Dermatomes and corresponding Nerve supply !!

Dermatomes and corresponding Nerve supply !!

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HIGH YIELD POINTS : NEUROLOGY 1

[1] Agenesis of

CORPUS CALLOSUM= AICARDI SYNDROME

OLFACTORY LOBES = KALLMAN SYNDROME***

 

[2]  = Q = In KERNICTERUS  following are charecteristically affected except*****

[A] subthalmic nucleus

[B] globus pallidus

[C] lateral thalmus

[D] corpus callosum

ANS = [D]

Kernicterus involves deep gray matter and brain stem nuclei with subthalmic nucleus, globus pallidus and  lateral thalmus being chareceristically effected. Other areas effected are Hippocampus CA2 , Lateral geniculate body, the colliculi , substantia niagra etc.

 

[3] Chiari type II malformation = herniation of cerebellar vermis + shallow posterior fossa +malformation and downward displacement of brain stem. It is almost invariably associated with a lumbosacral myelomningocoele and is accompanied by hydrocephalus at birth in 80 % of cases.

[4] Most common location of ARACHNOID CYST = SYLVIAN FISSURE (50% CASES)

[5] Acute infantile SPINAL MUSCULAR ATROPHY is also nown as WERDNIG HOFFMAN DISEASE*

[6] RASMUSSEN’S ENCEPHALITIS = Progressive subacute unilateral intractable seizure + histology suggestive of chronic viral encephalitis.

 

[7] NEURONS in cns which are sensitive to Hypoxia and so first to get affected by HYPOXIA are:-

[a] Hippocampal neurons in CA1 field(sommer sector) [NOTE : CA2 region is most resistant part in hippocampus]

[b] Pyramidal neurons in cerebellar cortex

[C] Cerebellar purkinje cells.

These three neuronal cells are most sensitive to hypoxia in brain

 

[8] HYPERTENSIVE BRAIN HEMORRHAGE : Most common site = PUTAMEN, localised by combination of hemiparesis + hemisensory loss+ visual field defect.

[9] Charcot- bouchard microaneurysm = formed in cerebral blood vessels in hypertension.

[10] Some points associated with VIRAL INFECTION OF BRAIN

[A] HSV ENCEPHALITIS most commonly involves = TEMPORAL LOBE

[B] NEONATAL HSV ENCEPHALITIS is mostly due to = HSV 2

[C] CEREBELLITIS is Caused by VARICELLA

[D] YOU know about NEGRI BODY ….Ie sharply demarcated, round/oval eosinophillic inclusions in neuronal cytoplasm. Now Q is what is LYSSA BODY ? In rabies some neurons display less well defined (although ultrstructurally similar) eosinophillic inclusions and these are termed as LYSSA BODIES 🙂

[E] SSPE is more likely to occur if exposure to measeles virus occurs at less than 18 months of age.

[F] MICROGLIAL NODULE is charecteristic finding of HIV ENCEPHALITIS (Microglial nodule is seen in brain of people with HIV and may be caused by HIV itself or by opportunists as CMV, TOXO)

 

 

[11] Some points on toxic injury to brain :

[a] ALUMINIUM TOXICITY =DIALYSIS ENCEPHALOPATHY SYNDROME= Dysarthria+ Apraxia of speech+ myoclonus + ataxia+ dementia = It is seen in patients undergoing chronic hemodialysis as there is high conc of aluminium in water usd for dialysis.

[b] ARSENIC does not cross blood brain barrier. It causes periferal neuropathy.

[c] METHANOL TOXICY = BLURRING OF VISION + PRESERVED SENSORIUM

[d] Carbon monoxide poisoning : Necrosis of  PALLIDUM is typical feature of delayed death from carbon monoxide poisoning.

[e] NEUROLATHYRISM = LATHYRUS TOXIN = BETA -N -OXALYLAMINO- L – ALANINE = SPASTIC PARAPLEGIA WITHOUT SENSORY LOSS****

[f] MARCHIFAVA-BIGNAMI DISEASE is seen in chroic alcoholics mainly involves CORPUS CALLOSUM.

 

[12] Some points on protozoal infection of brain :-

[a] Cerebral amebic abscess = E histolytica

[b] PRIMARY AMEBIC MENINGOENCEPHALITIS = Naegleria fowleri ( It is usualy acquired by swimming, diving or skiing in fresh water and is not associated with any predisposing codition). The presentation is of acute fulminant illness were patients develop meningitis that rapidly progresses to coma and death within 48-72 hrs)

[c] GRANULOMATOUS AMEBIC MENINGOENCEPHALITIS = Acanthoameba sp ( The infection is predominantly encountered in chronically ill, debilitated or immunosuppressed individuals. NOTE : Balamuthia mandrillaris is also a free living ameba which causes similar illness ie granulomatous amebic meningoencephalitis.

[d] Durck granulomas are seen in brain in cerebral malaria ( ideal DNB item 🙂 )

 

AND NOW A SHORT NOTE ON NEUROCYSTICERCOSIS

In global terms NEUROCYSTICERCOSIS is most common parasitic infection of CNS. The viable intraparenchymal cysticerci are usually 1-2 cm in diameter and contain a single invaginated scolex.

Escobar’s pathological staging is used for NEUROCYSTICERCOSIS***
STAGE 1 = Vesicular = 
In the vesicular stage, the cyst is filled with clear fluid, has a thin semitransparent wall and an eccentric opaque 4–5mm scolex. Vesicular cysts are viable, produce scarce inflammatory changes and are usually asymptomatic.

STAGE 2 = Colloidal vesicular( MOST SYMPTOMATIC STAGE )= When the host immune system overcomes the protective mechanisms of the cyst, the cyst starts degenerating and an inflammatory response is elicited, the larva undergoes hyaline degeneration and the clear cyst fluid is replaced with gelatinous material; this is termed the colloidal stage.

STAGE 3 = Granular nodular = The cyst then contracts, the walls are replaced by focal lymphoid nodules and necrosis, and the scolex is transformed into coarse mineralized granules forming the granular nodular stage.

STAGE 4 = Nodular calcified (NO oedema) = Finally the granulation tissue is replaced by collagenous structures and calcification giving rise to the nodular calcified stage.

In cases with symptomatic parenchymal neurocysticercosis, the most common CT finding is a single, small (<20 mm), low-density lesion with ring or disc enhancement. The scolex appears as a bright high-density eccentric nodule and is pathognomonic of neurocysticercosis.

 

🙂 To be continued …………….

 

 

 

COPPER : MENKES DS : WILSON DS

Why is copper  required in body ?

What if there is deficiency of copper ?

what if there is excess of copper ?

1. Copper acts as cofacter for various enzymes = TYROSINASE , LYSYL OXIDASE , SUPEROXIDE DISMUTASE, CYTOCHROME C OXIDASE, DOPAMINE BETA HYDROXYLASE. [Q]

2. If there is deficiency of copper these enzymes will not work properly as for eg in copper deficient state lysyl oxidase will not work and there will be ineffectual cross linking in collagen and elastin leading to weakened vascular wall and fragile skin.

MENKES DISEASE IS A X-LINKED RECESSIVE DISORDER DUE TO DEFICIENCY OF COPPER

PATHOGENESIS : Defect in ATP7A gene[Q] so that copper is absorbed in the intestinal eptithelial cells but cant be transported out of intestinal epithelial cells into blood stream so that the intestinal epithelial cells are loaded with copper but there is deficiency of copper in body.

CLINICS : Mental retardation , seizures , hypothermia , twisted and hypopigmented hair (pili torti) , loose skin , arterial rupture and death in early childhood.

TREATMENT : To give copper by any other route than oral becoz intestinal absorption is impaired. Subcutaneous route copper is given and show some clinical improvement in disease state.

WILSON DISEASE IS DUE TO EXCESS DEPOSITION OF COPPER IN VARIOUS PARTS OF BODY:

PATHOGENESIS : Defect in ATP7B gene( CHROMOSOME 13)[Q] leads to defective excretion of copper from hepatocytes into billiary tree leading to copper excess in body . Two most commonly effected organ is liver and brain so also known as HEPATOLENTICULAR DEGENERATION.

CLINICS : It usually presents with acute or chronic liver disease in childhood . Liver disease is progressive if left untreated. Adults develop neurological symptoms as dysarthria and diminished cordination. Copper accumulation can also lead to arthropathy , cardiomyopathy, kidney damage and hypoparathyroidism , decemets membrane formation.

TREATMENT : Chelating agents as penicillamine and ammonium tetrathiomolybdate.

so to compile

MENKES = COPPER DEFICIENCY = ATP7A GENE = X-LINKED RECESSIVE = DEFECTIVE COPPER ABSORPTION

WILSON = COPER EXCESS = ATP7B GENE = CHROMOSOME 13 = AUTOSOMAL RECESIVE = DEFECTIVE COPPER EXCRETION

SEIZURE RELATED QS IN AIIMS MAY 2013

Q1] Women of child bearing age presents with juvenile myoclonic epilepy and valproate not suited then next drug to be used is …..[AIIMS MAY 2013]
a. Levetiracetam
b.lacosamide
c.phenytoin
d.carbamazepine
ANS =[a] levetiracetam

JUVENILE MYOCLONIC EPILEPSY [ JANZ SYNDROME ]

Age at onset = late childhood and adolscence , peaking at 13 year.

clinical manisfestation = mild myoclonic jerks of neck and shoulder flexors after awakening , may also have absence and GTCS . Intelligence normal.

EEG = Interictal eeg shows variety of spike and wave discharges or 4-6 Hz multispike and wave complexes ( ” fast spikes”)

ANTICONVULSANTS BY ORDER OF CHOICE = VALPROATE > LAMOTRIGENE > TOPIRAMATE> LEVETIRACITAM [ Ref : current pediatric diagonosis and treatment pg 748/ 17 ed]

Carbamazepine, oxcarbazepine, and phenytoin can exacerbate absences and myoclonus and are therefore contraindicated
The drug of first choice in the treatment of JME is sodium valproate. Valproate should be avoided in women of childbearing age because of significantly increased risks of fetal malformations and neurodevelopmental delay. lamotrigine / Levetiracetam are alternative first-line options if valproate is contraindicated.

Q2] Which IV anesthetic agent should not be given to an epileptic patient posted for surgery under general anesthesia …[AIIMS MAY 2013 ]

[A] propofol

[B] Thiopentone

[C] Ketamine

[D] midazolam

ans = [c] = ketamine

PROPOFOL = induction is occasionaly accompanied by excitatory phenomena as muscle twiching, spont movements . Although these movements may mimic GTCS ,propofol appears to have predominantly anticonvulsant properties and has been successfily used to terminate status epilepticus and may be safely administered in epileptic patients [ ref : lange clinical anesthesiology page 174 / 3ed]

Barbiturates [thiopentone ] & benzodiazepines [ midazolam ] are anticonvulsants so can be safely administered in epileptic patients.

KETAMINE = It should be used with caution in epilepsy patients. SO the ans = [c] ketamine.

Q3] Inhalation agent of choice in a patient with intracranial SOL / raised ict…[AIIMS MAY 2013]

[A]ENFLUORANE

[B] ISOFLUORANE

[C] DESFLUORANE

[D] HALOTHANE

ANS =[B] isoflurane

HALOTHANE should be used with great caution in patients with intracranial SOL because of possibility of intracranial hypertension.

AMONG OTHER THREE, ISOFLURANE cause least increase in ICT  therefore agent of choice for neurosurgery.

Q4]Recomended drug to control seizure after alcohol withdrawl…[AIIMS MAY 2013]

[A] SOD VALPROATE

[B] DIAZEPAM

[C] PHENYTOIN

[D] CLONIDINE

ANS= [B] DIAZEPAM [ Ref : pocket handbook of clinical psychiatry table no 11-14, pg no 120 /5th ed]

CLINICAL PROBLEM AND DRUG TREATMENT IN ALCOHOL INTOXICATION , WITHDRAWL AND MAINTAINENCE.

1. Tremulousness and mild to mod agitation = chlordiazepoxide[ ORAL]

2. EXRTREME AGITATION = chlordiazepoxide[IV]

3. Hallucinosis = larazepam.

4. withdrawl seizures = diazepam.

5. delirium tremens = lorazepam****

6. maintainence = acamprosate = anticraving drug [ also came in AIIMS MAY 2013 ]

NOTE : ANTICRAVING DRUGS FOR ALCOHOL DEPENDENCE = NALTREXONE , ACAMPROSATE

 AND Aversive agents= disulfiram

 

AIIMS MAY 2013 QUESTIONS

1 KLUVER BUCY SYNDROME http://pguploads.com/2013/03/16/amygdal/

2. EYE Q = NHL OF ORBIT / METS TO ORBIT http://pguploads.com/2013/05/14/nhl-of-orbit-mets-to-orbit-aiims-may-2013/

3 . psychiatry ..jean piaget http://pguploads.com/2013/05/15/out-of-sight-is-not-out-of-mind-or-object-permanence-in-jean-piagets-development-theory-aiims-may-2003/

4. sudecks dystrophy http://pguploads.com/2013/05/15/reflex-symphathetic-dystrophy-cprs-i-sudecks-dystrophy-aiims-2013/

5 . isochromosome  http://pguploads.com/2013/05/14/q-how-is-isochromosome-formed-aiims-may-2013/

6 .seizure related qs in aiims 2013 http://pguploads.com/2013/05/14/seizure-related-qs-in-aiims-may-2013/

7. PSM Q’S http://pguploads.com/2013/05/16/psm-qs-aiims-may-2013/

PARKINSONS PLUS SYNDROMES : PSP

Parkinsons plus syndromes have features of parkinsonism but they differ from parkinsons disease in having some additional features and they r unresponsive to treatments directed against parkinsons disease.

NOW LETS SEE HOW THEY COME TO NOTICE :

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EXAMPLES of PARKINSONS PLUS SYNDROMES  r ;

1] Multiple system atrophy

2] Progressive supranuclear palsy

3] Parkinsonism-dementia-amyotrophic lateral sclerosis comple

4] Corticobasal ganglionic degeneration

5] Diffuse lewy body disease

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PROGRESSIVE SUPRANUCLEAR PALSY

It is a tauopathy due to deposition of tau doublet 64 ,69.

CLINICAL FINDINGS:

1. Tremor is rare.

2. Supra nuclear vertical gaze palsy : supra nuclear nature of palsy can be checked by presence of vestibulo-ocular reflex which can be clinically assesed by vertical dolls eye maneuvers . There will be slowing of verical saccades.

3. presence of  square wave jerks ( Square-Wave Jerks (SWJ) are inappropriate saccades that take the eye off the target, followed by a nearly normal intersaccadic interval  and then a corrective saccade that brings the eye back to the target.).These are fine movements, that can be mistaken for nystagmus, except that they are saccadic in nature, with no smooth phase.

4. Akinetic rigid syndrome = axial rigidity > limb rigidity

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This instability leads to frequent backwards fall……and patient makes very little effort to prevent the fall….

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COMBINATION OF VERTICAL SUPRANUCLEAR GAZE PALSY AND HISTORY OF FREQUENT FALL ( ESPECIALY BACKWARDS) IS CENTRAL TO DIAGONOSIS OF PSP

5. Dementia and frontal lobe signs as apathy , personality changes , disinhibition may be present.

IT HAS TWO TYPES ;

[A] STEEL RICHARDSON SYNDROME = EARLY POSTURAL INSTABILITY + COGNITIVE DYSFUNCTION + SUPRA NUCLEAR GAZE PALSY

[B] PSP PARKINSONISM = PREDOMINANT FEATURES OF TYPICAL PD AND IT IS MODERATELY RESPONSIVE TO LEVADOPA+CABIDOPA

NOTE : (1) HPE shows deposition of GLOBOSE NEUROFIBRILLARY TANGLES & TUFTED ASTROCYTES . (2) MRI shows HUMMING BIRD SIGN which is due to atrophied mid brain and relatively preserved pons

u can also read basal ganglia and parkinsonoism aon following link

http://pguploads.com/2013/03/23/parkinsonism-a-story-of-muhammad-alis-basal-ganglia/