On ECG after an MI infarction..What is the sign for left ventricular aneurysm?
It's persistent ST segment elevation. After MI, the ST segment does rise, but it falls gradually too, reaching a normal. But if its elevated then its aneurysm.
In any specific leads?
The same leads where infarction shows up.
2, 3 and AVF leads.
So basically the ST segment doesnot fall back to normal right?
Yup.
Great didn't know that concept.
Since it's MI..Review question.. Name a disease associated with right ventricular infarction?
Atherosclerosis?
I meant name a cause for right ventricular infarction, other than atherosclerosis.
It's pulmonary embolism.
The pulmonary embolus puts the right side of heart in strain and it dilates. This dilation obstructs the right coronary artery. This was my viva question on an ECG of right ventricular infarct.
So does not it lead to hypertrophy of the right ventricle?
In an acute setting, no.
If the pulmonary thromboembolism is chronic it will cause pulmonary hypertension. Then it causes right ventricular failure.
So the acute pulmonary embolus should be the answer.
Ohh that makes some sense! Good one!
Which is the reinfarction cardiac marker?
It's CK MB. The levels fall in 3-4 days. So if you get a reinfarction and see your troponin you can't be sure if it's from last time.
CK MB falls in 36-48 hrs.
Why isn't it myoglobin? Myoglobin rises and falls the fastest.
Because myoglobin is not a specific cardiac marker.
No but in these cases, it is the most preferred. Cause it returns to normal within 24 hours.
Dunno.
I think the time after which re-infarction occurs also matters.
Do let us know.
These things are confusing. Good thing is we are trying to sort them out.
Yes, it is.
We had a confusion between myoglobin and CK MB in the diagnosis of re-infarction.
The answer is CK MB simply because it is cardiac specific and falls within 2 days.
The only use for myoglobin is ruling out a Myocardial Infarction, early. (Cause it's the first to rise and is very sensitive!)
If the levels are not up, it's not a MI.
If myoglobin levels are up - it could be a skeletal muscle injury or a MI, you don't know until you look at the other markers.
Even though myoglobin levels fall early, it is not used for the diagnosis of reinfarction because it's not specific and if the levels are up after an infarction, it could mean something else as well.
Harrison says both CK MB and myoglobin can be used for reinfarction. I would hate the question maker for asking us to choose between the two & go with CK MB because it's specific.
Woah... Awesome discussion... Thank you everyone for the cocepts... I so love this group.
Does anyone have awesome things for amylodosis pathology?
Another concept you must understand is that the protein deposits in tissues depending upon where it was derived from.
For example, amyloid from immunoglobulins deposit in tissues of mesodermal origin like kidneys, heart, muscle, tongue.
When it's due to chronic inflammatory disease, it involves parenchymal organs like liver adrenals and pancreas.
Good concept.
Review question! Which amyloid protein is associated with Alzheimers disease?
Beta amyloid
Yes!
And why are patients with downs syndrome more susceptible to early Alzheimers?
Extra chromosome 21 which means extra copy of the presilline gene, I think.
Absolutely right!
Great.
Never knew that!
Oh oh one more!
Which condition is associated with amyloid deposition in the thyroid gland?
Are we talking about the medullary thyroid carcinoma?
Yep. The amyloid deposits are derived from calcitonin in that condition!
Which is the one in patients on dialysis?
Beta micro globulin?
B2 - microglobulin is seen in dialysis associated amyloid.
Derived from the MHC class 1 protein.
Yes. It's because the beta micro globulin is not filtered from the dialysis membrane.
Excellent stuff.
Acetaminophen toxicity is treated with N acetyl cyteine.
Mnemonic: ACETaminophen ACETyl cysteine!
Ethylene glycol is metabolized to oxalic acid. Ethylene glycol is found in anti freeze.
Mnemonic: Freeze your EGO.
Anti freeze
Ethylene Glycol
Oxalic acid
Methanol is metabolized to formic acid by alcohol dehydrogenase which causes visual disturbances. It is treated with fomepizole.
Mnemonic: There's more to me (FoMEpizol) than what meets (Methanol) the eye (Blindness).
What is the commonest sign on ecg for PE?
Nonspecific ST changes?
Nope.
SQ3 T3 something like that?
Nope.
Most common sign is sinus tachycardia. Most specific is S1q3t3 pattern..Positive only in 20-30% cases.
Ohhh!! Nice question.
Ooh.. We tend to forget common ones when looking out for rare signs!
What is the screening test for PE?
Screening test is d-dimer. If d-dimer is negative you virtually exclude the diagnosis of PE.
Which is the most specific diagnostic test for pulmonary embolism?
Pulmonary angiography.
Depends if the person is low risk or high risk! CT angiography is done though.
Which is the most preferred test for PE?
Spiral CT is preferred next to know location, size and blah blah.
What about VQ scan?
That's done if the patient is allergic to contrast.
Or has kidney failure.
Or CT isn't available.
Or the patient is pregnant.
In our hospital setting angiography would key since most patients can't afford CT.
Oh. But its invasive..and can be very harmful. It's only preferred when you are planning for thrombectomy..Or as a last resort to diagnose PE if all the other test are negative but d-dimer is positive.
Well money for a CT can feed a peasants family for a year.
True.
Venous doppler is preferred when CT or V/Q are inconclusive.
Whats d-dimer?
The clot thingy. It interlocks fibrin strands.
It is released from the thrombus.
Fibrin is non specific for clots
Because it is elevated in some other conditions as well. So d dimer to the rescue!
*Fibrin degradation products are.
Anyone over here who knows the management of ARDS?
PEEP
Positive end expiratory pressure and 100% oxygen.
It's like during expiration your alveoli collapse, especially in ARDS since their surfactant is gone, so to prevent that collapse you give a bout of positive pressure at the end of expiration.
I don't know how they generate it but this is the mechanism!
Aah.
PEEP is continuous flow generated at certain fixed pressure that stops the alveoli from collapsing during the expiration. Pressure usually kept around 5
So the pressure is kept continuous during the whole time?
Yeah it's continuous during the both inspiration and expiration!
Umm then why is it called "End expiratory"?
That's a very good question actually. Don't know exactly why it's named that way!
Ever heard of low tidal volume ventilation? Aka lung protective ventilation? Aka baby lung concept?
It's used in managing ARDS. Since many alveoli are fluid filled and the patient effectively will have lesser tidal volume than normal. If we give the normal tidal volume the patent alveoli will burst due to barotrauma!
Inspite of normal tidal volume - 8-12ml/kg, we give 4-6ml/kg body weight for ARDS.
Also, you treat the underlying cause of ARDS.
You even have to restrict fluid overload. That's the other most important point!
Yeah read that too, diuretics are beneficial to some extent. Steroids are of no use.
Yup.
Also NO (Nitrogen oxide) is of no use.
Yeah for ARDS. During the various trails for the treatment of ARDS they observed that increasing the tidal volume lead to worsening most probably due to inflammation due to repeated opening and closing of alveoli with each inspiration and expiration ultimately affecting the structure of alveoli and their ability to perform their job. Low tidal volume along with PEEP significantly reduced the mortality in the patients with ARDS. So that the standard treatment at present.
I read there is other device called high RR..it provides respiratory rate of 15 to 20 cycles per SECOND.
It has a very low tidal volume but..Almost 1-2 ml / kg
Can anyone tell me about the "Trial of scar" after C section procedures?
I have heard of trial of labour, not sure if its the same thing!
My searches lead me to trial of labour as well ..I guess they are.
It's especially indicated in cases of borderline cephalopelvic disproportion.
The obstetrician let's the lady go in to labour in a controlled environment. If the labour becomes to stressful and is prolonged unduly, the doctor immediately performs a C section
It's more like given the patient an opportunity to experience normal vaginal delivery.
Same thing i suppose can be applied to scar from previous C section.
You see the chances of rupture of the lower segment scar is highest during labour, so the patient is monitored especially for signs of impending scar rupture
Most common is pain and tenderness over the scar area.
A off topic thing due to c/s delivery a tv series named "the knick", a medicine based serie in the beginning of the 20th century in usa, i recommend it, the changes in surgery, hospitalization, treatments are baby steps, surgeons invent the tools they use, amazing!
PAin and TEmperature sensation carried by LAteral spinothalamic tract. Mnemonic is "PaTeLa" (which is present knee).
Significance of difference findings in urine analysis-
1) WBC in urine - Pyelonephritis
2) RBC - Glomerulonephritis
3) Hyaline cast - No significance
4) Broad waxy cast - CRF
5) Dirty brown/granular cast - Acute tubular necrosis
RBC's may also be present in case of calculi or tumors!
Correct!
"Approach to hematuria"
1) Dipstick - blood positive
Microscopy- RBC negative
It is myoglobinuria.
2) Dipstick - blood positive
Microscopy- RBC positive
It may be kidney pathology or bladder.
In that case if RBC is isomorphic (not distorted) - urinary bladder pathology like stones, cystitis.
If RBC is Dysmorphic - Kidney pathology (When RBC is passing thru tubules shape get distorted)
The dysmorphic RBC are a characteristic of glomerular pathology not tubular.
Can anyone simply compliance for me?
Compliance = Change in volume/change in pressure.
So it follows as lungs starting at zero before inspiration. At the end there will be 500mL of air. So 0.5L
The pressure of he lungs starting at -5cm H20 increases to -10cm after expiration.
It would be (Specific compliance)
0.5 L/ (-5cm H20 - (-10cm H20))
= 0.5L/5cm H20 = 0.1 per cm H20
Theres a few types of compliance. Static compliance and dynamic.
Static calculates the periods where here isnt any gas flow. So during the time where there isn't fas flow.
Dynamic calculates the periods of active(!) Inspiration.
But I know nothing about those two calculations.
