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.