Upper motor neuron lesions are characterized by which of the following? 1. Increased tone spasticity 2. Hyperreflexia 3. Absent plantar response 4. Motor weakness Select the correct answer using the code given below.
Understanding Upper Motor Neuron Lesion Signs
Upper motor neuron (UMN) lesions disrupt the descending motor pathways originating in the cerebral cortex and brainstem, affecting voluntary movement control.
Key Characteristics of UMN Lesions
Several clinical signs are typically associated with UMN lesions. Let's analyze the given points:
- 1. Increased tone (spasticity): This is a classic sign. UMNs normally exert inhibitory control over spinal reflexes. Damage leads to loss of this inhibition, resulting in increased muscle tone, often perceived as stiffness or spasticity (velocity-dependent resistance).
- 2. Hyperreflexia: Similar to spasticity, the loss of UMN inhibitory control exaggerates deep tendon reflexes (e.g., knee jerk, ankle jerk).
- 3. Absent plantar response: This is incorrect. UMN lesions typically cause an abnormal plantar response, known as the Babinski sign, where the big toe dorsiflexes and other toes fan out upon stroking the sole of the foot. A normal or absent (flexor) plantar response indicates intact UMN pathways to the corticospinal tract controlling this reflex.
- 4. Motor weakness: UMN lesions interrupt the pathway for voluntary movement, leading to weakness (paresis) in the affected muscles, often more pronounced proximally.
Conclusion on UMN Lesion Symptoms
Based on the analysis, the characteristic signs of upper motor neuron lesions among the choices are increased tone (spasticity), hyperreflexia, and motor weakness. The absent plantar response is incorrect; a positive Babinski sign is characteristic.
Therefore, points 1, 2, and 4 accurately describe UMN lesion characteristics.
Important Questions from Brain & Nervous System Surgery
Which of the following chromosomal abnormalities are associated with brain tumours?
1. Neurofibromatosis type 1
2. Neurofibromatosis type 2
3. Peutz-Jeghers syndrome
4. Hereditary nonpolyposis colorectal cancer
Select the correct answer using the code given below.
Consider the following clinical features:
1. Raised ICP
2. Seizures
3. Focal deficit
4. Headache
Which of the above clinical features are related to most brain tumours?
- The most common type of brain tumours associated with neurofibromatosis type 1 brain tumour syndrome is
A comatose patient after sustaining severe head injury has been admitted in neurosurgical ICU. Which of the following parameters should ideally be maintained in this patient ?
1. $pCO_2 = 4.5 – 5.0$ kPa ($33-38$ mm Hg)
2. MAP = $80 – 90$ mm of Hg
3. $pO_2 > 11$ kPa ($> 80$ mm Hg)
4. $Na^+ < 130$ meq/L
Select the correct answer using the code given below :
- A patient with suspected head injury is brought to the emergency following road traffic accident. At the time of examination, patient is conscious with GCS 14/15 and stable vitals. There is bleeding from right ear and CSF leak from nose. Bruising is present behind the right ear. The most probable clinical diagnosis in this patient is
