Friday, May 26, 2017

Types of barium-contrast imaging.

Hello everybody!

Let's quickly revise the types of Barium investigations.

So to enlist the investigations are: Barium swallow, barium meal, barium follow-through, and barium enema.

The barium swallow, barium meal, and barium follow-through are together also called an upper gastrointestinal series (study), whereas the barium enema is called a lower gastrointestinal series (study).


Procedure:

In upper gastrointestinal series examinations, the barium sulfate is mixed with water and swallowed orally, whereas in the lower gastrointestinal series (barium enema), the barium contrast agent is administered as an enema through a small tube inserted into the rectum.


Let's review individual examinations breifly:

Barium swallow X-ray examinations are used to study the pharynx and esophagus.

Barium meal examinations are used to study the lower esophagus, stomach and duodenum.

Barium follow through examinations are used to study the small intestine.

Enteroclysis also called small bowel enema is a Barium X-ray examination used to display individual loops of the small intestine by intubating the jejunum with a small tube and administering Barium sulfate followed by methylcellulose or air.

Barium enema examinations are used to study the large intestine and rectum.

Hope this was useful!

Let's learn Together!

-Medha.

Wednesday, May 24, 2017

Autism and ADHD : The clinical intersection

Hello

Autism and Attention - Deficit Hyperactivity Disorder (ADHD) may co - occur in upto 80% of children and they share about 50 - 75% of their genetic factors and pathologic features, thus resulting in some clinical intersection.

NBME 7 question on muscle weakness

Disclaimer: This is an NBME form 7 question for step 2 CK. If you are planning to take USMLE step 2 CK in the future, I would recommend that you DO NOT read this post because it will bias your assessments.

CMS neurology form 2 question on fibromuscular dysplasia with paresis, occulomotor palsy

Disclaimer: This is an CMS neurology form 2 question for step 2 CK. If you are planning to take USMLE step 2 CK in the future, I would recommend that you DO NOT read this post because it will bias your assessments.

CMS neurology form 2 question on headache, seizures, urinary incontinence, broad based gait

Disclaimer: This is an CMS neurology form 2 question for step 2 CK. If you are planning to take USMLE step 2 CK in the future, I would recommend that you DO NOT read this post because it will bias your assessments.

NBME 7 question on intoxication

Disclaimer: This is an NBME form 7 question for step 2 CK. If you are planning to take USMLE step 2 CK in the future, I would recommend that you DO NOT read this post because it will bias your assessments.

Tuesday, May 23, 2017

Fact of the day : Pinenes for refreshing your Airways

Hello

Did you know? One of the reasons your lungs feel refreshed ( increased mental focus and energy ) when you walk through the shades of beautiful pine forest is because of an anti - inflammatory compound called alpha -Pinene, that is found in conifers. It is used as a bronchodilator in the treatment of asthma and is abundantly present in marijuana.

- Jaskunwar Singh

Pill induced esophagitis mnemonic

Pill induced esophagitis is caused by a pill! :D

Causes of pill induced esophagitis mnemonic: A PILL.

Aspirin
Alendronate
Antibiotics like tetracycline, clindamycin

Potassium chloride
Iron
Less water
Lying down immediately

Interesting anatomy correlation:
The most common sites of injury are the proximal esophagus near the compression from the aortic arch and the distal esophagus in patients with left atrial enlargement.

The typical endoscopic appearance of pill-induced esophageal injury is a discrete ulcer with relatively normal surrounding mucosa.

That's all!
-IkaN

Motor nuclei in the brainstem : An overview

Hi everyone. Just thought of doing an overview of the various motor nuclei of cranial nerves in the brain stem.

So we can classify the motor nuclei into 3 groups -
1. Somatic motor efferent - 4
2. Branchial motor efferent - 4
3. Visceral motor efferent - 4
Now how are these classified ?

1. Somatic Motor Efferent

- In the embryological stage , there are certain precursors to muscle and skin segment groups called 'Somites'. These are processes of the paraxial mesoderm.
- Sach somite gives rise to a particular set of muscles called its myotome. 
- There 4 such important somite groups -->

A. Pre otic somites = 3.
So this is simple.
There are 3 pre otic somites giving rise to distinct groups of extraocular muscles supplied by their own cranial nerve.

Somite 1  =
Muscles -
All Extra ocular muscles except Lateral Rectus and Superior oblique.
Nerve -
Oculomotor nerve (III)
Nucleus -
Oculomotor nucleus in the Upper Midbrain.

Somite 2  =
Muscles -
Superior oblique.
Nerve -
Trochlear nerve (IV)
Nucleus -
Trochlear motor nucleus in the Lower Midbrain.

Somite 3  =
Muscles -
Lateral Rectus.
Nerve -
Abducent nerve (VI)
Nucleus -
Abducent motor nucleus in the Pons.

(I'm sure you remember the popular mnemonic - LR6 SO4)

B. Occipital somites
Muscles -
All muscles of the tongue except Palatoglossus
Nerve -
Hypoglossal I'm nerve (XII)
Nucleus -
Hypoglossal nucleus in the Medulla.

Since these nuclei represent the motor innervation to the derivatives of Somites , they're called Somatic Motor or General Somatic Efferent (GSE) Fibres. 


2. Branchial Motor Efferent - 

- In the embryological stage , there are various branchial or Pharyngeal arches that give rise to muscles , bones and cartilage supplied by a particular nerve of that arch.

- Each nucleus that supplies the muscles from such a Branchial arch is called Branchiomotor Efferent or Special Visceral Efferent. (SVE) 
- There are 4 such important arches - 

A. 1st Pharyngeal arch (mandibular arch)
Muscles -
All muscles of mastication + TT (Tensor tympani + Tensor veli Palatini) + Digastric anterior belly. ( And Meckel cartilage)
Nerve -
Mandibular branch of Trigeminal
Nucleus - 
Trigeminal motor nucleus in Pons 


B. 2nd Pharyngeal arch (hyoid arch) 
Muscles -
All muscles of facial expressions + Stapedius + Digastric posterior belly.  ( And Reichter cartilage)
Nerve -
Facial nerve (VII)
Nucleus - 
Facial motor nucleus in Pons 


C. 3rd Pharyngeal arch
Muscles -
Stylopharyngeus
(And the hyoid bone funnily.)
Nerve -
Glossopharyngeal nerve (IX)
Nucleus - 
Nucleus Ambiguus in Medulla


D. 4th and 6th Pharyngeal arches
Muscles -
- All muscles of  Soft palate ( except Tensor veli which is up in the 1st arch) by the 4th. + cricothyroid muscle of Larynx. 
- All muscles of Larynx by the 6th except cricothyroid which is by the 4th. 
(All laryngeal cartilage as well)
Nerve -
4th arch - Superior laryngeal nerve of the Vagus.(X)
6th arch - Recurrent laryngeal nerve of the Vagus (X)
Nucleus - 
Nucleus Ambiguus of Medulla 

Now there's another Motor nucleus - The Accessory nerve. It supplies Trapezius and Sternomastoid muscles but it's doubtful if it's Branchial or Somatic. 


3. Visceral Motor Efferent - General

- These nuclei are parasympathetic and stimulate a particular gland to secrete or a ganglion to function. 
- These are called Secretomotor or General Visceral Efferent Fibres 

Again , there are 4 of these. 

A. Ciliary ganglion 
Function mediated by - 
Sphincter pupillae - Constricts pupil 
(Mnemonic = Remember C and C - Cholinergic Constricts )
Nerve -
Oculomotor nerve
Nucleus - 
Edinger Westphal in Midbrain 


B. Pterygopalatine ganglion 
Function mediated by - 
Lacrimal glands, nasal mucosal, sinuses mucosal glands and pharynx mucosal - Secretomotor. 
Nerve -
Facial nerve  (Greater Petrosal)
Nucleus - 
Superior salivatory nucleus - Pons. 

C. Submandibular ganglion 
Function mediated by - 
Submandibular glands , sublingual glands - Secretomotor.
Nerve -
Facial nerve  (Chorda tympani)
Nucleus - 
Superior salivatory nucleus - Pons. 

D. Otic ganglion 
Function mediated by - 
Parotid gland
Nerve -
Glosspharyngeal nerve  (Lesser Petrosal)
Nucleus - 
Inferior salivatory nucleus - Pons. 

The Vagus nerve has the largest parasympathetic discharge and supplies a lot of visceral with this input in the guy as well.

Hope this helps you to re-orient yourself to neuroanatomy and grasp the roles of various brainstem structures ! 
Happy studying ! 
~ A.P.Burkholderia

Monday, May 22, 2017

Lacunar strokes : An Overview


      Hi everyone ! Here's a short post on Lacunar infarcts. Credits to IkaN without whom IKant have done this post. Haha ;;) here goes.

- A Lacunar infarct is an infarction occurring    in the deep penetrating branches supplying the deep subcortical structures - Mainly the Internal capsule and parts of thalamus. 

- These are some of the most common infarctions seen. 

- Causes of lacunar infarction include Hypertensive bleeds and Microthrombi. 

- So these infarcts can present as one of the following​ Syndromes --> 

1. Pure Motor 
2. Pure Sensory 
3. Combined Sensorimotor 
4. Ataxic 
5. Dysarthria- Clumsy hand syndrome. 

- The illustrations I've drawn below clearly depict the syndromes , their anatomical localization and the arteries commonly involved. 

- The commonest of the lot is the Pure Motor type of stroke that affects mainly the Internal capsule containing the motor corticospinal fibres. Since a multitude of Fibres is concentrated very judciously in the Internal capsule , the hemiplegia resulting from this type is a 'Dense' or total hemiplegia affecting both upper and lower limbs in equal measure. 
(click on the image to see them in better resolution ) 




- The management is much like the other strokes - 
1. Airway Breathing Circulation to be established. 
2. Check Blood sugar and BP.
3. Send for an emergency Non contrast CT scan to rule out hemorrhage. 
4. If within 3-4.5 hours and absence of hemorrhage = Thrombolyse. 
5. If hemorrhage - BP control and ICT management.
6. If beyond 4.5 hours = Symptomatic and Palliative care and treat risk factors.


- I hope all of these Syndromes are clear to you now !
 Let me know if you'll have any doubts. 
Happy Studying ! 
Stay awesome.
~ A.P.Burkholderia

Fact of the day: Marchiafava-Bignami disease

Marchiafava-Bignami disease is a rare disorder of demyelination or necrosis of the corpus callosum and adjacent subcortical white matter that occurs predominantly in malnourished alcoholics. Dementia, spasticity, dysarthria, and inability to walk may present as an acute, subacute or chronic condition.

Lesions appear as hypodense areas in portions of the corpus callosum on CT and as discrete or confluent areas of decreased T1 signal and increased T2 signal on MRI. Alcohol abusers without liver disease, amnesia, or cognitive dysfunction show thinning of the corpus callosum at autopsy and on MRI, suggesting that alcohol or malnutrition damages the corpus callosum commonly in the absence of the necrotic lesions of Marchiafava-Bignami disease.

Interesting, isn't it?
-IkaN

High ankle and low ankle sprain mnemonic

Hello!

High ankle and low ankle sprain