Select a Community
Are you sure you want to trigger topic in your Anconeus AI algorithm?
You are done for today with this topic.
Would you like to start learning session with this topic items scheduled for future?
Bacterial cell
0%
0/0
Endothelial cell
Oligodendrocyte
Schwann cell
Skeletal muscle cell
Select Answer to see Preferred Response
This patient presenting with unilateral vision loss, pain with extraocular movements, and upper motor neuron signs (increased tone, clonus) with a prior episode of motor weakness is most likely presenting with optic neuritis in the setting of multiple sclerosis (MS). MS is characterized by autoimmune destruction of myelin sheaths in the central nervous system (CNS), which are produced by oligodendrocytes. MS is caused by an autoimmune attack on oligodendrocytes, which are the myelinating cells of the CNS. Oligodendrocytes produce myelin, which forms a sheath that is a direct extension of the oligodendrocyte cell membrane that encircles axons to promote neuronal conduction. Autoimmune-mediated damage to these cells results in demyelination of the CNS, with clinical findings that are dependent on the neurological territory affected. MS is diagnosed by demonstration of CNS lesions disseminated in both space and time, which can be either clinical or assisted by magnetic resonance imaging (MRI). CT scans typically do not show these areas of focal demyelination. If lumbar puncture is performed, oligoclonal IgG bands are observed. Common clinical findings include optic neuritis, internuclear ophthalmoplegia, ataxia, upper motor neuron signs (e.g., Babinski sign), motor weakness, and/or sensory loss. Yeung et al. studied myelin degeneration and regeneration mediated by oligodendrocytes. They showed impairment in oligodendrocyte regeneration in most patients with MS. Incorrect Answers: Answer 1: Bacterial cells can produce toxins that cause motor weakness, such as botulinum toxin from Clostridium botulinum. Botulism presents with descending flaccid paralysis, diplopia, dysphagia, dysarthria, and difficulty breathing in a patient who ingested improperly canned food. It would not cause upper motor neuron signs or unilateral vision loss. Answer 2: Endothelial cells produce von Willebrand factor (vWF), which is involved in hemostasis and is abnormal in von Willebrand disease (vWD). In vWD, patients present with easy bruising and prolonged cutaneous or mucosal bleeding with minor trauma. While vWD could make a hemorrhagic stroke worse, it does not typically cause stroke. Also, hemorrhagic stroke presents in more severely ill patients with altered mental status, headache, and motor/sensory loss. Answer 4: Schwann cells produce myelin in the peripheral nervous system (PNS). PNS demyelination occurs in Guillain-Barre syndrome, which presents in patients after a recent genitourinary or gastrointestinal infection with areflexia and ascending paralysis. It causes lower motor neuron signs, not upper motor neuron signs. Answer 5: Skeletal muscle cells produce dystrophin, which is abnormal in patients with Duchenne or Becker muscular dystrophy. These patients are predominantly boys because these are X-linked disorders and present with proximal muscle weakness at a young age (younger in Duchenne compared to Becker muscular dystrophy). These would be unlikely in this woman. Also, these muscular dystrophies do not cause upper motor neuron signs or unilateral vision loss. Bullet Summary: Multiple sclerosis is caused by autoimmunity against oligodendrocytes and their myelin products.
0.0
(0)
Please Login to add comment