SENSORY LESIONS Flashcards
This is a subject that doesn’t have sensation in left half of his body. He can’t feel the deep sensations (vibration and others).
? It can only be in the right parietal cortex (or internal capsule), because all fibers that have decussated contralaterally are affected.
Diagnosis: Left facio-brachio-crural hypoesthesia / anesthesia
This patient has lost temperature sensation in the left hemi-face and in the right hemi-soma (= right half of the body) 🡪 called Alternate syndrome.
The lesion is the brainstem, particularly in the right lateral bulbar area. This is due to the fact that in the brainstem you have both the nuclei of the ipsilateral trigeminal nerve (🡪 face innervation, responsible for face sensation) and the passage of contralateral fibers of both motor and sensory systems (🡪 body innervation, these fibers crossed below the brain stem).
). Diagnosis: Sensory alternate syndrome (ballemberg syndrome), it’s usually an ischemic stroke in the brain stem
This subject has had complete resection of spinal cord, which is often what happens in car crashes unfortunately. He’s unable to move, completely paralyzed, but at the same time he’s lost sensation completely 🡪 the patient can’t feel anything below the lesion.
? The lesion is a cut of the spinal cord, which means that all fibers that enter can’t reach their target
Complete spinal cord lesion.
This subject has lost tactile sensation and position sense in the left half of his body and has temperature and pain hypoesthesia on the right side.
The lesion involves half of the spinal cord and the outcome is due to the fact that the spinothalamic and posterior column fibers decussate at different levels. In fact, the lesion causes damage to one half of the spinal cord, resulting in loss of proprioception (🡪 no deep and position sensation) in the ipsilateral side as the lesion (the patient’s left leg), since the dorsal columns didn’t decussate yet, and loss of pain, touch and temperature sensation on the contralateral side (🡪 the patient’s right leg), since the spinothalamic tract already crossed.
Diagnosis: Brown-Sequard syndrome
This subject has suffered a damage isolated to the posterior columns, whose fibers carry proprioception and deep sensation. This may be the result of syphilis infection, which may cause tabes dorsalis (= syphilis myelopathy), or of degenerative or nutritional diseases, that affect only the dorsal columns. If we test pain, these patients can feel it, same with touch and temperature.
Posterior columns, causing loss of sensation deep on both legs
Diagnosis: Isolated lesion of posterior columns
This subject has lost temperature and pain sensation in the chest and upper limb area.
We are dealing with loss of pain and temperature sensation (🡪 nociception 🡪 spinothalamic pathway) on both sides. These fibers enter the spinal cord posterior horn and decussate at the anterior white commissure. Now, the only way you can have this particular condition (which is also suspended, that’s to say that the subject has retained sensation in above and below areas) is because there’s a pathological process at the level of the anterior commissure.
Suspended anesthesia with syringomyelic dissociation due to cervical lesion (syringomyelia🡪enlargement of the ependymal canal only found at the upper part of the spinal cord leading to damage to the anterior commissure).
This subject has lost sensation in the hands and lower limbs. This is the most common type of sensory abnormality. This is the presentation of peripheral polyneuropathy.
This is the classical picture of polyneuropathy, as I said before. This condition affects all peripheral nerves, and it’s due to a systemic condition (🡪 often a metabolic, allergic or immunological one).
This neuropathy affects only the most distal parts of our body because it hits the long axons of peripheral nerves. Of course, at the end of the natural history of the disease, the patient will lose sensation even in the more proximal areas of the body, but it will only happen much further along.
Usually polyneuropathies affect both motor and sensory fibers, so we have both a motor and a sensory deficit. There are, however, some neuropathies that affect only the sensory system 🡪 for example, diabetes causes a sensory neuropathy.
Diagnosis: Hypoesthesia / anesthesia of hands and feet due to neuropathy (🡪 “socks & gloves neuropathy)
