Sunday, July 29, 2018

Trapezius and pericarditis.

Suppose a patient of 40 years of age male comes to you with complaints of  chest pain which is often heavy, squeezing and crushing.
You make up the diagnosis of MI based upon the symptoms in your mind. Proceeding for proper history of case you ask patient if the pain is radiating type.
Patient explains you that the pain is radiating and he is eventually experiencing pain in to the back of this some muscle. You find out that he is pointing towards the "Trapezius muscle" .
Now, this should raise an alarm in your mind. You should stop thinking about MI.
Both NSTEMI and STEMI shows pain which is radiating in nature. Pain involves the central portion of the chest, sometimes epigastrium and occasionally it radiates to the arms. Less common involves back, neck, lower jaw. Pain can radiate as high as occipital area but never below umbilicus.
but it never radiates to trapezius.
Depicting exact lines of Harrison textbook of medicine.
"Radiation of discomfort to the trapezius is not seen in patients with STEMI and is  useful in correct diagnosis of pericarditis"
Now, why pain radiates to trapezius?
Pericarditis, as name suggests inflames the pericardial sac of the heart. This causes irritation of the vagus nerve supplying heart. Vagus nerve is affected because it is closely related to pericardial sac. Vagus nerve acts as the afferent nerve fibers. These fibers reaches nucleus tractus solitarius in the medulla oblongata. From there it comes downwards reaches cervical plexus C2, C3 and C4. From there, the nerve fibers formed supplies lower part of trapezius.
Trapezius nerve supply:
Upper part is supplied by the spinal accessory nerve.
Lower part is supplied by the nerves from C3 and C4 only.
Hence pain radiates to trapezius in pericarditis.
-Vipul and Ojas.

Update from IkaN: It's wrong to say that the pain of MI "never" radiates to the trapezius (which is in the back) because occasionally, pain of MI can radiate to the back. Also, pain radiating to the back should alarm you to a more serious diagnosis - aortic dissection. 

Wednesday, July 18, 2018

Can you find Asterixis in Non-Hepatic disorders?

Hello Awesomites! :D

This doubt came to my mind when I saw a case of COPD with asterixis.
 I used to think of asterixis with respect to hepatic disorders only.
 So let see is it so?

"Asterixis"is a non-specific sign. It is also known as flapping tremor.

It is a non-specific neurologic finding which may accompany organic delirium in a variety of metabolic or toxic disorders which interfere with cerebral metabolism.

It can be found in the cases with:-

1. Chronic pulmonary insufficiency

2. Uremia

3. Drug induced electrolyte imbalance

4. Arterial hypoxemia

5. Other reasons of electrolyte imbalance.

 Stay Awesome!

Upasana Y. :)

Thursday, July 12, 2018

Authors' diary: Ponder

We were discussing a case today and learnt how important it is to take a second to think before we do something when dealing with patients.

Before you get a CT scan on the patient in the ER, stop and think - does the patient really need a CT scan? Will it get me the answers I'm looking for? Or will I need additional testing? Think of the harms of radiation exposure. Unless you don't want to rule out a hemorrhage that requires immediate intervention, do not order it STAT.

Tuesday, July 3, 2018

Dentinoenamel Junction

  • DEJ appears as a scalloped line.
  • The convexities of scallop are directed towards the dentine 
  • The surface of dentine appears pitted
  • DEJ provides strength to the union between enamel and dentin
Clinical Significance:
  • Prevents shearing of enamel when functioning.
  • Scalloping of the junction is seen more in the occlusal portion where masticatory stresses are high.
- Written by Anisha Valli

Enamel Lamellae

Thin, leaf-like structure that extends from enamel surface towards DEJ
Sometimes, they penetrate towards DEJ
They consist of organic material but with a little amount of mineral content.

Types of enamel lamellae:

  • Type A: Lamelle composed of poorly calcified rod segments
  • Type B: Lamelle consists of degenerated cells
  • Type C: Lamelle arising in erupted teeth where cracks are filled with organic material, originating from saliva

Type A is restricted to enamel
Type B and C are restricted to dentine

Clinical Significance: 

  • It is a site of weakness in a tooth.
  • It forms a road of entry for bacteria to initiate caries.
Written By Anisha Valli

Hunter-Schrengar bands

The change in the direction of rods is responsible for Hunter Schregar bands.

These bands are the functional adaptation to occlusal masticatory forces.

Alternating, light and dark bands of varying width that can be seen in longitudinal cross-section under the obliquely reflected light.

Dark bands: Parazones
Light Bands: Diazones

The angle between the bands is 40 degrees

- Written by Anisha Valli

Zone Of Weil

Zone of Weil is present below the odontoblastic zone.
  • Its a layer of 40um.
  • It is also known as the sub-odontoblastic layer.
  • It doesn't consist of cells.
  • This zone is prominently seen in the coronal pulp.
  • Cell-free zone decreases in size when dentin formation occurs at a rapid rate.
  • The cell-free zone consists of a network of nerve fibres which lost their myelin sheath. This is known as Plexus of Rashkow.
Written by Anisha Valli