Sunday, August 31, 2008

L LMN 7th CN palsy

One of the most common cranial nerve examination in MRCP and Medical student exams !

Look at this patient's face and proceed with the necessary.

I remember that when I was practising with eMRCPian before my MRCP PACES exam, he used to tell me that do the necessary and don't examine the cranial nerves from I to XII which would normally be done by most medical students.

It is obvious from inspection that there is loss of nasolabial fold on the left.
Start with cranial nerve VII
  • Loss of wrinkling of the forehead, unable to close the L eye tightly, unable to blow the cheeks, mouth deviated to the right on showing the teeth
  • Look for Bell's phenomenon - upward movement of eye and incomplete closure of eyelid when the patient attempts to shut the eyelids
After establishing that it is LMN 7th CN palsy, next we have to see whether other cranial nerves are involved.

  • Check the III, IV, VI CN by checking the eye movement, a CP angle tumour can extend to involve these cranial nerves or in cases of NPC where you get multiple CN involvement
  • Check the V cranial nerve esp corneal reflex (remember that afferent is V and efferent is VII for corneal reflex)
  • Check the VIII cranial nerve - will be involved in CP angle tumour
  • You can check other cranial nerves quickly - IX,X,XI,XII
  • It won't be necessary to check the CN I or II
Next, we need to establish the cause if it is solely the VII LMN 7th CN involved.

  • Shine a torch into the ear(the site of the 7th CN palsy) to look for vesicles in Ramsay Hunt syndrome
  • Examine the parotid glands for parotid enlargement (remember that the 5 branches of the 7th nerves comes out here - Used to remember "Clincal examination by Talley, O' Connor" which mentioned Two Zebras Bit My Car - Temporal, Zygomatic, Buccal, Mandibular, Cervical)
  • Check for lymph nodes enlargement - NPC
  • Check also for cerebellar signs of the upper limbs (CP angle tumour)
Offer to check the taste of the anterior 2/3 of the tongue and to look for hyperacussis.

For medical students, try to remember the pathway of the 7th cranial nerve and the branches of it.

Monday, August 25, 2008

Frank's sign

I just got back from Hong Kong recently for a holiday.During a morning of breakfast, while I looked around I noticed this man who was sitting eating 'Tim Sum' and I am sure he has coronary artery disease.
There was obvious Frank's sign.

Frank's sign is a diagonal crease in the lobule of the auricle :
Grade 3 - a deep cleft across the whole earlobe
Grade 2a - crease more than halfway across the lobe
Grade 2b - crease across the lobe, but superficial
Grade 1 - lesser degree of wrinkling

Ear lobe creases are associated statistically with coronary artery disease in most of the population groups.

For those who are medical students, if you get a case of Ischaemic heart disease or IHD, please look for this in addition to xanthalesma and corneal arcus in your exam.

For MRCP PACES candidates, if you still have not heard of this, you have not read enough of An Aid to the MRCP PACES by R.E,J Ryder, M.A Mir & E.A Freeman. It is on page 14 Section B on the 3rd edition and if I remember correctly it is in the first few pages in the 2nd edition when I read it long time ago during my medical student days.

Thursday, August 7, 2008

Lower limbs and Guillain Barre syndrome

This is a low power image of a peripheral nerve in GBS. It has been stained with a myelin stain (pink). Note the large areas of myelin loss in the center

The interesting about Neurology is that the history(eg pt with headache) & examination is still plays a very important role. In cardiology, Echo has sort of replaced cardiac examination, U/S abd and CT abd has sort of replaced gastroenteralogy cases and chest radiograph and CT has sort of replaced respiratory examination.
Well, I say sort of because it should not be the way and physicians and all doctors should be pasionate about the power of history taking and physical examination.
You may say that MRI brain has replaced Neurology but it is totally untrue because the most important question in Neurology is where is the lesion ? So, if you MRI the brain for a Guillain Barre syndrome then you are in the wrong direction !
Which now brings me to the topic of to locate the lesion

You are asked to examine a 33 years old man with weakness of the lower limbs in the exam.
How to start ?

Inspection - wasting of the thighs, no fasciculations, no scars
Tone - reduced bilaterally
Power - 2/5 distally and 3/5 proximally
Reflexes - absent bilateral knee and ankle reflexes
Plantar response - downgoing bilaterally

Cerebellar examination of lower limbs not able to be done in view of the weakness

Sensation - reduced pin prick bilaterally up to the knees

Gait unable to be test due to the power

SO, the first conclusion you should make is
this patient has LOWER MOTOR NEURON lesion of the lower limbs with peripheral sensory neuropathy

Next step is to locate the lesion.
It is anywhere from the anterior horn cell , nerve roots, plexus, peripheral nerve, neuromuscular junction, muscle.
It is not the ant horn cell or neuromuscular junction because of sensory involvement. It is at the peripheral nerve because of predominant distal neuropathy with distal sensory involvement.

So, this patient has peripheral motor sensory neuropathy (predominant motor).
Next are the causes of predominant motor peripheral neuropathy

Causes include :
Guillain Barre syndrome (acute)
Chronic inflammatory demyelinating neuropathy (chronic)
Charcot Marrie Tooth/Hereditary motor sensory neuropathy
Lead poisoning
Acute intermittent porphyria

This patient actually has Guillain Barre syndrome.
So, you can see how important your examination is and from there you can actually investigate treat the patient. MRI brain will be useless.
You could do an LP to look for cytoalbuminaemic dissociation and a nerve conduction study.

If you suspect GBS, examine the pulse for tachycardia(autonomic dysfunction) and cranial nerves(weakness of the facial muscles).
Also you could do a vital capacity to look for respiratory involvement.

Treatment would be IVIG or plasmapheresis (more effective if given early)

Tuberous sclerosis

This young man has epilepsy and mental retardation.
The picture shows Shagreen patch(leathery skin patch over the back) and adenoma sebaceum(shiny papules at the nasolabial fold), classical of tuberous sclerosis.
The 3 neurocutaneous syndromes that medical students and MRCPian need to know include neurofibromatosis, tuberous sclerosis and Sturge Weber syndrome.

Tuberous sclerosis is an autosomal dominant disease characterised by multiple organ hamartomas.

Skin - Adenoma sebaceum(angiofibromas), subungal fibroma, Shagreen patch, ash leaf macules
Renal - Angiomyolipomas
Cardiac - Rhabdomyosarcomas
CNS - Subependymal nodules, Cortical tubers, benign white matter lesions, subependymal giant cell astrocytoma
Eye - retinal phakomas

If you get this in the exam, dont forget to ask about seizures and mental retardation !

Also I just advised my houseman just now that if you see a patient in the ward that came in for seizure, do not forget to look for neurocutaneous signs.(was previously thought to me by my consultant neurologist)
THE EYE DON'T SEE WHAT THE MIND DON'T THINK !(was told to me by my lecturer)

Monday, August 4, 2008

Nail changes in Psoriasis

Psoriasis as I have mentioned is an important skin disorder - both medical students and MRCP candidates have to know.

The nail changes in psoriasis are :
1) Pitting of the nails
2) Onycholysis
3) Discolouration (Oil drop sign)
4) Ridging
5) Subungal hyperkeratosis

The arthritis in psoriasis are :
1) Oligoarthritis
2) Distal asymmetrical arthrtis
3) RA like arthritis
4) Ankylosing spondylitis like arthritis
5) Arthritis mutilans

The types of psoriasis are :
1) Chronic plaque
2) Guttate
3) Pustular
4) Erythrodermic
5) Inverse

Remember all in 5.....these are the few favourite questions

Sunday, August 3, 2008

Heart murmurs

The heart murmurs are something very fascinating ! At one time, I found it so fascinating that I thought of becoming a cardiologist. But it seems now that echo becomes the trend. Medical students need to know the murmurs well, not forgetting those who are sitting for the MRCP exam.

Pansystolic murmur at apex - axilla = Mitral regurgitation
Mid diastolic murmur at apex, best on L lateral position = Mitral stenosis
Early diastolic murmur at LSE, best on sitting up on expiration = Aortic regurgitation
Ejection systolic murmur at aortic, radiating to the carotids = Aortic stenosis

Pansystolic murmur at tricuspid, best on inspiration = Tricuspid regurgitation

Pansystolic murmur at LSE, 3rd intercostal space = Ventricular septal defect(VSD)
Ejection systolic murmur at pulmonary area, with wide fixed split S2 = Atrial septal defect(ASD)
Continuous murmur = Patent ductus arteriosus (PDA)

Memorise it medical students !!

Saturday, August 2, 2008

Internuclear opthalmoplegia

I am currently attending a MS workshop organised by KL GH with Bayer in Cyberview Lodge Resort & Spa. Nice place !

Well, multiple sclerosis is a common exam question and we discussed a little in the optic atrophy topic.

Remember that it is very common to be asked to examine the cranial nerves. Neuroopthalmology can be very interesting.

The above picture shows that the patient is looking to the right. There is failure of adduction of the L eye and nystagmus on the R eye.

The diagnosis is L INO (remember that the pathology is at the site of the failure if the abducted eye)

If you get bilateral INO - it is almost always MS especially when you see a young lady.

So if you get INO, remember to check for RAPD, Lhermitte's by flexing the neck, cerebellar signs and offer to do a fundoscopy to look for optic atrophy. You can also check the lower limbs for upper motor neuron signs in transverse myelitis and if you have that it is surely MS.

Where is the lesion ?

MLF - medial longitudinal fasciculus

Remember the pathway of PPRF and the 6th nerve. I am sure you can figure out the rest.

What is the criteria used for MS ?

Mc Donald's - previously it was Poser criteria

How would you investigate MS ?

MRI brain/spinal cord, neurophysiology study - VEP,SSEP, BAER, LP for oligoclonal band and IgG

McDonald's criteria focusses a lot on MRI.

What would you treat the patient in the acute phase ?

IV methylprednisolone

What is the long term treatment to reduce relapses ?

Beta interferon or glatiramer acetate

Friday, August 1, 2008

Rheumatoid arthritis

A very common exam question in undergraduate exam up to MRCP PACES.
Sing the song before you go into the exam hall and you'll be confident coz they are almost the same. Don't be over confident though coz the examiner is like the 'Joker' in Batman - you need to outsmart him, he is not that straight forwaard. You have to be the DARK KNIGHT !!

This patient has bilateral symmetrical deforming arthropathy involving the MCP/PIP joints but sparing the DIP joints.
There is Z deformity of the thumb, boutonnière's deformity and swan neck deformity
Tinel sign is positive suggesting carpal tunnel syndrome.
There is also limited movement of thumb abduction and opponens.
There are no nail changes or rashes to suggest RA like psoriatic arthropathy.
There is Rh nodules.
Functinally she can still write and unbutton her shirt.
There is no evidence of episcleritis/scleritis/scleromalacia perforans and the lungs are clear(rule out Rh lung). I would like to examine the abdomen for splenomegaly in Felty's syndrome or hepatosplenomegaly in amyloidosis.

My diagnosis is that this patient has RA and it is inactive as there joint swellings are hard suggesting subluxation and the joints are not warm of tender.

Questions :
What are the causes of anaemia in RA ?

What are the poor prognosis factors ?

How would you investigate this patient ?

What are the options of treatment ?