Podcast production, editing and sound design by Anton Helman; voice editing by Raymond Cho
Podcast content by Justin Morgenstern, Maria Ivankovic, Brit Long, Sarah Reid, Anand Swaminathan & Anton Helman
Written summary & blog post by Graham Mazereeuw, edited by Anton Helman
Cite this podcast as: Helman, A. Morgenstern, J. Ivankovic, M. Long, B. Reid, S. Swaminathan, A. EM Quick Hits 25 – Cerebral Venous Thrombosis, Diphenhydramine Alternatives, Abdominal Compartment Syndrome, Neonatal Constipation, Intubating Metabolic Acidosis. Emergency Medicine Cases. January, 2021. https://emergencymedicinecases.com/em-quick-hits-january-2021/. Accessed [date].
When to Consider Cerebral Venous Thrombosis
Presentation is nonspecific and highly variable:
Headache in nearly all patients (the only symptom in 25% of patients)
Other features: focal neurological deficit (40%), seizure (40%), encephalitis (rarely)
Young (39 years old on average)
Female (3x more commonly)
Usually at least one thrombotic risk factor
Consider this diagnosis in 4 groups of patients:
Group 1: severe or prolonged headache without a clear cause and with at least one thrombotic risk factor
Group 2: thunderclap headache with a negative CT head
Group 3: severe headache with stroke symptoms or neurological findings not clearly mapping to a vascular territory
Group 4: intracranial hemorrhage without a classic bleeding pattern, particularly younger patients or those with thrombotic risk factors
-MR venogram is gold standard; contrast CT venogram has good sensitivity (95%)
-Treat the sequelae (ABCs, treat seizure, treat raised ICP)
-Specific treatment is anticoagulation (even if intracranial hemorrhage!) in consultation with neurology/hematology
-Full recovery = 80%; 30-day mortality = 5%
Bottom line: CVT is the DVT of the brain; be on high alert for CVT in patients with thrombotic risk factors and atypical headache or stroke symptoms.
Tadi P, Behgam B, Baruffi S. Cerebral Venous Thrombosis. [Updated 2020 Aug 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459315/
First-generation antihistamines are “dirty drugs”: diphenhydramine and hydroxyzine have poor receptor selectivity, binding muscarinic, serotonergic, and alpha-adrenergic receptors, as well as cardiac potassium channels in addition to the H1 histamine receptor
First-generation antihistamines side effects:
CNS suppression, psychomotor impairment, delirium, coma, and death
A therapeutic dose of diphenhydramine (50mg) can impair driving similarly to a 0.1% blood-alcohol level (4-5 alcoholic drinks in some people)!
Second-generation antihistamines are generally safer: less likely to have drug-drug interactions, faster onset, much less sedating
A second-generation antihistamine is a reasonable (perhaps superior) alternative for post-anaphylaxis urticaria without the potential side-effects of diphenhydramine
Bottom line: First-generation antihistamines such as diphenhydramine and hydroxyzine have multiple side effects and can be replaced by second-generation antihistamines for allergy and post-anaphylaxis urticaria.
Fein MN, Fischer DA, O’Keefe AW, Sussman GL. CSACI position statement: Newer generation H1-antihistamines are safer than first-generation H1-antihistamines and should be the first-line antihistamines for the treatment of allergic rhinitis and urticaria. Allergy Asthma Clin Immunol. 2019;15:61.
Cook VE, Chan ES. Anaphylaxis in the acute care setting. CMAJ. 2014;186(9):694.
Huynh DA, Abbas M, Dabaja A. Diphenhydramine Toxicity. [Updated 2020 Oct 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557578/
Abdominal Compartment Syndrome
Abdominal compartment syndrome is a potentially deadly condition caused by increased pressure within the abdominal compartment and is most often diagnosed in the ICU
Abdominal compartment syndrome is defined by intra-abdominal pressure (IAP) > 20 mm Hg with organ dysfunction
Suspect abdominal compartment syndrome in penetrating abdominal trauma and post open abdominal surgery with abdominal pain out of proportion, abdominal distension and shortness of breath/increase work of breathing; note that these findings are not accurate for diagnosis, making the clinical diagnosis challenging
History, physical examination, labs and imaging may suggest the diagnosis, but they should not be used to exclude it
Diagnosis: IAP measurement, typically through measuring bladder pressure with a Foley catheter
Management: increase abdominal wall compliance, evacuate gastrointestinal contents, avoid excessive fluid resuscitation, drain intraperitoneal contents, and decompressive laparotomy in select cases; patients typically require admission to an ICU
Papavramidis TS, Marinis AD, Pliakos I, Kesisoglou I, Papavramidou N. Abdominal compartment syndrome – Intra-abdominal hypertension: Defining, diagnosing, and managing. J Emerg Trauma Shock. 2011 Apr;4(2):279-91.
Sosa G, Gandham N, Landeras V, Calimag AP, Lerma E. Abdominal compartment syndrome. Dis Mon. 2019 Jan;65(1):5-19.
Maluso P, Olson J, Sarani B. Abdominal Compartment Hypertension and Abdominal Compartment Syndrome. Crit Care Clin. 2016 Apr;32(2):213-22.
Sugrue M, De Waele JJ, De Keulenaer BL, Roberts DJ, Malbrain ML. A user’s guide to intra-abdominal pressure measurement. Anaesthesiol Intensive Ther. 2015;47(3):241-51.
Neonatal “Constipation” Red Flags, DDx and ED Management
Poor stooling in a newborn is common and often triaged as “constipation”; however, it is most often a result of breastfeeding not being fully established
Fractionated bilirubin if concerns about feeding, hydration or weight loss; use bilitool.org to determine the need for phototherapy or exchange transfusion
Abdominal X-ray with two views if concern for obstruction (bilious vomiting, abdominal distension) if you don’t have other imaging modalities available
IV fluid resuscitation with strong consideration of full septic workup and empiric antibiotics in any newborn who is lethargic, dehydrated, appears unwell
Home if: baby is well and there are no red flags; parents are comfortable with increasing feeds, stimulating baby to stay awake during feeds, seeking close follow up with primary care (in next 1-2 days for weight check)
Admission to paediatrics if: baby is significantly dehydrated, weight loss ³ 10%, concern about underlying abnormality on exam, or social concerns
General surgery consultationif: concerned about obstruction, Hirschsprung disease, or anal abnormalities
Bottom line: “constipation” in a newborn is likely attributable to ineffective breastfeeding, but be sure to assess for red flags and rule out serious illness
Tabbers MM, DiLorenzo C, Berger MY, Faure C, Langendam MW, Nurko S, et al. Evaluation and Treatment of Functional Constipation in Infants and Children: Evidence-Based Recommendations from ESPGHAN and NASPGHAN. JPGN 2014;58: 258–274.
Dr. Anton Helman is an Emergency Physician at North York General in Toronto. He is an Assistant Professor at the University of Toronto, Division of Emergency Medicine and the Education Innovation Lead at the Schwartz-Reisman Emergency Medicine Instititute. He is the founder, editor-in-chief and host of Emergency Medicine Cases.