Will upper and lower limb muscle tone on the left side increase or decrease in a patient with a hypertensive left thalamic (thalamus) hemorrhagic cerebrovascular accident (CVA)?

From the Guidelines

In a patient with a hypertensive left thalamic hemorrhagic CVA, you should expect increased muscle tone (spasticity) in both the upper and lower limbs on the right side of the body, not the left. This occurs because motor pathways cross in the brainstem, causing contralateral effects. The thalamus plays a crucial role in modulating motor function through connections with the basal ganglia and motor cortex. When hemorrhage damages the left thalamus, it disrupts these inhibitory pathways, leading to disinhibition of motor neurons on the opposite (right) side of the body. Initially after the stroke, patients may experience flaccidity, but this typically evolves into spasticity within days to weeks. Management of this increased tone may include physical therapy, positioning, range of motion exercises, and medications such as baclofen, tizanidine, or botulinum toxin injections if spasticity becomes functionally limiting, as supported by the 2025 guidelines from the U.S. Department of Veterans Affairs and U.S. Department of Defense clinical practice guidelines 1. Key recommendations for spasticity management include:

• Targeted injection of botulinum toxin into localized upper limb muscles to reduce spasticity, improve passive or active range of motion, and improve dressing, hygiene, and limb positioning, with a Class I, Evidence A recommendation 1.
• Targeted injection of botulinum toxin into lower limb muscles to reduce spasticity that interferes with gait function, also with a Class I, Evidence A recommendation 1. Early rehabilitation is essential to prevent contractures and optimize functional recovery. It's worth noting that evidence supports the use of botulinum toxin for patients with focal spasticity depending on patient characteristics and preferences, with a change in recommendation from “strong for” in 2019 to “weak for” in 2024 1.

From the Research

Expected Outcome for Muscle Tone

• In a patient with hypertensive left thalamic haemorrhagic CVA, the expected outcome for muscle tone on the left side is an increase in muscle tone, also known as hypertonia 2.
• This is because thalamic haemorrhage can cause damage to the thalamus, which is involved in the regulation of motor function, leading to increased muscle tone on the contralateral side of the body 3.
• The posterolateral type of thalamic haemorrhage, which is the most frequent type, is characterized by large haematomas and frequent extension into the posterior limb of the internal capsule, leading to marked sensory and motor signs, including increased muscle tone 3.
• Hypertensive thalamic hemorrhage is associated with a higher frequency of ventricular irruption and bad prognosis at short-term, which may also contribute to the development of hypertonia 4.

Factors Influencing Muscle Tone

• The location and size of the haematoma, as well as the presence of intraventricular irruption, can influence the development of hypertonia in patients with thalamic haemorrhage 3, 4.
• The management of blood pressure in patients with hypertensive thalamic haemorrhage is complex and requires an accurate diagnosis and precise definition of therapeutic goals, which can also impact the development of hypertonia 5.
• The use of intrathecal baclofen has been shown to be efficacious and safe in managing post-stroke hypertonia, including in patients with thalamic haemorrhage 2.