Often, the college asks the candidates to discuss diseases with a significant community prevalence which have some sort of serious impact on the ICU management of affected patients. it makes sense to expect final-stage CICM trainees to be able to discuss SLE or scleorderma, and the attention directed at these diseases is understandable.

On the other hand, there are occasionally questions in the Fellowship Exam which cannot be explained by this framework. There is a group of rare diseases which have only ever appeared once and which can reasonably be expected to never appear again. These are grouped here in no particular order, basically because there is nowehere else to put them.

Myotonic dystrophy

Question 30.1 from the first paper of 2017 asked for six clinical features of myotonic dystrophy, a  congenital disorder which results in an abnormal skeletal muscle myosin kinase protein. The college answer lists 11 features, but in fact there may be many more. An excellent review by Turner et al (2010) adds a few extra features.  Remixed with the college answer, the full list looks like this:

Neuromuscular phenomena
  • Myotonic facies
  • Wasting of facial muscles, sternocleidomastoids, muscles of distal extremities
  • Ptosis
  • Myotonic spasms (e.g. delay in opening fingers after making a fist)
  • "Warm up phenomenon" - grip strength increases with repeated contractions
  • Slurred speech (pharyngeal myotonia)
  • Percussion myotonia
  • Absent reflexes

Other features

  • Frontal baldness
  • Cardiomyopathy
  • Cardiac conduction defects
  • Cataracts / lenticular opacities
  • Testicular atrophy
  • Intellectual impairment
  • Insulin insensitivity


What ICU relevance might we wring from this? Well. These people do end up in ICU a lot. Not the least of their presentations are from theatre recovery, as they are referred to the ICU by concerned anaesthetists as elective post-operative admissions. An excellent (though somewhat dated) article by Mudge et al (1980) discusses some of these concerns, which remain relevant in the contemporary anaesthetic setting.

In short, the following anaesthetic problems usually arise, which are worth knowing about

  • Cardiac arrhythmias
  • Abnormal response to suxamethonium (persistant contraction of all muscles, occasionally making ventilation impossible)
  • Using neostigmine to reverse the curare toxins may in fact precipitate myotonia
  • Increased respiratory sensitivity to sedating agents, particularly narcotics (thus, safest to leave them intubated)
  • Myotonia in response to stimulation (which is unaffected by neuromuscular junction blockers) tends to frustrate the surgeons, so virtually every procedure can be expected to take longer. Apparently warming the operating theatre canhelp with this, but then you have to deal with sweaty surgeons whinging at you.
  • Cough will be weakened and clearance of secretions will be poor, with implications for extubation

Acromegaly

This also came up in Question 30.1 from the first paper of 2017, where the college wanted candidates to identify acromegaly from Wikipedia's copyright-free images (originally from Chanson et al, 2008). Additionally, some of the clinical features were asked for (specifically, biochemical abnormalities).

Clinical Features of Acromegaly
Pituitary tumour effect
  • Visual-field defects (bitemporal hemianopia)
  • Cranial-nerve palsy (usually 3rd nerve)
  • Headache
Skeletal effects
  • "Acral enlargement" - basically, "acral" is a term used to refer to the extremities, particulalry fingers and toes. "Acromegaly at a basic level is a disease of big hands and feet.
  • Large stature, "gigantism"
  • Arthralgias and arthritis
  • Carpal tunnel syndrome
  • Acroparesthesia (fingers and toes again)
  • Hypertrophy of the frontal bone of the skull, giving rise to a prominent brow ridge

Muscular effects

  • Proximal myopathy

Cutaenous manifestations

  • Hyperhidrosis
  • Oily texture
  • Skin tags
  • Prognathism
  • Jaw malocclusion

Airway consequences

  • Prognathism
  • Jaw malocclusion
  • Abnormally large larynx (thus, cuff leak with normal-sized tubes)
  • Large tongue
  • Enlarged thyroid (gets in the way of tracheostomy)
  • Large nasal polyps frustrate nasal intubation
  • Large stature makes ETT position difficult (i.e. it may not reach far enough into the trachea)

Respiratory effects

  • Sleep apnea (central and obstructive)
  • Narcolepsy
  • Restrictive disease due to kyphosis/scoliosis

Cardiovascular effects

  • Left ventricular hypertrophy
  • Asymmetric septal hypertrophy
  • Cardiomyopathy
  • Hypertension
  • Congestive heart failure
  • Mitral and aortic regurgitation

Electrolyte, endocrine and metabolic abnormalities

  • Menstrual abnormalities
  • Galactorrhea
  • Decreased libido, impotence, low levels of sex hormone–binding globulin
  • Low renin, cortisol and aldosterone levels 
  • Hyperglycaemia (impaired insulin sensitivity)
  • Hypercalcemia
  • Hypernatremia (due to DI)

Renal problems

  • Obstructive uropathy (prostatomegaly)
  • Kidney enlargement (may be reported as hydronephrosis)
  • Hypercalciuria

Haematological problems

  • Hepatosplenomegaly

Ankylosing spondylitis

This has come up in Question 2 from the first paper of 2019. The examiners asked for characteristic plain Xray findings in the C-spine series, which is baffling because nobody has ordered one since 2008. However, in case they ask it again, here they are, from Radiopedia and Østergaard (2012):

  • Romanus lesions of the spine (shiny corner sign): small erosions at the corners of vertebral bodies with reactive sclerosis
  • vertebral body squaring
  • Andersson lesion: noninfectious spondylodiscitis:
  • Bamboo spine: diffuse syndesmophytic ankylosis 
  • Dagger spine: interspinous ligament ossification
  • enthesophyte formation from enthesopathy
  • dural ectasia

Parkinson's disease

This appeared in Question 14.4 from the second paper of 2019, as a tiny shred of a question worth 25% of the marks (i.e. 2.5 marks out of the total 300 for the paper). The college wanted to know what problems might arise in a patient who has severe Parkinson’s disease and who must miss out on their medications because of bowel rest. There are a couple of excellent articles which appears almost designed to answer this sort of question (Freeman et al, 2007, and Katus et al, 2014).  The contents of these was distilled into what follows:

  • Airway issues:
    • Upper airway obstruction may develop due to laryngeal muscle involvement, which may complicate extubation by virtue of stridor (Vincken et al, 1984)
  • Respiratory issues:
    •  Swallowing difficulty predisposes this patient to aspiration
    • The rigidity of chest wall muscles makes total lung compliance worse
    • Post extubation, this rigidity predisposes them to atelectasis
    • While ventilated, muscle tremor may cause patient-ventilator dyssynchrony, and rigidity may make triggering more difficult
  • Haemodynamic issues
    • There may be haemodynamic instability because of autonomic involvement (i.e. the patient will remain hypotensive even though their sepsis is resolving
  • Neurological problems
    • Parkinsonian medications may need to be converted to parenteral forms (eg. rotigotine patches).
    • Often, anti-Parkinsons medications are themselves a risk factor for delirium and confusion, as is abrupt withdrawal thereof
    • There is an increased sensitivity to sedative medications
    • Once they do become confused, anti-dopaminergic medications (eg. antipsychotics) are relatively contraindicated
  • Gastrointestinal problems
    • Autonomic dysfunction of the gut leads to slower recovery from bowel surgery
    • The patient may be coming from a poor nutritional baseline 
    • Perioperative antiemetics and prokinetics (mainly metoclopramide and droperidol) are antidopaminergic and will worsen the symptoms

Problems of routine housekeeping:

  • Once a normal diet is permitted, it may be difficult to institute because of swallowing difficulty
  • There is an increased risk of DVT and PE due to immobility and rigidity
  • There is often delayed mobilisation due to this movement disorder, which promotes muscle wasting and deconditioning
  • Autonomic dysfunction also leads to a failure of thermoregulation (piloerection and cutaneous vascular supply is not under such tight control as it should be).

References

Mudge, Barbara J., Peter B. Taylor, and Abraham FL Vanderspek. "Perioperative hazards in myotonic dystrophy." Anaesthesia 35.5 (1980): 492-495.

Turner, Chris, and David Hilton-Jones. "The myotonic dystrophies: diagnosis and management." Journal of Neurology, Neurosurgery & Psychiatry 81.4 (2010): 358-367.

Philippe Chanson and Sylvie Salenave - AcromegalyOrphanet Journal of Rare Diseases 2008, 3:17. doi:10.1186/1750-1172-3-17

Molitch, M. E. "Clinical manifestations of acromegaly.Endocrinology and metabolism clinics of North America 21.3 (1992): 597-614.

Melmed, Shlomo. "Acromegaly." New England Journal of Medicine 355.24 (2006): 2558-2573.

Østergaard, Mikkel. "Imaging of ankylosing spondylitis." Arthritis Research & Therapy. Vol. 14. No. 2. BioMed Central, 2012.

Freeman, William D., et al. "ICU management of patients with Parkinson's disease or Parkinsonism." Current Anaesthesia & Critical Care 18.5-6 (2007): 227-236.

Vincken, Walter G., et al. "Involvement of upper-airway muscles in extrapyramidal disorders: a cause of airflow limitation." New England Journal of Medicine 311.7 (1984): 438-442.

Katus, Linn, and Alexander Shtilbans. "Perioperative management of patients with Parkinson's disease." The American journal of medicine 127.4 (2014): 275-280.