Monday, June 19, 2017

Lacunar infarction notes + mnemonic

Lacunar infarcts are small (0.2 to 15 mm in diameter) noncortical infarcts caused by occlusion of a single penetrating branch of a large cerebral artery.

Pathophysiology:
Lipohyalinosis of the penetrating arteries. (Mnemonic: L for Lipohyalinosis, L for Lacunar)
Microatheroma of the origin of the penetrating arteries.
Lacunar stroke is usually related to a chronic vasculopathy associated with systemic hypertension.

Clinical features:
Penetrating artery occlusions usually cause symptoms that develop over a short period of time, typically minutes to hours. However, a stuttering course may ensue, as with large artery thrombosis, and symptoms sometimes evolve over several days.

As a general rule, lacunar syndromes lack findings such as aphasia, agnosia, neglect, apraxia, or hemianopsia (so-called "cortical" signs). Monoplegia, stupor, coma, loss of consciousness, and seizures also are typically absent.

These syndromes are common :
● Pure motor hemiparesis
● Pure sensory stroke
● Ataxic hemiparesis
● Sensorimotor stroke
● Dysarthria-clumsy hand syndrome

Pure motor hemiparesis: Characterized by weakness involving the face, arm, and leg on one side of the body in the absence of "cortical" signs (aphasia, agnosia, neglect, apraxia, or hemianopsia) or sensory deficit.

Artery / structure involved: Posterior limb of the internal capsule.

Mnemonic: PM - Pure Motor, Posterior limb of internal capsule.

Pure sensory stroke: Numbness of the face, arm, and leg on one side of the body in the absence of motor deficit or "cortical" signs.

Artery / structure involved: Thalamogeniculate branches of the posterior cerebral artery (Ventral posterolateral and ventral posteromedial nuclei)

Mnemonic: MIST
Motor - Internal capsule
Sensory - Thalamus

Ataxic hemiparesis: Ipsilateral weakness and limb ataxia that is out of proportion to the motor deficit. Some patients may exhibit dysarthria, nystagmus, and gait deviation towards the affected side. As with other lacunar syndromes, the above-mentioned "cortical" signs are absent.

Artery / structure involved:  Fibres of the fronto-ponto-cerebellar system in the internal capsule / corona radiata.

Sensorimotor stroke: Characterized by weakness and numbness of the face, arm, and leg on one side of the body in the absence of the aforementioned "cortical" signs.

Artery / structure involved: Sensorimotor strokes arise from infarcts involving the posterolateral thalamus and posterior limb of the internal capsule. The exact vascular anatomy is debated. 

Dysarthria-clumsy hand syndrome: Facial weakness, dysarthria, dysphagia, and slight weakness and clumsiness of one hand are characteristic. There are no sensory deficits or "cortical" signs.

Artery / structure involved: Lacunar infarctions of the anterior limb of the internal capsule, genu of the internal capsule, or corona radiata.

Treatment:
Intravenous alteplase (recombinant tissue-type plasminogen activator or rt-PA) improves outcomes for patients with ischemic stroke in general if administered within 4.5 hours of symptom onset. The available evidence suggests that intravenous thrombolysis is beneficial for patients with lacunar stroke. Most patients with acute ischemic stroke who are not eligible for thrombolytic therapy should be treated with aspirin.

That's all!
-IkaN

Sunday, June 18, 2017

Changes in glomerular dynamics mnemonic

Hello everyone!

If you forgot the afferent - efferent stuff from step 1, I have a mnemonic.

Remember ACE ID, PDA ANC.

Step 2 CK: Management of thromboembolic stroke

Here are my notes. The most simplified version you'll get. 



That's all!
-IkaN

So I've been questioned the most about the last point, regarding heparin. Here's the source and reading material:

There are additional situations of high thrombotic risk after ischemic stroke where anticoagulation may be beneficial but for which there are little or no data. These include mechanical heart valves, carotid artery dissection, and large artery atherosclerotic stenosis.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031793/

Drugs used to lower BP acutely in severe preeclampsia mnemonic

Drugs used to lower blood pressure acutely in severe preeclampsia (Maternal hypertensive crisis) mnemonic

"Lower Hypertension Now"

Labetalol iv preferred (Avoid in bradycardia)

Hydralazine iv

Nifedipine oral

That's all!
-IkaN

Micturition and Neurological diseases


Here, presenting you a detailed description of Pathologies of Bladder in Neurology. I believe this is the best resource on this topic available online for free. :)

Diaphragmatic hernia : Mnemonic and Review

Here's a short post on the key points about Congenital Diaphragmatic Hernia.

So there's deficiency in the diaphragm during development causing abdominal contents to budge into the Thorax.

There are 2 main types -->

1. Bochdalek.

2. Morgagni.

Now out of these 2, Bochdalek is commoner.
(It's hard to remember the word Bochdalek. I struggle with it every day. )

You can memorize it by realising that it rhymes with ' Scotch da Lake '
(Which means a lake of scotch in Punjabi)

Key points about Bochdalek -
BBBB

- Back  - Located posteriorly
- Big - Bigger than the Morgagni form
- Bad - Poor prognosis
- Bag and Mask Contra indicated. 

Also realise - Bochdalek
So it's got an L in it. L = Left. So it's more common on the left side. These hernia classically cause a scaphoid abdomen and Mediastinal shift to the opposite side.

Morgagni can be remembered by the opposite of the BBB
So it's
- Not on the back - Anteriorly
- Not Big - Small sized.
- Not as Bad - Prognosis is alright.

Also realise - Morgagni
It's got an R in it = Right. So it's more common on the right side. And it contains the Transverse colon generally.

So that's all !
Happy studying! 
Stay awesome !

~ A.P.Burkholderia 

Croup : Review of key points

Here's a short Mnemonic/Review of Important facts about Croup - Acute Tracheobronchitis !

Remember :
CROUPS

C - Common respiratory disease
R - Respiratory viruses like Parainfluenza
O - Oxygen Treatment (Humidified)
U - Ugly Cough - Barking / Seal like cough
P - Prodrome of illness followed by Inspiratory Stridor
S - Steeple sign on X Ray

It's helpful to remember Acute EPIGLOTTITIS as the complete opposite of CROUPS using similar ideas.

- Not as common.
- Caused by Bacteria generally (Strep , Hib)
- Oxygen Therapy + AntiBiotics
- Ugly - Sniffing dog like position + Drooling
- Prodrome not particularly, but Stormy acute onset.
- Shows Thumb print appearance on X Ray.

Hope this helped !
Happy Studying !
Stay awesome.

~ A.P.Burkholderia

CMS neurology form 2: Question on numbness, tingling and decreased grip strength

Disclaimer: This is an CMS neurology form 2 question for step 2 CK. If you are planning to take USMLE step 2 CK in the future, I would recommend that you DO NOT read this post because it will bias your assessments.

Differentiating C8 radiculopathy from ulnar neuropathy

Hello. This is a very short post (because I am super busy studying)

It's on differentiating C8 radiculopathy from Ulnar neuropathy based on a question I solved the other day. How would you differentiate the two in clinical practice?

C8 radiculopathy:
- Thumb abduction weakness: abductor pollicis brevis (C8, T1)

- Triceps affected (C6, C7, C8)

- Radiculopathies are often painful.

Ulnar neuropathy:
- Hand intrinsics (C8, T1) affected:
Palmar and dorsal interossei
Lumbricals III & IV
Abductor/opponens/flexor digiti minimi

- Basically, all hand intrinsics except for the median-supplied "LOAF" muscles (lumbricals I & II, opponens/ abductor/flexor pollicis brevis)

- Triceps not affected.

- Focal neuropathies aren't painful.

Conclusion: The ulnar nerve innervates all intrinsic hand muscles, except the abductor and flexor pollicis brevis, opponens pollicis, and lateral two lumbricals, which are innervated by C8 and T1 via the median nerve which helps differentiating the ulnar neuropathy from C8 radiculopathy.

That's all!
-IkaN

Saturday, June 17, 2017

Pills of knowledge in Ophthalm- Anterior ciliary artery

The point where the anterior ciliary artery pierces the sclera is often marked by a pigment. This is of particular importance while cauterization as in a bid to make everything look neat and shiny, the pigmented part shouldn't be cauterized as it will cause necrosis of the structures supplied by the artery. 


Effects of Angiotensin-II on GFR


So this is a highly confusing topic. No matter how many times you read it, some amount of doubt is always there in your mind. So an advice to the readers, bookmark this post because you will be needing to read it more than once to get the drift.

First of all, let us review the effects of Angiotensin II on Glomerulus.

It constricts both the afferent and efferent arterioles but preferentially increases efferent resistance. Why? 3 reasons:

1. Efferent arterioles have a smaller diameter in their basal state.

2. Ang II stimulates the release of vasodilator NO from the afferent arteriole.

3. Ang II minimizes vasoconstriction at the afferent arteriole via the stimulation of Ang II type 2 (AT-2) receptors, which result in vasodilatation through a CYP450 dependent pathway.

The net effect of preferential rise in efferent arteriolar resistance is that the glomerular pressure is increased or stabilized(in hypoperfusion states), which helps to maintain or increase GFR. But in the long run, lots of fluid have been filtered out leaving behind the proteins which raise the colloid osmotic pressure, eventually enough to overrule the hydrostatic pressure and hence it leads to decrease in GFR.

Ang II also reduces GFR by causing constriction of the mesangial cells which reduces the effective surface area for filtration. 


-VM

Pills of knowledge in Ophthalmology- Squint and refractive errors

1.A refractive error should be thoroughly assessed prior to surgical squint correction or the squint may recur.

2. Divergent squint occurs in myopes as the divergent system of muscles is more active during far vision. So, the far vision in myopes being hampered, the eyes try to diverge more.

3. Same goes for hypermetropes. They end up with a convergent squint if left uncorrected.

-That's all!

Sushrut Dongargaonkar


Differentiating peroneal neuropathy, sciatic nerve injury and L5 radiculopathy

This post is on differentiating weak dorsiflexion of foot - I made a little algorithm on it. (I'll add images later)

If there's weakness in foot dorsiflexion, check plantar flexion and inversion.

If plantar flexion and inversion is normal: Peroneal neuropathy.

If plantar flexion and inversion is weak: Check hip movements.

If weakness at hip joint: S5 radiculopathy.
If no weakness at hip joint: Sciatic nerve compression.

You can differentiate based on sensory levels and reflexes too but this is easier.

Conclusion:
Peroneal nerve supplies the dorsiflexors and evertors of the foot. There will be no weakness in plantar flexion and inversion in peroneal nerve injury.

Hip abduction is an action of Gluteus medius and minimus muscles. These are Superior gluteal nerve innervated muscles. This nerve arises from L4, L5 and S1 roots . If there is hip abduction deficit with foot drop, it means pathology at the radicular ( root) level. 


Here's the reading material.

Common peroneal neuropathy presentation:
- Acute foot drop (difficulty dorsiflexing the foot against resistance or gravity).
- Patients describe the foot as limp; there is a tendency to trip over it unless they compensate by flexing the hip higher when walking, producing what is called a "steppage" gait.
- Patients may also complain of paresthesias and/or sensory loss over the dorsum of the foot and lateral shin.
- Examination typically reveals weakness in foot dorsiflexion and foot eversion (deep and superficial peroneal nerve-innervated, respectively), with normal inversion and plantar flexion (posterior tibial nerve).
- Sensory disturbance is confined to the dorsum of the foot, including the web space between digits 1 and 2 and the lateral shin.
- Reflexes are normal.

Sciatic nerve injury presentation:
- Weakness affecting most of the lower leg musculature, including the hamstrings.
- Hip flexion, extension, abduction and adduction, and knee extension are normal.
- Sensory loss involves the entire peroneal, tibial, and sural territories.
- In the lower leg, however, the medial calf and arch of the foot may be spared secondary to innervation by the preserved saphenous nerve (a branch of the femoral nerve). Sensation is also spared above the knee both anteriorly and posteriorly.
- The knee jerk is normal, but the ankle jerk is unobtainable.

L5 radiculopathy presentation:
- Back pain that radiates down the lateral aspect of the leg into the foot.
- On examination, strength can be reduced in foot dorsiflexion, toe extension, foot inversion, and foot eversion.
- Mild weakness in leg abduction may also be evident in severe cases due to involvement of gluteus minimus and medius. Atrophy may be subtle; it is most readily observed in extensor digitorum brevis.
- Sensory loss is confined to the lateral shin and dorsum of the foot.
- Reflexes are generally normal.

That's all!
-IkaN

Friday, June 16, 2017

Alvarado Score Parameters Mnemonic ; For Appendicitis

Alvarado score is one of the most famous scores to clinically diagnose Appendicitis. Without further adieu let us delve into it.

            Anorexia or ketones in urine           - 1 
            Leukocytosis >10,000                      -2  
            Vomiting/Nausea                             -1
     migrAtory pain to right iliac fossa            -1
           Rebound tenderness                         -1
 temperAture above 37.3 celsius                 -1
      tenDerness in right iliac fossa              -2
   neutrOphilia >70%                                 -1

Of these the second parameter from above and second parameter from below have 2 points credited for each. Every other parameter is credited with 1 point each.

The overall aggregate comes out of 10, which the highest possible score for Alvarado score.

If, the aggregate is,

<3 - Low risk for appendicitis
4-6 - Mid risk for appedicitis
>=7 - High risk for appendicitis

In some hospitals where a differential count is difficult to find, use a modified score with 9.

That's all guys, if you find any mistake let me know.

With love,
Jay~

P.S. - yayyy.....missed me much awesomites? I was away from the blog for the last 6 months from posting, because I had very disastrous scores for surgery in my university and I didn't feel worthy enough to write for you guys. (So my activity was largely concentrated in the Whatsapp Medicowesome groups, and the Author's page.) Anyways, I had to take a remedial exam for Surgery 2 weeks ago. And BAAM!!!!.....the results were released today, and yayyyyy.....I passed surgery! :)

I must thank all my Medicowesome admin/author collegues for tolerating my rants and, help me to push through the hellish scary time together. Thanks everyone. Finally I'm through it, and I'm back to writing for you all guys. So thought to start the first post after returning, with a General Surgery Diagnosing score with the help of Schwartz Textbook of Surgery.

See ya soon peepz! :)


Thursday, June 15, 2017

Pills of knowledge in Ophthalm- Posterior staphyloma

A posterior staphyloma is common because the durability of the layers of the eye where the optic nerve enters the eye is lesser in comparison.

-That's all!

Sushrut Dongargaonkar


Pills of knowledge in Ophthalm- Moxifloxacin

Moxifloxacin is the preferred antibiotic in Ophthalmic surgeries and pathologies because it gets concentrated into the anterior chamber and the aqueous.

That's all!


-Sushrut Dongargaonkar


EMG and NCS - Review


Hello there!

Today we'll see some important points on Electromyography (EMG) and Nerve conduction studies (NCS).

EMG evaluates abnormal electrical activity in muscles, and NCS investigates how electricity flows through a nerve.

They help to locate and determine the causes of diseases that affect muscles and peripheral nerves.

Procedure:
In EMG, a small needle is inserted into a muscle, to measure its electrical activity. In NCS, electrodes are placed on the skin overlying a nerve, and other recording electrodes are attached at a different point over the same nerve and a small shock is applied, and the electrical impulse is recorded​.

Understanding the terminologies and results of these tests-

 Amplitude: The electrical signal is represented as a wave, and the amplitude is its height.

ConductionVelocity (CV): The conduction velocity describes the speed at which the electrical impulse travels along the nerve.D

Duration This describes the width of an electrical wave.

ConductionBlock: The diminution of signal across an anatomical region such as the wrist. This suggests nerve entrapment.

So when a nerve stimulates a muscle to contract, there is a brief burst of electrical activity called a motor unit action potential (MUP).

Some of the abnormal responses seen are:

1)Fibrillations & positive sharp waves on the monitor seen in diseases of peripheral nerves.

Muscles sometimes start having spontaneous activity on their own.

2)Fasciculations: Sometimes the abnormality causes visible muscle twitches.

3)Abnormally large MUPS : These are seen If a nerve has been injured and then regrows.

 On regeneration the nerve tends to branch out to include a wider area of the muscle and hence we get large motor unit potentials on the screen.

4) Abnormally small MUPS: When they're  abnormally small or brief it suggests the presence of a disease of a muscle (a myopathy) where the muscle is unable to contract to and fails to provide the normal amplitude of the wave.

5)"Recruitment pattern":  As a muscle is contracted, nerve fibers signal more and more bits of muscle (called motor units) to join in and help. 

In a neuropathic disorder, the amplitude of different motor units is strong, but there are fewer of them because the nerve is unable to connect to as many units.

 In myopathies, the number of motor units is normal, but the amplitude is smaller

You may never come across an actual EMG for an interpretation,but it is always good to know the investigation.

The interpretation of EMG and NCSs is not always straightforward and may not always lead to just one possible diagnosis — but the tests can reduce the number of diagnostic possibilities.

Hope this was helpful!

Let's Learn Together!

-Medha.

New TB Risk Factor

People with low levels of vitamin A who live with individuals who were sick with tuberculosis were 10 times more likely to develop the disease than people with high levels of the nutrient, according to research led by investigators at Harvard Medical School.

Vit A rich foods: Liver, fish, hard-boiled egg(not omelette), cheese, butter, cheddar etc

And now some vegetables: Sweet potato, Carrot, Squash, Spinach, Lettuce

Some fruits: Mango, Papaya, Guava, Watermelon, Apricot, Passion fruit

Another reason to love Mango!

-VM

Research update: Statins may increase risk of Parkinsons' disease

Hey Awesomites

A new research by neuroscientists has updated our knowledge about the association between high cholesterol levels in people and prevalence of neurodegenerative diseases such as the Parkinson's.

Mind - wandering : How your body reacts to it?

Hey Awesomites

First lets have a word about mind - wandering.. "Mind- wandering (or task-unrelated thoughts) is an experience of thoughts which are totally unrelated to the task you are doing right now, especially when it demands attention. It involves activities such as reading, driving, attending lectures, etc."

Wednesday, June 14, 2017

Dibucaine Number.

Hello !
Let's see what this Dibucaine number is.

So Dibucaine is a local anesthetic.

Dibucaine inhibits 80% of the normal Pseudocholinesterase enzyme and 20% of the Atypical enzyme.

The number is determined by measuring the percentage of Pseudocholinesterase enzyme that remains unchanged in the blood of individuals administered a standard dose of Dibucaine intravenously.

Normal Dibucaine number is 70-80% i.e 70-80%of normal enzyme is inhibited by Dibucaine.
If there is a point mutation in the enzyme making it a Atypical Pseudocholinesterase then Dibucaine will not be able to inhibit it and the number will decrease.

This number is used to measure the activity of Atypical Pseudocholinesterase,and to assess the likely hood of prolonged apnea after succinylcholine administration.

Sodium Fluoride can also be used in place of Dibucaine.

If you know more on it Add to this information.

Let's learn Together!
-Medha.