This hot case is usually not about the aetiology of weakness, but rather about its influence on the overall management strategy. It may be integrated with the topic of weaning from ventilation.

If the candidate is invited to offer a diagnosis (or discuss a diagnostic strategy), they would do well to remember the general approach to the patient with weakness. Below is an abbreviated table of possible aetiologies, organised by level of dysfunction.

Previous hot cases with this sort of theme to them can be found below.

Causes of Weakness in Intensive Care Patients

Level of pathology	Aetiology
Brainstem	Locked-in syndrome
Motor neuron	Motor neuron disease (eg, amyotrophic lateral sclerosis)
Spinal cord	Transverse myelitis
	Compression by tumour
	Compression by abscess
	Spinal cord infarction
Peripheral nerve	Critical Illness Neuromyopathy
	Guillain–Barré syndrome
	Vitamin B12 deficiency
	Heavy metal poisoning
Neuromuscular junction	Myasthenia gravis
	Lambert–Eaton syndrome
	Botulism
	Organopshosphate poisoning
Muscle	Steroid myopathy
	Electrolyte disturbance
	Atophy due to hypercatabolic state and malnutrition
	Critical Illness Neuromyopathy

Examination of the Critically Ill Patient with Weakness

The standard introduction Listen to the introductory statement. Wash hands; don gloves and gown. Ask examiners about turning up the lights   The environment Monitoring Ventilator Urine catheter Drains (surgical, intercostal, etc) Dialysis IABP / ECMO Infusions EVD   The physical examination The details of this section can be seen in the opposite column.   The obs and investigations Temperature, urinalysis, drain output, urine output ABG, ECG, bloods, culture results CXR, CT images and CSF analysis. The Presentation "I know the diagnosis" "I have no idea what is going on"

The Physical Examination in Brief Detail Ask the examiners to sit the patient up Expose to the waist and observe. Ask the examiners about any language barriers GCS Hands, the nail signs, pulse and arterial line Arm tone and upper limb lymph nodes Neck lymph nodes, trachea, thyroid Pupils and the higher cranial nerves Airway and the lower cranial nerves - ask about the sputum Chest palpation, percussion, auscultation, and ask to roll over Praecordium palpation, auscultation, and ask for Valsalva Ask examiners to lay the patient flat. Abdominal palpation, percussion, auscultation Pelvis: groins, lines, and ask about performing a PR Legs: oedema and calf compressors. Leg muscle tone. Feet and Babinsky; clonus. Dorsi/plantarflexion power, knee and hip power Sit the patient back up again Hand, wrist, biceps, shoulder and shrug power Reflex testing, in hand-to-foot order Sensory testing, 13 points in foot-to-hand order Cerebellar exam of upper limbs and torso

The standard introduction

• The examiner will give you a history.

The prelude to the dance

• Wash hands.
• Gown and glove.
• Ask, if relevant:
  • "Can I turn on all the lights?"
  • "Are there any movement restrictions? Can I sit them up, or roll them on their side?"
  • "Is there a language barrier?"
• Introduce yourself: “Hi Mr or Mrs Bloggs, I’m Dr So-and-so. I’m going to examine you.”

The Monitors

• Rhythm
• Rate
• Morphology: QRS width, etc.
• MAP and abnormal morphology of the arterial waveform
  • It would be useful to note any sort of hemodynamic instability. An autonomic dysfunction associated with weakness may be the marker of a demyelinating polyneuropathy, eg. Guillain-Barre.
• CVP and abnormal morphology of the CVP waveform
• Ancillary waveforms eg. the PA catheter waveform
• Oxygen saturation measurement, and the quality of the waveform
• End-tidal CO₂ waveform and level

The Ventilator

One can ask the examiners the following questions:

• How are we oxygenating this patient?
• How are we ventilating this patient?

One should ask about the following parameters:

• FIO₂
• PEEP
• Peak pressure
• Plateau pressure
• Tidal volume and minute volume

One should ask to look at the pressure-volume loops.

The ventilation strategy offers a clue as to the degree of weakness.

Is the patient fully supported on a mandatory mode? Are they able to trigger? Is NAVA ventilation in use?

Urine catheter

• Unusual colour
• Anuria

Drains (surgical, intercostal, etc)

There may be surgical drains (what is in them? How much of it?). Asking how much has been coming out may be relevant in a hot case which focuses on the diagnosis of a shock state.

The pleural catheters are also interesting. One should make a mental note of whether the ICCs are on free drainage or on suction. The content of these drains could be informative, especially if one notices blood or chyle.

Dialysis

A CVVHDF or SLEDD process may be in progress. The savvy candidate may wish to ask the following questions:

• Which modality is being used?
• What is the dose of dialysis?
• What is the rate of fluid removal?
• How is the circuit anticoagulated?
• How long has this filter lasted?

These questions may go unanswered.

IABP / ECMO

The patient you are examining may have some sort of extra gadget hooked up. If ECMO is in progress, one may wish to ask about the following parameters:

• VA or VV?
• Flow rate
• Fresh gas flow
• Any recent problems with the circuit

If IABP counterpulsation is in progress, it raises additional questions. One may wish to ask the examiners whether one may be able to switch it to 1:2, to assess the efficacy of augmentation.

Infusions

This stage is critically important. The drug and fluid infusions which are currently in progress give a clue as to what problem is currently being addressed. One should not neglect the labelled bags; the choice of antibiotics gives one some idea of where the source of sepsis is thought to be.

A bottle of IV immunoglobulin may be present, carelessly left to dangle where the candidate can see it. Suspicion of autoimmune demyelination develops.

EVD

One should observe the following features of an EVD:

• Set height
• Whether it is open or closed
• The CSF colour - eg. is it full of blood?

---

The physical examination

Expose and observe

Ideally, one should get the patient sitting up to 30-45°. This may not be possible. However, one should still ask for it.

Ideally, the patient should be exposed from the waist up. The candidate can then stand back and look for anything externally obvious:

• Skin colour, eg. jaundice or the discolouration of chronic renal failure
• Muscle wasting, obesity
• The evidence of trauma, wound dressings, etc
• The pattern of breathing (eg. whether there is a characteristic chest flail)

GCS

Performing the GCS should be the first step. The patient should be reasonably conscious - otherwise the examination of their weakness would be rather pointless.

A traditionalist, who is examining Mr Bloggs, would approach the GCS in the following manner:

• Grab hold of both of the patient's hands.
• "Mr Bloggs!" One pauses to observe for eye opening.
• "Can you squeeze my hands?"
• If hand squeezing and eye opening is not observed, one administers a painful nail bed stimulus to both hands, to observe the response to pain. The patient selected for the weakness hot case will likely be conscious - it is important to ask the examiners for permission before one inflicts excruciating nail-bed pain on an awake immobilised patient.

Hands, nail signs, pulse and the arterial line.

One has just performed a GCS assessment; one is still holding the hands.

Now, time to look at them more closely.

First, one should spent a second assessing whether they are warm or cold.

Then, one can focus on the nails. Nail signs are numerous and deserve their own page.

In brief, the nail signs one could look for are as follows:

Done with the nails, one may want to briefly consider (and maybe even comment upon) the presence of any sort of characteristic deformities, eg. assymetrical wasting of the small muscles, or the joint changes of rheumatoid arthritis.

Next comes the pulse. While one still has both of the patient's hands, one ought to try to compare the radial pulses. It would be worthwhile to look up at the arterial line trace at this stage; abnormalities such as the widened pulse pressure of aortic regurgitation may not have been noticed until this stage.

Arms

Tone of the upper limbs

Move up from the hands. While you are still holding the hands, you can perform a sort of gross examination of tone by pronating and supinating the wrists, and by flexing and extending the elbows.

Asterixis

It may be possible to assess asterixis by asking the patient to hold both their arms up with the wrists dorsiflexed. The weak patient may not be able to perform this trick - they cannot lift their arms.

Cubital fossa

Examine the cubital fossa for

• Peripheral lines
• Evidence of multiple venepunctures
• Lymph nodes
• Brachial pulse
• The presence of an obvious AV fistula

One should then palpate the axillary lymph nodes.

The Neck

• Inspect any central lines
• Look again at the CVP

Palpate the neck:

• Trachea: is it midline? Is there a new tracheostomy there?
• Thyroid gland
• Cervical lymph nodes
• Carotid pulse - one side at a time!
• Submandibular lymph nodes
• Pre- and post-auricular lymph nodes

Ask the patient to lift their head off the bed.

Pupils and the higher cranial nerves

The weakness hot case patient will likely be fully conscious. Therefore, one needs to spend a reasonable time examining their cranial nerves in satisfactory detail.

The upper cranial nerves	The lower cranial nerves
Visual acuity Light reflex Corneal reflex Eye movements Facial pain sensation Facial movements	Gag reflex Cough reflex Tongue movements Uvula deviation Shoulder shrug

Visual acuity

A Snellen chart is ideal, but probably will not be available.

The extubated patient should be able to read the time on the clock in the room.

One performs this test with each eye individually.

This tests CN II.

Light reflex

Ask the examiners to dim the room lights.

Open both eyes. Each eye is exposed to light. The opposite pupil should constrict consensually.

This tests CN II (afferent) and CN III (efferent).

Corneal reflex

The cornea (not the sclera) is touched lightly with a moistened corner of a piece of gauze.

A normal reflex is to blink.

This tests CN V (afferent) and CN VII (efferent)

Eye movements

The conscious patient will be able to follow the tip of the candidate's finger.

The pattern of movements should be tracing the six cardinal points: superior left, inferior left, superior center, inferior center, superior right, inferior right.

This tests CNs II, IV and VI.

Facial pain sensation

Typically, this is performed by putting some pressure on the superior orbital notch.

The patient should either open their eyes or localise.

This tests CN V.

Again, it is important to ask for permission before doing this. Sometimes a simple light touch test would be more appropriate.

Facial movements

The conscious patient will be able to perform a series of grimaces to assess the bilateral motor control of facial muscles:

• Raise eyebrows to wrinkle forehead
• Squint eyes to assess periorbital muscles
• Bare teeth to assess nasolabial muscles
• Blow out cheeks

Airway and the lower cranial nerves

Now that one has finished with the upper cranial nerves, one can move on to the mouth, airway, and swallowing apparatus.

Gag reflex

The Yankeur sucker is used to probe the posterior pharynx, on both sides. A gag reaction should result from this.

This collectively tests CN X and IX.

Cough reflex

While on the subject of CN X, one may test the cough reflex by suctioning the trachea.

This tests CN X.

This is also a convenient time to ask about the volume and character of the secretions.

Tongue movements

The conscious patient is asked to protrude their tongue, and move it from side to side.

This tests CN XII.

Uvula deviation

The uvula deviates away from the lesion.

This tests CN X and IX.

Shoulder shrug

The conscious patient is asked to shrug their shoulders against resistance.

This tests CN XI.

During the cranial nerve examination, one will inevitably end up tripping over the endotracheal tube. One should note whether there is anything unusual there; for instance, is there a dual-lumen tube, or a bronchial blocker?

The tracheostomy should not be neglected, with particular attention being paid to the cuff (is it deflated?)

Chest palpation, percussion and auscultation

Palpation:

One puts both their hands on the chest to assess the symmetry of chest expansion. A unilateral phrenic nerve paralysis may be a clue to an intrathoracic malignancy, as a cause of a paraneoplastic weakness syndrome.

Percussion:

One might wish to percuss the chest.

Changes in percussion resonance may be worth commenting on.

Auscultation:

One may begin by auscultating the apices anteriorly. Then, one should auscultate as posteriorly as possible. The money is in the bases.

Palpation and auscultation of the praecordium

Palpation:

The clever candidate will make a big show of palpating both the apex and the right sternal edge.

Auscultation:

One should auscultate in the following sequence:

• Apex
• Left sternal edge, lower
• Left sternal edge, upper
• Right sternal edge, lower
• Left sternal edge, upper
• Both carotids

The various clicks and murmurs one encounters are discussed elsewhere.

Abdominal palpation, percussion and auscultation

For this, one should ask to lay the patient flat.

Abdominal observation

• Take a moment to behold the abdomen. One may ask the examiners to look under any surgical dressings; one is likely to be denied this part of the examination (they will tell you the wound looks clean and dry).

Abdominal palpation

• All quadrants should be palpated.
• Then, feel for the liver edge; observe respiratory excursion
• Then, feel for the spleen.
• Then, try to ballot the kidneys. Enquire about renal tenderness.
• Abdominal distension may be a feature of weakness syndromes which result in autonomic dysfunction with resulting ileus.

Abdominal percussion

• This can double as a test for peritonism.
• If there is some suspicion of ascites, one may ask to roll the patient, so shifting dullness can be better appreciated. The examiners may not permit this test.

Abdominal auscultation

• One should spend a good length of time on this, if one suspects bowel obstruction or ileus.

Examination of the pelvis and groins

The pelvic content would have been palpated during the abdominal examination.

The more important part of this examination is the groin.

At this stage, the patient should be re-draped - cover them from the waist up, and uncover their legs.

Observation and palpation of the pelvis:

• There may be a rash of thrush, or a groin haematoma, or an external fixation device.
• The posterior pelvis and sacrum should ideally be palpated for pitting oedema.

Examination of the lines

• One should take notice of anything going into or coming out of the femoral vessels.
• There may be a vascath, a PiCCO catheter or some sort of angiography sheath. These are important clues. Why did this patient get an angiogram? What is the PiCCO for?

Examination of the genitals and rectum

• A complete examination would call for the palpation of the testes, and a comment on their size. However, this may not be practical.
• One should take note of any sort of waste management devices, eg. rectal tube, SPC or IDC.
• One should definitely ask about performing a PR.
• If one is forbidden from performing the PR, one should ask about the anal sphincter tone - it may be very important.

Once one is finished with the pelvis, one should cover it again, so that only the legs are sticking out.

Examination of the lower limbs

One should ask to remove TEDs and compression stockings.

• One should observe whether the lower limbs are mottled, and whether they are of the same size (assymetrical swelling leads one to suspect lymphoedema or DVT)
• One should palpate the larger muscles. Muscle wasting - especially of the quads- is an important feature of malnutrition.
• Pitting oedema should be palpated.

Leg muscle tone

The best way to test muscle tone is by holding the knee. Roll the knee gently to distract the patient; then try to lift it off the bed. In the presence of increased tone, the leg will remain straight and the whole thing will lift up; with normal or decreased tone, only the knee will bend

Calf tenderness

In the conscious patient, one might be able to assess whether a gentle calf squeeze produces the characteristic pain which suggests a DVT may be present.

This brings one to the feet, and to the beginning of the neurological examination.

Feet and the Babinsky reflex

The feet would have already been palpated to assess their temperature, and to look for pitting oedema.

Observation of the feet

One should look specifically for changes suggestive of chronic diabetic foot disease, or chronically poor vascular supply.

Palpation of the feet

This should consist of palpating the dorsalis pedis and posterior tibial pulse.

Babinsky reflex

One should test the Babinsky bilaterally.

Clonus

One should attempt to assess clonus in both feet.

Power in the lower limbs

Now is the time to properly start the neurological examination of this patient.

Power of the muscle groups may be tested in the following sequence:

• Ankle dorsi and plantarflexion
• Knee flexion and extension
• Hip flexion, extension, adduction and abduction.

Power in the upper limbs

The patient has spent most of this time flat and supine. Time to sit them back up again.

Power of the upper muscle groups may be tested in the following sequence:

• Hand grip
• Wrist dorsiflexion/palmarflexion
• Elbow flexion/extension
• Shoulder adduction / abduction

Reflex testing

Now that one is back to the upper limb, one may as well start their reflex tests there.

The reflexes may be tested in the following order:

• Brachioradialis
• Biceps
• Triceps
• Knee jerk
• Ankle jerk

Sensory testing

After testing the ankle jerk reflex, one is again back to the feet.

At this stage, with a conscious patient, one may wish to test light touch sensation.

The following order (with corresponding dermatomes) is suggested:

• Sole of the foot (S1)
• Lateral lower leg (L5)
• Medial lower leg (L4)
• Medial knee (L3)
• Anterior upper quads (L2)
• Umbilicus (T10)
• Nipple level (T5)
• Medial forearm (T1)
• Pinky finger (C8)
• Middle finger (C7)
• Thumb (C6)
• Lateral forearm (C5)
• Posterior shoulder (C4)

The cerebellar examination of the critically ill patient

Now, usually, the cerebellum requires all sorts of dynamic manoeuvres- one should assess the gait, balance, speech, and so forth. The intubated ICU patient does not permit the majority of these. They are so entangled in tubes they may not be able to perform dysdiadochokinesis.

The following is a list of cerebellar tests one may be able to perform with an intubated ICU patient.

Many of these findings would have been discovered during earlier stages of the examination.

The weakness hot case patient may not be able to perform many of these tests. However, cerebellar dysfunction and incoordination may form a part of their stroke syndrome, and thus it would be unwise to omit this part of the examination.

Nystagmus

This would have become apparent during the testing of the eye movements.

Resting tremor

This would have become apparent during the test for nystagmus

The finger-nose test

This is an assessment of coordination. The patient is asked to alternate between touching their nose and touching the finger of the candidate, who keeps changing its position.

The heel-shin test

The patient is asked to run the heel of one foot along the shin of the opposite leg.

The measured observations

Ask to see the obs chart. If it is not allowed, ask for the following:

• Trends of blood pressure and heart rate
• Temperature
• Drain output
• Urine output

One may also wish do demonstrate an interest in the trends of any sort of advanced haemodynamic monitoring, eg. cardiac index as measured by PAC or PiCCO

The laboratory investigations

One needs to show an interest in the following labs:

• Electrolyte levels
• CK level
• B12 level
• Acetylcholine receptor antibodies (for myasthenia gravis)
• CXR looking for malignancy (as support for a diagnosis of Eaton-Lambert syndrome)
• Inflammatory markers

Also, one might wish to show some interest in the routine investigations:

• ABG
• Routine bloods
• Urinalysis
• Culture results

Imaging and other investigations

One should always ask for the following:

• Lumbar puncture
• Nerve conduction studies
• Electromyography
• MRI of the brainstem and spine
• Muscle biopsy with immunohistochemical staining and electron microscopy

 

Case presentation and discussion: when you have a good idea of what is going on

"Mr Bloggs' weakness is likely due to [insert clever diagnosis here]."

"I have come to this conclusion on the basis of the following findings: [insert clinical findings here]"

"I would like to confirm my diagnosis with the following investigations: [insert appropriate investigations]"

"The current management issues are as follows: [a brief list of management priorities]"

"I would approach the management of these issues in the following manner: [list of management strategies; it helps to organise this into an A,B,C,D,E approach if one has a complex multisystem problem to manage]"

Case presentation and discussion: when you don't have a clue

”Mr Bloggs' weakness is likely multifactorial."

"During my examination, I noted the following clinical signs [list of features]."

"On the basis of these, I have arrived at the following list of differentials: [insert list of differentials]."

"In order to discriminate between these differentials, I would like to perform the following investigations: [list of investigations]"

"Furthermore, I would like to enlist the help of the following specialties [insert list of consults], for whom I will have the following specific requests/questions: [what questions will you ask these specialist teams]"

"While working on a diagnosis, I will offer the following supportive management [blah]"