Archive | March, 2012

septic arthritis vs. transient synovitis in kids

29 Mar

HOW CAN WE TELL THE DIFFERENCE?
–lots of overlap in signs/symptoms
–one article came up with a decent decision rule

J Bone Joint Surg Am. 1999 Dec;81(12):1662-70.
–looked at 282 cases, excluded 114 atypical patients (e.g. immunocompromised), leaving 168
–38 had “true” septic arthritis
septic arthritis defined by positive culture or joint WBC >= 50,000 cells/mm3

–four things they decided on that might differentiate:

  • history of fever
  • non-weight-bearing
  • erythrocyte sedimentation rate (ESR) >= 40 mm/hr
  • serum WBC > 12,000 cells/mm3

–predicted probability of septic arthritis using these four predictors:

  • < 0.2 percent for zero predictors
  • 3.0 percent for one predictor
  • 40.0 percent for two predictors
  • 93.1 percent for three predictors
  • 99.6 percent for four predictors

BOTTOM LINE:
–septic arthritis is bad, transient synovitis not so bad
–hard to tell sometimes, signs/symptoms are often similar
–useful: history of fever, non-weight bearing, ESR>40, WBC>12k
–if none of the above: unlikely septic arthritis
–more of the above: worry a bit more

Submitted by S. Lee.

Reference(s): kocher article, picture

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chest pain with recent negative stress test

27 Mar

EP MONTHLY EXCERPT:
–nice overview on stress tests from March 2011(see reference link)

DOES THE RECENT NEGATIVE STRESS MEAN THIS PATIENT CAN’T HAVE ACS?
–No.
–stress tests are good, not great

SOME ROUGH EXAMPLES:
–Sensitivity for single vessel CAD:

  • exercise ECG stress test ~68%
  • exercise nuclear stress test (thallium) 60-82%
  • exercise nuclear stress test (sestamibi) 82-97%
  • adenosine/dipyridamole nuclear stress 77-92%
  • dobutamine nuclear stress 80-100%

BOTTOM LINE:
–stress sensitivity is not perfect
–negative stress test does NOT rule out ACS

Reference(s): ep monthly article, picture

blood gas vs. serum electrolytes

26 Mar

HOW CLOSE ARE THEY?
–not a lot of data
–pubmed biopsy produced only 2 articles

ARTICLE 1:
–“Diagnostic accuracy of venous blood gas electrolytes for identifying diabetic ketoacidosis in the emergency department”
–looked at 46 DKA patients, compared serum and VBG electrolytes

  • sensitivity of VBG electrolytes for diagnosing DKA: 97.8%
  • specificity of VBG electrolytes for diagnosing DKA: 100%
  • Correlation coefficients between VBG and serum chemistry
    • sodium 0.90
    • chloride 0.73
    • bicarbonate 0.94
    • anion gap 0.81

ARTICLE 2:
–“Comparison of the point-of-care blood gas analyzer versus the laboratory auto-analyzer for the measurement of electrolytes”
–looked at 200 ICU patients, compared ABG and serum lab Na+ and K+

  • mean ABG sodium value was 131.28 (SD 7.33)
  • mean lab sodium value was 136.45 (SD 6.50) (p < 0.001).
  • mean ABG potassium value was 3.74 (SD 1.92)
  • mean lab potassium value was 3.896 (SD 1.848) (p = 0.2679).

–conclusions: no significant difference between the potassium values; however, the difference between the measured sodium was found to be significant
–decisions can be made by trusting the K+ values obtained from ABG (less so with the sodium)

BOTTOM LINE:
–how close are blood gas electrolytes to the lab serum electrolytes?
not much data, seems close enough for acidosis, potassium
–not as good for sodium

Submitted by S. Lee.


Reference(s): article 1, article 2, picture

should you give prophylactic antibiotics for intraoral wounds?

23 Mar
GOOD QUESTION:

–(anecdotally) many intraoral lacerations seem to be people biting themselves or somehow teeth-related
–do we need to treat these like other bite wounds? (e.g. with antibiotics)

THE DATA (sort of):
limited studies with small numbers

no statistically significant differences in the incidence of infection with systemic oral antibiotics vs placebo.

trends indicate a decrease in the rate of infection if patients comply with antibiotic regimens

–a report showing no infection in 28 children who did not receive antibiotics

–suggestions include prescribing antibiotics for dirtier wounds, through & through lacs, and bite-related wounds

BOTTOM LINE:
–data is inconclusive (awesome)
use your clinical judgment (wasn’t this helpful?)
–deeper, dirtier, delayed presentation, etc—common themes for recommending antibiotics
–augmentin or clindamycin are decent choices, if antibiosing

Submitted by S. Lee.

Reference(s): annals review; trauma review; uptodate.com: evaluation and repair of tongue lacerations; picture

should we pack an abscess after I&D?

22 Mar
ABSCESS PACKING DATA:

–very limited, based on Pubmed biopsy

REVIEW ARTICLE:
–referenced one small article, and that was it

ONE SMALL ARTICLE:
–“determine whether the routine packing of simple cutaneous abscesses after incision and drainage (I&D) confers any benefit over I&D alone”
–prospective, randomized, single-blinded trial, N =48

  • no significant difference in need for a second intervention at the 48-hour follow-up between the packed (4 of 23 subjects) and nonpacked (5 of 25 subjects) groups (p = 0.72; relative risk = 1.3, 95% confidence interval [CI] = 0.4 to 4.2)
  • higher pain scores immediately postprocedure in packed group and at 48 hours postprocedure
  • greater use of ibuprofen and oxycodone/acetaminophen in packed group 

ABOUT PERIANAL ABSCESSES:
–“designed to show that perianal abscess may be safely treated by incision and drainage alone” vs. I&D + packing
–50 patients were recruited (7 lost to follow-up); 20 in the packing and 23 in the nonpacking arm

  • Mean healing times were similar ( P = 0.214).
  • The rate of abscess recurrence was similar ( P = 0.61).
  • Postoperative fistula rates were similar ( P = 0.38).
  • Pain scores at the first dressing change were similar ( P = 0.296).
  • Although pain scores appeared much reduced in the nonpacking arm, this did not attain statistical significance

BOTTOM LINE:
limited data out there on packing abscesses
–packing doesn’t seem to improve healing or reduce recurrence
–packing might hurt more
probably ok to NOT pack abscess after I&D

Submitted by S. Lee.

Reference(s): review article, one small article, perianal abscess article, picture

management of diabetic ketoacidosis (DKA) in adults

21 Mar
DKA Basics
-Definition:  Blood glucose >250 (e.g. diabetic), moderate ketonemia, anion gap >10, Bicarbonate <15, and pH <7.3 (acidosis)
-Metabolic acidosis, hyperglycemia, hyperosmolality, potassium depletion, and hypovolemia
-Infection is often a precipitating event

Initial Labwork:
-Serum electrolytes
-Calculate Anion gap
-CBC
-UA
-Plasma osmolality
-ABG
-EKG
-Blood cultures, urinalysis, CXR to determine possible infectious cause

Hyperglycemia and Serum Sodium:
Corrected Serum Na = Measured Na + 0.024 * (Serum glucose – 100)
-boils down to this: add 1.2 to the sodium for every 50 mg/dL over 100

Management:
Order of priorities is volume first, correction of potassium deficits, and then insulin administration
1.      ABCs
2.      get labwork and investigate source of DKA/HHS (infectious causes)
3.      Fluid resuscitation with isotonic saline (Increases insulin responsiveness by lowering plasma osmolality)
4.      Insulin therapy (after confirmation of potassium greater than 3.3) —bolus of Regular Insulin IV followed by an insulin drip
5.      KCl is generally added to the replacement fluid once the serum K+ falls below 5.3
6.      When the serum glucose reaches 200 in DKA or 250-300 in HHS, saline is switched to dextrose containing solution
NOTE:  Use of supplemental bicarbonate in the DKA is not recommended
Submitted by J. Grover.
Reference(s): Tintinalli’s 7th edition, uptodate.com, picture

the TASER-ed patient

20 Mar

PHYSIOLOGY OF TASERS:
–nice article in Emergency Medicine News from Feb ’12 (link below)

HIGHLIGHTS:
–TASERs deliver electrical current to cause diffuse muscular contraction, thus incapacitating

–people who need to be TASERed may be drugged up, overexherted, or sustain trauma, so there are other things to think about

–in studies with healthy subjects, there were minimal (returning to baseline in 10 minutes) or no changes in pulse, 02 saturation, bicarb, lactate, electrolytes, troponin, EKGs, acidosis

EVERYTHING’S RELATIVE:
TASER joule output: 0.36-1.76 joules

RANDOM FACT:
–TASER stands for “Thomas A. Swift’s electric rifle”, after the developer’s childhood hero

BOTTOM LINE:
–asymptomatic, awake post-TASERed patient, unlikely to need routine labs/monitoring

Submitted by S. Lee.

Reference(s): EMN article, review article, taser joules, picture