Step 3 NBME Form 4 answers explanations

Publishing incomplete post form drafts :)

Platypnea-Orthodeoxia Syndrome in interatrial right-to-left shunt

Hi everyone! This is a short post :)

Platypnea (flat breathing): Dyspnea induced by upright posture and relieved by recumbency.

Orthodeoxia: Arterial oxygen desaturation accentuated by upright posture and improved by recumbency.

Peripartum heart failure associated with prolonged tocolytic therapy

Did you know?

What's Wrong With My Gallbladder, Doc?

A quick mini-post to help you make a quick diagnosis.

[Please click on the image to enhance it]

Please remember to practise caution as the presentations may overlap.

Thank you for reading.

- Ashish Singh

Post-LP Headache

Hey guys! 

Here's all you need to you know about that nasty headache some patients get, after a lumbar puncture (LP).

How common?
Up to one-thirds of all cases.

What are the risk factors?
None. Despite years of anecdotal advice to the contrary, none of the following has ever been scientifically shown to be a risk factor: position during or after the procedure; hydration status before, during or after; amount of CSF removed; immediate activity or rest post-LP.

When does it happen?
Within 24 hours of LP.

How does it present?
Let's SOCRATES the pain here.

Site: Frontal > Occipital
Onset: Acute
Character: Dull aching
Radiation: None
Association: Mild neck stiffness, nausea
Time Course: Lasts for 2 days to 2 weeks
Exacerbating factor: Sitting upright or standing, and so the relieving factor is lying down
Severity: Varies 

What is the pathology?
Thought to be continued leakage of CSF from the puncture site and intracranial hypotension. Other neuro-vascular mechanisms may be involved.

How do I prevent it?
Using the smallest practical needle and keeping the bevel facing up. Before withdrawing the needle, reinserting the stilette.

How do I treat it?
It's self limiting. Can use analgesia, as per WHO Pain Ladder. In extreme cases, can also involve an anaesthetist for an epidural 'blood patch'.



Know something you'd like to add? Let me know.

Thank you for reading. Have a nice rest of the day, you.



- Ashish Singh

Ashman beat

Hello!

What's an Ashman beat?

An aberrant PVC, usually of RBBB morphology, which follows a short RR interval and is preceded by a relatively prolonged RR interval.

The mechanism is pretty cool!

Retinoic Acid and Malignancy

Hello Awesomites !

This is going to be short post.
Relevant for exams.

All trans retinoic acid is used in APML (ACUTE PROMYELOCYTIC LEUKEMIA)

Cis retinoic acid and derivatives like 13-cis-retinoic acid (13-cRA) reduces second aerodigestive tract tumors in patients with resected head and neck cancers.
13-cis RA is used in Neuroblastoma.

Happy studying.
-Upasana Y.

Differentiation syndrome

Hello Awesomites !

AML (M3) also known as acute promyelocytic leukemia.
The drug is ATRA+As2o3 ( All trans retinoic acid +arsenic trioxide).

After few days from therapy :-
unexplained fever,
acute respiratory distress with interstitial pulmonary infiltrates,
and/or a vascular capillary leak syndrome
leading to acute renal failure.

Suspect :-

Differentiation syndrome (DS), formerly known as retinoic acid syndrome, is the main life-threatening complication of therapy with differentiating agents (all-trans retinoic acid [ATRA] or arsenic trioxide [ATO]) in patients with acute promyelocytic leukemia (APL).

The differentiation of leukemic blasts and promyelocytes induced by ATRA and/or ATO may lead to cellular migration, endothelial activation, and release of interleukins and vascular factors responsible of tissue damage.

 Roughly one quarter of patients with APL undergoing induction therapy will develop the DS.

Treatment -
Early therapy with intravenous corticosteroids. The use of invasive diagnostic techniques, such as bronchoscopy and bronchoalveolar lavage or lung biopsy, is not usually required in patients with suspected DS and respiratory distress with lung infiltrates.
Be careful with invasive procedure as these patients have concomitant coagulopathy (DIC like state)

The early administration of high-dose dexamethasone at the onset of the first signs or symptoms of DS is crucial, since it appears to dramatically reduce mortality of this complication.

 HAPPY STUDYING :)
-Upasana Y.

Route of bisphosphonate administration mnemonic

Mini post!

IVZ: Intravenous zoledronic acid (once a year)

oRAl: Oral bisphosphonates are Risedronate and Alendronate

- IkaN

Denosumab

Hi! Long time no see :)

This post is on Denosumab!

MOA:
- Monoclonal antibody against the receptor activator of nuclear factor κB ligand (RANKL)
- Reduces bone resorption by inhibiting the development of osteoclasts

Route: SC
Dosing: Administered twice yearly

Quinsy Complication

This post is written by Sweta Senthil.
I don't know why she targeted me to make this mnemonic but it makes sense to remember the complication of Quinsy.

So mnemonic is "OJAS Pee"

Edema of larynx
Jugular Vein Thrombosis
Abscess of Lung/Pneumonitis
Septicemia, Spontaneous hemorrhage
Parapharyngeal Abscess

That's it!

IOLs- most important optical zone

Most common answer would be the centre.

That however is not the case as the light rays pass undeviated right through the centre.

In fact, phakic IOLs have an opening right in the centre for aqueous to circulate.

The most important part is the pericentral area, as the refracted rays through this area get focussed on the macula.

-Sushrut

Bell's phenomenon

It is the motion of the eyeball during lid closure and is a reflex between the occulomotor and the facial nerves.  There are 4 types-

1. Normal- Upward and outward movement of
                           the eyeball.

2. Inverse- Upward but inward movement.*

3. Reverse- Downward movement.*

4. Perverse- Lateral movement.

*Some authors opine that inverse is downward and outward while reverse is upward and inward.

The Bell's phenomenon is of importance in ptosis and lag ophthalmos surgeries .

-Sushrut