Seizures and Deficits...What to Do?

Today, we have, back by popular request, another lesion localization practice case! Enjoy!!

Signalment: 7 year old MC Pitbull-X (maybe Boxer dog?)
History: The dog presented with a history of 2 seizures, 1 day apart. Since the seizures, the dog has been walking compulsively to the left, and appears to bump into objects. Although a decreased appetite has been appreciated, the dog is still eating when hand fed.

Physical Examination: unremarkable

Neurologic Examination:
Mentation: Obtunded
Cranial nerves: Absent menace OD, intact PLR OU, mild head turn left, remainder normal.
Gait: Ambulatory with intermittent compulsive circling to the left. He is able to walk to the right when asked but will not continue the circles without inspiration.
Postural reactions: normal all limbs.
Reflexes: Normal all limbs.
Palpation: no spinal pain and normal cervical ROM and tail jack.

Neuroanatomic lesion localization (NALL) Practice

Let's look at the examination is sequence as it is listed above. If you wish to use the table format that I prefer, please look at the tables provided in the Small Animal Neuroanatomic Lesion Localization Practice Book (publisher CABI, date 2022 by yours truly). We'll discuss it in conversation format for this TidBit Tuesday.

Seizures: Seizures ALWAYS localize to the forebrain and are not readily lateralized (left or right side).

Obtunded: reduced mentation is noted with lesions in the forebrain and brainstem. This is NOT a clinical sign of cerebellar, spinal cord or neuromuscular disease, nor a non-neurologic finding. This narrows our lesion localization to forebrain or brainstem.

Cranial nerves: The menace pathway, in it's most basic sense, involves CN 2, the forebrain and CN 7. PLR involves CN 2, midbrain and CN 3. The blink reflex is not states as being abnormal above (blink reflex: CN 5 and CN 7) therefore by process of elimination, the menace deficit OD is most likely due to a forebrain lesion. The second part of the story is lateralization. Only the right eye is affected. This is a crossing tract (mostly) which means that the lesion should be on the left side of the forebrain.

Gait: The compulsive circling to the left is localized to the forebrain and, rarely, vestibular system. Localization to the vestibular system is most likely when a head tilt is present. Without a head tilt, I would consider a forebrain lesion most likely and they circle TOWARDS their lesion. This would further support a left forebrain lesion.

NALL: Left forebrain

How'd you do? Did anything surprise you with the NALL? If you enjoyed this case, thank your colleagues for suggesting a seizure NALL case for practice. :)

As a reminder, I will be out of the country starting next week through November 14th. I will be available by email ONLY (no cell phone service) and will be doing my best to keep up on emails. Please expect minor delays in my response because I will be lecturing and we'll be on different time zones but I will do my best to be as responsive as possible. Have a great week!