CARPAL TUNNEL SYNDROME (CTS)

A. Characterized by : fluctuating numbness, paresthesia & pain in the hand due to compression of the median nerve at the wrist. - 80 % occurs in women.

B. Etiology & Pathology :- Many causes of compression : 1. Hereditary2. Traumatic3. Infectious.4. Metabolic5. Endocrine6. Neoplastic7. Vascular8. Degenerative9. Iatrogenic.

C. Clinical features:- Earliest symptoms: numbness + paresthesias in the sensory distribution of median nerve in the hand (thumb, index, middle, and lateral half of the ring fingers).- Later: pain develops extending up into the forearm & often the shoulder.- The pain is worse at night. - Late event: weakness inability to unscrew bottle cap or grip properly.

D. Diagnostic Procedures:1. EMG : reveal fibrillations in the muscles of the thenar eminence.2. Distal latency of median nerve is prolonged.3. Sensory nerve conduction velocities & sensory distal latency are prolonged on stimulating the digital nerves of the index finger.

E. Tx: - The area around the nerve is infiltrated with 2- 3 ml of 1% Lidocaine; followed by an inj of 40 mg Methylprednisolone.- Fail to respond to inj surgical division of the transverse carpal ligament.

F. Prognosis:- Excellent if the cause is removed / treated.

TARSAL TUNNEL SYNDROME(POSTERIOR TIBIAL NERVE)A. Pathophysiology: - Just below the medial malleolus lies a passage through pass the medial & the lateral plantar nerves.- In cases of excessive pronation of the foot, the load increases in the tissues that surround the flexor tendons inflammation swelling trapping of these nerves.B. Diagnosis :The pain may be aggravated by pressure over the posterior tibial nerve just below & behind the medial malleolus.C. Tx:- Infiltration of the tarsal tunnel with 1 % Xylocaine, followed by 40 mg of Methylprednisolone (Medrol).- In intractable cases Surgical.

References:

1. Peterson, L; Renstrom, P. Sport Injuries : Their prevention and treatment: 1988; p.363 .2. Gilroy, J. Basic Neurology. International Edition:1992; p. 371

MYASTHENIA GRAVIS (MG)

A. Background:- Myasthenia gravis is an autoimmune disease caused by an immunologic attack directed against the postsynaptic neuromuscular junction (NMJ).- can occur at any age.- sometimes associated with rheumatoid arthritis, disseminated lupus erythematosus.- 70 % have thymic hyperplasia.- 10 % have thymoma.

B. Pathophysiology:MG is an acquired autoimmune disorder of neuromuscular transmission resulting from antibodies directed against the acetylcholine receptor (AChR) or against the muscle-specific receptor tyrosine kinase (MuSK).

C. Dx :- Clinical feature: Fluctuating weakness characterized by abnormal fatigability that improves with rest.

D. Testing: - Tensilon (Edrophonium) test can be helpful in diagnosing MG.Edrophonium is an anticholinesterase and will result in transient increase in AChR in NMJ. Edrophonium is given I.V. Dose is 10 mg(1 ml) : * 2 mg is given initially. * The remaining 8 mg: approximately 30 seconds later if the test dose is well tolerated. There is an obvious improvement in the strength of weak muscles that lasts for about 5 minutes.

E. Clinical features:- Fluctuating weakness. - Tends to involve: * the eyes in 90% of Pts.(diplopia, ptosis). * face, neck & oropharynx: 80 % * limbs: 60 %.

F. Tx :- Acetylcholinesterase inhibitors: # Pyridostigmine(Mestinon): start with 4x 30 -60 mg (the dosage is gradually titrated). Most adults require 4-6x 60-120 mg.# Mestinon Timespan (is a timed-released): 180 mg can be given at night for Pts who have generalized weakness upon awakening.- Immunosuppressive- Plasma Exchange (PE).- Thymectomy.

#. Ref.:1. On Call Neurology, 1997, pp.198 201.2. Gilroy, J. Basic Neurology. International Edition, 1992.3. Greenberg, DA et al. Clinical Neurology 7th. Ed. The McGraw-Hill Companies, Inc. 2009, pp. 185 188.

HYPOKALEMIA

A. Background:- is defined as a serum potassium (K) level below 3.5 meQ/L.B. Pathophysiology :1. Because of abdominal intracellular or extracellular potassium balance or excessive potassium losses (renal or extra renal). 2. Due to excessive cellular potassium uptake.3.Extrarenal potassium loss (urine K < 20 mEq/d) may be caused by: - Diarrhea - Cathartics; sweating. - Vomiting4. Renal potassium loss (urine K > 20 mEq/d) may be due to: - Hyperreninemia - Diuretic use.- Hyperaldosteronism. - Hypomagnesemia- Renal tubular acidosis.

C. Prognosis:- Severe hypokalemia (serum Potassium < 1.5 mEq) may be life threathening due to cardiac arrhythmia and severe muscle weakness.D. Dx:- The Dx is made with a serum potassium measurement. E. Tx: 1. Correct Potassium balance problems.2. Dietary sodium restriction (< 80 mEq/d) will reduce renal potassium losses.3. Oral KCl for mild hypokalemia (30-35 mEq/d).4. For moderate (1.5-3.0 mEq/L) or severe (< 1.5 mEq/L) hypokalemia, especially with cardiac arrhythmias and/or severe muscle weakness, IV KCl at the rate of 15 mEq over 15 minutes with continuous cardiac monitoring, aiming for a 1 mEq/L increase in the serum potassium.

PERONEAL PALSYA. LESION OF THE COMMON PERONEAL NERVE:- Common peroneal nerve arise in the posterior aspect of the thigh as one of the two terminal branches of the sciatic nerve.- Injured by: # penetrating wounds of the lower portion of the posterior aspect of thigh / popliteal fossa.# involved in fractures of the lower portion of the femur / head of the fibula.- Symptoms:# Foot drop# High steppage-gait# Wasting of the muscles of the anterior compartment of the leg# Sensory loss extending over the lateral aspect of the leg + dorsum of the foot.

B. LESION OF THE SUPERFICIAL PERONEAL NERVE:# This nerve arises at the level of bifurcation of the common peroneal nerve just below the neck of the fibula.# The nerve down anterior to the fibula between peroneal & extensor digitorum longus muscles. # Lesions produce paralysis of peroneal muscles + loss of eversion of the foot and a tendency to invert the foot on dorsiflexion.# There is variable sensory loss over the lower lateral aspect of the leg & dorsum of the foot.

C. LESION OF THE DEEP PERONEAL NERVE:#. Arises just below the head of the fibula as one of the two terminal branches of common peroneal nerve.#. Lesion commonly affected by pressure over the head of the fibula, often by sitting with legs crossed for a prolonged period of time. produces weakness of the dorsiflexors of the foot & extensors of the toes resulting in := foot drop= steppage gait= weakness of the muscles of the anterior compartment of the leg= sensory deficit of the 1st & 2nd toes.

POLYMYOSITISA. DEFINITION :- is an inflammatory disease of skeletal muscle.- skin involvement dermatomyositis.B. Etiology : unknown, but is believed by autoimmune reaction initiated by virus infection, including the AIDS virus.- the condition may be associated with :* malignancy* rheumatoid arthritis* Sjogrens syndrome* SLEC. Pathology:- inflammatory infiltration of sceletal muscle with necrosis of fibers and active phagocytosis.

D. DIAGNOSTIC PROCEDURES1. May be presents:- polymorphonucleocytosis.- ESR - lymphocytosis.- Rh. Factor +- hypoalbuminaemia. - serum muscle enzymes +- anemia.2. EMG myopathic process, but often present :- fibrillations- positive sharp waves- bizarre high frequency discharges.3. ECG:- often abnormal.

E. Tx: (Bradley, 2000; p. 692)1. Corticosteroids:- Prednisone: initial dose 2 mg/kg, not ecxeed 100 mg.- Significant improvement the dose is reduced to 60 mg daily or converted to alternate-day dose.2. An alternative to corticosteroids is Azathioprine (Imuran) 1.5-2 mg/kg,-Cyclophosphamide & Methotrexate maybe effective in some patients.

PNP (POLINEUROPATHY)A. ANATOMY OF THE PERIPHERAL NERVES:# MOTOR NERVE FIBERS originate from the anterior horn cells of the spinal cord and leave the cord through the anterior nerve root.# SENSORY FIBERS originate from neurons in the posterior root ganglia and enter the spinal cord through the posterior nerve root.- The anterior & posterior nerve roots unite distal to the cord to form a mixed spinal nerve.- The mixed spinal nerves unite in the cervical & lumbar areas to form the cervical, brachial & lumbosacral plexus. Each plexus gives rise to a number of individual mixed nerves distributed to the periphery to supply: * Muscle* Skin* Blood vessel

B. CLINICAL PATTERNS:These include:1. Mononeuropathy:- implies involvement of 1peripheral nerve.- commonly the result of trauma, also occurs in:* DM* Infarction of peripheral nerves (e.g., in polyarteritis nodosa).2. Mononeuritis multiplex:- involvement of several nerves in a haphazard fashion.- etiology = mononeuropathy.3. Radiculoneuropathy:- involvement of the nerve root as it emerges from the spinal cord.- commonly seen with herniated disks or with epidural masses (e.g.tumor).

4. Polyradiculitis = Radiculopathy:- Characterized by involvement of several nerve roots.- Commonly seen in postinfectious polyneuritis or post-vaccinal polyneuritis.5. Plexitis:- inflammation of a plexus such as the brachial plexus brachial plexitis.6. Polyneuritis:- in polyneuritis / polyneuropathy there is a symmetric involvement of peripheral nerves.- the commonest causes:* DM* Alcoholism.

# Neuropathies no matter what their cause & type present with specific signs & symptoms.- Involvement of motor axons muscle wasting & weakness atrophy + fasciculations.- Tendon reflexes depressed / absent.- Involvement of sensory axons paresthesia / dysesthesia.- Involvement of axons supplying autonomic function produces: * loss of sweating* alteration in bladder function* constipation* impotence (in male).

# Causalgia (a very painful peripheral dysesthesia) probably related to disturbance of autonomic axons in peripheral nerves.

DMP (Dystrophia Musculorum Progressiva)# Ref.:1. Gilroy J: Basic Neurology 2nd ed., McGraw-Hill Inc., 1992, pp.383-386.

DUCHENNE MUSCULAR DYSTROPHY

A. DEFINITION:- is the most common form of progressive muscular dystrophy.- almost exclusively in young males.

B. ETIOLOGY & PATHOLOGY:- due to an inborn error of metabolism that produces abnormal cell membranes.- also excessive collagen formation.

C. CLINICAL FEATURES:- inherited as a sex-linked recessive trait.- of cases due to spontaneous gene mutation.- Affected children normal at birth delay in standing & walking GOWERs SIGN (walk up his lower extremities).

- Then develops a clumpsy, waddling gait & pseudohypertrophy of the calf muscles- Has difficulty climbing stairs & rising from a chair.- Progressive involvement of heart muscle.- Progressive loss of respiratory reserve- Many Pts die from the effect of a relatively minor resp.infection.

D. DIAGNOSTIC PROCEDURES:1. Muscle enzymes:- Serum creatine phosphatase - Serum levels of other muscle enzymes GOT & GPT.2. ECG: abnormal at early stage initial tachycardia R-wave voltage +RBBB + deep Q-waves.3. EMG myopathic.4. Muscle biopsy the establishment of the Dx.

E. DD:1. Other form of dystrophy.2. Neurogenic muscular atrophy.3. Polymyositis & dermatomyositis.4. Polyneuritis.5. Benign congenital myopathies.

F. Tx:1. No specific Tx.2. Physical Tx; obesity should be avoided.3. Upper resp. tr. infection should be treated.4. Genetic counseling.

G. PROGNOSIS:- Duchenne muscular dystrophy progressive.- Death in late teens or early 20s.