EM PULMONOLOGY QUICK HITS

31 Mar

Submitted by Amit Kumar, M.D.

ABG vs VBG:

Due to the ease/lack of another stick, VBG often preferred and sufficient in ED.

Two main indications to get ABG for accurate results:

  • patient in severe shock,
  • VBG PCO2 >45mmHg

 

BPAP basics:

-EPAP = CPAP = PEEP

-IPAP = Pressure support (what makes BPAP > CPAP)
Respiratory Failure:

Type I respiratory failure:

  • O2 problem (hypoxia)
  • Ex: ARDS, pneumonia, pulmonary edema, CHF
  • Treatment: ? EPAP, start with FiO2 100%

Type 2 respiratory failure:

  • CO2 problem (hypercarbia)
  • Ex: COPD, asthma
  • Treatment: ? IPAP, may start with FiO2 ~40% (hypoxia not the problem)

 

Continuous EtCO2 uses in ED:

Definition: Partial pressure of CO2 in exhaled breath

-During procedural sedation: Measure of ventilation. Increase to >50mm Hg/>10mmHg from baseline usually indication of oncoming hypoxia (in theory, hypoventillation preceeds hypoxia)

-During CPR: Measure of cardiac output. <10 mmHg hints towards inadequate compressions –> switch. Sudden increase (to ~35-45 mmHg) is a sign of ROSC.

 

References:

EM: RAP (Resp Failure types)

http://www.alaskasleep.com/blog/what-is-bipap-therapy-machine-bilevel-positive-airway-pressure (BiPAP vs CPAP)

http://www.med.upenn.edu/emig/capnography%20for%20procedural%20sedation%20in%20the%20ED.pdf (EtCO2 + procedural sedation)

 

 

C1-C2 Fractures (quick review)

23 Feb

Submitted by Christina Brown, M.D.

C1-C2 FRACTURES/DISRUPTION

Occipital Condyle Fracture  – Neurologic impairment such as lower cranial nerve deficits and/or limb weakness.  It’s rarely visible on plain films.

Occipito-atlantal Disassociation –Skull displaced anteriorly/posteriorly or distracted from cervical spine.  It frequently results in death.  “Basion-dental interval” – Distance between basion and superior cortex of dens.  Normally distance is less than 8.5mm on CT. (1)

C1 (ATLAS) Fractures

 Jefferson Fx.  – Due to axial loading resulting in outward displacement of lateral masses of C1.  If displacement is >7mm in total, rupture of the transverse ligament and likely unstable.  (1)

Transverse Ligament Disruption – TV ligament is crucial to stability of C1 and C2. 

  • On lateral radiograph, the predental space should be less than 3mm in adults vs <2mm on CT. 
  • A predental space >3mm on lateral radiograph implies damage to TV ligament. 
  • >5mm indicates rupture. 

Avulsion Fx of Anterior or Posterior Arch of Atlas – Hyperextension injury.  Lateral XR.  An isolated avulsion of anterior tubercle is considered a stable fracture. 

 

C2 (AXIS) Fractures

Odontoid Fx – Frequently involve other injuries to cervical spine and multisystem trauma.  Clinical signs – Severe, high cervical pain w/ muscle spasm worsened by movement.  Neurologic injury in 18-25% odontoid fractures ranging from paresthesias to quadriplegia.  (1)

Type I – Avulsion of tip.  Stable, good prognosis. 

Type II – Junction of odontoid w/ body of C2, unstable. 

Type III – Through body of C2.  Unstable.  (1)

 

 

Hangman’s Fx – C2 (Axis) pedicle fractures.  Unstable injury d/t hyperextension following abrupt deceleration. 

Initial Management

Spinal Immobilization – There is no high quality evidence stating that it prevents spinal injury or improves outcome (2).  It’s recommended to remove patient from the backboard as soon as possible. 

Definitive Management – If a spinal column injury is deemed unstable, hospital admission and spine surgery consultation is mandatory.

Conservative Management – Closed reduction under fluoroscopy and halo-vest immobilization. The halo vest = graphite or metal and is secured to the frontal and parietal areas of the skull with metal pins.  The halo is the most common device applied for treatment of unstable cervical fractures.  (4)

 

Common Pitfalls

  • No spine immobilization
  • Low suspicion of spinal injury in multi trauma patient
  • Accepting radiographs that are inadequate to appropriately evaluate for spinal column injury
  • Failure to appreciate the high false negative rate of plain radiographs in diagnosing unstable burst fractures; failure to obtain a CT scan in such cases (2)
  • Failure to radiograph the entire spine when a fracture at one spinal level is demonstrated

 

 

References:

  1. Baron BJ, McSherry KJ, Larson JL, Jr., Scalea TM. Baron B.J., McSherry K.J., Larson J.L., Jr., Scalea T.M. Baron, Bonny J., et al.Chapter 255. Spine and Spinal Cord Trauma. In: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. Tintinalli J.E., Stapczynski J, Ma O, Cline D.M., Cydulka R.K., Meckler G.D., T Judith E. Tintinalli, et al.eds.Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011. http://accessmedicine.mhmedical.com/content.aspx?bookid=348&Sectionid=40381743
  2. http://www.uptodate.com/contents/evaluation-and-acute-management-of-cervical-spinal-column-injuries-in-adults?source=search_result&search=cervical+fracture&selectedTitle=2~30
  3. http://www.uptodate.com/contents/spinal-column-injuries-in-adults-definitions-mechanisms-and-radiographs?source=search_result&search=cervical+fracture&selectedTitle=1~30
  4. Botte MJ, Byrne TP, Abrams RA, Garfin SR. Halo Skeletal Fixation: Techniques of Application and Prevention of Complications. J Am Acad Orthop Surg 1996; 4:44.
  1. Images +: https://www.med-ed.virginia.edu/courses/rad/cspine/index.html
  2. Odontoid types image: http://accessemergencymedicine.mhmedical.com/data/Books/schw1/schw1_c042f012.gif 

 

strength in numbers: Pyelonephritis

3 Feb

some interesting stats, via a recent emdocs overview of pyelonephritis:

Clinical:

  • fever – present in up to 77% of patients
  • flank pain or CVA tenderness – 86%
  • elderly patients with NO fever – up to 33% (just to make our jobs difficult)

 

Urinalysis:

  • needs 10,000 colony forming units (CFU) per mm3 to confirm diagnosis
  • leukocyte esterase (LE):
    • sensitivity: 72% to 97%
    • specificity: 41% to 86%
  • nitrites:
    • sensitivity: 19% to 48%
    • specificity: 92% to 100%
  • Urine cultures positive in 90%

urine-analysis-28-638

Patient with symptoms, but negative dipstick: what now?

“urine dipstick showed sensitivities as low as 75%, which is not acceptable if the patient has symptoms.”

also beware of pyelo mimics (e.g. pneumonia, PE, AAA, chronic pyelonephritis, PID, pelvic pain syndrome, prostatitis, diverticulitis, appendicitis, ovarian/testicular torsion, HZV, epidural abscess, and ectopic pregnancy)

 

Food for thought.

 

References: emdocs article; picture

Spinal Fractures in AS vs. DISH

14 Jan

submitted by Matthew Kongkatong, M.D.

FIRST, SOME DEFINITIONS:

Ankylosing spondylitis:

-Chronic inflammation of the spine causes progressive ossification of the paraspinous ligaments

-Prevalence 0.1%-1.4%

-Male>Female

AS

AS: “bamboo spine”, ossification of disc spaces

 

Diffuse Idiopathic Skeletal Hyperostosis (DISH):

-Non-inflammatory process of known etiology causes progressive ossification of paraspinous ligaments.

-Prevalence varies 2.9%-25%

-Associated with obesity, advanced age, and diabetes mellitus

DISH

DISH: “flowing candle wax”, preserved disc spaces

WHY DOES IT MATTER?

Spine fractures in DISH and AS

-Review article of 93 papers including 345 AS patients and 66 DISH patients

65% of AS and 69% of DISH patients sustained fractures via low energy mechanisms life falling from sitting or standing

Most (80% in AS and 60% in DISH) fractures were in the cervical spine and most were hyperextension type injuries.

-67% of AS and 40% of DISH patients had a neurologic deficit on presentation and 13% of AS and 15% of DISH patients had neurologic deterioration❤ months from presentation (compared to 0.08% in other population studies).

Most spine fractures are considered unstable because they extend into calcified ligaments and surrounding soft tissue, including into the intervertebral discs.

Calcified ligaments can transmit force and cause fractures in areas remote from the area of trauma.

References: Westerveld LA, Verlaan JJ, Oner FC: Spinal fractures in patients with ankylosing spinal disorders: a systematic review of the literature on treatment, neurological status and complications. Eur Spine J 2009, 18:145-156.; http://www.orthobullets.com/spine/2045/dish-diffuse-idiopathic-skeletal-hyperostosis

orthostatics: useless?

8 Jan

came across this great video via LITFL: a quick talk 2410395945_a7240381d1by Anand Swaminathan, which looks at the (limited) evidence for orthostatics in the ED.

here’s the link (only 7-ish minutes, worth the watch):

http://lifeinthefastlane.com/futility-orthostatic-measurements/

 

QUICK TAKEAWAYS:

orthostatics (change in vital signs with positional change) is different from symptomatic orthostasis (stand up, feel lightheaded)  –[personally, I care about the latter, not so much the former]

a large number of asymptomatic patients have orthostatics by numbers (~50%)

orthostatics in moderate blood/fluid loss ~25%-range sensitivities (pulse change)

 

BOTTOM LINE:

orthostatic vital signs not particularly helpful

There you go.

 

References: LITFL post; picture

 

 

Lithium Toxicity

5 Jan

Submitted by Christina Brown, M.D.

QUICK PEARLS:lithium-300x225

Use – Mood stabilizing drug for bipolar disorder and depression.

Epidemiology – In 2010, there were 6307 cases of lithium intoxication reported to the American Association of Poison Control Centers [2,3].  A large proportion of patients on chronic lithium therapy experience at least one episode of toxicity during treatment [4].  

Pharmacodynamics – narrow therapeutic index. 

GI absorption: 

Therapeutic –

  • immediate release – Peaks at 1 to 2 hours s/p ingestion.
  • Sustained release – 2 to 4 hours s/p ingestion. 

Up to 12 hours or longer may be required before peak levels are reached in acute overdose [5,6].

Lithium is a small molecule (74 Daltons) with no protein or tissue binding and is therefore amenable to hemodialysis.  Renal excretion. 

Risk factors – GI losses, acute decompensated heart failure, cirrhosis, diuretics, NSAIDs or ACE inhibitors [7-9].   Elderly patients have a lower glomerular filtration rate and a reduced volume of distribution (d/t to reductions in lean body mass and total body water). 

 

Clinical Presentation

Acute – Nausea, vomiting, and diarrhea; late neurologic sequelae

Chronic  – Neurologic findings; sluggishness, ataxia, confusion, agitation, and/or neuromuscular excitability (tremors, myoclonus)

Severe – Seizures, non-convulsive status epilepticus, or encephalopathy

 

Diagnostic Evaluation

Normal [Lithium] – 0.8-1.2 mEq/L.  Concentration may not correlate w/ severity.

Labs – BMP, CBC, Acetaminophen, Salicylate

EKG

 

Management:

ABCs

Hemodialysis  – Indications:

Lithium > 4 mEq/L; regardless of clinical status

Lithium > 2.5mEq/L + signs of significant lithium toxicity (eg, seizures, depressed mental status), has renal insufficiency or other conditions that limit lithium excretion, or suffers from an illness that would be exacerbated by aggressive IV fluid hydration (eg, heart failure) [1].

References:

  1. http://www.uptodate.com/contents/lithium-poisoning?source=search_result&search=lithium+toxicity&selectedTitle=1~35#references
  2. Pauzé DK, Brooks DE. Lithium toxicity from an Internet dietary supplement. J Med Toxicol 2007; 3:61.
  3. Bronstein AC, Spyker DA, Cantilena LR Jr, et al. 2010 Annual Report of the American Association of Poison Control Centers’ National Poison Data System (NPDS): 28th Annual Report. Clin Toxicol (Phila) 2011; 49:910.
  4. Amdisen A. Clinical features and management of lithium poisoning. Med Toxicol Adverse Drug Exp 1988; 3:18.
  5. Ward ME, Musa MN, Bailey L. Clinical pharmacokinetics of lithium. J Clin Pharmacol 1994; 34:280.
  6. Dupuis RE, Cooper AA, Rosamond LJ, Campbell-Bright S. Multiple delayed peak lithium concentrations following acute intoxication with an extended-release product. Ann Pharmacother 1996; 30:356.
  7. Jefferson JW, Kalin NH. Serum lithium levels and long-term diuretic use. JAMA 1979; 241:1134.
  8. Phelan KM, Mosholder AD, Lu S. Lithium interaction with the cyclooxygenase 2 inhibitors rofecoxib and celecoxib and other nonsteroidal anti-inflammatory drugs. J Clin Psychiatry 2003; 64:1328.
  9. Timmer RT, Sands JM. Lithium intoxication. J Am Soc Nephrol 1999; 10:666.
  10. Boton R, Gaviria M, Batlle DC. Prevalence, pathogenesis, and treatment of renal dysfunction associated with chronic lithium therapy. Am J Kidney Dis 1987; 10:329.
  11. picture

Vertebral Osteomyelitis/Discitis

23 Dec

submitted by Amit Kumar, M.D.

QUICK HITS:

3 main mechanisms of infection:

  • Hematogenous spread
  • direct inoculation (trauma, spinal surgeries/procedures)
  • contiguous spread from adjacent tissues

 

Culprit:

  • Staph aureus (>50%)
  • enteric gram-neg bacilli (following GU procedures)
  • psuedomonas/candida (often due to IV sepsis or IVDU)
  • group B strep (esp. in diabetics)

Signs & symptoms:

  • Localized spinal pain
  • leukocytosis
  • elevated ESR/CRP
  • fever
  • new radicular symptoms

Diagnostic strategies: Blood culture, MRI (most sensitive radiologic technique), biopsy (open/CT guided)

Differentials: Spinal epidural abscess, psoas abscess, herniated disc, spinal metastasis, vertebral compression fracture

Treatment: Pain control, ANTIBIOTICS (empiric followed by pathogen-directed. Routinely for minimum of 6 weeks), surgery (indications: neuro deficits, abscess needing drainage, cord compression)

Complications:

  • Posterior extension leading to epidural/subdural abscess or meningitis.
  • Anterolateral extension leading to paravertebral/psoas abscess.

***Picture: High signal is T2-weighted MRI at the disc and adjacent vertebral body compatible with diagnosis

Sources:

http://www.uptodate.com/contents/vertebral-osteomyelitis-and-discitis-in-adults?source=search_result&search=discitis&selectedTitle=1~51

http://www.med.harvard.edu/jpnm/tf03_04/jan6/writeup.html

-Picture:http://www.med.harvard.edu/jpnm/tf03_04/jan6/MRI.gif

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