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Medical Pearls

  • From time to time we will post a medical pearl.
  • These are meant to be very short medical facts that can be useful clinically and are many times accepted general medical knowledge.  
  • If you have one that you would like to share please feel to contact us

2016 Medical Pearls

    November 2016 - Kanavel's Criteria

    The following criteria are useful at identifying patients who might have flexor tenosynovitis:

    • Finger is held in slight flexion position
    • Fusiform swelling of the entire finger ("sausage finger")
    • Tenderness along the flexor tendon sheath
    • Pain with passive extension
    • Little, JS et al. JAMA 1984;252(21):3003-4.
    • Goldstein EJ. Clin Infect Dis 1992;14(3):633-8.
    October 2016 - Finger Amputation

    If an amputation of the finger occurs do the following:

    • Wrap finger in saline soaked gauze
    • Place finger inside a dry bag
    • Place the bag in a container with ice water
    • Note:
      • NEVER place amputated part directly on ice or ice water
      • Attempt to get amputated part reimplanted within 6 hours
      • Contraindications to reimplantation include: amputated part is crushed or severely deformed or prolonged ischemia
    September 2016 - High Pressure Injection Injury
    • Injuries to the hand associated with grease, oil, oil-based paint are at greater risk and initially look relatively normal.  
    • This type of injury is considered a medical emergency and requires early operative exploration and debridement.
    • References: 
      • Gelberman RH. J Bone Joint Surg Am 1976;57(7):935. 
      • Childress MH. J Natl Med Assoc 1977;69(9):663-4.  
      • Hayes CW et al. South Med J 1982;75(12):1491-8.  
      • Hogan CJ. J Orthop Trauma 2006;20(7):503-11.
    August 2016 - Cauda Equina vs Conus Medullaris Syndrome

    It is important to be able to differentiate Cauda Equina from Conus Medullaris since one is a upper motor neuron disease and the other is a lower motor neuron disease:

    • Cauda Equina Syndrome is a LOWER motor neuron condition commonly described as gradual in onset, unilateral findings, impaired reflexes, radicular pain, numbness that is more common and localized to the saddle area, asymmetrical or unilateral, and associated with urinary RETENTION​.
    • Conus Medullaris Syndrome is an UPPER motor neuron condition that tends to be sudden onset, bilateral in nature, reflexes preserved, less radicular pain, numbness is localized to perianal area and is symmetric and bilateral, importance, urinary retention and atonic sphincter with overflow urinary incontinence and fecal incontinence.
    July 2016 - Ovarian Cyst Size & Torsion Risk
    • Females less than 18 years of age with ovarian cysts > 4 - 5 cm and women of reproductive age with ovarian cysts > 5 cm are at increased for ovarian torsion.
    • Ovarian torsion is considered a medical emergency.
    April 2016 - Button Batteries & Time to Removal
    • Due to the risk of perforation, a child who swallows a lithium button battery is considered a medical emergency. 
    • The button battery should be removed within 4 - 6 hours from the time of ingestion.
    March 2016 - Changes in Levothyroxine Dose in Pregnancy

    • Pregnancy increases the thyroxine-binding globulin (TBG), which causes an increase in the bound portion of T4 and T3 and thus decreases the free-fraction available to be used by the cells, including the those cells in the developing baby. 
    • Therefore, the dose of levothyroxine will need to be increased early in pregnancy by as much as 48% from the patient's baseline stable dose being used prior to pregnancy.
    February 2016 - Air Gas Embolization
    • If a scuba diver ascends too quickly and without exhaling, the diver can develop an air gas embolization that could lead to the development of a stroke, pulmonary embolism, cardiac arrest, and/or loss of consciousness. 
    • This is due to Boyles law which is equal to pressure x volume.  As the scuba diver comes up to the surface, the volume of gas in the body begins to also increase since the pressure is less as you get closer to the surface.  
    January 2016 - Treatment of Tar Burns
    • The treatment of a burn to the skin from hot tar includes placement of cold water and then large amounts of an emulsifier such as Neosporin or Bacitracin ointment that is removed in 24 hours. 

2015 - Medical Pearls

    December 2015 - Na+ Correction in Hyponatremia
    • When treating hyponatremia (ie., serum Na+ < 135 mEq/L), it is important to avoid over correcting the serum Na+ by > 12 mEq/L in a 24 hour period to time due to the risk of developing central pontine myelinolysis.
    • This means you do not want to correct the serum Na+ by more than 0.5 mEq/L/hr.
    November 2015 - AKA vs. DKA
    • The primary difference between alcoholic ketoacidosis (AKA) versus diabetic ketoacidosis primarily resides in the serum glucose level.  
    • Both conditions have a pH < 7.35, bicarbonate < 18, anion gap > 10-12, ketones in the urine, but the glucose level in AKA is < 250 mg/dL whereas in DKA it is > 250 mg/dL.
      • Exception to the Rule! Some case reports have suggested that a patient on one of the sodium-glucose cotransporter 2 (SGLT2) inhibitors for the treatment of type 2 diabetes mellitus. Patients on this new class of medications can lose large amounts of glucose in the urine and thus appear to have normal to low blood glucose levels.  
    October 2015 - Starting of IV Fluids for Burns
    • When patients come into the emergency department (ED) with significant 2nd, 3rd, or 4th degree burns and IV fluids are going to be started based on the Parkland formula, the time for administering the first 24 hours of fluid requirement starts from the time of the burn, NOT the time of arrival to the ED.
    • This is relevant as the first half of the fluid replacement needed based on the Parkland formula is supposed to be given in the first 8 hours and then the remaining amount is then given over 16 hours.  That is 8 hours from the time the burn occurred. 
    September 2015 - Electrical Alternans
    • Electrical alternans is described as alternating amplitudes in the QRS complex between beats on a 12-lead ECG.
    • It is most commonly seen in patients with a large pericardial effusion where the heart is floating in a bag of fluid creating a swinging motion that generates the alternating sizes or amplitudes of the QRS complexes seen. 
    August 2015 - Power in Statistical Analysis
    • Power is defined as 1 - β, where β is the chance of making a type 2 error (i.e., the chance of not finding a difference when one exists) 
      • Therefore, Power is the ability to detect a difference between 2 groups if a difference actually does exist.
    • EBM Consult - Biostatistics Reference: Power Analysis
    July 2015 - Heart Transplants & Atropine
    • Patients who have had heart transplants have hearts that are denervated and specifically lose paraysympathetic nervous system influence because the vagus nerve has been cut.  As such, they do not generally respond to atropine, a commonly used medication for symptomatic bradycardia because of its anticholinergic influence.
    • Therefore, if a heart transplant patient comes in with symptomatic bradycardia, they will either require transcutaneous pacing or some other medication (eg.,dopamine, dobutamine, theophylline)
    • EBM Consult - Anatomy Overview: The Heart
    June 2015 - PRBCs & Iron
    • Each unit of PRBC provides the patient with about 200 mg of elemental iron.
    • Repetitive blood transfusions without proper monitoring can result in iron overload.