Botulism

Today’s pearl is courtesy of North Korea. They claimed that Otto Warmbier, an imprisoned American who unfortunately died a few days after his return to the US, had suffered brain damage after contracting botulism. If you think that sounds wonky, you’re probably right. If you thinks that sounds probable, here is a refresher on botulism, a rare but deadly disease.

 

Anaerobic Clostridium botulinum produces an endotoxin that inhibits ACh release, resulting in neuromuscular paralysis; untreated can lead to respiratory failure. The spores can be found in soil, and are heat resistant.

 

(OK, I don’t want to agree with NK, but I suppose theoretically he could have had anoxic brain injury from botulism induced acute resp failure. I’m no federal agent [or am I?], but I think it is more probable that they accidentally overdosed him.)

 

There are multiple ways to acquire botulism:

  • Foodborne – ingest preformed toxin; home canned products
  • Wound – toxin produced by C botulinum once it infects the wound (mostly IVDU)
  • Infant – ingest spores that then produce toxin; affects ages 1 week – 11 months; honey
  • Adult enteric – similar to infant’s (ingest the spore that then goes on to make the toxin in vivo)
  • Iatrogenic – due to botox injections
  • Inhalation – aerosolized as act of bioterrorism
    • Characterized as a category A bioweapon (the most lethal) by the CDC

 

Symptom onset: 6-48 hours s/p toxin poisoning

  • Foodborne and enteric: GI upset
  • Descending symmetric paralysis
  • Starts with cranial nerves – diplopia, blurred vision, dysarthria
  • Anticholinergic symptoms
  • Pupils dilated and nonreactive (how to differentiate from MG)
  • Infants – “floppy” baby; lethargic, weak, constipated

 

Diagnosis is made clinically; exclude other conditions (ie, LP to r/o GBS).

Assay not commonly available; can ID toxin in serum or stool.

Food source can also be tested for toxin.

 

Treatment:

  • Botulinum equine antitoxin effective when used early; decreases days on vent
  • Human botulism immunoglobuin decreases vent requirements and ICU stay
  • Supportive. Intubation if respiratory failure. 
  • Report to health department

 

 

Look who wrote this Tintinalli topic –

Andrus, Phillip, and J. Michael Guthrie. “Acute Peripheral Neurologic Disorders.” Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e Eds. Judith E. Tintinalli, et al. New York, NY: McGraw-Hill, 2016, http://accessemergencymedicine.mhmedical.com/content.aspx?bookid=1658&sectionid=109437018.

52 in 52: Canadian Head CT Rule

Stiell IG, Wells GA, Vandemheen K, Clement C, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001 May 5;357(9266):1391-6. PMID: 11356436

 

What we already know: Prior to this study, there was disagreement and lack of standardization in the use of CT in patients with minor head trauma. Though a number of studies had already been done to identify high risk features, they were not robust enough to create clinical decision rules, and guidelines were sometimes contradictory.

Why is this study important: There are over a million cases of minor head trauma treated yearly in EDs. Use of CT in these cases carry a high cost but low yield. While most of these patients can be safely discharged, a small percentage decompensate and require intervention for intracranial hematoma. The researchers sought to establish sensitive, valid, and reliable guidelines for identifying high-risk minor head trauma patients who should undergo head CT.

Brief overview of the study:

  • Prospective cohort study in 10 Canadian EDs
  • Defined minor head injury as blunt trauma with LOC, amnesia, or disorientation and GCS 13-15
  • Primary outcome: need for neurologic intervention
  • Secondary outcome: clinically important brain injury on CT
  • Patients had CT based on physician discretion
    • Those who did not had a 14 day telephone proxy outcome measure; if they did not fulfill criteria, they were recalled for a reassessment and CT

The researchers found that high risk features associated with need for neurologic intervention were: GCS <15 at 2 hours after injury; open or depressed skull fracture; sign of basal skull fracture; vomiting 2 or more times; 65 years or older. Medium risk features associated with clinically important brain injury on CT were amnesia > 30 minutes before accident or dangerous mechanism.

Limitations: There may be disagreement on the authors’ definition of clinically important brain injury, which was any acute brain finding revealed on CT that would require hospital admission and neuro follow up. They also deemed clinically unimportant lesions to include localized SAHs or isolated contusions < 5 mm diameter. Another limitation is that not all of the patients underwent CT; those that did not had follow-up 2 weeks later via a phone call, which relies on self reported data.

Take home message: The Canadian Head CT Rule is a useful clinical aid for identifying which patients with minor head trauma should undergo head CT. In subsequent studies, it was found to be 100% sensitive in identifying patients requiring neurosurgical intervention.

Lateral Lumbar Puncture

If you are unsuccessful with an LP, consider ditching the midline angle and instead approaching laterally.

The lateral approach allows you to avoid the supraspinous and interspinous ligaments, which are often crunchy and calcified in older patients.

  • Prep the patient the same way you would as the traditional approach.
    • Patients can be in either the lateral decubitus or sitting position.
  • Insert the needle 1.5 – 2.0 cm lateral to the midline
    • If lateral decubitus, approach from the inferior aspect
    • If sitting, it doesn’t matter if you approach from the right or left.
  • Direct the needle 10-15° cephalad and 10-20° midline
  • If you hit bone, withdraw the needle and redirect more cephalad.

For other LP tips and tricks, check out Randy’s LP Pearls from August 2016.

Happy graduation day!

 

Chapter 115. Lumbar Puncture. In: Reichman EF. eds. Emergency Medicine Procedures, 2e New York, NY: McGraw-Hill; 2013. http://accessemergencymedicine.mhmedical.com/content.aspx?bookid=683&sectionid=45343758. Accessed June 20, 2017.

http://www.acepnow.com/article/techniques-performing-paramedian-approach-lumbar-puncture/?elq_mid=18713&elq_cid=4683198

http://blogs.brown.edu/emergency-medicine-residency/lumbar-puncture-part-2-pearls-pitfalls-and-troubleshooting/

Roberts & Hedges’ Clinical Procedures in Emergency Medicine, 6th ed, 2013.