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

Top 10 series: Magnesium sulfate

Here is the video!

By A. P. Burkholderia

Fact of the day: Talking to yourself is a sign of smartness

"Look at that guy, roaming around here and there in the marketplace, muttering words and talking to himself. He seems totally insane. Doesn't he?"

Micro-organism series: Staphylococcus aureus

Hello awesomites here is our first bacteria of micro-organism series - Staphylococcus aureus

Morphology:
Aerobes and facultative anaerobes
Diameter: 1 micrometer
Gram profile: Gram positive Cocci
Arrangement: Grape like clusters
Motility: Non-motile
Sporeing or not: Non-sporing
Capsule: Usually capsulated. Non-capsulated strains have small amount of capsular material on the surface

Cultural characteristics:

Ordinary media: They grow readily with temperature range of 10-42°C ( Best at 37°C) and pH around 7.4 - 7.6

Nutrient agar:
You can remember how colony looks by the name STAPHYLOCOCCUS it self.
S - Smooth
O - Opaque
C - Circular
C - Convex
Easily emulsifiable.
It produces golden yellow pigment. Pigment production occurs best at 22℃ and only in aerobic culture. Growth represents "Oil-paint appearance".

Blood agar: Shows beta type of hemolysis when incubated under 20-25% carbon dioxide.

MacConkey agar: Pink colour small colonies (Because it ferments lactose!)

Selective media:
Ludlam's medium - Lithium chloride and tellurite.
Mannitol salt agar or salt milk agar- 1%Mannitol, 7.5%NaCl, Phenol red indicator.
Columbia colistin nalidixic acid agar.

Liquid media: Turbidity.

Biochemical Reactions:

Catalase : Positive
Oxidase : Negative
Mannitol: Positive
Indole: Negative
MR andVP: Positive
Phosphatase : Positive (Useful for screening as S epidermidis is negative or slightly positive )
Urease : Positive

Produces thermonuclease enzymes.

Virulence factors :
Extracellular enzymes :
Coagulase (Most virulent)
Lipase
Hyaluronidase
Staphylokinase

Toxins:

5 types of Cytolytic toxins: Alpha, Beta, Gamma, Delta and Leucocidins
Alpha: Most important hemolysin.
Beta: It is sphingomyelinase. Exhibits hot and cold phenomenon.
Leucocidin and gamma lysin is grouped under synergohymenotropic toxins.

9 types of enterotoxins: Responsible for staphylococcal food poisoning. Causes nausea, vomiting and diarrhoea within 2-6 hours.
A, B, C1, C2, C3, D, E, H and I.

Super antigens:

Toxic shock syndrome toxin (TSST)
Exfoliative
Enterotoxins
(What are superantigens and how do they work?)

Disease caused:
Remember " SOFT PENIS"
S - Skin infections
O - Osteomyelitis and arthritis
F - Food poisoning
T - Toxic shock syndrome
P - Pharyngitis and Pneumonia (Rarely)
E - Endocarditis
N - Necrotizing fascitis
I - Impetigo
S - Sepsis

Laboratory diagnosis:

Specimen and lesions

Pus - Suppurative lesions
Sputum - Respiratory Infections
Blood - Septicaemia
Urine - UTI
CSF- Meningitis
Faeces - Food poisoning

Collection and transport :
Sterile containers should be used
Sterile swabs for specimen from nose/perineum.

Direct microscopy :
Gram stained smears is useful in case of pus, cocci in clusters may be seen.

Treatment:
Sensitive to penicillin: Penicillin G is DOC (Drug of choice)
Penicillin allergy: Cefazolin is DOC
Methicillin resistant S.aureus: Vancomycin
Vancomycin resistant: S.aureus: Streptogramins, Linezolid, Telavancin.

That's all!
Finally done!
Stay awesome :)

~Khushboo shaikh,IkaN,and ojas

Submissions: Adverse effects of Glucocorticoids mnemonic

Adverse effects of GLUCOCORTICOIDS:

Mnemonic is glucocorticoids itself!

Introduction to micro-organism series

Hello awesomites!

We have started with micro-organism series where we will discuss bacterias and viruses. But before that let's have a little introduction of Gram positive bacteria and negative bacteria!

Fanconis anemia mnemonic

Hello!

Here's a post on Fanconis anemia!

Fact of the day: Factors that are lost in stored blood

Hello awesomites !

What happens to blood that is stored in blood bank ?

Pierre Robin Sequence mnemonic

Hey Awesomites

Pierre Robin Sequence is one of the most common causes of isolated cleft palate in the newborns. Here's the mnemonic for the triad of symptoms- PRS

P- Cleft Palate only
R- Retrognathia (abnormal posterior position of jaw and maxilla)
S- Support to the lingual muscles is lost (Glossoptosis)

The sequence is known to be caused by genetic anomalies at chromosome 2, 11 or 17.


That's all

- Jaskunwar Singh

A Neurology Case Discussion

Hey guys, let's ponder upon the following case.
Before reading this case, just know that this is a case of cerebellar tumor. Now try to localize the tumor in the cerebellum by taking help of the symptoms of this kid. This will help you in the differential diagnosis given later.

A 4 year old complains of headache, drowsiness and occasional diplopia; he is unsteady on his feet with frequent falls. Examination demonstrates truncal ataxia, sometimes accompanied by incoordination of the limbs; variable ophthalmoparesis and papilledema on fundoscopic examination.

Any guesses on what this could be?

Ok so here goes the case discussion:

Medulloblastoma typically presents with a midline cerebellar syndrome, with hydrocephalus and resultant increased intracranial pressure.
Clinically, it can be distinguished from ependymoma involving the fourth ventricle by the early appearance of nausea and vomiting in the latter, due to involvement of area postrema. Cranial nerve palsies may appear with either tumor, and increasing intracranial pressure is typical of both.
The predominance of signs suggesting primary involvement of vermis distinguishes medulloblastoma from cystic or solid astrocytoma of the cerebellum which typically involves a cerebellar hemisphere rather than the vermis. Although rarely there are midline midline astrocytomas.

You are awesome if you were able to get this one right. :)

-VM

Fact of the day: Genesis of the U wave

Hey guys!!

As you know the U wave in the ecg is seldom seen especially in leads V2 and V3 physiologically especially during bradycardia.
And it is seen pathologically in Hypokalemia.

So how is it generated?
If you are thinking due to repolarization of papillary muscles, let me tell you that this hypothesis is now obsolete.

There are three trending theories at present trying to explain it:

1. Delayed repolarization of the subendocardial Purkinje fibres.

2. Prolonged repolarization of the midmyocardium ( M cells)

3. After-potentials resulting from mechanical forces in the ventricular wall.

That's it!

-VM

Fact of the day: Citrobacter causes brain abscesses in neonates

Citrobacter species are Gram-negative enteric bacilli found in the intestinal tract of humans and animals, and are also present in soil and water.

Why does cyanotic heart disease predispose to brain abscess?

Ever wondered why cyanotic heart disease predisposes to brain abscesses?

Step 2 CK: Treatment of Multiple Sclerosis and mnemonics!

Hello!

This post is all about treatment of Multiple Sclerosis.

Creutzfeldt jakob disease mnemonic

Here's one on Creutzfeldt jakob disease :D

Picks disease mnemonic

Hello!

After my infinite struggle, I think I have finally found a way to remember it :D

Percutaneous endoscopic gastrostomy.

Hello awesomites let's know about PEG .

PEG stands for Percutaneous Endoscopic Gastrostomy .We normally use PEG tube .
also known as Feeding tube,Esophagogastroduodenoscopy  tube.=P

In simple language PEG is method of placing a tube into the stomach percutaneously followed by endoscopy .
Tube is passed into a patient's stomach through abdominal wall .
It is preferred route of nutritional support in patients having dysphagia or in unconscious patients.
It offers superior exposure to GI systems.
Most of the PEG tube has mushroom shaped device at the end that holds it in the stomach and prevent it from falling .If it falls do not wait till next day the hole may heal and this may create complications.

Whereas PEG  is also contraindicated in:-
-Distal enteral obstruction.
-Hemodynamic instability.
-Severe ascites.
-Sepsis
-Severe Gastroparesisi.
-Thrombocytopenia.