Serotonin receptor agonist and antagonist notes

1. 5-HT 1A receptor :- 

Partial agonists of this receptor are BusPIRONE,

IsaPIRONE, GePIRONE.

These are useful as anti-anxiety drugs.

2. 5-HT 1B/1D receptor :-

Agonists at this receptors are sumaTRIPTAN, NataTRIPTAN.

These are useful for the treatment of acute migraine attacks.

3. 5-HT 2A/2C receptor :-

Antagonists are clozapine and risperidone.

These are used as atypical antipsychotic agents.

4. 5-HT 3 receptor :-

Antagonists are ondanSETRON, graniSETRON, tropiSETRON.

These agents are used in chemotherapy induced vomiting.

5. 5-HT 4 receptor :-

Agonists on this receptors are cisaPRIDE, 

mosaPRIDE.

These are useful in the treatment of GERD.

-Upasana Y. :)

mPFC activation in depression: The Associations

Hey Awesomites

I had talked about how people with neuroticism also have an advantage of being creative in a previous post.
Lets now know the basis of this in brief -

Sinus of Morgagni- Contents

There occurs a gap in the pharyngeal wall between the base of the skull and superior constrictor muscle called as Sinus of Morgagni. This space is closed by the pharyngeobasilar fascia.

Contents- (mnemonic PLATE)

1. Palatine branch of ascending pharyngeal artery
2. Levator palati muscle
3. Ascending palatine artery
4. Tensor vetli palatini
5. Eustatian tube

In nasopharyngeal carcinoma, the tumor may extend laterally and involve this sinus involving the mandibular nerve. This produces a triad of symptoms known as Trotter's Triad. 

These symptoms are:

1) Conductive deafness 

2) Ipsilateral immobility of the soft palate

3) Trigeminal Neuralgia

Hope that helped!

Ashita Kohli

Zenker's Diverticulum

Zenker's Diverticulum is a posterior pulsion diverticulum which occurs through the Killian's Dehiscence.

Killian's Dehiscence is a potential gap between the oblique and transverse fibres of the inferior constrictor muscle. It is also known as the gateway of tears as it is a potential site of perforation during oesophagoscopy. 

Zenker's diverticulum occurs due to the outpouching of the pharyngeal mucosa at the site of Killian's dehiscence.
There is incoordination between the descending peristaltic wave and the cricopharyngeus muscle at the upper oesophageal spincter which leades to high intra luminal pressure and the mucosal herniation through the weak area of Killian's Dehiscence.

It is not a true diverticulum as it has just the herniation of the pharyngeal mucosa. ( A true diverticulum has all the layers of the oesophageal wall)

It is usually seen in elderly above the age of 60.

Symptoms-

1. The most common symptom is Dysphagia, which is intermittent initially and later becomes progressive.
2. Halitosis ( ie. bad breath, well ofcourse because food can get trapped in this pouch)
3. Regurgitation of food and cough.
4. There maybe regurgling sounds in the neck, gurgling sensation on palpation is known as Boyce sign.

Malignancies may develop in 0.5-1% cases.

Diagnosis- Barium Swallow and videofluoroscopy

Treatment-
1. Endoscopic stapling of the diverticulo esophageal sphincter.
2. In patients not fit for major surgeries, Dohlman's surgery may be done.

Hope that helped!
Ashita Kohli

Waldeyer's Ring

Waldeyer's Ring is an aggregation of lymphoid tissue seen in the subepithelial lining of pharynx guarding the nasopharynx and oropharynx in the form of a ring.

The ring is bounded by-

1. Palatine Tonsils ( also called as Faucial Tonsil)- Situated in between the anterior and posterior pillars on each side of oropharynx
2. Adenoids (aka Lushka's Tonsil)- Lies at the junction of roof and posterior wall of nasopharynx
3. Tubal Tonsils ( aka Gerlach's Tonsil)- Lies in the fossa of rosenmuller behind the eustatian tube opening
4. Lateral Pharyngeal Band and Nodules

Hope that helped!
Ashita Kohli

Rhinolalia Aperta

Rhinolalia Aperta is a speech disorder which involves hypernasality in voice.
The defect is seen in the failure of the nasopharynx to cut off from oropharynx.

Some fibres of palatopharyngeus muscle make the posterior pillar, go posteriorly in the posterior wall of nasopharynx and along with the lower fibres of the superior constrictor muscle forms a ridge known as the Passavant's Ridge. 

During swallowing and speaking the passavant's ridge closes the nasopharyngeal isthmus.
When this doesn't happen (eg- cleft lip, paralysis of palate) it leads to nasal regurgitation of food and nasal tone in speech known as Rhinolalia Aperta.

Treatment-

1. In children with cleft palate, special exercises can help in strengthening the muscles so as to reduce the nasality in voice.

2. Surgery- Posterior Pharyngeal Flap
                   Sphincter Pharyngeoplasty


Hope this helps!
Ashita Kohli 

Differentials of lower limb ulceration: Venous, arterial or neuropathic?

Hello!

Q. Today, in our OPD, a 45 year old diabetic Male, farmer by profession presented with an ulcer on left lateral malleolus.

He had a history of edema in lower limb associated with an itching 2 years ago. Since 6 months he got a non-healing ulcer on left lateral malleolus.

On examination:-

Pigmentation of skin, eczema lipodermatosclerosis, atrophied Blanche are present and dilated veins on the medial aspect of left lower limb.

My question is how to differentiate whether the ulcer is due to neuropathy, venous stasis or obliteration of artery.

Why do the above doubt arise?

Because venous ulcer are commonly found at the lower third of the leg usually on the medial side and even on the foot.

Ans.

(I) to rule out neuropathy,

1. Ask whether he feel the ground and pebble while walking barefoot

2. Test for the pain sensation, whether it is intact or not.

(II) Venous ulcer have characteristic findings. History is utmost important. They are shallow and flat. The edge is sloping and purple blue color.

The floor: - appears pink due to presence of granulation tissue. If it is a chronic ulcer there is more white fibrous tissue. Most important is A FAINT BLUE RIM of advancing epithelium may be seen at the margin.

(III) To check for arterial obliteration

1. Feel the dorsal pedis pulsation.

2. Ask for claudication also.

Conclusion: - It was venous ulcer.

Then why did it appear on the lateral side? Remember! On inspection dilated veins were found on the medial side.

Before answering the above question. Let us ask why is it most common on medial side?

There are more perforating veins on the medial side means more pressure in that area. But that doesn't mean lateral side is spared .There is some rise in pressure on lateral side also. The only thing that precipitated this was “Trauma”. Due to more itching on lateral side, he traumatised that area .It was initially small in size, non-healing ulcer which is gradually increasing in the size.

Found this great article on the lower limb ulcers.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1127371/

Take care:)

-Upasana Y.

Authors diary: Tip for solving multiple choice questions

So this random tip comes from a fun conversation that I was having with my study partner today.

Baclofen for treatment of alcohol dependence

Hello!

Recent evidence suggest that the gamma-aminobutyric acid-B receptor agonist baclofen is a promising agent for the treatment of alcoholism.

Yep!

Baclofen produces an effortless decrease or suppression of alcohol craving. It decreases alcohol consumption including in those with poor motivation. The drug causes few side effects and does not add to the intoxication effect of alcohol.

It benefits patients with alcohol dependence (even those who are still in precontemplation stage of motivation!)

Research has shown that baclofen reduces withdrawal symptoms of alcohol and is safe in those with liver impairment.

Although further studies that compare long-term alcohol-related outcome of baclofen with established drugs such as naltrexone and disulfiram are needed.

Interesting, isn't it?

-IkaN

More than what you know about vitamins!

Hello! :)

These were the questions asked during my pharmacology vivas. And I found it fascinating after studying. I have never studied these points about vitamins before! 

Q. Which vitamin deficiency is related with lowering of seizure threshold?

Ans. Pyridoxine Vitamin B6. 

Why? As it is associated with synthesis of neurotransmitter GABA. Therefore, it is indicated during isoniazid induced convulsions. :)

Q. Why laropiprant (20mg) + Niacin (1g) is used in combination?

Ans. Nicotinic acid (a derivative) results in flushing of face.

Why? Vasodilation of cutaneous vessels.

Therefore, we combine it with specific anti-flushing drug called laropiprant.

Q. In hyperemesis gravidarum, what do you give for associated Wernicke's encephalopathy following hyperemesis? 

Ans. I thought of anti-emetics at first but the answer is vitamin B1. (Wernicke's encephalopathy doesn't always result from alcohol :P )

That's for today.
Take care. :)
-Upasana Y.

Lacunar infarction notes + mnemonic

Lacunar infarcts are small (0.2 to 15 mm in diameter) noncortical infarcts caused by occlusion of a single penetrating branch of a large cerebral artery.

Pathophysiology:
Lipohyalinosis of the penetrating arteries. (Mnemonic: L for Lipohyalinosis, L for Lacunar)
Microatheroma of the origin of the penetrating arteries.
Lacunar stroke is usually related to a chronic vasculopathy associated with systemic hypertension.

Clinical features:
Penetrating artery occlusions usually cause symptoms that develop over a short period of time, typically minutes to hours. However, a stuttering course may ensue, as with large artery thrombosis, and symptoms sometimes evolve over several days.

As a general rule, lacunar syndromes lack findings such as aphasia, agnosia, neglect, apraxia, or hemianopsia (so-called "cortical" signs). Monoplegia, stupor, coma, loss of consciousness, and seizures also are typically absent.

These syndromes are common :
● Pure motor hemiparesis
● Pure sensory stroke
● Ataxic hemiparesis
● Sensorimotor stroke
● Dysarthria-clumsy hand syndrome

Pure motor hemiparesis: Characterized by weakness involving the face, arm, and leg on one side of the body in the absence of "cortical" signs (aphasia, agnosia, neglect, apraxia, or hemianopsia) or sensory deficit.

Artery / structure involved: Posterior limb of the internal capsule.

Mnemonic: PM - Pure Motor, Posterior limb of internal capsule.

Pure sensory stroke: Numbness of the face, arm, and leg on one side of the body in the absence of motor deficit or "cortical" signs.

Artery / structure involved: Thalamogeniculate branches of the posterior cerebral artery (Ventral posterolateral and ventral posteromedial nuclei)

Mnemonic: MIST
Motor - Internal capsule
Sensory - Thalamus

Ataxic hemiparesis: Ipsilateral weakness and limb ataxia that is out of proportion to the motor deficit. Some patients may exhibit dysarthria, nystagmus, and gait deviation towards the affected side. As with other lacunar syndromes, the above-mentioned "cortical" signs are absent.

Artery / structure involved:  Fibres of the fronto-ponto-cerebellar system in the internal capsule / corona radiata.

Sensorimotor stroke: Characterized by weakness and numbness of the face, arm, and leg on one side of the body in the absence of the aforementioned "cortical" signs.

Artery / structure involved: Sensorimotor strokes arise from infarcts involving the posterolateral thalamus and posterior limb of the internal capsule. The exact vascular anatomy is debated. 

Dysarthria-clumsy hand syndrome: Facial weakness, dysarthria, dysphagia, and slight weakness and clumsiness of one hand are characteristic. There are no sensory deficits or "cortical" signs.

Artery / structure involved: Lacunar infarctions of the anterior limb of the internal capsule, genu of the internal capsule, or corona radiata.

Treatment:
Intravenous alteplase (recombinant tissue-type plasminogen activator or rt-PA) improves outcomes for patients with ischemic stroke in general if administered within 4.5 hours of symptom onset. The available evidence suggests that intravenous thrombolysis is beneficial for patients with lacunar stroke. Most patients with acute ischemic stroke who are not eligible for thrombolytic therapy should be treated with aspirin.

That's all!
-IkaN

Changes in glomerular dynamics mnemonic

Hello everyone!

If you forgot the afferent - efferent stuff from step 1, I have a mnemonic.

Remember ACE ID, PDA ANC.

Step 2 CK: Management of thromboembolic stroke

Here are my notes. The most simplified version you'll get. 

That's all!

-IkaN

So I've been questioned the most about the last point, regarding heparin. Here's the source and reading material:

There are additional situations of high thrombotic risk after ischemic stroke where anticoagulation may be beneficial but for which there are little or no data. These include mechanical heart valves, carotid artery dissection, and large artery atherosclerotic stenosis.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031793/