Pseudocoma
Reviewed and revised 20 September 2016
OVERVIEW
- Pseudocoma is the term used for a patient feigning a comatose state, however it is sometimes also used for conditions like locked-in syndrome where patients may involuntarily appear unconscious but are actually self aware
- This document focuses on how to distinguish feigned coma from true coma
DISTINGUISHING FEATURES
The pattern of clinical findings are not consistent with a specific neurological syndrome or anatomical lesion.
- Pupils:
- pupils are equal and reactive to light.
- passive eyelid opening results in pupillary constriction, whereas if the patient is sleeping or comatose (with intact pupillary reflexes) the pupils dilate on passive eyelid opening.
- Eye movements and oculovestibular reflexes:
- fluttering of the eyelids when the eyelashes are gently stroked
- the patient may resist passive eye opening. Occasionally patients with metabolic or structural lesions may resist eye opening.
- any spontaneous eye movements are saccadic (rapid and jerking) rather than slowly roving
- the patient actually makes eye contact with the examiner when the eyelids are opened; or the eyes always look to the side away from the examiner, or the eyes always look towards the ground
- the awake patient’s eyes move concomitantly with head rotation when assessing the oculocephalic reflex. It is nearly impossible for an awake patient to mimic the brainstem oculocephalic responses of a truly comatose patient.
- on cold caloric testing the patient may wake up or exhibit preservation of the fast component of nystagmus.
- Motor
- active resistance or varying resistance to passive motor tone testing, or cog-wheeling resistance with sudden “giving-away” phenomena
- no abnormal reflex posturing in response to painful stimuli
- the patient may occasionally make voluntary movements or change body position in bed
- the patient will show avoidance of ‘self injury’ — do not allow the patient to be injured!
EYELID APRAXIA
- Eyelid apraxia (or lid opening apraxia) is the inability to voluntarily open eyes despite intact frontalis muscle contraction and normal oculomotor function
- Is an unusual coma mimic
- Caused by injuries of:
- the non-dominant hemisphere (e.g. R MCA stroke)
- medial frontal lobe
- bilateral thalami (e.g. bilateral thalamic stroke)
- brainstem (e.g. progressive supranuclear palsy)
- Suspect this condition if the patient tries to raise their eyelids by contracting forehead muscles when asked to open eyes
References and Links
CCC Neurocritical Care Series
Emergencies: Brain Herniation, Eclampsia, Elevated ICP, Status Epilepticus, Status Epilepticus in Paeds
DDx: Acute Non-Traumatic Weakness, Bulbar Dysfunction, Coma, Coma-like Syndromes, Delayed Awakening, Hearing Loss in ICU, ICU acquired Weakness, Post-Op Confusion, Pseudocoma, Pupillary Abnormalities
Neurology: Anti-NMDA Encephalitis, Basilar Artery Occlusion, Central Diabetes Insipidus, Cerebral Oedema, Cerebral Venous Sinus Thrombosis, Cervical (Carotid / Vertebral) Artery Dissections, Delirium, GBS vs CIP, GBS vs MG vs MND, Guillain-Barre Syndrome, Horner’s Syndrome, Hypoxic Brain Injury, Intracerebral Haemorrhage (ICH), Myasthenia Gravis, Non-convulsive Status Epilepticus, Post-Hypoxic Myoclonus, PRES, Stroke Thrombolysis, Transverse Myelitis, Watershed Infarcts, Wernicke’s Encephalopathy
Neurosurgery: Cerebral Salt Wasting, Decompressive Craniectomy, Decompressive Craniectomy for Malignant MCA Syndrome, Intracerebral Haemorrhage (ICH)
— SCI: Anatomy and Syndromes, Acute Traumatic Spinal Cord Injury, C-Spine Assessment, C-Spine Fractures, Spinal Cord Infarction, Syndomes,
— SAH: Acute management, Coiling vs Clipping, Complications, Grading Systems, Literature Summaries, ICU Management, Monitoring, Overview, Prognostication, Vasospasm
— TBI: Assessment, Base of skull fracture, Brain Impact Apnoea, Cerebral Perfusion Pressure (CPP), DI in TBI, Elevated ICP, Limitations of CT, Lund Concept, Management, Moderate Head Injury, Monitoring, Overview, Paediatric TBI, Polyuria incl. CSW, Prognosis, Seizures, Temperature
ID in NeuroCrit. Care: Aseptic Meningitis, Bacterial Meningitis, Botulism, Cryptococcosis, Encephalitis, HSV Encephalitis, Meningococcaemia, Spinal Epidural Abscess
Equipment/Investigations: BIS Monitoring, Codman ICP Monitor, Continuous EEG, CSF Analysis, CT Head, CT Head Interpretation, EEG, Extradural ICP Monitors, External Ventricular Drain (EVD), Evoked Potentials, Jugular Bulb Oxygen Saturation, MRI Head, MRI and the Critically Ill, Train of Four (TOF), Transcranial Doppler
Pharmacology: Desmopressin, Hypertonic Saline, Levetiracetam (Keppra), Mannitol, Midazolam, Sedation in ICU, Thiopentone
MISC: Brainstem Rules of 4, Cognitive Impairment in Critically Ill, Eye Movements in Coma, Examination of the Unconscious Patient, Glasgow Coma Scale (GCS), Hiccoughs, Myopathy vs Neuropathy, Neurology Literature Summaries, NSx Literature Summaries, Occulocephalic and occulovestibular reflexes, Prognosis after Cardiac Arrest, SIADH vs Cerebral Salt Wasting, Sleep in ICU
- Posner JB, Saper CB, Schiff N, Plum F. Plum and Posner’s Diagnosis of Stupor and Coma 4e Oxford university Press, 2009.
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
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