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Table of Contents
CICM First Part Exam Revision Notes and Questions
CICM Second Part Exam Revision Notes and Questions
New Chapters
On the concept of motor units
Sunday, November 27 (2022); Musculoskeletal system
The motor unit is the smallest functional unit of the motor nervous system, and consists of a single spinal alpha motor neuron and all the muscle fibres it innervates.
Anatomy and physiology of skeletal, smooth, and cardiac muscle
Tuesday, November 22 (2022); Musculoskeletal system
Muscle tissue is classified into striated (skeletal and cardiac) vs smooth muscle tissue according to the arrangement of the contractile proteins, or lack thereof. Striated muscle organises actin and myosin into sarcomeres where these proteins are regularly spaced, whereas in smooth muscle these elements are organised into a more flexible arrangement that favours a larger range of possible lengths.
Airway Pressure Release Ventilation (APRV) for ARDS
Thursday, November 3 (2022); Respiratory Medicine and Mechanical Ventilation
APRV has never come up in the CICM exams, and may never come up, because it would be unfair to test the candidates on something even the examiners themselves have little understanding of. It is a promising but poorly researched strategy that maximises alveolar recruitment and embodies the main principles of open-lung ventilation for ARDS.
Power of mechanical ventilation
Sunday, October 23 (2022); Respiratory system
The power of ventilation is defined as the work over time, and is normally 2-3 J/min. All other lung-protective strategies (low tidal volumes, low driving pressures) are ultimately all aspects of the same equation, i.e. all these strategies converge in their aim to reduce the power of mechanical ventilation
Dialysis adjustment for hyponatremia
Sunday, October 23 (2022); Renal Failure and Dialysis
Dialysis for the severely hyponatremic patient can be a) avoided, b) delayed, c) underdosed, or d) performed with a "hacked" set of dialysate bags which have been altered to contain a lower concentration of sodium. Another option, which is easier and less satisfying, is to administer free water systemically in the form of 5% dextrose.
Dialysis disequilibrium syndrome
Friday, October 21 (2022); Renal Failure and Dialysis
Dialysis disequilibrium syndrome is cerebral oedema resulting from the rapid removal of urea, and the resulting osmotic movement of water into CNS tissue. It has clinical manifestation similar to other forms of cerebral oedema and is treated in the same way (eg. with osmotherapy). Slower gentler dialysis is the most important preventative measure.
Regulation of body water
Saturday, October 29 (2022); Body fluids and electrolytes
Body water content is regulated mainly by vasopressin. Circumventricular organs sense tiny (<3 mOsm/kg) changes in tonicity and modulate the release of vasopressin from the posterior pituitary, which results in the increased or decreased expression of aquaporins at the cortical collecting duct, where water is reabsorbed. This way urinary concentration mechanisms can be used to modify the loss of body water. The same hypothalamic control centre activates the sensation of thirst and affects behaviour to increase water intake.
Pharmacology of vasopressin and its analogues
Saturday, October 1 (2022); Endocrine System
Vasopressin is a nonapeptide, and its analogues are various modifications of that same basic molecular structure, used to change the pharmacokinetics and receptor selectivity of the end product. Terlipressin is a prodrug for lysine vasopressin which has a higher selectivity for V1 receptors, making it an almost pure vasopressor, and desmopressin (DDAVP) has a higher selectivity for V2 receptors, making it a more pure antidiuretic.
Pharmacology of oral hypoglycaemic drugs
Sunday, September 18 (2022); Endocrine System
Numerous chemically diverse classes of oral hypoglycemic agents with various mechanisms of action exist, including biguanides, sulfonylureas, α-glucosidase inhibitors, meglitinides, thiazolidinediones, DPP-4 inhibitors, and SGLT-2 blockers. Unsurprisingly, for the majority of these (with some exceptions), hypoglycaemia is the most clinically important adverse effect.
Pharmacology of insulin preparations and glucagon
Tuesday, September 6 (2022); Endocrine System
Regular human insulin (eg. Actrapid) is an exact duplicate analog of the human peptide hormone, consisting of 51 amino acids. Other insulin variants modify the normal molecule to adjust the self-association behaviour of the drug, leading to longer or shorter absorption from the subcutaneous depot.
Control of plasma calcium
Wednesday, August 31 (2022); Endocrine System
Calcium homeostasis is regulated by three main hormones: parathyroid hormone (PTH), calcitriol, and calcitonin. PTH and calcitriol work to increase plasma calcium by increasing its absorption from the intestine and bone, and by resisting its loss in the renal tubule. Calcitonin, on the other hand, defends against hypercalcemia by inhibiting bone resorption and encouraging renal elimination.
Physiology of adrenal hormones
Tuesday, August 30 (2022); Endocrine System
Adrenal hormones include cortisol, aldosterone, androgens, and catecholamines. Each hormone is secreted from structurally and functionally distinct zones of the adrenal gland. The synthesis of steroid hormones occurs on demand in the adrenal cortex, whereas catecholamines are constantly being synthesised and stored in chromaffin granules inside cells of the adrenal medulla. The stimuli for their release can be broadly summarised as "stress".
Physiological effects of corticosteroid therapy
Sunday, August 21 (2022); Endocrine System
Corticosteroids have numerous effects, some often described as "adverse", but their undeniable safety needs to be highlighted, as there are very few endogenous substances for which, following the administration of an exogenous dose one hundred times the normal level, nothing serious happens.
Systemic corticosteroids for specific indications
Thursday, August 18 (2022); Endocrine System
Different corticosteroid drugs tend to be used for different conditions because of some peculiarities in their pharmacokinetics and pharmacodynamics. For example, methylprednisolone penetrates best into the lung, whereas dexamethasone can cross the blood-brain barrier more easily mainly because it is less protein-bound. These differences in pharmacology dictate the specific use case scenarios for corticosteroids.