Archive | June, 2016

THORACIC AORTIC DISSECTION

27 Jun

submitted by Christina Brown, M.D.

Definition – Blood entering intimal tear in aortic wall.  Blood subsequently dissects through the media under aortic systolic pressure.

Risk Factors – HTN, Tobacco abuse, pregnancy, congenital heart disease (bicuspid AV, Coarctation), Marfan’s, Ehler’s Danlos, Inflammation (Lupus, syphilis, endocarditis, GCA)

Location:

a_dissection

Proximal – Occur at the aortic root, coronary ostia and/or pericardium.  

Distal – Dissect distally to involve any or all branches of the aorta ie -carotid and subclavian arteries.

Stanford classification:

  • Type A: Ascending aorta
  • Type B: Distal to ascending aorta

Peak Age for Occurrence

  • Proximal dissection: 50–55 yr
  • Distal dissection: 60–70 yr

Complications:

  • Occlusion of the coronary ostia, aortic valve incompetence, or cardiac tamponade.

 

Signs & Symptoms

Chest Pain:

  • May be absent in as many as 15% of patients
  • Acute onset, sharp
  • Substernal -> type A dissection
  • Intrascapular -> descending thoracic dissection
  • Lumbar -> abdominal aorta involvement

Back pain:

  • Commonly interscapular or lumbar. May present as combination of chest, back, and abdominal pain.

Neurologic complaints: Stroke symptoms, Vision changes

 

Physical Exam

Hypertension: 35–40% may be normotensive.

Pulse deficits: Discrepancies in BP in upper extremities

Neurologic/spinal cord deficits

New murmur of aortic regurgitation: Occurs in up to 31% of patients

 

Management

EKG – Dissection may involve coronary ostia and cause MI:

  • Inferior MI (RCA territory) is more common than LCA territory.
  • A normal EKG + severe, acute-onset chest/back pain/shortness of breath – high suspicion for aortic dissection.

Labs

  • CBC, BMP, UA – Evaluate renal function, hematuria
  • Amylase – May be elevated d/t bowel ischemia
  • Troponin – May be elevated d/t myocardial ischemia

 

Imaging

Unstable Patient:

CXR – Widened mediastinum or abnormal aortic contour.

Echocardiogram – Transthoracic vs Transoesophageal (if intubated) – Tamponade, valvular incompetence for evaluation. 

Stable Patient:  CT, Aortography

 

ED Treatment

BP Control = Reduce shear force on aortic wall and slow down the dissection process.

  • Esmolol (IV) or labetalol (IV): Start before Nitroprusside therapy to prevent reflex tachycardia. 
    • Contraindications:Bradycardia,  COPD, hypotension
  • Nitroprusside

 

Emergent surgery:

  • Treatment of choice for type A dissection
  • Treatment for type B dissections in those who have failed medical therapy

Medical management:

  • Treatment of choice for stable type B dissections

 

Disposition

ADMIT – All patients with an evolving aortic dissection should be admitted to the ICU.  C/S  cardiothoracic surgery for type A dissection.

 

References

1] Jeffrey I. Schneider and Jonathan S. Olshaker.  Aortic Dissection, Thoracic. Rosen & Barkin’s 5-minute Emergency Medicine Consult.
2] Erbel R, Alfonso F, and Boileau C et al.: Diagnosis and management of aortic dissection. Eur Heart J. 2001; 22(18):1642–1681. [PMID: 11511117]
[3] Hagan P G, Nienaber C A, and Isselbacher E M et al.: The international registry of acute aortic dissection: New insights into an old disease. JAMA. 2000; 283(7):897–903. [PMID:10685714]
[4] Khan I A and Nair C K.: Clinical, diagnostic, and management perspectives of aortic dissection. Chest. 2002; 122(1):311–328. [PMID: 12114376]
[5] Klompas M.: Does this patient have an acute thoracic aortic dissection? JAMA. 2002; 287:2262–2272. [PMID: 11980527]
[6] Mészáros I, Mόrocz J, and Szlávi J et al.: Epidemiology and clinicopathology of aortic dissection. Chest. 2000; 117(5):1271–1278. [PMID: 10807810]
[7] Moore A G, Eagel K A, and Bruckman D et al.: Choice of computed tomography, transesophageal echocardiography, magnetic resonance imaging, and aortography in acute aortic dissection: International registry of acute aortic dissection. Am J Cardiol. 2002; 89:1235–1238. [PMID:12008187]
picture

 

tox bradycardias: fingerstick for clues

7 Jun

often taught, often forgotten clue to help differentiate beta-blocker vs. calcium channel blocker overdoses:

REMINDER:

Calcium Channel Blockers can present with hyperglycemia (CCBs prevent insulin release)

Beta Blockers can present with hypoglycemia (BBs  inhibits both glycogenolysis and gluconeogenesis)

 

VISUAL AIDS:

The above difference has been difficult to remember for me, and I frequently look it up as a reminder, so here’s an attempt to associate/remember which is which:

CALCIUM CHANNEL BLOCKERS:

HYPERglycemia

visual association:

046435__53574_stdbabydeal-keo-gummy-2

 

BETA BLOCKERS:

hypOglycemia

stop-the-sugar

 

 

Appreciate any other tips/mnemonics y’all have on remembering the difference.  

 

References: emdocs post, beta blocker, ODs, picture 1, 2, 3

 

 

tendon repair – Kessler stitch

2 Jun

via a nice quick review of tendon lac repair concepts in last December’s ACEP Now:

modified Kessler stitch for tendon repair:

basic idea: stronger stitch, tension distributed across multiple points (e.g. with mattress sutures)

the stitch:

acep_1215_pg13c

concept walkthrough (tune in from 2:00-4:00 if tight on time):

live action video (start at 0:30 if tight on time)

There you go. Add one more technique to the toolbox.

 

References: ACEP Now article (& picture); concept video; live video