPMS)// *//arterial pectoralis minor syndrome (APMS)// **Neurogenic TOS** (95% of all TOS) presents with pain, weakness, numbness and tingling in the hand and arm. *neck pain and headache in the back of the head are common. *usually caused by neck trauma - whiplash injuries or repetitive stress injury at work commonly initiate symptoms. The original injury said to cause over-stretching of the neck muscles which heal by forming irritative scar tissue **Venous TOS**, also known as **//Paget-Schroetter disease//**, presents with arm swelling, blue or dark discolouration, and a feeling of fullness or aching in the arm *usually an anatomical variation leading to compression or thrombosis (**//Paget-Schroetter disease//**) **Arterial TOS** presents with coldness, numbness, tingling, pain, and white discolouration in the fingers or whole hand. *Cramping of the forearm and hand with activity (claudication) is common. *Pain usually involves the hand and arm, but not the neck or shoulder. *more commonly related to thrombus **Useful tests:** *Wright test - hyperabduction leading to increased pain or loss of pulse in vascular TOS *Adson test - ipsilateral head rotation and inspiration leading to increased pain or loss of pulse in vascular TOS. ====Brachial plexus==== {{ :wiki:neurology:brachial-plexus.jpg?300|}} ===Brachial Neuritis=== (Parsonage-Turner Syndrome) *otherwise known as idiopathic or hereditary **//neuralgic amyotrophy//** *uncommon, characterized by severe shoulder pain followed by patchy muscle paralysis and sensory loss involving the shoulder girdle and upper extremity. *any nerve or branch within the brachial plexus can be involved *auto-immune and biomechanical causes implicated *ultimately inflammatory processes predominate *lower trunk worse prognosis c/w upper trunk *recovery over many months - 2/3 have motor function ≤1/12 ==Presentation== *Often in stages *sudden severe pain - may last weeks *painless flaccid paralysis - more often upper branches *slow recovery over months - 6-18/12 recovery period for motor function ==Differential Diagnosis== *Cervical spine radiculopathy - pain and weakness follows a specific nerve root distribution *Rotator cuff pathology - shoulder pain persists despite development of shoulder weakness *Entrapment neuropathy - shoulder pain with progressive weakness in a specific peripheral nerve distribution *Idiopathic hypertrophic brachial neuritis (IHBN) - rare and painless. Characterized by weakness in upper limb muscles and hypertrophy of the brachial plexus ====Lumbar plexus nerve entrapments==== *Groin pain of neural origin can be caused by pelvic surgeries, blunt trauma, sports injury, hypertrophy of the abdominal muscles from excessive training, or from unknown causes *//**genitofemoral**// and //**lateral femoral cutaneous**// nerve entrapments can result from tight clothing *//**Obturator**// nerve entrapment can be caused by pelvic trauma and tumours or normal pregnancy *Among athletes, most cases of entrapment of the //**ilioinguinal**// nerve are linked to hypertrophy of the abdominal muscles as a result of excessive training *//**Iliohypogastric**// nerve injury combined with tears in the external oblique aponeurosis has been described in soccer and rugby players *In athletes, //**obturator**// nerve entrapment appears to be the result of a fascial band at the distal end of the obturator canal, esp in skaters, Australian Rules football players, and soccer players as a result of adductor muscle development {{ :wiki:neurology:ilioinguinal_ns.jpg?300|}} {{ :wiki:neurology:lumbar_plexus.png?200|}} ====Beriberi==== a condition due to deficiency of Thiamine (vit B1)\\ *Dry Beriberi - neurological symptoms *Wet Beriberi - Cardiac symptoms with or without neurology *infantile Beriberi - neurocardiac symptoms in infant <1/12 *sensorimotor neuropathy of **dry Beriberi** can mimic the signs and symptoms of acute or chronic [[wiki:neurology:guillainbarresyndrome#guillain_barr%C3%A9_syndrome|GBS]]. *mild-to-moderate reduction in all sensory modalities in a stocking distribution with reduced reflexes. *may have mild, predominantly distal weakness. *//**Wet beriberi**// can present with fulminant CVS collapse with overload and severe lactic acidosis which rapidly responds to Thiamine replacement *//**Thiamine deficiency:**// *reduced thiamine intake - alcohol abuse, anorexia nervosa, dieting, or malabsorption following bariatric surgery *Malabsorption - diarrhea, celiac disease, tropical sprue, or dysentery. *Other - burns, pregnancy, dialysis, and malignancy *Thiamine repletion leads to rapid clinical improvement in dry beriberi c/w [[wiki:neurology:guillainbarresyndrome|Guillain Barré Syndrome]] ====Cauda Equina Syndrome==== Red flags: *Severe low back pain (LBP) *Sciatica: often bilateral but sometimes absent, especially at L5/S1 with an inferior sequestration *Saddle and/or genital sensory disturbance *Bladder, bowel and sexual dysfunction *Mostly commonly large lumbar disc herniation *Less common - epidural haematoma, infections, malignancy, trauma 3 main variations: -Rapid onset without a previous history of back problems. -Acute bladder dysfunction with a history of low back pain and sciatica. -Chronic backache and sciatica with gradually progressing CES often with canal stenosis. Important to distinguish between Complete and Incomplete as CES-Incomplete has a good prognosis with emergency surgical intervention. CES-Complete does not respond as well and surgery may even be delayed: ***//CES-Incomplete//** *urinary difficulties of neurogenic origin including altered urinary sensation *loss of desire to void, poor urinary stream and the need to strain in order to micturate *Saddle and genital sensory deficit is often unilateral or partial *trigone sensation<@anno:[10;;anno_dylan]>an inflated urinary catheter is gently pulled and should elicit the desire to micturate should be present. ***//CES-Complete//** *painless urinary retention and overflow incontinence (CES-Retention) *There is usually extensive or complete saddle and genital sensory deficit *deficient trigone sensation. ---- ==References include:== [[https://journals.lww.com/acsm-csmr/Fulltext/2011/03000/Lumbar_Plexus_Nerve_Entrapment_Syndromes_as_a.14.aspx?WT.mc_id=HPxADx20100319xMP|Lumbar Plexus N entrapment syndromes - groin pain in athletes]]\\ https://www.orthobullets.com/shoulder-and-elbow/3065/brachial-neuritis-parsonage-turner-syndrome\\ https://basicmedicalkey.com/summary-of-cranial-nerves/\\ https://cks.nice.org.uk/topics/bells-palsy/\\ [[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3082683/|Cauda equina review 2011]]\\ https://rarediseases.org/rare-diseases/thoracic-outlet-syndrome/\\ [[https://thejns.org/focus/view/journals/neurosurg-focus/39/3/article-pE7.xml|J NeuroSurg. Thoracic Outlet synd 2015]]\\