Neurology

Sometimes Neurology Is Symmetrical

Huntington disease is a problem of too many CAG repeats. The mutated HTT gene codes for the huntingtin protein. It’s located on chromosome 4.

To remember this, note that H is a rather symmetrical letter. It can be divided into quadrants.

The next time you cut a cake, consider doing it in 4 equal pieces and think of this unfortunate neurological condition.

Bibliography

  1. MedlinePlus Genetics. 2020. HTT gene. [online] Available at: <https://medlineplus.gov/genetics/gene/htt/> [Accessed 1 September 2021].

Advertisement

Broca And Wernicke Memory Aids

Facebook and Twitter! Two important procrastination tools of our time! Many a student has suffered gloriously from these distractions. Finally, they help us to learn medicine, just like you’ve always wanted.

Broca’s Area

Location

  • In the frontal lobe of the brain
  • Facebook
    • Frontal Broca
    • FB

Lesion

  • Broca’s aphasia is expressive aphasia
    • Patient understands things but cannot talk well

Wernicke’s Area

Location

  • In the temporal lobe of the brain
  • Twitter
    • Temporal Wernicke
    • TW

Lesion

  • Wernicke’s aphasia is receptive aphasia
    • Affectionately known as “word salad”
    • Patient says fluent gibberish but does not understand things

Unity

  • Both are usually on the left side
  • Connected by the arcuate fasciculus nerve fibres

References

  1. THE BRAIN FROM TOP TO BOTTOM. (n.d.). BROCA’S AREA , WERNICKE’S AREA, AND OTHER LANGUAGE-PROCESSING AREAS IN THE BRAIN. [online] Available at: http://thebrain.mcgill.ca/flash/d/d_10/d_10_cr/d_10_cr_lan/d_10_cr_lan.html [Accessed 26 Aug. 2018].

Contraindications To Lumbar Puncture

A lumbar puncture is a procedure that involving drawing out cerebrospinal fluid, fondly known as CSF. For example, it can be used to check CSF for immune cells and glucose levels in suspected meningitis.

Lumbar puncture is considered an invasive procedure. But even with that aside, it’s not appropriate for everyone. That is, it does not suit all patients.

Contraindications to lumbar puncture are:

  • Skin infection at the lumbar puncture site
  • Uncorrected coagulopathy
  • Increased intracranial pressure
  • Trauma to the spinal cord

References

  1. Queen’s University School of Medicine. (n.d.). Contraindications. [online] Available at: https://meds.queensu.ca/central/assets/modules/lumbar_puncture/contraindications.html [Accessed 2 Feb. 2018].

The Point Of Stretching

Muscles are a grand amalgamation of thin actin, thick myosin, calcium ions binding to troponin, tropomyosin and Z-lines. They require ATP to be relaxed and use ATP when they undergo contraction.

Stretching helps realign and lengthen muscles to prevent them from being tight and easily injured.

How are muscle contractions triggered in the first place?

Motor neurons use the neurotransmitter acetylcholine to send messages to muscles, prodding them into action. This causes the in-flow of sodium ions, propagating the action potential onward through the muscles. In turn, this invokes the release of calcium ions inside the cells.

The calcium binds to troponin and the obstructive bits move out of the way, allowing actin and myosin to meet for a sweet, brief moment. This is cross-bridge cycling

References

  1. Biology Stack Exchange. (2015). How is ATP involved in muscle contraction?. [online] Available at: https://biology.stackexchange.com/questions/31323/how-is-atp-involved-in-muscle-contraction [Accessed 26 Jan. 2018].
  2. Anon, (n.d.). Muscle Fiber Contraction and Relaxation. [online] Available at: http://oerpub.github.io/epubjs-demo-book/content/m46447.xhtml#fig-ch10_03_01 [Accessed 26 Jan. 2018].
  3. The MIT Tae Kwon Do Club. (2008). STRETCHING AND FLEXIBILITY – Physiology of Stretching. [online] Available at: http://web.mit.edu/tkd/stretch/stretching_2.html#SEC13 [Accessed 26 Jan. 2018].
  4. Harvard Health Publishing. (2013). The importance of stretching. [online] Available at: https://www.health.harvard.edu/staying-healthy/the-importance-of-stretching [Accessed 26 Jan. 2018].

Types Of Multiple Sclerosis

Time heals all wounds except relapsing-remitting MS.

And primary-progressive MS.

And secondary-progressive MS.

And whole bunch of other age-related illnesses, like glaucoma, age-related macular degeneration and malignancy.

At least time is good for adhesive capsulitis, alternatively known as frozen shoulder!

Multiple sclerosis

MS is a chronic disease involving immune-mediated attacks on the central nervous system. Demyelination causes mayhem.

As a parallel, Guillan-Barre acutely affects the peripheral nervous system. When it’s chronic, it’s called chronic inflammatory demyelinating polymyopathy.

Symptoms

Neurological symptoms ensue after the disease has passed a threshold.

  • Optic neuritis, characterised by painful visual loss in an eye
  • Numbness, weakness
  • Ataxia, spasticity
  • Fatigue
  • Pain
  • Sexual and urinary dysfunction, such as detrusor overactivity causing urgency

Clinically isolated syndrome is a one-off presentation of demyelination that can progress to MS.

Investigations

MRI can show brain lesions.

CSF analysis can show inflammation.

Evoke potential measurement can show demyelination.

Treatment

Ongoing: immunotherapy agents.

Acute relapse: high-dose corticosteroids.

Spasticity: baclofen

Spasms: benzodiazepines

Mobility: fampridine

Paroxysmal symptoms: carbamazepine

Urinary symptoms: oxybutynin

Pregnancy

The risk of MS relapse is lower during pregnancy and higher in the first 3 months after giving birth.

Summary of major demyelinating illnesses

Central nervous system: clinically isolated syndrome (acute), MS (chronic)

Peripheral nervous system: Guillan-Barre (acute), CIDP (chronic)

References

  1. MS Australia. (2001). Types of MS | MS Australia. [online] Available at: https://www.msaustralia.org.au/about-ms/types-ms [Accessed 20 Jan. 2018].
  2. National Multiple Sclerosis Society. (n.d.). Definition of MS. [online] Available at: https://www.nationalmssociety.org/What-is-MS/Definition-of-MS [Accessed 20 Jan. 2018].
  3. Johns Hopkins Medicine. (n.d.). Guillain-Barre and CIDP. [online] Available at: https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/peripheral_nerve/conditions/guillain_barre_and_cidp.html [Accessed 20 Jan. 2018].
  4. Multiple sclerosis. In: eTG complete [Internet]. Melbourne: Therapeutic Guidelines Limited (eTG November 2017 edition); 2017 Nov.

Myelinating Cells

Myelin is the fatty, insulating sheath that surrounds some neurons, specifically their axons. It allows electrical impulses to travel faster down nerves.

Here are the cells that make myelin.

  • Central nervous system: oligodendrocytes
    • Memory aid: o is symmetrical and central-looking, like the cross-section of a stick; dictators wave batons around while giving heinous orders and they’re rather central to autocracy
  • Peripheral nervous system: Schwann cells
    • Memory aid: s is for side, in reference to the periphery

References

  1. Agamanolis, D. (2011). Oligodendroglia and ependymal cells. [online] Neuropathology. Available at: http://neuropathology-web.org/chapter1/chapter1cOligodendroglia.html [Accessed 11 Jan. 2018].