Abstract
Background and Purpose Children often are referred for physical therapy with the diagnosis of hypotonia when the definitive cause of hypotonia is unknown. The purpose of this case report is to describe the clinical decision-making process using the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II) for an infant with hypotonia and gross motor delay.
Case Description The patient was a 5-month-old infant who had been evaluated by a neurologist and then referred for physical therapy by his pediatrician. Physical therapist evaluation results and clinical observations of marked hypotonia, significant gross motor delay, tongue fasciculations, feeding difficulties, and respiratory abnormalities prompted necessary referral to specialists. Recognition of developmental, neurologic, and respiratory abnormalities facilitated clinical decision making for determining the appropriate physical therapy plan of care.
Outcomes During the brief episode of physical therapy care, the patient was referred to a feeding specialist and diagnosed with pharyngeal-phase dysphasia and mild aspiration. Continued global weakness, signs and symptoms of type 1 spinal muscular atrophy (SMA), and concerns about increased work of breathing and respiratory compromise were discussed with the referring physician. After inconclusive laboratory testing for metabolic etiologies of hypotonia, a genetics consult was recommended and confirmed the diagnosis of type 1 SMA at 9 months of age.
Discussion Physical therapists use clinical decision making to determine whether to treat patients or to refer them to other medical professionals. Accurate and timely referral to appropriate specialists may assist families in obtaining a diagnosis for their child and guide necessary interventions. In the case of type 1 SMA, early diagnosis may affect outcomes and survival rate in this pediatric population.
Children with hypotonia often are referred for physical therapy treatment of associated impairments such as weakness, postural abnormality, and developmental delay. Although genetic-metabolic etiologies account for up to 60% of cases of hypotonia in infants,1 in many cases, the presentation of hypotonia is idiopathic, with no definitive cause or underlying disorder.2 Physical therapists who evaluate and treat children with hypotonia should be an integral part of the medical team, contributing to the diagnostic processes and offering interventions designed to prevent problems. Following a conceptual model for clinical decision making such as the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II) allows physical therapists to focus on patient-centered outcomes, identify existing problems, and identify potential problems that may occur and require prevention.3
The HOAC II is an algorithm for patient management that provides a means for using evidence in decision making and serves as a template for linking documentation to practice. In recognizing existing and anticipated problems in part 1 of the HOAC II, therapists generate hypotheses as to the cause of the problems; formulate meaningful, functional goals; establish testing criteria to evaluate the outcome of the interventions; and plan intervention strategies based on hypotheses and anticipated problems. In part 2 of the HOAC II, therapists follow reassessment paths for both existing and anticipated problems and determine deficiencies in patient management, including whether the original goals were viable. Several steps throughout the algorithm highlight consulting with specialists as needed as an integral part of the decision-making process.3
In describing the practical use of the HOAC II, Thoomes and Schmitt4 reported a case of clinical decision making and therapeutic interventions in an elite athlete with low back pain. Using the HOAC II and the World Health Organization's International Classification of Functioning, Disability and Health model for patient management, the patient-oriented outcome measures and goals were met within 3 weeks of the initial evaluation. The authors suggested that utilizing the structured approach of the algorithm aids the clinician's clinical-reasoning and decision-making processes and ultimately improves patient outcomes.
The purpose of this case report is to demonstrate the clinical decision-making process using HOAC II for an infant with hypotonia and gross motor delay. In patient care, physical therapists should use a systematic and comprehensive approach to decision making to maximize patient outcomes. Physical therapists must determine when a patient is appropriate for intervention and when referral to other health care professionals is warranted. Accurate and timely classification expedites appropriate testing and treatment and may prolong survival.
Case Description: HOAC II–Part 1, Initial Data Collection
A 5-month-old male infant was referred by his pediatrician for physical therapist evaluation and treatment in a hospital outpatient clinic with a diagnosis of hypotonia and gross motor delay. The infant was born at term by vaginal delivery without reported complications, weighing 3,827 kg (8 lb 7 oz). According to his mother, the infant aspirated amniotic fluid during the birth process, which resulted in continual chest congestion. The infant had been receiving albuterol via inhalation since 2 months of age, with notable improvement in breathing quality when given approximately every 4 hours.
At 4 weeks of age, the infant ceased breastfeeding due to difficult latching. Within the first 2 months, the family observed decreased head control, and at 4 months of age, the infant was referred to a neurologist by the pediatrician with concerns about hypotonia and gross motor delay. The neurologists' clinical examination was inconclusive for an etiology of hypotonia; therefore, several diagnostic tests were ordered, including: serum carnitine and acylcarnitine levels to evaluate fatty acid chain metabolism; urine amino acid profiles for hepatic and renal function; metabolic acid levels to assess kidney and lung function in controlling pH; creatine phosphokinase levels to diagnose muscle damage from heart attack, stroke, or injury; and chromosome analysis. A physical therapist evaluation was initiated within the same month to evaluate for hypotonia and gross motor delay.
The infant lived at home with his parents and 3 older siblings who were developing typically. The parents' expectation for physical therapy was to “strengthen muscles for developing skills.”
Initial observations during parent and family interview were documented. The infant made no observed attempts at antigravity movement of the head or upper or lower extremities during parent handling or transitioning to the examination room. Pulmonary screening revealed audible chest congestion and abdominal breathing. The infant's skin color was normal during the evaluation.
The family reported no family history of neurologic disorders but several genetic or neurologic conditions present with hypotonia in infancy. Genetic syndromes such as Angelman syndrome, Prader-Willi syndrome, and Marfan syndrome are known to be associated with hypotonia.5 Spinal muscular atrophy (SMA), Charcot-Marie-Tooth disease, and congenital myopathies are motor unit disorders that may result in hypotonia.5 Disorders of carbohydrate metabolism also may result in hypotonia and developmental delay. The results of the diagnostic tests ordered by the neurologist would begin to narrow the possible diagnoses for this infant.
Clinical Impression 1
The infant's history of cessation of breast feeding, difficulty latching, and chronic chest congestion since birth were important details to examine further for oral motor strength and skills. Because this infant presented marked postural abnormalities, significant hypotonia, and weakness, the initial clinical impression of the infant's problems was one of neurologic or metabolic origin. Using the HOAC II model for clinical decision making,3 after the initial data were collected, the problems identified by the family were recorded (Fig. 1).
Hypothesis-Oriented Algorithm for Clinicians II (HOAC II) model for clinical decision making, part 1. PT=physical therapist, SMA=spinal muscular atrophy. Adapted from Phys Ther. 2003;83:455–470 with permission of the American Physical Therapy Association. This material is copyrighted and further reproduction or distribution requires written permission from APTA.
Patient-Identified Problems
In this pediatric case, the patient-identified problems (PIPs) were problems reported by the family during the history and interview. The family reported being content with the infant's development; however, they recognized problems, including decreased head control, chest congestion, and difficulty latching.
Examination Strategy
In following the HOAC II, therapists develop a strategy for the examination based on initial hypotheses derived from the data collection, patient history, and PIPs. As hypotonia and gross motor delay in infants can be associated with genetic, metabolic, or neurologic disorders,1 the physical therapist examination would assess impairments contributing to functional limitations of decreased head control, mobility, and postural control. Therefore, the examination had 4 objectives: (1) to assess muscle tone, (2) to assess balance and postural control, (3) to assess gross motor skill development and strength in antigravity and gravity-minimized positions necessary for gross motor skills for a 5-month-old infant, and (4) to assess range-of-motion restrictions if present and limiting mobility.
Physical Therapist Examination
In assessing muscle tone, the infant's upper- and lower-extremity joints were passively moved to determine resistance to stretch. In clinical practice, therapists determine muscle tone based on resistance to passive stretch with subjective rating scales such as the Modified Ashworth Scale.6 This subjective scale, however, continues to be scrutinized for reliability and validity in different populations.7,8 In infants, several measures have been found useful in assessing tone, especially low tone. These measures include pull-to-sit testing, scarf sign, shoulder suspension, and ventral suspension.5 In pull-to-sit testing, the infant demonstrated a full head lag with no arm participation or traction present. When testing ventral suspension, the infant's head and upper and lower extremities remained below the level of the trunk. With testing vertical suspension, the infant was unable to stabilize the scapulae, essentially “slipping” through the examiner's hands. Decreased muscle tone or hypotonicity was documented.
Balance and postural control were assessed as significantly delayed for a 5-month-old infant. The infant required maximal assistance at the proximal trunk to maintain a sitting position and was unable to bring his head upright from a fully flexed position. Equilibrium and righting responses were absent when the infant was gently tilted laterally in supported sitting and vertical suspension.
Gross motor skills assessment was completed with the Alberta Infant Motor Scale (AIMS),9 a performance-based, norm-referenced test used to measure motor maturation of infants from term to the age of independent walking. The AIMS assesses sequential achievement of motor milestones in 4 positions: prone, supine, sitting, and standing. Concurrent validity has been demonstrated between the AIMS and the Peabody Developmental Motor Scales, edition 2 (PDMS-2) for infants at risk for developmental delay10; however, the AIMS was chosen as it was appropriate for his age, required little time to administer, and is an observational assessment requiring minimal handling. The infant's total score on the AIMS was 2, placing him significantly below the fifth percentile. When placed in a prone position, the infant maintained his head rotated to the left. He was unable to turn his head to clear his nose from the surface with auditory or visual stimulus. When placed in a prone-on-elbows position, he was unable to elevate his forehead from resting on the mat table. In a supine position, neither midline head position nor antigravity reaching toward midline was observed. The infant demonstrated occasional distal movements at the feet and hands and weak bilateral grasp. In a gravity-minimized side-lying position, the infant was unable to reach to shoulder height. Reciprocal kicking movements were not observed or reported at home by the family. In supported standing, the infant was unable to bear weight through his feet.
While in a supine position, the infant's hips rested in abduction and external rotation, resisting adduction toward midline. Range of motion was generally assessed as a screening for formal goniometric measurements. The infant had mild joint range-of-motion restrictions in hip, knee, elbow, and wrist extension; however, such mild limitations were not deemed the primary source of his immobility. The infant's pain was assessed as 0 using the Face, Legs, Activity, Cry Consolability Scale11 and confirmed with the parents.
The infant had full mobility passively for cervical rotation; however, a preference for left cervical rotation position was observed. Moderate to severe plagiocephaly was present, with left posterior skull flattening, left anterior ear shift, and left forehead bossing or prominence. Measurements for cranial asymmetry using the cranial vault asymmetry index (CVAI)12 were taken to determine possible recommendations for treatment. The CVAI is an absolute value of 2 diagonals found at 30 degrees from the midline of the nose and represents significant asymmetry when a difference of 3.5% or greater is measured. The infant's CVAI was 9, correlating with a level 4 out of 5 for severity of plagiocephaly. In our clinical practice, the family can obtain further objective assessment of plagiocephaly with a referral to an orthotist.
The infant was noted to demonstrate fasciculations of the tongue and very limited babbling and cooing for a 5-month-old infant. Because the infant had a history of difficulty latching on to the mother's breast for breast feeding and chest congestion, we determined it was necessary to discuss with the pediatrician referral to a speech-language pathologist for a feeding evaluation. Specifically, concerns with possible aspiration with feeding were discussed with the referring physician following the physical therapist evaluation. Together with the pediatrician, we determined the plan of action was to consult neurologic, genetic, and feeding specialists and educate the parents about feeding concerns and the possible relationship to the infant's chronic chest congestion. Although we did not have a definitive diagnosis for his hypotonia, the plan of care was to treat the existing problems, identify anticipated problems, and monitor the infant for signs of respiratory distress.
Plan of Care/Intervention
Non–Patient-Identified Problems
Non–patient-identified problems (NPIPs) are the existing and anticipated problems identified by the therapist during the examination. The existing problems we identified included decreased gross motor skills, poor postural control, poor head control, plagiocephaly, and limited range of motion in extremity joints. The anticipated problems, which, if not prevented from occurring, may lead to diminished health status and disability, including acquired torticollis, joint contractures, aspiration, and muscle atrophy.
For each existing problem, we generated a hypothesis as to why the problem existed. The hypothesis provides the necessary link between the therapist's diagnosis and the intervention. Hypotheses often identify an impairment causing a problem or a pathological process contributing to the problem, which may require specialist consultation (Tab. 1).
Hypotheses for Why Each Problem Existed and Recommended Treatment Intervention
The problem list from the PIPs and NPIPs was refined to determine whether the problems could be addressed by physical therapy intervention. The created goals establish a measurable target level of function and, when met, support the original hypotheses. The goals created for the refined problem list are presented in Table 2.
Functional Short-Term Goals
In the HOAC II, the level of improvement in the impairment that the infant needs in order to eliminate the problem is called the “testing criteria.”3 In this manner, a therapist can test the original hypothesis because when testing criteria are met, the problem should have been eliminated and related goals achieved. Essentially, attainment of a goal is the testing criteria if the hypothesis is correct.
We initially recommended weekly physical therapy to educate the family on: (1) active repositioning to reduce deformational plagiocephaly; (2) positioning and handling techniques to reduce contracture development; (3) activities to increase strength, improve postural control, and promote gross motor skills; and (4) monitoring for signs of respiratory distress.
Prior to his first physical therapy treatment, the infant was evaluated by a speech-language pathologist. Given the likelihood of aspiration in infants with marked hypotonia, a modified barium swallow study was performed. The results confirmed pharyngeal-stage dysphagia with mild aspiration of thin liquids. Modifications to the infant's diet were recommended by the speech therapist, including increasing thickness of liquids, as well as parent education for positioning to improve swallow function.
Initiation of physical therapy intervention was delayed several weeks due to authorization processes and schedule conflicts with the family. Once scheduled at 6 months of age, the infant demonstrated minimal to no functional progress over the first 3 consecutive weekly physical therapy visits. The infant continued to require maximal assistance to rotate his head in a prone position, rotated his head from left rotation to midline only in a supine position, reached below shoulder level in a side-lying position with weak, inefficient grasp, and continued with minimal lower-extremity active movement. Adaptive positioning and range of motion to prevent contracture deformity, acquired torticollis, and worsening plagiocephaly were reviewed with the family weekly. Although the infant was not obtaining the goals, we believed our hypotheses were correct.
Clinical Impression 2
Based on the physical therapist examination, including assessments of gross motor skills and results of AIMS testing, marked weakness and hypotonia, history of latching and feeding difficulties, and tongue fasciculations, the initial impression of characteristics typical of SMA were discussed with the referring physician after the second physical therapy visit. The physician, having been unfamiliar with specific cases of SMA, was educated on the urgency of obtaining a genetic diagnosis, specifically with concerns for life-threatening type 1 SMA. Children with acute childhood SMA (type 1) present primary impairment of muscle weakness due to progressive loss of anterior horn cells in the spinal cord. Within the first 4 months of life, weakness, contractures, and fasciculations of the tongue are most commonly reported.13 Respiratory distress is present early, and increased work of breathing and accessory muscle use is common.
According to the family, the genetics referral, which the family discussed with the referring physician by the third physical therapy visit, was dependent on the neurologists' test findings. On the fourth physical therapy visit, xiphoid retraction and mild intercostal retractions were observed in the infant at rest in a supine position. His respiratory rate was elevated and inconsistent, approximately 70 to 80 breaths per minute. His mother reported that his prescription for albuterol had not been refilled. Concern for the infant's respiratory health and the signs and symptoms similar to SMA observed in this infant were discussed again with the referring physician after the treatment session. He was seen promptly by the pediatrician after the therapy session and provided with a breathing treatment with albuterol, and his symptoms improved. It was clear that the infant's function was declining, and a definitive diagnosis was necessary for moving forward with appropriate referrals and treatment.
The diagnostic tests ordered by the neurologist were inconclusive, resulting in a referral to a geneticist. The infant attended 2 additional physical therapy sessions, for a total of 6 visits in 6 consecutive weeks. He was admitted to the emergency department for cessation of bottle feeds at 7 months 24 days of age and diagnosed with influenza and pneumonia, treated, and sent home. The infant was unable to return for physical therapy while he was ill, and his health continued to decline (Fig. 2).
Time line of events. MD=medical doctor, SMA=spinal muscular atrophy.
Outcome/Diagnosis
It is unclear what circumstances contributed to the unfortunate delay in obtaining a diagnosis despite continued communication with the pediatrician. Finally, at 9 months of age, the infant received a diagnosis of type 1 SMA from the geneticist based on clinical presentation and a positive survival motor neuron (SMN) 1 gene deletion test. In infants with SMA, diagnosis may be confirmed by clinical presentation with genetic testing, and by muscle biopsy or electromyographic testing if genetic results are inconclusive.14 Spinal muscular atrophy is an inherited autosomal recessive disorder characterized by degeneration of the anterior horn cells in the spinal cord, resulting in progressive weakness and paralysis.15 The reported incidence is approximately 1 in 10,000,15 with severity inversely proportional to the amount of SMNs in the anterior horn cells.16 Childhood-onset SMA can be divided into 3 groups based on clinical presentation and age of onset. In type 1 SMA (Werdnig-Hoffman disease), onset occurs at birth or before 6 months of age, and children do not attain the ability to sit. Death due to respiratory failure usually occurs within the first 2 years. In type 2 SMA, children develop the ability to sit but are unable to walk or stand unaided. In type 3 SMA (Kugelberg-Welander disease), onset occurs later, and children are able to attain walking.16
In the week after receiving the diagnosis of type 1 SMA, the infant was admitted to the hospital due to respiratory distress (Fig. 3). At this point, the terminal course of the disease process was discussed with the parents by several physicians. The parents were educated on the chronicity of the problem and poor likelihood of being weaned from ventilator assistance if intubated. As the infant's health continued to decline, social workers provided counseling to the family and discussed hospice care. Social workers are integral members of interdisciplinary hospital teams providing psychosocial, emotional, financial, and planning aspects of end-of-life care.17 On the fifth day of hospital admission, the infant was transferred to hospice care for comfort care in his last few days of life. Pediatric hospice is a program to care for children with life-limiting illnesses or conditions who have a life expectancy of several months or less.18 In transitioning from the hospital setting, hospice care is a valuable program specifically tailored to the needs of the child and family for medical care, pain management, and social and spiritual support.
Infant displaying hypotonic posture with notable chest retractions in respiratory distress.
Discussion
Hypotonia and gross motor delay are common diagnoses treated by pediatric physical therapists. Common characteristics of children with hypotonia include: weakness, limited tolerance to activity, delayed motor skills, postural abnormalities, joint hypermobility, and poor attention and motivation.19
In this case, following the structured approach of the HOAC II, we identified existing and anticipated problems treatable with physical therapy, recommended consultations when appropriate, and contributed to the diagnostic process for this infant with hypotonia. First, we discussed the history of difficulty latching and cessation of breast feeding combined with chronic respiratory congestion with the referring physician and recommended a feeding evaluation. During the brief episode of care for physical therapy, the pediatrician was consulted twice with concerns of signs and symptoms of SMA, which prompted referral to a geneticist. With the possibility of aspiration, we were keenly observant for signs of respiratory distress, which were apparent on his fourth physical therapy visit, prompting a same-day consult with the pediatrician.
A physical therapist's effective and timely communication with the medical team is necessary, especially in diagnostic cases that may be life threatening. In this case, although the referring physician was aware of the suspected diagnosis of type 1 SMA, the need for obtaining a prompt genetic diagnosis and referral to a pulmonologist should have been articulated clearly. Social service issues related to delays in obtaining authorizations and a genetics consultation could have been explored with additional resources such as a case manager or social worker. Finally, every practitioner must consider the family's emotional state and their ability or willingness to follow through with recommendations provided. It is possible that the delay in diagnosis could be attributed to the family's desire not to know the expected outcome.
Early diagnosis of type 1 SMA is important for several reasons. It allows the parents to be educated about the natural history of the disease and to decide whether to intervene with the course of the disease process. Furthermore, as clinical trials with gene therapy progress to increase full-length SMN protein levels from the SMN2 gene, early detection is an important component of long-term survival.15 Ultimately, the decision to intervene rests with the parents of the child with SMA, provided the diagnosis was obtained early enough for intervention to affect survival.
The prognosis for children with early-onset or type 1 SMA has been the subject of debate in the medical literature. In a 3-year prospective cohort study of 34 cases of infants with genetically proven type 1 SMA, 74% died before the age of 1 year.20 The cause of death uniformly was respiratory insufficiency with or without pulmonary infection. Increased survival, although not statistically significant in this study, was related to increasing proportions of SMN2 genes. Interestingly, the authors noted survival rates may differ depending on the country of origin. In the Netherlands, the standard of care for children diagnosed with type 1 SMA does not include the use of artificial ventilation, treatment for infections, or other life-threatening complications.
In contrast, in the United States, Bach et al16 reported survival beyond the age of 2 years in children with type 1 SMA when treated with noninvasive respiratory support or tracheostomy. The use of a mechanical insufflation-exsufflation (MI-E) device for ineffective coughs and positive inspiratory pressure plus positive end-expiratory pressure (PIP+PEEP) demonstrated decreased hospitalization rates after the age of 5 years, and long-term survival was reported with tracheotomy.
Oskoui et al21 demonstrated a change in survival pattern in 2 groups of children with type 1 SMA from 1980 to 1994 and from 1995 to 2006. Infants born between 1995 and 2006 had a 70% reduction in risk of death compared with the infants born between 1980 and 1994. Specifically, the use of ventilation for more than 16 hours per day, use of an MI-E device, and gastrostomy tube feedings (to protect against aspiration and maintain nutritional intake) significantly reduced the risk of death. These findings suggest a growing trend of more proactive care among physicians and parents of children with SMA.
Counseling and education for families are paramount in the management of children with type 1 SMA. Nutritional compromise as a function of the neurologic degeneration associated with SMA results in an accelerated disease course.15 Proactive care via nutritional interventions may help manage the disease process if identified early. Additionally, the use of MI-E devices to clear airway secretions may help reduce respiratory morbidity and extend the life span when interventions are implemented early. The management of SMA not only involves supportive strategies but includes preventive strategies as well. In clinical trials, treatments based on increasing the expression of full-length SMN protein levels from the SMN2 gene are being investigated. Early detection of the disorder before irreversible loss of motoneurons occurs may affect outcomes. Prevention of new cases through carrier detection and prenatal diagnosis also has been suggested in the literature until effective treatment or a cure becomes available.15
As physical therapists become practitioners of choice for treating individuals with movement disorders and recognized as specialists in movement science, it is our responsibility to patients and families to provide the most appropriate patient management within our scope of practice. Following a consistent management model such as the HOAC II for each infant allows for physical therapists to evaluate clinical signs, which may necessitate referrals to other medical professionals.
As our profession moves toward increasing autonomy of practice with direct access, physical therapists must demonstrate effective clinical decision making. In particular, the physical therapist must be able to treat collaboratively with other health care professionals.22
Footnotes
Dr Malerba provided concept/idea/project design, data collection and analysis, and patient. Both authors provided writing.
This work was completed by Dr Malerba as partial fulfillment of the requirements for the doctor of physical therapy degree.
- Received November 8, 2011.
- Accepted February 15, 2013.
- © 2013 American Physical Therapy Association
References
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