Is she ok?

BCS

100

Define tonicity. How do you estimate tonicity in the body?

- ability of solution surrounding cell to cause that cell to gain or lose water 

- intravascularly it is measured through osmolarity

200

What are causes of hyponatremia?

hypovolemic hyponatremia:

- GIT loss 

- diuretics

- third spacing 

hypervolemic hyponatremia 

- renal failure

- heart failure 

euvolemic hyponatremia 

- drugs: SSRIs, thiazide diuretics, NSAIDs, MSMA, 

- SIADH

- hyperthyroidism 

300

Outline the reticular activating system and its role in consciousness 

network within the brainstem between the midbrain and pons that connects the brainstem to the cortex and plays a role in regulating alertness/arousal 

• regulated by hypothalmic neurons which activate modulatory systems --> keep brain active
• tuberomamillary nucleus - histamine containing neurons
• lateral hypothalamus - hypocretin/orexin peptide
• ventrolateral preoptic nucleus (VPLO) in hypothalamus periodically inhibits histamine containing neurons and hypocretin (orexin) --> wakes us up

400

Name the pathological proteins implicated in the following diseases:

- Alzheimer's disease

- MND

- Huntington's disease

- Parkinson's disease

- Multisystem atrophy 

- frontotemporal dementia

- Alzheimer's disease: tau, amyloid beta

- MND: TDP43, FUS

- Huntington's disease: polyglutamine

- Parkinson's disease: alpha synuclein

- Multisystem atrophy: alpha synuclein

- frontotemporal dementia: TDP43, FUS

500

What is the Monro-Kellie principle and how does it relate to ICP?

• volumes of intracranial blood, CSF and brain within the cranium are constant 
• this means that an increase in one component volume will be compensated by a decrease in other
• this initial compensation allows for minimal changes in ICP
• once these compensatory mechanisms are exhausted --> RICP

Clinical

100

Define consciousness 

- self-awareness with the ability to access memories, manipulate abstract ideas and focus attention

200

What is the raccoon sign?
What does it indicate?

• periorbital ecchymosis (bruising): pooling of blood around the eyes 
• indicates base of skull fracture

300

Outline the ICD 10 Criteria for Dependence

at least three of the criteria concurrently in the last 12 months:

- strong desire or compulsion to take substance

- impaired control 

- withdrawals upon cessation or reduction 

- evidence of tolerance

- neglect of interests 

- persistent use despite harm 

400

Calculate this patient's GCS:
Patient opens eyes to sound, speaks with confusion, and pulls away from painful stimuli  

E3: open eyes in response to speech

V4: responds with confusion 

M4: withdraws from pain 

GCS 11

500

What are CAGE questions for screening for excessive alcohol use?

• cutting down: have you ever felt you needed to cut down on your drinking?
• annoyed: have people annoyed you by criticizing your drinking?
• guilt: have you ever felt guilty about drinking?
• eye-opener: have you ever felt you needed to drink first thing in the morning to steady your nerves or get rid of a hangover?

Spiral Learning

100

What are the impacts of acute and chronic sleep deprivation

• acute = cognitive difficulties, mood changes, psychotic experiences (hallucinations)
• chronic = CVD, obesity, hypertension, diabetes mellitus, anxiety symptoms, depressed mood, alcohol use

200

What are signs and symptoms that help indicate ovulation?

• regular cycle 
• egg white, stretchy mucus 
• one-sided lower abdo pain 
• 0.5 degree raise in morning temp
• PMS: breast tenderness, breast engorgement, temper, water retention

300

Describe the DSM5 criteria for major depressive disorder 

• depressed mood (dysphoria) and anhedonia 
• over 2 week period
• presence of five or more symptoms: sleep disturbances, interest decreased, guilt, energy decreased, concentration problems, appetite, psychomotor agitation, suicidal ideation 

400

Outline the direct pathway 

at rest the GPi and SN pars reticulata release GABA to inhibit thalamus to prevent stimulation of primary motor cortex

1. if we want to initiate movement, neurons from cortex release glutamate to activate striatum 
2. SN pars reticulata can amplify this response by releasing dopamine that acts on D1 receptors in striatum 
3. striatum released GABA to inhibit GPi and pars reticulata
4. GPi can no longer suppress thalamus 
5. thalamus releases glutamate to excite primary motor cortex --> movement 

500

Outline the indirect pathway 

at rest, GPe releases GABA to inhibit SNT

1. if we want to inhibit unwanted movement, neurons from cortex release glutamate to activate striatum 
2. SN pars compacta facilitates this by releasing dopamine which acts on D2 receptors in striatum 
3. striatum releases GABA to inhibit GPe 
4. GPe stops inhibiting SNT --> activating STN 
5. STN releases glutamate to activate GPi 
6. GPi and SN pars reticulata release GABA to suppress thalamus 
7. thalamus can't activate motor cortex --> no unwanted movement 

Peter Carroll

100

Why don't you administer both antiplatelet and anticoagulant drugs together

• low dose aspirin inhibits platelet aggregation (primary haemostasis)
• anticoagulants inhibit clot formation (secondary haemostasis)
• using them together means both primary and secondary haemostasis is inhibited leading to increased risk of bleeding

200

A patient in palliative care requires long term use of opioids. What are the side effects of opioids on the GIT and what can be done to manage this?

-GIT has lots of opioid mu receptors 

• activation causes increase in tone of GIT smooth muscle (due to unopposed parasympathetic input) but reduction in peristalsis 
• causes constipation
• can administer stimulant laxatives or stool softeners

300

Outline interaction between organic nitrates and PDE5 inhibitors
Why can't you give both?

• PDE5 is responsible for degrading cyclic guanosine monophosphate (cGMP)
• PDE5 inhibitors are used in the treatment of erectile dysfunction ---> increase cGMP levels
• organic nitrates increase cGMP levels 
• combination therapy with organic nitrates and PDE5 inhibitors --> severe hypotension and cardiovascular collapse

400

Outline the mechanism of action eplerenone and spironolactone. What must you be careful of when considering it?

Mechanism of action:

• competitive antagonists of aldosterone
• increase sodium and water excretion (reduce preload and work on heart)
• Aldosterone receptors in the heart may produce fibrosis, hypertrophy and dysrhythmias

Considerations:

• using in conjunction with ACEI or ARB 
• all three medications reduce excretion of K --> potential hyperkalaemia
• Combination with ACE inhibitors and A II antagonists may produce severe hyperkalaemia and death

500

What are drugs used in the treatment of nausea and vomiting? Name 3 and outline the mechanism of action

• dopamine D2 receptor antagonists (inhibit D2 receptors in CTZ)
• 5HT3 receptor antagonists (antagonise actions of 5HT in GIT and CTZ)
• acetylcholine muscarinic M1 receptor antagonists  (blocks acetylcholine from acting on M1 receptors in labyrinth --> reduce motion sickness)
• histamine H1 receptor antagonists (block histamine from acting on H1 receptors in labyrinth --> reduce motion sickness)
• neurokinin-1 receptor antagonists (inhibits substance P)
• cannabinoids (stimulate CB1 receptors in gut reducing vagal input into CTZ also activate 5HT1A receptors to reduce 5HT1 release)
• dexamethasone

More Spiral Learning

100

What are infective organisms that cause community acquired pneumonia in the Kimberley?

• s pneumoniae, H influenzae, staph aureus, klebsiella
• specific: burkholderia pseudomallei (esp during wet season), acinetobacter baumanii

200

Outline the relative volumes in the body fluid compartments

• females: 55% water, 45% solid
• males: 60% water, 40% solid

60% of total fluid:

• 2/3 intracellular fluid (inside cells)
• 1/3 extracellular fluid: 80% interstitial fluid (between cells), 20% plasma (inside blood vessels)

300

Outline the physiology of the follicular phase

• hypothalamus releases GnRH in a pulsatile fashion --> acts on anterior pituitary to produce FSH
• FSH promotes follicular development
• follicular granulosa cells produce estrogen which proliferate the endometrium 
• increasing estrogen production has negative feedback on HPA via inhibin to stop further FSH production (so only one wave of maturation of follicles occurs per cycle)

400

What are the four dopamine pathways in the brain? Which nuclei do they orignate from?

• tuberoinfundibular - arcuate nucleus
• mesolimbic - ventral tegmental area
• mesocortical - ventral tegmental area
• nigrostriatal - substantia nigra

500

Why can high flow oxygen worsen hypercapnia in patients with severe COPD?

• worsening of VQ mismatch from reversal of hypoxemia pulmonary vasoconstriction 
• if you give O2 --> vasodilation --> blood flows to areas that aren't ventilated --> worsen VQ mismatch
• Haldane effect: reduced CO2 binding to Hb as blood gets more oxygenated --> increases CO2 --> worsens hypercapnia