AmyExam4

Muscle Contractions and Movement Disorders

• Sustained muscle contractions can lead to abnormal postures and repetitive twitching.
• Conditions can be focal (e.g., blepharospasm, spasmodic dysphonia, torticollis) or segmental and generalized.
• Idiopathic primary causes include torsion dystonia, inherited in an autosomal dominant manner.
• Secondary causes may involve Wilson's disease, Huntington's disease, Parkinson's disease, anoxia, stroke, or drug-induced conditions.

Wilson's Disease

• An autosomal recessive disorder impacting copper metabolism.
• Excessive serum copper accumulation leads to deposition in liver, kidneys, cornea, and CNS, specifically in the basal ganglia.
• Key sign is Kayser-Fleischer ring, a golden brown-green deposit in the iris.
• Clinical features include hyperkinetic movement, tremor, parkinsonism, dysarthria, and cognitive disturbances.
• Diagnosis through increased serum copper, decreased ceruloplasmin, and increased 24-hour urine copper; liver biopsy is definitive.
• Management includes chelation therapy with penicillamine, trientine, and zinc.

Brown-Sequard Syndrome

• Caused by hemisection of the spinal cord, often due to trauma.
• Symptoms include ipsilateral weakness and joint position sense loss, with contralateral pain and temperature loss.
• Rarely involves bowel and bladder dysfunction.

Salter-Harris Type III Fracture Complications

• Salter-Harris classification details fractures involving the growth plate in pediatric bones.
• Type III: Fracture through the growth plate and epiphysis, leading to potential premature growth plate fusion and osteoarthritis.
• Type IV: Involves the growth plate, epiphysis, and metaphysis, similar complications to Type III.

Myasthenia Gravis (MG)

• Neonatal MG arises from maternal antibody transplacental transmission, resolving within two months.
• Congenital myasthenic syndrome is a hereditary form present from birth.
• AChR-positive MG constitutes 80% of cases, primarily affecting proximal limb muscles, with facial and respiratory weakness.
• Three antibody subtypes: binding (most common), modulating (found in thymoma), and blocking (less than 1% of cases).
• MuSK-positive MG involves mainly facial and bulbar weakness, less limb weakness, and is common in younger females.
• Classification of MG severity ranges from ocular MG (Class I) to generalized MG requiring intubation (Class V).
• Pathogenesis involves AChR antibodies causing postsynaptic membrane damage and muscle contraction failure.

Clinical Manifestations of Amyotrophic Lateral Sclerosis (ALS)

• Initial signs include asymmetrical limb weakness, cramping, gait instability, and fatigue.
• Symptoms progress to symmetrical weakness affecting multiple muscle groups.
• Speech and swallowing difficulties (dysarthria and dysphagia) are common.
• Exaggerated emotional expressions, pseudobulbar affect, and frontotemporal dementia may develop.
• Muscle atrophy, spasticity, and fasciculations indicate advanced disease.
• Typical complications include weight loss and poor executive functioning.

Treatment of Myasthenia Gravis

• Indications for hospitalization include severe bulbar symptoms, low vital capacity, and respiratory distress.
• Outpatient management is suitable for mild cases.
• First-line pharmacotherapy includes acetylcholinesterase inhibitors like pyridostigmine.

Menstrual Cycle and Hormonal Regulation

• Regular menstrual cycles last 24–38 days, with perimenopause causing shorter, more frequent cycles.
• Follicular phase: Begins on day 1 of menses and lasts until LH surge, facilitating follicle development.
• Luteal phase: Follows ovulation, supporting potential pregnancy for about 14 days.
• Endometrial cycle phases include desquamation, proliferation, and secretion in preparation for pregnancy.
• Hormonal regulation involves the hypothalamic-pituitary-ovarian axis, with GnRH stimulating FSH and LH release, which in turn stimulates ovarian functions and ovulation.