In Part 1 of Killer Coma Cases – The Found Down Pateint, Dr. Helman presents two challenging cases to Dr. Brian Steinhart and Dr. David Carr, who tell us loads of key clinical pearls in their approaches to the ‘found down’ patient. They discuss the important components of the neurological exam in the comatose patient, the differential diagnosis of altered mental status and hyperthermia, the controversies around when to get a CT head before performing a lumbar puncture, and much more in this Killer Coma Cases episode. In Part 1 of this episode, we discuss the limitations of plain CT, the interpretation of CSF and the many faces of seizures. Any more information would be giving away the cases…..
Written Summary and blog post by Lucas Chartier, edited by Anton Helman April 2011
General approach to Killer Coma Cases (the comatose patient) in ED
- Structural (i.e. reticular activating system dysfunction in brainstem) vs. metabolic (bilateral cerebral hemisphere insult)
- An approach to coma based on priorities: 3 causes of coma that we need to think about for every patient who presents with altered LOC and treat immediately are hypoglycemia, hypoxia and opiate overdose as they have simple rapid treatments
- “AEIOU TIPS”
- Alcohol (incl. toxic alcohols)
- Electrolytes (incl. endocrinopathies)
- Insulin (i.e. glucose)
- Overdose (or withdrawal from drug)
- Trauma (eg, intracranial bleeds, incl. spontaneous)
- Infection (eg, sepsis, meningitis)
- Seizure (incl. non‐convulsive status epilepticus)
Neurological exam in comatose patient should include GCS with focus on motor exam, eyes – pupils, reactivity, deviation and movement, fundi (consider bedside U/S for detection of papilledema; complete vitals with focus on RR (high RR may be sign of acidosis), signs of meningismus (helpful only if present), upper motor neuron signs (Babinski, Hoffman’s) and ankle clonus, and brainstem reflexes (doll’s eyes, cold caloric)
Six pearls for ‘found down’ patients
- Don’t assume it’s (only) ethanol
- Thorough examination, full neurologic exam
- Consider C‐spine injury in unclear mechanism
- Aggressive airway management, avoid sux
- Don’t delay advanced neuro‐imaging (CT/MR‐A)
- Thorough approach to toxidromes (pupils, skin)
Pearls from our experts
- Some causes of seizures that require additional specific treatment besides supportive therapy and antisiezure meds: carbon monoxide poisoning (clue: multiple people from the same location are involved, Tx 100% O2), INH toxicity (Tx: pyridoxine), and pre/eclampsia in pregnant and postpartum patients (Tx: magnesium and labetolol); Do not use dilantin in alcoholics or toxicologic cases as it is pro‐arrhythmic
- How to confirm pseudocoma: (i.e. psychiatric): patients will roll their eyes up when opened to avoid eye contact with the provider; lift their arm above their face and let it drop, which the conscious patient will redirect to avoid hitting themselves in the face; use cold caloric test as a last resort
- Suspect pseudoseizures when ‘gross theatrics’ are involved, there is no post‐ictal state, or the response to benzodiazepine is physiologically too quick (i.e. wake up within seconds)
- Naloxone: Usual starting dose of naloxone is 0.4mg, then increase to 1mg, then 2mg until desired effect; patients in coma often do not respond to doses <2mg; however, there may be another toxin on board, and so reversing them fully may bring out undesired effects of the other toxin; also, you can precipitate narcotic withdrawal in chronic narcotic users causing severe myalgias, diarrhea and agitation; avoid repeat boluses of naloxone since its effect wears off in 30‐60mins – rather, consider starting an infusion at 2/3rd the converting dose as the hourly infusion rate
Differential diagnosis of altered LOC and elevated temperature
- Infection, sympathomimetic (incl. amphetamines) and anticholinergic toxidromes, neuroleptic malignant syndrome (NMS), serotonin syndrome, malignant hyperthermia, endocrinopathies (eg, thyroid storm), withdrawal syndromes (eg: GHB, alcohol) heat exhaustion/stroke (esp. in summer and in psychiatric patients as antipsychotics effect thermoregulation)
Altered LOC and hypothermia should prompt a differential of infection, environmental exposure, hypothyroidism or hypoadrenalism
Nonconvulsive status epilepticus (NCSE)
- Defined as convulsions for at least 30min, with change in cognition or level of consciousness (LOC); probably less damaging to neurons than convulsive status epilepticus, although they may progress to it, and patients at high risk of aspiration due to failure of protecting their airway
- When to consider NCSE: any patient with altered mental status, especially those patients with known seizure disorders, a history of recent seizures, or patients who are comatose with no readily identifiable structural, metabolic, or traumatic causes; it sometimes follows generalized convulsive status epilepticus (up to 25%), so if the patient’s not back to baseline after an hour or 2 after a prolonged seizure, you should think about NCSE
- Often presents as altered LOC plus subtle automatisms such as blinking, twitching, grabbing at things, facial grimacing or clenching of the teeth, or simply change in behavior or psychosis – perform a thorough neuro exam before intubation and paralysis!
- EEG is diagnostic if available (or once in the ICU), or a diagnostic and therapeutic trial of benzodiazepine may be attempted if EEG is not immediately available
- Although most don’t present classically (esp. immunocompromised & elderly patients), consider the diagnosis of bacterial meningitis in the face of fever, nuchal rigidity, headache or altered LOC (incl. lethargy or behaviour and personality changes as per family)
- Herpes encephalitis often presents with pronounced alteration in LOC, associated with psychiatric symptoms, seizures or dysarthria; LP may appear traumatic due to hemorrhage in the temporal lobes
- Physical exam: Jolt accentuation sign (turning head rapidly left‐right several times) has the highest PPV of any maneuver for meningitis, while Brudzinski and Kernig signs have very poor sensitivity
- Textbook indications for CT scan before LP to identify patients with raised ICP who theoretically might herniate from LP are: focal neurological sign, papilledema, seizure, immunocompromised, malignancy; however this is controversial and some experts believe that herniation following LP has never been proven to be caused by the LP and that a normal scan does not exclude raised ICP
- When to start antibiotics: after an immediately performed LP, or if doing CT first, do pan‐cultures (which often will yield the offending bacteria) and start antibiotics before the LP, while doing everything you can to minimize the time to LP; note ‐ PCR on CSF is very good at identifying organism despite antibiotics
- Textbook CSF findings (interpret with caution!):
- Bacterial meningitis: opening pressure >300 (in recumbent position), WBC >1,000, neutrophils >80%, protein >200
- Viral meningitis: WBC <300, neutrophils <20%, normal protein and glucose levels
- HSV encephalitis: viral findings as above + RBCs (due to temporal lobe hemorrhage)
- EMC experts recommend using dexamethasone 10mg IV within 15min of 1st antibiotic dose when bacterial meningitis is suspected esp. with a GCS of <12, as it may lead to decreased mortality, decreased hearing loss, improved cognitive outcome, no adverse events demonstrated in metaanalyses and as recommended by Cochrane review (NNT=9)
- Antibiotic regimen:
- Ceftriaxone 2g IV for all, plus vancomycin 2g IV if MRSA is suspected, plus ampicillin 2g IV if Listeria is suspected (immunocompromised patients, incl. AIDS and alcoholism), plus acyclovir 1g IV if herpes encephalitis is suspected (altered, seizure, neuropsych symptoms, RBCs in CSF)
- Post‐exposure prophylaxis, only for those in close contact with affected patients (eg, sharing saliva, bodily fluids), is Ciprofloxacin 500mg PO x1 dose
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Tintinalli J, Stapczynski J, Ma OJ et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, Seventh Edition (Book and DVD). Mcgraw-hill; 2010.
De gans J, Van de beek D. Dexamethasone in adults with bacterial meningitis. N Engl J Med. 2002;347(20):1549-56.
Attia J, Hatala R, Cook DJ, Wong JG. The rational clinical examination. Does this adult patient have acute meningitis?. JAMA. 1999;282(2):175-81.
Meierkord H, Holtkamp M. Non-convulsive status epilepticus in adults: clinical forms and treatment. Lancet Neurol. 2007 Apr;6(4):329-39. Review.
Dr. Steinhart, Dr. Carr and Dr. Helman have no conflicts of interest to declare.