• Exposure to organophosphates can lead to “intermediate syndrome.”

• It is a syndrome characterized by weakness of neck flexors and proximal limbs, cranial nerve palsies, and respiratory muscle weakness, which can lead to respiratory paralysis.

• It follows acute cholinergic syndrome and precedes a delayed neuropathy, thus it is an “intermediate syndrome,” typically developing 24-96 hours post exposure.

• The pathophysiology of IMS remains unclear.

• Serum cholinesterase levels and electrophysiological studies are helpful in confirming the diagnosis.

• With supportive therapy, including artificial ventilation, complete recovery occurs within 5-18 days.

Right Heart Failure in the Critically Ill

• In its most simplistic form, right heart failure (RHF) is due to either to right ventricular contractile dysfunction or elevated right ventricular afterload.
  • Primary causes of RV contractile dysfunction include: coronary ischemia, sepsis, drug toxicity, and acute pulmonary hypertension
  • Primary causes of increased RV afterload include: LV dysfunction, venous thromboembolism, hypoxic pulmonary vasoconstriction, and lung injury
• Management of the patient with RHF centers on identifying and treating reversible causes, optimizing preload, inotropes, and possible implantation of a right ventricular assist device.
• Importantly, excessive volume loading can worsen RV contractile function, increase RV dilatation, and impair LV output and systemic perfusion.
• Consider early use of inotropic agents, such as dobutamine, in critically ill patients with RHF.

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Question

32 year-old female presents with 5 days of fever, chills, and flank pain. She is hypotensive on presentation and urinalysis shows pyuria. Click here for the non-contrast CT scan. What's the diagnosis and what type of antibiotics should be started empirically?

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Lyme disease is the most prevalent arthropod zoonosis in the Northern hemisphere

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Carbapenems (meropenem, ertapenem, doripenem, imipenem/cilastatin) are broad-spectrum antibiotics that have good gram-negative and anaerobic coverage and are used to treat resistant bacterial infections.

• Early retrospective studies showed ~10% cross-reactivity in penicillin-allergic patients.

• More recent prospective studies verified penicillin allergy by the accepted standard (ie, skin test to the major and minor penicillin determinants) and tested for carbapenem allergy by administering a full therapeutic dose to carbapenem skin test-negative patients.

• The cross-reactivity between skin tests appears to be around 1%, with all carbapenem skin test-negative patients tolerating the challenge.

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I was reading the biography of Steve Jobs looking for incredible insights into leadership and innovation. I have realized that you basically have to be a genuis and it doesn't matter what you do. His favorite drug was LSD which he believed was necessary to improve creativity and innovation. His description of the hallucinations confirm that he was taking this drug.

We describe LSD hallucinations as a crossing of the senses or "synesthesias" - you hear the color blue, you see the smell of roses.

Steve Jobs describes a moment in a wheat field while on LSD and (paraphrasing from the biography) ..." the wheat was playing Bach beautifully"

If you have a patient describing this type of hallucination you can almost be guaranteed that they have taken LSD or some other tryptamine.

A Cochrane review of 37 studies concluded that Succinylcholine (SUC) is superior to Rocuronium (ROC) during rapid sequence intubation.

The authors claim that compared to ROC, SUC has a faster onset of action (45 vs. 60 seconds) and overall a shorter duration of action (10 vs. 60 minutes).

Dr. Reuben Strayer wrote a letter to the journal editors and stated that these findings should be interpreted carefully; he highlighted that most of the studies in the review used doses of ROC less than 0.9 mg/kg (most studies used 0.6mg/kg).

Dr. Strayer asserted that ROC’s onset of action is dose dependent; when using doses of 1.2 mg/kg, ROC’s onset is indistinguishable from that of SUC. He also stated another major benefit of ROC is the lack of adverse effects that SUC possesses (hyperkalemia and malignant hyperthermia).

What are your thoughts on this? Go to http://www.facebook.com/Criticalcarenow and take the poll (there are 5 choices). Results will be posted next week.

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Question

56 year-old male presents with chest pain. You perform an ultrasound of the heart and see the clip below. What's the diagnosis? Thanks to Dr. Ken Butler for the case.

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Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable form of cardiomyopathy, characterized by the replacement of myocytes with adipose and fibrous tissue leading to arrhythmias, right ventricular failure, and sudden cardiac death (SCD)

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Apprehension test for shoulder dislocation

Tests for chronic shoulder dislocation                                                       

Similar to the patellar apprehension test

Designed to place the humeral head in a position of imminent subluxation or dislocation

http://www.maitrise-orthop.com/corpusmaitri/orthopaedic/112_kelly/kelly-fig11.jpg

ABduct and externally rotate arm to a position where the shoulder may dislocate

If the shoulder is about to dislocate, the patient will experience apprehension due to the familiar pattern of dislocation, report the laxity and resist further motion.

Types:
- Uniphasic anaphylaxis: occuring immediately after exposure to allergen, resolves over minutes to hours and does not recur
- Biphasic anaphylaxis: occuring after apparent resolution of symptoms typically 8 hours after the first reaction. Occur in up to 23% of adults and up to 11% of children with anaphylaxis

Treatment:
1. First line: IM epinephrine 1:1000 solution
   - vasoconstrictor effects on hypotension and peripheral vasodilation; bronchodilator effects on upper respiratory obstruction
   - NO absolute contraindication for use in anaphylaxis
   - Dosage: Adult: 0.3 - 0.5mg; Peds: 0.01mg/kg (max 0.3mg)
   - can be repeated every 5-15 minutes
2. Adjunctive therapy:
   - H1 Blocker: diphenhydramine 1-2mg/kg up to 50mg IV
   - H2 Blocker: ranitidine 1-2mg/kg
   - Corticosteroid: 1-2 mg/kg for prevention of biphasic reactions
   - Bronchodilator: Albuterol for bronchospasm
   - Glucagon: for refractory hypotension or if patient is on beta blocker
          - Dosage: Adult: 1-5 mg; Peds 20-30microgm/kg
          - Dose may be repeated or followed by infusion of 5-15 mg/min
   - place patient in recumbent position if tolerated with lower extremities elevated
   - supplemental O2
   - IV fluids for hypotension

Fatalities: typically seen with peanut or treenut ingestions from cardiopulmonary arrest. Associated with delayed or inappropriate epinephrine dosing

Disposition:
   - Mild reaction with symptom resolution: observe for 4-6 hrs (ACEP, AAP)
   - Recurrent symptoms or incomplete resolution: admit

Reference:
1. World Allergy Organization Guidelines for the Assessment and Management of Anaphylaxis, Feb 2011
2. Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel Oct 2010

Patients that experience altered mental status (specifically lethargy) and are on valproic acid - check a serum ammonia level regardless if it is an overdose or just therapeutically on VPA.

If the ammonia is elevated in combination with the mental status change consider administration of L-carnitine either po or IV. It will lower the ammonia and improve the mental status  within hours.

High risk patients for hyperammonia who therapeutically take VPA are certain pediatric patients that experience malnutrition, have seizure disorder and are on multiple seizure medications.

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AKI and Fluid Balance

• Up to 70% of critically ill patients develop acute kidney injury (AKI), with 5-6% of ICU patients requiring renal replacement therapy (RRT). 
• Maintaining adequate renal perfusion is central to the management of AKI in the critically ill patient.  As such, fluids are frequently administered.
• As we've highlighted in previous pearls, there is mounting evidence to indicate that a positive fluid balance may be detrimental for select critically ill patients.
• Results from a recent publication suggest a positive fluid balance in patients with AKI may be harmful.
  • Bellomo, et al analyzed data from the RENAL trial to determine the association between daily fluid balance and outcomes.
  • Investigators found a 70% reduction in 90-day mortality for critically ill patients who had a negative mean daily fluid balance compared to those that had a positive balance.
  • A negative fluid balance was also associated with decreased ICU length of stay and the need for RRT.
• Take Home Point: Once critically ill patients with AKI are resuscitated, maintaining a slightly negative daily fluid balance may be beneficial.

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Question

36 year-old female presents with left knee-pain following a motor vehicle crash (XRs are shown). What's the diagnosis AND what is the first test that should be performed to assess for vascular injury?

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Pulmonary P waves (S1Q3T3 pattern + clockwise rotation) are specific for PE, but not sensitive.
This study examines if an ECG can discriminate between ACS vs. PE
- 40 patients with PE & 87 patients with ACS 
- All had negative T waves in the precordial leads (V1-V4) on the admission ECG
The PE group had negative T waves commonly present in leads II, III, aVF, V1, V2, but less frequent in leads I, aVL, and V5 to V6 (p <0.05).
The ACS group had negative T waves in leads III and V1 in 1% compared with 88% of patients with PE (p <0.001).
Sensitivity, specificity, positive predictive value, and negative predictive value for Dx of PE were 88%, 99%, 97%, and 95%, respectively.
Negative T waves in both leads III and V1 may suggest PE can be differentiated from ACS in patients with negative T waves in the precordial leads.

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The Analysis of Synovial Fluid Analysis

When trying to diagnosis a septic joint, it is common to order the following labs on the synovial fluid:

• Synovial WBC count
• Glucose
• Protein
• Gram Stain
• Culture

Unfortunately, there is no value of glucose or protein that has enough sensitivity and specificity to make the tests diagnostically helpful.  Gram stains are only postive in culture positive septic joints in approximately 50% of the cases.  Cultures take too long to be helpful in the ED.  The synovial WBC count can be helpful if very high, but a low value does not ensure that the patient does not have a septic joint.

The one test that has been shown to have a Positive Likelihood ratio of Infinity is a synovial lactate level >10.  A synovial lactate should be sent on all synovial fluid as a level of 10 and greater makes the diagnosis of septic arthritis, regardless of the gram stain or synovial WBC level.

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If you have a patient who meets (or has had close exposure to someone meeting) the clinical case definition of pertussis (a cough lasting at least 2 weeks with one of the following: paroxysms of coughing, inspiratory “whoop,” or post-tussive vomiting) here are some important points to keep in mind:

Vaccination

• Be wary that children younger than 7 might not be “up to date” for pertussis vaccination.
  • The recommended schedule is four primary doses of DTap at 2, 4, 6 and 15-18 months, and a fifth DTap booster at 4- 6 years old. ACIP now recommends kids 7 and older get a Tdap booster if their immunizations were previously incomplete.

Testing

• The available testing modalities for routine surveillance are culture and/or PCR (from a posterior nasopharyngeal swab or aspirate) and serologic testing.
  • Serologic results are not currently accepted as laboratory confirmation for purposes of national surveillance, but may be more useful for testing patients in the convalescent stage.

Treatment

• The CDC recommends treatment of clinical or confirmed cases with one of these regimens:
  • Azithromycin daily x 5 days
  • Clarithromycin BID x 7 days
  • Erythromycin QID x 14 days
  • Trimethoprim/sulfamethoxazole (Bactrim) BID x 14 days if resistance or allergy to macrolides
    • However, a 2011-updated Cochrane review showed that short-term antibiotics (azithromycin for 3-5 days, or clarithromycin or erythromycin for 7 days) were as effective as long-term (erythromycin for 10-14 days)  (RR 1.01) (95% CI  0.98-1.04). Trimethoprim/sulfamethoxazole for seven days was also effective.
• Insufficient evidence to decide whether there is clear benefit for treating healthy contacts, but the CDC does recommend prophylactic treatment of close contacts and family members.

References:

Altunaiji SM, Kukuruzovic RH, Curtis NC, Massie J. Antibiotics for whooping cough (pertussis). Cochrane Database of Systematic Reviews 2007, Issue 3. Art. No.: CD004404. DOI: 10.1002/14651858.CD004404.pub3

http://www.cdc.gov/vaccines/pubs/surv-manual/chpt10-pertussis.html

Femoral venous access is typically limited to the acute resuscitation of critically-ill patients. Several practice-guidelines recommend avoiding the femoral site, or removal once admitted to the ICU, because of the risk of catheter-related bloodstream infection (CRBI) and deep-vein thrombosis (DVT).

A recent systematic review and meta-analysis (including two randomized-control trials and eight cohort-studies) evaluated the risk of CRBI and DVT for catheters placed in either the internal jugular, subclavian, or femoral-venous sites. No difference in the rate of CRBI or DVT was found between the three sites, although the DVT data was less robust (i.e., contained heterogeneous data).

The authors hypothesized that improvements in sterility during central-line placement (e.g., full-barrier precautions), improved nursing care (e.g., central-line site care), and ultrasound guidance may have led to a reduction in femoral site complications. 

Although a prospective randomized-control trial is necessary to confirm these results, this meta-analysis challenges the traditional teaching that femoral central-access should be avoided.

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Placement of central-lines through the subclavian (SC) route has several advantages over other sites of venous cannulation:

•    Lower rates of infection

•    Lower rates of deep vein thrombosis

Placing a central-line through the "blind" SC approach increases the risk of non-compressible vessel injury and pneumothorax as compared to other approaches (e.g. internal jugular).

Ultrasound can help place central-lines in the SC vein while reducing the risk of complications; this video demonstrates the technique: http://ultrarounds.com/Ultrarounds/Subclavian_Ultrasound.html

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