FROM MY PT SCHOOL NOTES · NEUROLOGY · UNIT 6 · CHAPTER 22
How do peripheral neuromuscular disorders differ?
A patient with weakness may have a motor-neuron disorder, a peripheral nerve problem, a neuromuscular-junction disorder or a primary muscle disease. Their typical patterns and safety needs are not interchangeable.
Build the clinical picture
Think about the affected structure
Motor-neuron disorders can produce progressive weakness with varying upper and/or lower motor-neuron findings. Polyneuropathies commonly alter distal sensation, reflexes and motor control, sometimes affecting balance and foot protection. Myopathies may cause proximal weakness and fatigue without the same primary distal sensory pattern.
Myasthenia gravis (MG) affects neuromuscular-junction transmission and can produce fluctuating fatigable weakness, ptosis, diplopia, bulbar and sometimes respiratory symptoms. Lambert–Eaton syndrome is a different neuromuscular-junction disorder and must not be treated as a subtype of MG.
Choose the next examination based on the pattern
Document time course, distribution, sensory findings, strength, reflexes, fatigability, hand and foot function, gait and functional demands. Consider relevant medical workup and electrodiagnostic information, but do not infer a precise diagnosis from a single manual strength test.
In peripheral sensory loss, evaluate foot protection and balance, including environmental demands. In suspected motor-neuron or neuromuscular-junction conditions, bulbar/respiratory status is an especially important medical safety consideration.
Adjust exercise to disease and response
Functional practice, individualized resistance/endurance work, assistive equipment and fatigue management can be appropriate, with different precautions across diagnoses and stages. Avoid rigid prescriptions that assume all neuromuscular conditions respond identically to high-intensity strengthening.
New or worsening breathing or swallowing problems in MG are urgent. Severe or progressive breathing difficulty may signal myasthenic crisis and requires emergency medical care, not an exercise trial. Refer to the Myasthenia Gravis Foundation of America.
At a glance
| Polyneuropathy | Often distal sensory/reflex and balance changes |
| Myopathy | Often proximal muscle weakness and task endurance concerns |
| MG / NMJ dysfunction | Fluctuating fatigability; bulbar/respiratory safety is critical |
| Motor-neuron disease | Progressive strength/function concerns and team-supported planning |
Clinical reasoning
A patient with MG says they can walk in the morning but develops progressively slurred speech and difficulty swallowing later in the day. Is an endurance exercise test the next step?
Answer: No. Changing bulbar symptoms may signal medical deterioration and warrant urgent evaluation. Escalate rather than increasing exercise demands.
Check your understanding
Which findings make a distal sensory neuropathy different from a condition causing fatigable ocular/bulbar weakness?
Source notes: 1 Neuromuscular Diseases.pdf; Myasthenia gravis.pdf; Diabetic Neuropathy and Balance.pdf. Historical note: Some old disease categories and treatment percentages have changed. Compare your class notes with current condition-specific guidance, particularly MG emergency recommendations. Educational content; not an individual diagnosis or medical protocol.
