ESA3/PPE

Question 1

Spina bifida

Answer 1

Spina Bifida
​
is failure in the caudal neuropore fusion. Whilst it can occur anywhere along the
along its length, it nearly always occurs in the lumbosacral region. Neurological deficits occur, yet
rarely associated with mental retardation; hydrocephalus nearly always occurs (this is due to the
lengthening of the vertebral column, causing the cerebellum to be pulled into the magnum
foramen,cuttingofftheCSF).Twomaintypesofspinabifidacanoccur:
∙ Spina bifida occulta is a defect in the vertebral arches whereby there is a lack of fusion of
thevertebralarches
∙ Spina bifida cystica is a severe NTD whereby neural tissue and / or meninges protrude
through the skin to form a cyst like sac.
If only fluid‐filled meninges are in the sac, it is
termedmeningocele,whereasifneuraltissueisinthesac,itistermedmeningomyelocele.

Question 2

Di george syndrome

Answer 2

Autosomal dominant
Microdeletion: part of long q arm

CATCH22:
Cardiac abnormality (tetralogy of fallot)
Abnormal facies
Thymic aplasia
Cleft palate
Hypocalcaemia / hypoparathyroidism

Question 3

Cauda equina syndrome

Answer 3

Cauda Equina Syndrome results from dysfunction to the
lumbar and sacral nerve roots in the lumbar vertebral
canal, affecting the cauda equina. Cauda equina syndrome
presents with dysfunction of the bladder, bowel, or sexual function, and sensory changes in saddle
or perianal area, as well as potential back pain (with or without sciatic‐type pain), sensory
changes or numbness in the lower limbs, lower limb weakness, reduction or loss of reflexes in the
lowerlimbs,orunilateralorbilateralsymptoms.
Whilst it is commonly caused by large central IV disc herniation at L4/5 or L5/S1 level, it can also
be caused by tumours, direct trauma, spinal stenosis, or inflammatory disease. It is a medical
emergency as if left untreated, patients can be left incontinent, affects motor function, and many
otherpossiblecomplications.Treatmentistreatingtheunderlyingcause.

Question 4

Hydrocephalus

Answer 4

Hydrocephalus is an increase in CSF volume within the ventricular system, and it occurs when the
circulation of CSF is blocked or absorption is impeded whilst CSF formation continues to occur at a
constant rate. This may also result in an increased ventricular pressure and ventricular dilation,
whichcancausecompressiononadjacentneuraltissue.Thetwotypesofhydrocephalusare:
­ Non‐communicating (obstructive) hydrocephalus is wheremovement of the CSF out of the
ventricular system is impeded, thus cannot enter the subarachnoid space. Causes include
tumourorDandy‐WalkerSyndrome
­ Communicating (non‐obstructive) hydrocephalus is where reabsorption of the CSF into the
dural venous sinuses is impeded due to functional impairment at the arachnoid villus.
Causes include subarachnoid haemorrhage or meningitis, whereby there is resultant
scarringandfibrosisofthesubarachnoidspace
To distinguish between the two types of hydrocephalus, a tracer dye is injected into the lateral
ventricle; if the dye appears in the spinal tract it is communicating, and if it does not it is
non‐communicating.

Question 5

Shingles

Answer 5

Shingles
​
is caused by VZV, whose primary infection causes chicken pox yet reactivation from the
dorsal root ganglia produces the condition of shingles. Shingles increases the sensitivity of the
dorsal root neurones, which triggers burning and tingling sensations which are extremely painful
and the skin of the affected dermatome (due to restriction of infection to 1 or 2 dorsal root
ganglia)becomesredandblisters.

Question 6

Tabes dorsalis

Answer 6

Tabes Dorsalis is a late complication of a syphilis infection (part of tertiary syphilis) where the
central processes of the dorsal root ganglion degenerate, thus affects the dorsal columns
(fasciculus gracilis and cuneatus) specifically. As a result, patients develop a loss to fine touch and
consciousproprioception(resultinginlosstotwo‐pointdiscriminationandataxia).

Question 7

Brown sequard

Answer 7

Brown-Séquard syndrome refers to a hemisection (one sided lesion) of the spinal cord. This is most often due to traumatic injury, and involves both the anterolateral system and the DCML pathway:

DCML pathway – ipsilateral loss of tactile sensation and proprioception
Anterolateral system – contralateral loss of pain and temperature sensation.
It will also involve the descending motor tracts, causing ipsilateral hemiparesis.

caused by the lateral hemisection of the
​
spinal cord
​
. It can
be caused by a tumour, trauma, ischaemia, or infectious
or inflammatory conditions. As a consequence of the
damage,theindividualwillpresentwith:
∙ Spasticparalysisofipsilateralside
∙ Loss of fine touch and proprioception to the
ipsilateral side due to damage to fasciculus gracilis and
cuneatus
∙ Loss of pain, temperature, and pressure sensation
to the contralateral side due to damage to the
spinothalamictract.
Treatment involves correcting the underlying condition; the classic cause is a stab wound to the
back.

Question 8

Syringomyelia

Answer 8

Syringomyelia /sɪˌrɪŋɡɵmaɪˈiːliə/ is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord. This cyst, called a syrinx, can expand and elongate over time, destroying the spinal cord. The damage may result in pain, paralysis, weakness,[1] and stiffness in the back, shoulders, and extremities. Syringomyelia may also cause a loss of the ability to feel extremes of hot or cold, especially in the hands. The disorder generally leads to a cape-like loss of pain and temperature sensation along the back and arms. Each patient experiences a different combination of symptoms. These symptoms typically vary depending on the extent and, often more critically, to the location of the syrinx within the spinal cord.

development of a
cyst/cavity around central canal, which grows and spreading out over
time. It typically disrupts spinothalamic tract as this decussates just
ventral to central canal. The result is reduced temperature and pain
sensation at level of lesion, yet fine touch, proprioception and vibration are affected. It can affect

Question 9

ALS

Answer 9

Amyotrophic Lateral Sclerosis (Lou Gehrig’s disease) is a progressive degenerative disease in
which the corticospinal tracts and ventral horn cells degenerate, often beginning with lower limbs
and later involving the upper limbs. Degeneration results in weakness and loss of control to
muscles in the hand, trunks, and lower limbs. Bladder and bowel function can become impaired
duetolossofdescendingautonomicpathways.Causeofthediseaseisunknown.

Question 10

Parkinsons

Answer 10

Nigra. Consequently, there is a reduced direct pathway action and an increased indirect pathway
action. The overall outcome is reduced so there becomes a reduction in movement amplitude to
brainstemandspinalcord.Theclassictriadofsymptomsbecomes:
∙ Tremoratrest,reducedbymovement
∙ Hypertonia(‘leadpipe’or‘cog‐wheel’rigidity)
∙ Bradykinesia

Question 11

Huntingtons

Answer 11

Autosomal dominant
mutation of Huntingten gene
Expansion of triplet repeat
causing degeneration in the GABAergic neurones in the neostriatium of the indirect pathway.
Theresult is excessive excitation to the thalamus from loss of the inhibition from the indirect pathway, producingthechoreiformmovementsassociatedwithHuntington’sdisease.

Question 12

Cerebellar dysfunction: DANISH

Answer 12

Dysdiadochokinesia
Ataxia
Nystagmus
Intention tremor
Scanning speech / dysarthria
Hypotonia

Question 13

Autonomous bladder

Answer 13

AutonomousBladder
An autonomous bladder is caused by LMN lesions, when there is damage to above S2‐4 level.
There is consequently a loss of parasympathetic and afferent neurones. This results in an
individualwithoverflowincontinenceandnoabilitytomicturate.

Question 14

Automatic reflex bladder

Answer 14

AutomaticReflexBladder
Any damage above the sacral region (i.e. T12 and above) can cause damage to the UMN and result
in automatic reflex bladder. There is a loss of the descending inhibitory control which results in
lossofbladdercontrolandinvoluntaryleakageofurine,producinganurgeurinaryincontinence.

Question 15

Spinal shock

Answer 15

When descending tracts of spinal cord severely damaged•
May last weeks - months•
Characterised by flaccid paralysis & areflexia (even though ventral roots may be intact) •
Thought to be due to loss of motor influences by descending fibres from reticular tract◦
Eventually, limbs become spastic & show hyperactive deep reflexes, typical of UMN damage•
As fibres from reticular tract degenerate, intact connections in reflex circuits become dominant & ◦
show themselves as UMN signs

Question 16

Lateral medullary syndrome

Answer 16

caused by occlusion of the
posterior inferior cerebellar artery and causes acute vertigo with cerebellar and other
signs.
Loss of pain/temp:
In trunk - contralateral side
In face - ipsilateral side

Question 17

phaeochromocytoma

Answer 17

an adrenal catecholamine‐secreting tumour, producing large amounts ofadrenaline and noradrenaline. Diagnosis is made by urinary catecholamines and by imaging, and
treated initially with non‐selective alpha‐adrenoreceptor antagonists to prevent the action of thecatecholaminesonthereceptors

Question 18

Conn’s syndrome

Answer 18

aldosterone‐secreting adenoma and will result in a primary
hyperaldosteronism; the excessive secretion of aldosterone will cause significant fluid
reabsorption.Itistreatedwithaldosteroneantagonists,suchasSpironolactone.

Question 19

Idiopathic Parkinson’s

Answer 19

neurodegenerative disorder that has a progressive clinical course whereby there is a loss
of dopaminergic neurones in the Substantia Nigra. The result is a classic triad of Tremor, Rigidity,
and Bradykinesia, yet can also cause mood changes (e.g. depression), pain, cognitive change,
urinary symptoms, sleep disorders (e.g. REM‐sleep behaviour disordermay be an early onset sign),
orsomnolence.

Question 20

Myasthenia Gravis

Answer 20

the nAChRs at the NMJ. The result is a fluctuating fatigability in skeletal muscles; commonly the
extraocular muscles (causing diplopia or ptosis) are the first to be affected yet it can result in
bulbar involvement (causing dysphagia and dysphonia), limb weakness, and respiratory
involvement.
It is mainly treated with acetylcholinesterase inhibitors

Question 21

Osteoarthritis vs Rheumatoid arthritis

Answer 21

OA:
articular cartilage & subchondral bone undergo destruction
Commonly affectsweight-bearing joints (e.g.Vertebral column, hips, knees)
Radiology: narrow joint space, osteophytes, cysts
Asymmetrical

RA:
Autoimmune: Systemic CT disorder affecting joint synovium
Shows chronic inflammatory changes (synovitis): soft, warm, tender
Eventually leads to invasion & erosion of underlying cartilage &
subchondral bone
Usually affects small joints of hand
Radiology: soft tissue swelling, ill-defined marginal erosion
Symmetrical

Question 22

Tetralogy of fallot

Answer 22

Pulmonary stenosis
Overriding aorta (connected to both R and L ventricle)
Ventricular septal defect
Right ventricular hypertrophy

= Right to left shunt (cyanotic)

Question 23

Phynlketonuria (PKU)

Answer 23

Autosomal recessive

Impaired metab of phynylalanine (amino acid)
Used to make aspartamine, tyrosine (oxidation, protein synth, catecholamines, thyroxine)

Absent phenylalanine hydroxylase (PAH) enzyme:
Breaks down excess phenylalanine from food
Excess phenylalanine toxic to nervous system: can cause intellectual disability

Low protein diet / no phenylalanine or aspartamine
Amino acid supplements

Part of newborn screening

Question 24

Homocysteinuria

Answer 24

Autosomal recessive

Disorder of methionine (amino acid) metabolism

Often involves CBS enzyme:
Converts homocysteine to cysteine (from methionine)
Defect = excess homocysteine (detected in serum/urine)

Affects CT, MSK sys (can mimic marfans clinically), CVS (homocysteine excess = endothelial injury)

Cysteine a precursor to antioxidant glutathione and iron-sulfur clusters

Question 25

G6PD deficiency

Answer 25

X linked recessive

Glucose 6 phosphate dehydrogenase: involved in pentose phosphate pathway, esp important in red blood cell (only source of glutathione in rbc’s)
Provides reducing energy to maintain levels of NADPH
which maintains supply of glutathione: mops up free radicals in oxidative damage

Predisposes to hameolytic anaemia and jaundice
Some protection against malaria

Avoid foods e.g. Fava beans

Question 26

Conn’s syndrome

Answer 26

Primary aldosteronism: excess production of aldosterone
= low renin (high BP: poor vision/headache)

May be due to enlargement of adrenal glands or adrenal adenoma, adrenal cancer, familiar hyperaldosteronism

Question 27

Pheochromocytoma

Answer 27

Neuroendocrine tumour of medulla or adrenal glands (originating in chromaffin cells)
Secretes high amt of catecholamines

Sympathetic NS hyperactivity

Question 28

Cushings disease/syndrome

Answer 28

Disease:
Increased secretion ACTH from ant pituitary
Often from pituitary adenoma
or excess production CRH from hypothalamus
Stimulates release of cortisol from adrenal glands

Syndrome:
Prolonged exposure to cortisol (released from zona fasciculata)

Signs/symptoms:
High BP (mineralocorticoid effect)
Fat re-distribution (central obesity), buffalo hump
Moon face
Purple striae
Women: irregular periods

Diagnosed with dexamethasone suppression test (a glucacorticoid; should normally -vely feedback and inhibit ACTH)

Question 29

Addison’s disease

Answer 29

Prumary adrenal insufficiency:
Adrenal glands dont produce sufficient steroid hormones (glucocorticoid and mineralocorticoid)

Signs/symptoms:
Fatigue, light headed, weight loss, musc weakness, low BP
Hyperpigmentation e.g. Palmar creases (alpha MSH and ACTH from same precursor POMC)

Addisonian crisis:
When stressed, accident, injury, infection etc
low BP

Question 30

SIADH

Answer 30

Syndrome of inappropriate antidiuretic hormone secretion:
Excessive release of ADH from posterior pituitary
ADH not inhibited in normal way by plasma osmolarity

E.g. From ADH-secreting tumour, drugs, small cell lung carcinoma

Increase in blood vol:
Dilutional hyponatremia (retain water and not solute);
Body responds to water retention by decreasing aldosterone, losing more sodium

Anorexia, nausea, ataxia, hyporeflexia, cyasrthria, lethargy, seizures

Question 31

Diabetes insipidus

Answer 31

Excessive thirst and excretion of large amounts of dilute urine
Reduction in fluid intake has no effect on conc of urine

Central DI:
Deficiency of ADH

Nephrogenic DI:
Kidney/nephron insensitivity to ADH

Question 32

Glaucoma:

open angle vs angle-closure

Answer 32

Increased intraocular pressure
Damage to optic nerve

Open angle:
More common
Wide/open angle btw iris and cornea
Blockage of drainage canals
Slow dev
Painless

Closed Angle closure:
Less common
Closed/narrow angle btw iris and cornea: iris in contact with trabecular meshowrk, blocking outflow of aqueous humour
Often Fast presentation

Question 33

Duchenne muscular dystrophy

Answer 33

recessive X-linked
results in muscle degeneration and premature death
caused by a mutation in the gene dystrophin which codes for the protein dystrophin. Dystrophin is an important component within muscle tissue

Progressive proximal muscle weakness of the legs and pelvis associated with loss of muscle mass is observed first. Eventually this weakness spreads to the arms, neck, and other areas. As the condition progresses, muscle tissue experiences wasting and is eventually replaced by fat and fibrotic tissue (fibrosis).
average life expectancy is around 25.