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A four-month-old child with spinal muscular atrophy requires frequent position changes. The patient’s form of spinal muscular atrophy is classified as Type 1 Werdnig-Hoffmann disease. What finding would MOST likely result from the patient being placed in a prone position?

1. Respiratory impairment
2. Hypertonia
3. Proximal muscle weakness
4. Skin breakdown

Transcript

Welcome back to the Scorebuilders’ Question and Answer Podcast! This podcast provides members of the Scorebuilders’ team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination. My name is Scott Giles and I will be your host for today’s journey.

Ready? Let’s go!

A four-month-old child with spinal muscular atrophy requires frequent position changes. The patient’s form of spinal muscular atrophy is classified as Type 1 Werdnig-Hoffmann disease. What finding would MOST likely result from the patient being placed in a prone position?

1. Respiratory impairment
2. Hypertonia
3. Proximal muscle weakness
4. Skin breakdown

Spinal Muscular Atrophy
Spinal muscular atrophy (SMA) is characterized by progressive degeneration of the anterior horn cell. The causative factor of this disease is autosomal recessive genetic inheritance. 

Categories of spinal muscular atrophy include: 

Acute Infantile SMA (Type 1 Werdnig-Hoffmann disease) - Occurs between birth and two months of age. Motor degeneration progresses quickly and life expectancy is less than one year. 

Chronic Childhood SMA (Type 2 Chronic Werdnig-Hoffmann disease) - Presents after six months to one year and has slower progression than infantile SMA. Impairment is steady, however, a child can survive into adulthood. 

Juvenile SMA (Type 3 Kugelberg-Welander disease) - Occurs later in childhood from 4-17 years of age. Children with juvenile SMA typically survive into adulthood.

One of the most common questions I receive related to preparing for the examination is – How do I know the appropriate amount of time to spend on each examination topic. 

This question offers a great opportunity to touch on this topic since it involves a pathology that is somewhat off the beaten path. To frame this discussion, I am going to go back to my MBA training and will explore the production of Guns and Butter 

I don’t remember a lot from my macroeconomic course, but I clearly remember the professor stating that if you want more guns, you are going to have less butter. When I realized this was a real economic concept, it made me feel slightly better about the mental health of the professor.

Basically, the example demonstrates the need to use resources judiciously. Due to scarcity of resources, allocating resources to one area (guns) will mean allocating less resources to another area (butter).

This same concept can be applied to studying for the NPTE. For example, if I spend more time studying diabetes, I will invariably have less time to study spinal muscular atrophy.

This phenomenon occurs since time is a scarce resource, especially for students preparing for the NPTE. 

The key to using your time efficiently when studying pathology is to determine how important each diagnosis is. Importance is based primarily on the frequency in which physical therapists encounter the pathology in clinical practice.

In the example provided, we know that diabetes is likely to dominate spinal muscular atrophy in importance on the examination. However, this is not to suggest that we don’t have to be familiar with spinal muscular atrophy. 

In my opinion, you should know that it is a genetic condition characterized by progressive degeneration of the anterior horn cell. Further, I would expect you to know that there are three different types of spinal muscular atrophy with different times of onset and dramatically different outcomes. I would also expect you to possess a very basic idea of the typical clinical presentation and problem list associated with this condition.

It's probably not realistic to be intimately familiar the specific characteristics of each of the three types Acute Infantile, Chronic Childhood, and Juvenile. In summary, take a superficial, not a deep dive into pathologies slightly off the beaten path. 

Now let’s get back to spinal muscular atropy.

Characteristics for all categories of spinal muscular atrophy are the same, but vary in onset and speed of progression. Characteristics include progressive muscle weakness and atrophy, diminished or absent deep tendon reflexes, normal intelligence, intact sensation, and end-stage respiratory compromise.

Remember, the question is asking what finding would most likely result from the patient being placed in a prone position. 

Let’s explore each of the options:

Option 1 - Respiratory impairment
Respiratory weakness or diminished head control, both common with Type 1 Werdnig-Hoffmann disease, may prevent a child from tolerating prone positioning.

The use of prone positioning must be evaluated and monitored carefully by the therapist since children with spinal muscular atrophy breathe primarily with the diaphragm and prone positioning significantly restricts abdominal expansion.

Rock Solid! 

Option 2 - Hypertonia
Hypertonia is defined as abnormally increased resistance to passive movement at a joint. In the literature, this may be referred to as spasticity or rigidity and is often associated with damage to the central nervous system. 

Spinal muscular atrophy is characterized by hypotonia, not hypertonia, regardless of patient position.

No dice! 

Option 3 - Proximal muscle weakness
Spinal muscular atrophy is characterized by progressive muscle weakness, most prominently affecting the muscles closer to the body’s center (i.e., proximal muscles). This finding can lead to difficulty with activities such as sitting, climbing stairs, rising from a sitting position, walking, and breathing. 

The presence of proximal muscle weakness is independent of the patient’s position.

Yes, but not unique to being in a prone position.

Option 4 - Skin breakdown
The lack of mobility and the absence of normal muscle function around bony areas leads to muscle atrophy and an increased risk of skin breakdown. Each position of the body (e.g., prone, supine, sidelying) places different areas of the body at risk for skin breakdown. 

Despite this fact, the risk of skin breakdown in a child with spinal muscular atrophy is not significantly greater in prone than in other positions. 

Yes, but like with option 3, not unique to being in a prone position 

The correct answer is Option 1

Let’s explore the all student data:
56% of students selected Option 1, Respiratory impairment, the correct response
21% of students selected Option 2, Hypertonia
11% of students selected Option 3, Proximal muscle weakness
12% of students selected Option 4, Skin breakdown

System Classification
This question is a Nervous and Neuromuscular Systems question which represents approximately 24% of all exam items.

Content Outline Classification
This question is an Interventions question which represents approximately 29% of all exam items.

Level Classification
This question is a Level 2 question since the question requires students to integrate numerous pieces of information or to apply knowledge in a given clinical scenario. Remediation of Level 2 questions occurs by increasing flexibility with academic content and by carefully analyzing decision making processes when answering applied examination questions.

Academic Focus Area
Looking to review related academic content? Check out page 322 in PTEXAM: The Complete Study Guide. 

Thanks for joining us on the Scorebuilders Q and A podcast! See you next week!