Genetic & Developmental Disorders PDF

GENETIC & DEVELOPMENTAL DISORDERS PTA 104: FUNDAMENTALS OF DISEASE  COURSE OBJECTIVES 4. List and describe common diagnostic studies and tests used to diagnose and monitor diseases. 5. Discuss the use of pharmacological agents in the treatment of disease and...

GENETIC & DEVELOPMENTAL DISORDERS PTA 104: FUNDAMENTALS OF DISEASE  COURSE OBJECTIVES 4. List and describe common diagnostic studies and tests used to diagnose and monitor diseases. 5. Discuss the use of pharmacological agents in the treatment of disease and associated implications for physical therapy. 6. List and describe major disorders and diseases caused by inherited genetic code defects. X-LINKED DISORDERS  X-LINKED DISORDERS Present more in males than females – why? Also called sex linked X & Y chromosomes do not carry the same information X tends to carry more genetic information than Y chromosomes X-linked diseases usually occur in males because males have only one X chromosome Single recessive gene on that X chromosome will cause the disease Females have a second copy of “normal” on other X chromosome so affected mildly or not at all = carriers  X-LINKED DOMINANT DISORDERS Inherited dominant allele carried on X chromosome Males and females can be affected Example: Fragile X Syndrome Results in intellectual disability, behavioral and learning challenges Tends to affect males more severely than females  X-LINKED RECESSIVE DISORDERS Either two affected X chromosomes in a female or one affected X chromosome in a male must be present Females with one affected X chromosome are carriers Examples of disorders/diseases: Red-green colorblindness Hemophilia A Duchenne’s Muscular Dystrophy Becker’s Muscular Dystrophy  HEMOPHILIA Bleeding disorder characterized by lack of clotting factor Bleeding – spontaneous or due to trauma Can see internal hemorrhage or hematuria Clinical manifestations: excessive bruising, persistent bleeding, bleeding into joints (hemarthrosis) Knee most frequently involved (also ankle, elbow, hip) Hemarthrosis signs and symptoms: tingling, joint held in position of comfort (usually flexion), swelling, decreased ROM, warmth, pain, protective muscle spasm Hemorrhage into muscles: Forearm flexors, iliopsoas, gastric/soleus Pain, decreased mvmt  HEMOPHILIA Complications: Joint contracture – hip, knee, elbow flexion, ankle PF Muscle weakness around affected joints Leg length discrepancies Scoliosis, gait deviations Decreased aerobic fitness Management: Medical – infusion with (clotting) factor replacement, Tylenol for pain mgmt., NO weight- bearing during acute bleed RICE, prevent deformity  MUSCULAR DYSTROPHIES Largest and most common group of inherited progressive neuromuscular disorders of childhood Can present at any time in life span Six major types: Duchenne’s Muscular Dystrophy (DMD) – X-linked recessive Becker’s Muscular Dystrophy (BMD) – X-linked recessive Facioscapulohumeral Dystrophy (FSHD) – autosomal dominant Limb-girdle Dystrophy (LGMD) – autosomal recessive or dominant depending on type Myotonic Dystrophy (MD) – autosomal dominant Congenital Muscular Dystrophy (CMD) – autosomal recessive  DUCHENNE MUSCULAR DYSTROPHY (DMD) X-linked recessive disorder carried by mothers and passed on to sons = MALES The most common type of muscular dystrophy DMD causes a lack of functional dystrophin - a protein found mainly in skeletal and cardiac muscle tissue Without dystrophin, muscle tissue is easily damaged, causing inflammation The overall effect of dystrophin deficiency is muscle weakness  DUCHENNE MUSCULAR DYSTROPHY (DMD) Boys usually begin to show signs of muscle weakness between 1 and 6 years of age. The disease progresses, affecting gait (waddling gait) and other functional activities. Standing up from the floor becomes difficult - child will demonstrate a positive “Gower’s sign,” walking his hands up his thighs in order to stand upright Usually identified when child has difficulty getting off floor or climbing stairs, falls frequently, walks with waddling gait Death due to respiratory failure or heart failure usually occurs between the ages of 16 and 35 in most individuals with DMD Tx: corticosteroids - improve muscle strength and function for 6 months to 2 years and slow the process of muscle weakening  DUCHENNE’S MUSCULAR DYSTROPHY – CLINICAL MANIFESTATIONS Progressive weakness Toe walking due to contracture of calf muscles and weakness of anterior tibialis Hip abductor weakness (Trendelenburg gait) Ambulation deteriorates – most no longer able to walk around 10-12 y/o – using w/c by time they reach teenage Shoulder girdle weakness and excessive scapular winging – often prevents use of crutches to aid with gait Scoliosis and increased lumbar lordosis Respiratory dysfunction due to muscle weakness Calf pseudohypertrophy due to fat infiltration  DUCHENNE MUSCULAR DYSTROPHY (DMD) Physical Therapy: Assist with developmental milestones Maintain available strength, encourage mobility, adapt to loss of function Gentle exercise to maintain strength Cardiovascular activity to tolerance Breathing exercises Orthotics - lower extremity, trunk bracing devices Assistive device and wheelchair training are important Family members and caregivers - instruction on transfer techniques, positioning, general mobility expectations for patient ROM, prevention of contracture, positioning  DMD https://www.youtube.com/watch?v=IZoOVkafFYA https://www.urmc.rochester.edu/neurology/our- divisions/neuromuscular/clinics/duchenne-muscular-dystrophy- clinic/videos-patient-stories.aspx  OTHER MUSCULAR DYSTROPHIES Becker’s Muscular Dystrophy: Similar to DMD, but slower progression and longer life expectancy Facioscapulohumeral Dystrophy: mild form and begins with weakness in facial muscles and shoulder girdle Limb-girdle Muscular Dystrophy: progressive muscle weakness, primarily in the shoulder and hip muscles Slow course and often only mild impairment Myotonic Dystrophy: severity varies greatly, but generally more mild Congenital Muscular Dystrophy: affects both brain and muscle OTHER DEVELOPMENTAL DISORDERS  SPINA BIFIDA Congenital neural tube defect – failure of neural tube to close during development (by day 28 of gestation) Etiology: multifactorial, and related to interaction of genetic predisposition, certain drugs, environmental, folic acid deficiency Occurs in low thoracic, lumbar, or sacral regions – Most occur in the lumbosacral region Affects CNS, musculoskeletal and urinary systems  SPINA BIFIDA Spina Bifida Occulta Meningocele Myelomeningocele Not visible (occulta = Saclike cyst Most serious hidden) outside spine Saclike cyst outside External spine Non-fusion of Protrusion of vertebral spinous protrusion of meninges, CSF, process; no neural meninges and spinal cord tissue protruding (dura, May or may not arachnoid) be covered by May have dimple in and CSF skin skin, hairy patch, or mole at site Neuro Motor loss below dysfunction rare level of spinal cord No neuro dysfunction defect  SPINA BIFIDA - MMC In MMC, many other problems can occur: flaccid or spastic paralysis of the lower limbs Sensory deficits urinary and or fecal incontinence poor trunk control musculoskeletal complications Scoliosis, osteoporosis hip dysplasia, hip dislocation hip/knee muscle contracture, clubfoot (talipes equinovarus) muscle atrophy cognitive limitation  SPINA BIFIDA - MMC Because of decreased sensation and mobility, children and adults with MMC are at risk for developing skin irritation and pressure sores. Latex allergy is common in people with spina bifida. Many children with MMC also have an Arnold- Chiari II formation - the brainstem and cerebellum slip downwards into the foramen magnum. This disrupts cerebral spinal fluid flow, causing hydrocephalus - an abnormal accumulation of cerebral spinal fluid (CSF) in the brain. Surgical intervention is common in children with MMC, even after the defect is surgically closed. Ventro-peritoneal (V-P) shunts are often used to treat the hydrocephalus.  SPINA BIFIDA Shunt precautions: Don’t put pressure on shunt Don’t stretch neck Don’t place in Trendelenburg position (elevating the feet and legs of the patient above the level of the heart in the supine position) Signs of shunt malfunction: vomiting, irritability, bulging fontanel, lethargy, headache, change in behavior or coordination, seizure Tethered cord syndrome: spinal cord becomes tethered or bound down as the child grows Signs and symptoms: Watch for older children who show a rapid decline in function or increase in new symptoms appearing incontinence, progressive weakness, back pain  SPINA BIFIDA – TREATMENT Surgical closure (now sometimes performed prenatally) Ventriculoperitoneal (V-P) shunt – drains CSF due to hydrocephalus PT treatment: Family Ed on positioning (prevent joint deformity), handling (reduce fx risk), ROM, ther ex Developmental milestones, skin care, strength, balance, mobility, adaptive equipment, w/c, orthotics Function – strength through play Child’s ability to walk outdoors and use wheelchair by age 7 usually suggests good prognosis If functional ambulation is not present by age 9 it is unlikely to occur  SPINA BIFIDA https://www.youtube.com/watch?v=ci3VLVjmno0  CONGENITAL TORTICOLLIS “Wry neck” Unilateral tightness/spasm of SCM Most often identified in first 2 months of life Presents with lateral cervical flexion to same side, rotation toward opposite side of contracture; fascial asymmetries = head to tilt to one side and their chin to turn toward the opposite side Predisposing factors: restrictive uterine environment, poor muscle tone, cerivcal-vertebral abnormalities, birth trauma  CONGENITAL TORTICOLLIS – TREATMENT Physical Therapy: ROM exercises, heat, STM, positioning, strengthening, posture, rearrange environment, taping Pharmacological management: nonsteroidal anti- inflammatory drugs (NSAIDs), acetaminophen, muscle relaxants, local intramuscular injection of botulinum toxin Surgical release if conservative management has failed and the child is over 1 year old  CONGENITAL HIP DYSPLASIA Malalignment of the femoral head within the acetabulum Develops during last trimester in utero Etiology: malposition in utero, environmental and genetic influences, breech birth, female sex Signs/symptoms: asymmetrical hip abduction with tightness and asymmetric shortening on the side of the dislocation (Galeazzi sign) Treatment: dependent on age and severity; Pavlik harness Physical therapy for stretching, strengthening, and caregiver education  CONGENITAL LIMB DEFICIENCIES Malformation that occurs in utero secondary to altered developmental course a limb or part of a limb doesn't form normally A limb that's missing, extra, or abnormally shaped Fingers or toes that are fused together, missing, or extra A limb that's longer or shorter than normal Etiology: most are idiopathic or genetic in origin; poor blood supply, constricting amniotic bands, infection, maternal drug exposure Treatment: strengthening, ROM, weight bearing, prosthetic training (if appropriate), encourage symmetrical movements  ERB’S PALSY Paralysis of the UE typically resulting from a traction injury to the brachial plexus It’s most common in infants who injured their shoulders during delivery Clinical presentation: Arm held in add and IR at shoulder, lower arm pronated and fingers flexed (waiter’s tip) Some cases resolve on their own, typically resolve completely in the first year of life Physical Therapy: Maintain functional ROM Prevent shoulder subluxation, positioning Improve active movement – NMES Activities and exercises to promote recovery of movement and muscle strength Sensory stimulation to promote increased awareness of the arm Provision of splints to prevent secondary complications and maximize function Educating parents on appropriate handling and positioning of the child and home exercises to maximize the child’s potential for recovery  ARTHROGRYPOSIS MULTIPLEX CONGENITA (AMC) Extensive contractures (presentation can vary) Etiology: unknown, small % autosomal dominant, any condition that limits fetal movement Clinical presentation: Joint contractures Joint dislocations Muscle weakness/atrophy Commonly develop arthritis as adults Cylinder-like extremities Treatment: positioning, strengthening, stretching, functional adaptation, splinting, gross motor skills  AMC https://www.youtube.com/watch?v=9lVvQxjZCNc&t=2s  FETAL ALCOHOL SYNDROME (FAS) A result of maternal alcohol use during pregnancy Characterized by growth retardation, cognitive disabilities, and physical disabilities Heart problems and limb dislocations are also more common in children with FAS Many children with FAS experience seizures Microcephaly is often seen Facial features are also affected, usually small eyes and flattened upper lip area All areas of the brain can be affected in FAS Areas that are most often noted as affected in FAS are the corpus callosum, frontal lobe, hippocampus, and cerebellum  FETAL ALCOHOL SYNDROME (FAS) No specific diagnostic tool to identify FAS, so diagnosis is made through maternal history and physical appearance and disabilities of the child. The brain damage in FAS is permanent. Medications are often used to control seizure disorders. Children with FAS may need special education to manage intellectual disability, behavioral therapy to manage emotional and behavioral problems PT and OT to manage motor delays, and SLP to manage receptive and expressive speech difficulties.  SCOLIOSIS Abnormal lateral curvature of the spine Etiology: most cases idiopathic (80%) Functional – can be reversed if underlying cause treated; leg length discrepancy, poor posture Structural – fixed curvature Neuromuscular or degenerative Curves less than 20 degrees – mild scoliosis Curves greater than 60 degrees – severe scoliosis may lead to pulmonary insufficiency, degenerative arthritis, disc disease, vertebral subluxation  SCOLIOSIS Signs/symptoms: shoulder asymmetry, lateral spinal curvature, posterior rib hump, pain possible as curve progresses Treatment: Monitor curves < 25 degrees every 4-6 months Spinal orthoses for curves 25 – 40 degrees Surgery for curves > 40 degrees PT treatment focused on education and general strengthening Has not been found to change degree of curve, but may reduce pain  KYPHOSIS & KYPHOSCOLIOSIS Scheuermann’s disease: Structural deformity classified by anterior wedging of 5 degrees or more of three adjacent thoracic bodies Affects adolescents aged 12 to 16 years Usually asymptomatic & resolves when growth stops Treatment includes bracing, surgery, and PT Adult kyphoscoliosis more likely to develop due to poor posture, aging, disc degeneration, vertebral compression fractures, or osteoporosis PT treatment: postural exercises, STM, stretching, thoracic extension exercises, strengthening  CEREBRAL PALSY (CP) Developmental disorder Cerebral palsy (CP) is actually a group of disorders. Etiology: CP results from an injury, lesion or malformation in the brain that occurs before, during, or soon after a baby’s birth. Non-progressive damage: The area of damage remains unchanged and is permanent = the disorder is non-progressive. Functional abilities can improve, and changes in motor skills can occur, but the actual area of brain damage remains the same. Motor function: The impairments include problems with motor function. Other impairments may also exist, but impaired motor function is always part of CP.  CEREBRAL PALSY (CP) There are many possible causes and risk factors for CP: preterm birth (most prevalent risk factor; the earlier the baby, the higher the risk) low birth weight anoxia in fetus/baby (prenatal, during birth, or just after birth) fetal or neonatal stroke/ intracranial hemorrhage intrauterine infection postnatal infection in infant (especially meningitis and encephalitis) maternal event (eclampsia, toxemia) maternal seizure lack of prenatal care (maternal ill health, drug use, smoking, etc.) genetics (although a specific genetic disorder does not directly cause CP, genetic influences can cause small effects on many genes)  CEREBRAL PALSY (CP) 3 main types of cerebral palsy: 1. Spastic CP – most common type, associated with damage to the cerebral cortex 2. Dyskinetic CP - associated with damage to the basal ganglia 3. Ataxic CP - associated with damage to the cerebellum Each type can include involvement from very mild to very severe. Some children will experience minimal disability due to CP, while others will require special educational arrangements and lifelong care and healthcare services. Most children with CP experience delays in motor milestone achievement  CEREBRAL PALSY (CP) Categorized by area of involvement. Quadriplegia - all 4 limbs are involved Triplegia - 3 limbs involved Diplegia or paraplegia - 2 limbs (LEs) Monoplegia - 1 limb involved Hemiplegia - if either just the right or left side is involved Children and adults with CP by definition must have motor involvement, but other kinds of disability often accompany a CP diagnosis: Impairments in cognition, vision, hearing, speech, feeding, and mood are not uncommon in people with CP. The risk for experiencing seizures is higher in individuals with CP. Orthopedic concerns, such as spinal scoliosis and hip dysplasia are also common.  CEREBRAL PALSY (CP) Spastic CP (Pyramidal CP) – cerebral cortex Spastic CP affects voluntary muscle control by causing increased muscle tone. The tone can be affected in any muscles; the most common areas of spasticity include: hip flexors and adductors knee flexors, and ankle plantar flexors shoulder adductors, and elbow, wrist, and hand flexors  CEREBRAL PALSY (CP) Spastic CP Children with spastic CP generally show decreased ROM in the affected limb(s) and have limited options on patterns of movement. If they are ambulatory, they often walk with a scissors gait (thighs and knees together, feet sometimes crossing) because of short hip adductor muscles, and an equinus gait (walking on toes) because of short plantar flexors in the ankle. Their range of motion is limited in affected areas, and they are likely to develop muscle contractures. https://www.kennedykrieger.org/patient-care/conditions/cerebral-palsy-cp  CEREBRAL PALSY (CP) Dyskinetic CP (Athetoid CP) – basal ganglia Marked by atypical movement patterns, such as dystonia, chorea, and athetosis Dystonia - involuntary movements leading to sustained positions and unusual postures. Chorea - a series of irregular, nonpurposeful, uncontrolled movements that can occur in a limb or throughout an entire body. Athetosis - slow, writhing movements that are often repetitive or rhythmic. Muscle tone varies from low to high Lack of motor control is evident in all movements Movements look similar to the movement patterns seen in Parkinson’s or Huntington’s disease, which also affect the basal ganglia. https://youtu.be/mlMQw6xMn6k https://youtu.be/r83oNybOtrc  CEREBRAL PALSY (CP) Ataxic CP - cerebellum Hyptonia - muscle tone tends to be decreased Coordination disorders and balance problems Children and adults with ataxic CP usually learn to walk, but often do so with a wide base of support and heavy footfall. They have difficulty with more complex skills requiring higher levels of coordination, such as jumping, balancing on one foot, and karaoke (grapevine) stepping.  CEREBRAL PALSY (CP) Mixed-type CP - Some children exhibit characteristics from more than one of the categories listed above Dx: clinical presentation, brain MRI Tx: causative factors of the damage need to be addressed immediately, but once the brain damage has occurred, there is no treatment for the actual damage PT, OT, SLP - initiated as soon as possible to observe developmental milestones, provide frequent therapeutic interventions, and provide caregivers with activities to help children progress in their development Adaptive seating, bracing and orthotics, assistive device training, wheelchair selection and training, and adaptive assistance for home and school  CEREBRAL PALSY (CP) Pharmacological intervention: muscle relaxants for spasticity pain reducing medications anti-seizure medications sleep aids Surgical interventions: orthopedic surgeries for scoliosis and hip dysplasia For spasticity, short, spastic muscles can be surgically stretched and lengthened Specific nerves can be cut in selected dorsal rhizotomies in order to decrease spasticity in certain muscles. Botox injections can help decrease spasticity Intrathecal pump can be inserted in to help relax spastic muscles through the delivery of medications, such as baclofen.  CEREBRAL PALSY (CP) TYPES https://www.youtube.com/watch?v=cOfUGUNxEqU https://youtu.be/fCyyL3X7uY8  BOARD QUESTION A PTA employed in a school setting observes a 10 year old boy attempt to move from the floor to a standing position. During this activity, the boy has to push on his legs with his hands in order to attain an upright position. This type of finding is MOST commonly associated with: A. Cystic fibrosis B. Down syndrome C. Duchenne muscular dystrophy D. Spinal muscular atrophy  BOARD QUESTION A PTA employed in a school setting observes a 10 year old boy attempt to move from the floor to a standing position. During this activity, the boy has to push on his legs with his hands in order to attain an upright position. This type of finding is MOST commonly associated with: A. Cystic fibrosis B. Down syndrome C. Duchenne muscular dystrophy D. Spinal muscular atrophy