Pathophysiology of myopathy caused during hypothyroidism and hyperthyroidism

Hello awesomites! Today's topic of discussion is - Myopathy in thyroid disease.

Interestingly, it is caused by both, hypothyroidism as well as hyperthyroidism.

What is myopathy?

It is a disease of muscle tissue where, ultimately, muscles get weak and are unable to perform work due to deficiency of ATP.

Why is there myopathy in hyperthyroidism?

The thyroid hormone is a catabolic hormone. Hyperthyroidism increases energy expenditure, glucose turnover, lipolysis, and protein breakdown (proteolysis). But here is the catch - Hyperthyroidism increases whole-body protein turnover and breakdown before any measurable changes in energy expenditure or glucose and fat metabolism, suggesting that amino acid and protein metabolism is an early and primary target for thyroid hormone action in humans. It was therefore concluded that the thyroid-hormone concentration may be an important factor in regulating muscle proteolysis. The altered protein metabolism causes myopathy.

Then, one may ask, why myopathy in hypothyroidism? Less thyroid hormone should lead to less protein breakdown, shouldn't it?

Well, this is a good question! Slightly complex and tricky to answer though. 

In hypothyroidism, there is abnormal glycogenolysis, defective mitochondrial oxidative metabolism and triglyceride storage.

Abnormal glycogenolysis and triglyceride storage: Less glucose is released and utilised because of this. The body starts using more proteins usually derived from muscles leading to myopathy.

Mitochondrial oxidative metabolism defect: Thyroid hormone is responsible for activation of bc1 complex also known as complex 3 & succinate dehydrogenase. Less activation of bc1 leads to less formation of ATP from glucose.... So again, the body switches to proteins from muscles as a source of energy!

That's all!
Stay cool :)

~Ojas

Medicowesome secret project: Exam time

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Medicowesome secret project: Embryo – Male or female?

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Medicowesome secret project: Ghrelin

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Medicowesome secret project: Biostatistics

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Fact of the day: Regulate brain activity with your type of music

Hey Awesomites

Which genre or type of music do you like the most? Well, it surely has to do a lot with the functioning of our brain. Some of you may like slow music while others like to rock n roll on the floor while listening to their favourite beats. I am more of the latter type too, depending on the mood. ;p

Pediatric drawing milestones mnemonic

I share two mnemonics in this video - The count numbers on your hand mnemonic and the draw it yourself mnemonic xD

Medicowesome secret project: Life of a blind man

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Medicowesome secret project: Who am I?

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Medicowesome secret project: An Alcoholic's Tale

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Tricyclic antidepressants (TCAs) - MOA and side effects

Hello!
This is a fun and concise post on the pharmacology of TCAs. Excited? :D

Fact of the day: Green - The colour of medicine

Green used to be the "Colour of medicine"

Why?

Fact of the day: Paradoxical undressing in fatal hypothermia

Hypothermia causes paradoxical undressing.

This typically occurs during moderate to severe hypothermia, as the person becomes disoriented, confused, and combative. They may begin discarding their clothing, which, in turn, increases the rate of heat loss. It is estimated that twenty to fifty percent of hypothermia related deaths are due to paradoxical undressing.

Why does this happen?

Fact of the day: Psychosomatic symptoms love to travel

Hey Awesomites

Yes, you read it right. The symptoms of psychosomatic disorders flit from one body part to another, and just too easily and quickly ( they love to travel a lot ;p ) . Just as one symptom is discovered, it disappears and another one emerges in some other part of the body.

The psychosomatic symptoms have been linked to a chameleon. Every time a medicine tries to pin them down,  they become something different.

That's all
- Jaskunwar Singh

The colours of a chameleon are not more numerous and inconstant than the varieties of the hypochondriac and hysteric disease.
 - Robert Whytt

NYHA Classification Mnemonic

Hey guys, this post will help you to remember the definitions of the four NYHA classes.

So first just remember two phrases-
"Patient with a heart disease" and "in ordinary or accustomed activities". For convenience I will use letters A and B to refer to these phrases respectively. Now I will just fill in the gap between them.

1. NYHA Class I:
A--- will not get dyspnea ---B.

2. NYHA Class II:
A--- will get dyspnea ---B.

3. NYHA Class III:
A--- will get dyspnea in less than ---B.

4. NYHA Class IV:
A--- will get dyspnea at rest.

This system of classification has its flaws since the definition of "ordinary and accustomed activities" is entirely subjective. Like for example if a rich businessman gets breathless after walking 1 km, you may label him as NYHA Class II, but the same case in a hard working labourer will have to be labelled as NYHA Class III.

And another thing that NYHA has recently clarified NYHA Class III a bit further, it has included self-care activities in it's spectrum. As a supposition, if a 56 year old male person gets breathless while shaving or bathing then it is NYHA Class III.

-VM

Authors' diary: Medicowesome secret project

We initially introduced the secret project very mysteriously and kept the details highly confidential just for fun! Let me tell you more about it...

Grave's ophthalmopathy features mnemonic

Hey Awesomites

Grave's disease, a common cause of primary hyperthyroidism causes some epic features of ophthalmopathy apart from lid retraction and lid lag. Mnemonic: EPIC

E- Exophthalmos
P- Periorbital Edema
I- Involvement of ocular muscles (diplopia)
C- Conjunctival irritation and chemosis

- Jaskunwar Singh

Amiodarone- induced thyroid dysfunctions

Hello

Amiodarone, a potent class III anti- arrhythmic drug is contraindicated in thyroid patients or those with subclinical disease. The reason lies in the pharmacokinetic profile of this drug.

The drug has a structural resemblance to triiodothyronine (T3) and thyroxine (T4). In the body, it is metabolized by dealkylation to Desethylamiodarone (DEA), the intrathyroidal concentration of which is higher than the parent drug.

Normal daily recommended intake of iodine for adults is approx. 0.15mg (150mcg).  Each 200mg tablet of amiodarone contains about 74.4mg of iodine with 7.4mg (10%) being released as free form. This is roughly 50- fold higher than the normal. Therefore, total body stores may remain increased for upto 9 months after stopping the drug.

High iodine content of this drug inhibits  local type-1 5'- deiodinase activity (blocking conversion of T4 to T3) and type- II 5'- deiodinase activity in the pituitary. As a result, TSH is increased initially (mild elevation) and then return to normal or may even decrease in euthyroid patients after weeks, while T4 is normal or raised, and T3 levels decrease.

The increased delivery and uptake of iodine by the thyroid gland may cause increase in hormone production and release, a condition called type-1 Amiodarone- induced thyrotoxicosis (AIT) . In other cases, excessive thyroid tissue destruction due to destructive thyroiditis may lead to type-2 Amiodarone- induced thyrotoxicosis. These are hyperthyroid states!!
Discontinuation of the drug is recommended, if not, then high doses of thioamides and corticosteroids may work in AITs.

Amiodarone may also cause hypothyroidism (AIH) in  patients depending upon the iodine status of individuals and prior thyroid disease. Wolff- chaikoff effect is shown by thyroid cells due to failure of thyroid hormonogenesis. Levothyroxine is the drug of choice.


Thats all
- Jaskunwar Singh

Fact of the day: Burning the heart to ashes

An interesting fact about heart I read today:

The heart is resilient, literally. When a body is burnt, the heart is the last organ to oxidize. While the rest of the body can catch flame like a polyester sheet on campfire, it takes hours to burn the heart to ash because it's deep inside!

That's all!

Did you know? According to Hindu mythology, when Arjuna cremated the body of Lord Krishna, his whole body turned into ashes, except his heart which was still burning. Arjuna washed the ashes and burning heart into the river.

- Jaskunwar Singh

Munchausen's syndrome

Hello

"Psychosomatic disorders are conditions in which a person suffers from significant physical symptoms (causing real distress and disability), that is out of proportion to that which can be explained by medical tests and physical examinations."

Karl Friedrich Von Munchausen, the "Baron of Lies" gave his name to the syndrome. Munchausen's syndrome (now more correctly called factitious disorder in DSM- 5 classification of somatic symptom and related disorders ) refers to patients who imitate illness (may be in an exaggerated form ) for medical attention and care and may even expose themselves to life- threatening operations, amputations, unnecessary medications and toxic treatments.

Lets take an example: A woman presents to hospital with a headache and a dilated pupil. On investigations, scans were normal and no other systemic abnormality seen. Then, a nurse walks into her room and finds the patient self- administering dilating eye drops into the affected eye.

The person has an awareness of the lies they are telling but they surely do it to seek medical care and attention, being unaware of their own motivation and uncontrolled behavior.

Upto one- third of patients in neurology ward suffer from psychosomatic illness and most often, an emotional cause is suspected.


Thats all
- Jaskunwar Singh

Parinauds syndrome notes, mnemonic and a video

Parinauds syndrome notes + mnemonic + video!

Is it okay to wish a man "Happy Women's Day"?

Hello awesomites!

Happy women's day to everyone - Male and female!

Study group discussion: PGE and congenital heart diseases

We had a discussion on this question on our study group today :)

PGE causes clinical worsening in an infant with?
A. PS without VSD
B. Hypoplastic left heart syndrome
C. Obstructive TAPVC
D. Obstruction in Aorta

Let's work this out - choice by choice!

Acute intermittent porphyria mnemonic

Acute intermittent porphria - AIP - That's the mnemonic!

Asbestosis and Silicosis mnemonics

Here are a few mnemonics to help you not mix these conditions up!

Hyperthermia in Pontine Haemorrhage

Hey guys!

This post will be focused on the pathophysiology of Hyperthermia in Pontine Haemorrhage( which may manifest as the Locked-in Syndrome, remember that super-awesome House episode? <3 )

1. First try the easy simple reason. Hypothalamus has been basically cut off from the body below pons and there has been Haemorrhage. Therefore, there will be a Sympathetic outflow causing peripheral vasoconstriction. Meanwhile the internal visceral organs are still functioning and consequently producing heat. So without hypothalamus, the body's ability to produce heat has transcended it's ability to lose heat.

2. The next reason is a bit "cooler", literally. Our body hates Hypothermia more than Hyperthermia, thanks to evolution. (Ice Age!!!) Now there is no central thermoregulation but peripheral one is still intact. And the peripheral thermoreceptors are much more sensitive to lower temperatures or basically cold environment. Once again, without the Hypothalamus, the body is defending itself too vigorously against Hypothermia as to contribute ironically to Hyperthermia.

3. This reason is the only one which you should know since this will explain how Baclofen, a GABA-B Agonist works to treat this Hyperthermia. Remember the Medial Forebrain Bundle, it connects Hypothalamus to a lot of structures, one of them being Nucleus Raphe in the Pontine reticular formation. This is a very crucial portal in control of Sympathetic nervous system outflow by Hypothalamus. Simply speaking, if the body is hot, Hypothalamus will send inhibitory (GABAergic and Dopaminergic) signals to this nucleus and if the body is cold, it will send excitatory (Glutaminergic and Serotonergic) signals. And apparently this connection is lost in Pontine Haemorrhage, so we substitute it with a drug.

P.S. Now you can guess how Bromocriptine and Apomorphine cause Hypothermia. :)

-VM

Fact of the day: Blood coagulopathies in Familial Hypercholesterolemia

Hello

It is known since long that familial hypercholesterolemia is associated with increased risk of cardiovascular disease as a consequence of atherosclerotic plaques in blood vessels. But Its NOT due  to high cholesterol levels in blood !!

The cause of such consequences lies in genetics. Genetic aberrations in patients with FH include variations in Prothrombin gene which increases coagulation and clot formation. This ultimately blocks the arteries by forming plaques!

Heart patients with FH also have higher concentrations of Fibrinogen and Factor VIII in their blood in addition to other factors, compared to healthy ones.

People with familial hypercholesterolemia tend to live a longer life than those with low cholesterol levels, suggesting a minor role of high cholesterol in pathogenesis of the disease.

However, cholesterol is still associated with other systemic diseases, though recently LDL has been considered 'good' too!


That's all
- Jaskunwar Singh

Fact of the day: Proton pump inhibitors and osteoporosis

Chronic PPI usage is associated with an increase occurrence of bone fractures, at present, the likely mechanism of this affect, is not at all clear.

The assumed mechanism is that long-term PPI use leads to decreased intestinal absorption of calcium resulting in negative calcium balance, increased osteoporosis, development of secondary hyperparathyroidism, increased bone loss and increased fractures.

An acidic environment in the stomach facilitates the release of ionzed calcium from insoluble calcium salts, and the calcium solubilization is thought to be important for calcium absorption. 

That's all!
Happy studying!
-IkaN

Facts and Fallacies: Almonds for Migraine

Hello

Some people who suffer from migraine are found to be deficient in magnesium and certain  vitamins. This proves to be one of the factor for causing such attacks!

Almonds are rich in magnesium and vitamin B2 ( riboflavin ) and contain salicin, an anti-  inflammatory agent and ingredient in aspirin. So 10- 12 almonds a day, equivalent to 2 aspirins helps in preventing acute attacks of migraine.

However, for those who are allergic to salicin, almonds may even trigger migraine attacks! Therefore prior testing is important in such cases.

Many recent updates and drugs have become available to treat the attacks but no single one is effective in long- term. For those deficient in magnesium and allergic to salicin,  infuse magnesium sulfate solution i.v.  over 3- 5 minutes.


That's all
- Jaskunwar Singh

The story of Medicowesome (With Q&A)

Here's the video to the many questions people have asked me till date:
How did Medicowesome start? How do you manage blogging and studying? etc etc.

Pediatric milestones mnemonic

Another awesome video by Shilika!

Fact of the day: Multi- vitamin supplements beneficial for schizophrenics

Hello

Recent studies suggest that high- doses of vitamin B help in reducing the symptoms of schizophrenic patients and those with other neuropsychological disorders, when added to the normal treatment in early stages. (Source)


- Jaskunwar Singh

Glasgow coma scale mnemonic video

Hello!

This video on the Glasgow Coma Scale (GCS) was made by Shilika :)

Dealing with psm

Hello.
This was a question from one of our readers..as to how to deal with psm.

Personally I too have dealt with a lot of trauma related to it. So I will share you my own tips and tricks.

Just keep this basic funda in your head while dealing psm. YOU DONT HAVE TO READ EVERYTHING.

Never start reading psm chapters from the very first page. You will be lost in a whirlpool so huge and exhaust yourself to the limits in a matter of hours..and you are bound to never touch the book again.

Now how to approach it..if say your professor is teaching a chapter on contraceptives. Just go through ONLY last three year worth questions..and mark out all the questions just for contraceptives. Never do the whole ten years or five years  questions together. Cause you will end up marking the whole book..and that depresses you. So first start last three years.

Once you have done the marking. Psm has one lovely plus point..that apart from the humongous text..it also has charts and diagrams. READ the diagrams first..the flow charts those should be the ones you should learn first. And for answers who don't have flow charts..and have things like components and sub headings of this and that and shit..I suggest just mugg up the names of the sub topics. Just the names only. Make mnemonics, make weird stories..do whatever but you need to learn them.
This trick is important cause think of your examiner. He is tired of reading the same old answers over and over again. So if you go ahead and make beautiful flow charts..or if you just emphasise on the various components and sub headings itself..your job is half done.

And regarding the actual reading of the text. Do it later when you feel more confident..and that time also just stick to the specific answers from previous yr papers.

psm is crazy huge..I have learnt that during exams it was more easy to make up matter to write for psm..but what I didn't remember was that one word of the sub headings or details of the flow chart.
And that's where you go wrong.

Let me know if it helped you and also if any other doubts.

-sakkan

Fish oil for treatment of asthma

Hello

Asthma is a chronic, exaggerated and allergic inflammatory response in the respiratory airways to certain allergens that vary according to seasons.

Omega- 3 fatty acids in high- quality fish oils and other products reduce the inflammation by regulating B- cell function. IgE production is reduced, which otherwise acts to cause asthma symptoms and allergic reactions in patients with mild form of asthma.

The fatty acids are used up by the cells in the lining of respiratory passages to produce hormones that tend to "turn- off" certain factors responsible for attracting white blood cells to the site of inflammation such as leukotrienes, interleukins, and other cytokines.

However, these oils are less effective in severe forms of the disease and in the majority of patients taking corticosteroids.

According to a study, prenatal exposure to fish oils (mainly in third trimester) reduces the risk of wheeze and asthma in children.


Thats all
- Jaskunwar Singh

Ischaemic Preconditioning

Hey, guys!!

This post is on a very interesting condition. To put it in simple terms, Ischaemic preconditioning is a defensive technique adopted by those cardiac myocytes which have faced ischaemia in the past against future ischaemic episodes. There is another defensive procedure called Collaterals but that occurs in chronic ischaemia while Preconditioning occurs in acute conditions.

It was first observed while monitoring the ECG of a patient undegoing coronary balloon angioplasty. When the coronary artery was occluded by inflated balloon transiently, the ECG showed QRS distortions indicative of ischaemia but when it was occluded once again, ECG showed almost normal QRS waveforms.

Mechanism of Ischaemic preconditioning has something to do with Katp channels, the one blocked by Sulfonylureas like Glibenclamide, and also Adenosine receptors. But how exactly these components are involved, isn't clear yet.

That's all!

-VM

Basics of Coagulase test

Hello awesomites let's today see today about enzyme "Coagulase".

Coagulase is an enzyme produced by several micro-organisms to protect them from host's immune system . Coagulase  is especially produced by S.aureus hence we use coagulase test to differentiate between S.aureus and other species of Staphylococcus.

How does Coagulase enzyme act in S.aureus  ?

Basically it enables conversion of fibrinogen to fibrin.In case of S.aureus Coagulase reacts with prothrombin and forms Staphylothrombin

complex which helps enzyme protease to convert fibrinogen to fibrin which results in clotting of blood.Coagulase in S.aureus is tightly bound to surface and hence fibrin thus formed coats ,the bacteria and hence bacteria is protected from  host's immune system .

Two forms of coagulase exist:
1) Clumping factor (Bound to cell).
2) Free Coagulase or Coagulase.

What is Clumping factor?

It acts directly on the fibrinogen in plasma and helps in adherence of the organism to fibrinogen resulting in clumping .

Detected by slide coagulase test.

What is free coagulase ?

It is excreted from the cell as a free enzyme.It first acts on prothrombin ,the product so formed acts on fibrinogen and forms a fibrin clot.

It needs coagulase reacting factor (CRF).
8 types of coagulase have been identified .Most human strain forms coagulase A
It is detected by tube coagulase test.

Trick to remember test ?

Slide coagulase test -Clumping factor

And you can simply put other test for free coagulase.! =P
Stay cool and awesome:)

~Ojas

Beck's triad mnemonic

Hello

Acute cardiac tamponade is an emergency condition in which fluid accumulates within the pericardial sac resulting in inability of heart to pump blood. The Beck's triad of medical signs a/w this condition - (mnemonic: DIM )

D- Decreased arterial and pulse pressure
I- Increased venous pressure (JVD)
M- Muffled heart sounds


- Jaskunwar Singh

Right IJV for assessment of right heart hemodynamics

Hello

Internal jugular vein of right side is preferred for right heart hemodynamics. This is because-

Aminoglycoside mnemonic

Hello all, let me slip in a quick mnemonic on Neomycin and Amikacin

1.Highest nephrotoxic drug-
   Neomycin

2.Highest auditory toxicity is with-
    Amikacin

N for N and A for A. Easy one to remember for the MCQs!

That's all!

-Sushrut

Osteogenesis imperfecta mnemonic

I just wanted to enlist a few points on Osteogenesis imperfecta so....

Fact of the day: Milk and acidity

Milk is commonly recommended as therapy for patients with peptic ulcer.

Indications for oestrogen therapy mnemonic

Hello
Indications for oestrogen hormonal therapy mnemonic: 8Ds


D- Deficiency states of oestrogen
D- Development of secondary sexual characters
D- Diagnosis of pregnancy ( along with progestogen )
D- Dysmenorrhea
D- Depression ( post- partum and perimenopausal )
D- Diastolic dysfunction ( in postmenopausal women )
D- associated Diseases (dermatologic, neurologic, autoimmune)
D- Decubitus ulcer


That's all
- Jaskunwar Singh

Differentiating gram positive cocci

Hello awesomites!

Today, let's see how can we differentiate between Staphylococci and Streptococci!

Delirium and Dementia mnemonics

Hello

Delirium- "It is a transient, usually reversible cause of mental dysfunction that results in a wide range of neuropsychiatric abnormalities, mostly presented by elderly as
- waxing and waning type of acute- confusional state
- fall in attention- span
- decreased awareness of surroundings
- low cognition levels."

Causes of Delirium- (mnemonic: DELIRIUM)
D- Drugs (anti- cholinergics, antipsychotics etc)
E- Encephalopathy (Wernicke's)
L-  LSD intoxication
I- Infections
R- Respiratory failure
I- Insomnia
U- (v) visual sphere hallucinations
M- Metabolic disorders


Dementia- "A group of neuropsychiatric disorders characterised by chronic and gradual decrease in the ability of person to think, create memories, express emotions and other mental symptoms that affect the general well being."

Causes of Dementia (mnemonic: DEMENTIA)-
D- Degeneration (Primary cerebral)
E- Endocrinal dysfunction
M- Multiple sclerosis
E- Embolisation (vascular pathology)
N- Normal tension hydrocephalus
T- Tumors
I- Infections
A- Alcohol intoxication


That's all
- Jaskunwar Singh

Skin cancer mnemonics

Here are some memory aids that I use :)

Fact of the day: Cocaine addiction and iron concentration in brain

Do you know? Cocaine addiction leads to increased concentration of iron in globus pallidus. The more one takes this drug, more amounts of iron get accumulated in this region of brain, which normally acts as a 'brake' for inhibiting behaviour.

Also, the increased concentration of iron in brain is accompanied by iron deficiency in rest of the body.

This is possibly attained by decreasing absorption of iron from food and increasing permeability of blood- brain barrier.


- Jaskunwar Singh

Long QT Syndrome

Hey guys this post will be on Long QT syndrome as evident from the title :P.

In a brief introduction, it can be said that LQTS is simply because of abnormal myocardial repolarization most often due to a mutation in ion channel-associated gene. It can lead to fatal ventricular arrhythmias such as torsades de pointes.
So there is increased risk of Sudden Cardiac Death.

It has 3 common variants:

1. LQT1: Loss of function mutation in KCNQ1 gene. And in ECG you see early-onset broad-based T wave.

2. LQT2: Mutation in KCNH2 gene. In ECG T waves are of low amplitude, broad based and maybe bifid.

3. LQT3: Mutation in SCN5A gene. In ECG, there is prolonged ST segment with late-appearing T wave.

We use the ECG to diagnose LQTS and we estimate the probability by using Schwartz score.
Some of the important criteria are :-

1. QTc more than 480msec
2. T wave alternans (Varying amplitudes)
3. Torsades de pointes
4. Notched T waves in atleast 3 leads
5. Syncopal attacks with and without stress
6. Congenital deafness
7. Significant family history

That's all!

- VM

Fact of the day: Muscle relaxant of choice during anaesthesia in renal and hepatic failure

Did you know? Atracurium, cisatracurium, and mivacurium have theoretical advantages for patients with hepatic or renal failure because these drugs undergo extensive plasma degradation. 

Stigmata of Hypercholesterolemia

Hello

There are certain physical stigmata of hypercholesterolemia that help the clinician to suspect FH in a patient with a premature cardiovascular disease:

- Xanthelasma (cholesterol deposits on both eyelids)
- Arcus corneae (bilateral; detected by fifth decade of life)
- Tendinous xanthomas (in hand and feet)


That's all
- Jaskunwar Singh