UMEM Educational Pearls

Most cases of normal anion gap metabolic acidosis result from either urinary (RTA) or gastrointestinal HCO₃^- losses (diarrhea).  A number of xenobiotics can also cause this disorder:

1. Acetazolamide
2. Acidifying Agents: Ammonium chloride, arginine hydrochloride, hydrochloric acid, lysine hydrochloride
3. Cholestyramine
4. Toluene
5. Topiramate (Topamax)

• Transverse Myelitis (TM) is the development of grey and white matter inflammation of the spinal cord, which can result in demyelination.
• Hallmark characteristics of this condition include: (1) isolated spinal cord (not brain) dysfunction, and (2) the lack of associated cord compression.
• TM can be acute or subacute, such that it progresses over the course of hours to several days.  Nearly half of cases will reach its maximal deficit within 1 to 10 days of onset.
• The diagnosis of TM is primarily based on the history and physical examination findings.  MRI of the spinal cord and myelography are often used as diagnostic adjuncts.
• This condition typically presents with paresthesias, back pain, and ascending leg weakness.
• Febrile illnesses often serve as a precursor; one series found this to be the case in 37% of complete TM cases.
• While steroids are sometimes administered over the first several days of illness to decrease inflammation, there is no cure for TM and treatment is largely supportive in nature. 

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Linezolid is used for gram-positive infections resistant to conventional therapy (e.g., Vancomycin-resistant enterococcus and Methicillin Resistant Staph Aureus). Linezolid is an oxazolidinone, but more importantly it is a weak monoamine oxidase inhibitor (MAOI) and serotonin syndrome (e.g., altered mental status, neuromuscular abnormalities, autonomic instability) may occur when combined with selective serotonin re-uptake inhibitors (SSRIs) or with recent discontinuation of SSRI. 

Be aware that the following drugs can precipitate serotonin syndrome when combined with Linezolid:

Mirtazpine       Buproprion       Fentanyl

Trazodone       Buspirone         Bromocryptine

Levodopa        Lithium               Amphetamines

Cocaine           Codeine            Reserpine

Ergots               MAOI's

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Got Symptomatic Hypertension? Why not try Fenoldopam?

Fenoldopam is a rapid-acting vasodilator.

• It is an agonist for D1-like dopamine receptors and binds with moderate affinity to α2-adrenoceptors.
• Effective as nitroprusside, however, it has the advantages of increasing renal blood flow (6 times as potent as dopamine in producing renal vasodilitation) and sodium excretion
• Not associated with the accumulation of toxic metabolites, and not requiring shielding from light.
• Fenoldopam can be safely used in all hypertensive emergencies, and may be particularly beneficial in patients with renal insufficiency.

Dosing (Adult): After a starting dose of 0.1 to 0.3 mcg/kg/minute, the dose is titrated at 15 minute intervals, depending on the BP response. May be increased in increments of 0.05 to 0.1 mcg/kg/minute every 15 minutes until target blood pressure is reached. Maximal infusion rate reported in clinical studies: 1.6 mcg/kg/minute.

Onset/duration: 5-10 minutes/~ 1 hour.

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In order to minimize interruptions in compressions due to pulse checks, continuous end tidal CO₂ (ETCO₂) monitoring during compressions is recommended. Before spontaneous circulation returns, the ETCO₂ is likely to be on the order of < 10 mmg Hg. At the moment spontaneous circulation returns, the ETCO₂ is expected to abruptly increase to at least 35-40 mm Hg. Be wary, though, that the administration of sodium bicarbonate may transiently increase the ETCO₂ even in the absence of return of spontaneous circulation (ROSC).

Use of ETCO₂ in this manner allows one to assess the patient for ROSC without ever having to stop compressions for pulse checks.
 

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Dr. Corwell covered Spondyloysis in July 2010  https://umem.org/res_pearls_referenced.php?p=1134 but if you are like me you might have trouble remembering the differences between the following terms:

• Spondyloysis: A unilateral or bilateral defect in the pars interarticularis portion of a vertebrae.  Typically L5 or L4.
• Spondylosis: is a term referring to degenerative osteoarthritis of the joints between the spinal vertebrae and/or neural foraminae.
• Spondylolisthesis: describes the anterior displacement of a vertebra or the vertebral column in relation to the vertebrae below. Usually due to spondyloysis or a fracture of the pedicles of the vertebrae.  Can occur anywhere along the vertebral column. Most common at the L4 and L5 level.  For example,  a hangman's fracture is a spondylolisthesis of the C1 vertebra being displaced anteriorly relative to the C2 vertebra.
• Spondylitis: is an inflammation of the vertebra. As can be seen with ankylosing spondylitis, Pott’s disease or any infection or arthritic disorder of the spine.

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We've all been there.  It's 2am, and a 4 week old with a temperature of 38.1 rolls in the door.  You grab the LP kit and your "best holder."  This person then holds the baby's head and neck flexed with one hand, while the other brings the bottom and legs up to the chest as much as possible...all, usually, without pulse oximetry monitoring.

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Toxic Holiday Plants

Of the three plants listed, which is NOT poisonous?

1.     Holly plant

2.     Poinsettia

3.     Mistletoe

Poinsettia plants were once thought to be very poisonous. Contrary to popular belief, poinsettias are safe to have in the home during the holidays.

Although there are reported cases of death with ingestion of Holly plants in older literature, recent experience shows gastrointestinal effects in small doses, and serious toxicity such as CNS depression in large ingestions.

Mistletoe ingestion of few of the berries would, at most, produce mild gastroenteritis; however, ingesting concentrated extracts of the plant, including the berries, may produce serious effects such as seizures, mental confusion, drowsiness, and hallucinations.

Happy holidays!

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• Patients with multiple sclerosis (MS), the most common autoimmune, inflammatory, demyelinating neurological condition, often present to  the emergency department with their first episode of symptoms and for treatment of future exacerbations.
• While the diagnosis of MS is ultimately made based on clinical findings such as visual abnormalities, sensory and motor complaints, gait abnormalities, and fatigue, use of brain MRI and cerebrospinal fluid (CSF) studies may be helpful in making the diagnosis.
• Brain MRI findings that are suggestive of MS include ovoid-shaped, demyelinated plaques often situated in periventricular regions and near the corpus callosum.  Seventy to 95% of MS patients will have an abnormal brain MRI.
• CSF findings suggestive of MS include oligoclonal IgG banding and is discovered in 85 to 95% of cases.

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Beware Trendelenburg Positioning in the Critically Ill Obese Patient

• When inserting a central venous catheter (CVC) into the internal jugular or subclavian vein, clinicians often place patients in the Trendelenburg position to increase the size of the vein.
• When possible, avoid Trendelenburg position for CVC placement in the morbidly obese patient.
• These patients can quickly deteriorate in this position due to reduced lung volumes, increased right heart pressures, decreased cardiopulmonary reserve, and the effects in intra-abdominal pressure.

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In the second half of pregancy, we've traditionally learned that the gravid uterus compresses the inferior vena cava and therefore decreases cardiac output when patient is in a supine position. Therefore, we've learned that patients in the second half of pregnancy the patient should be placed in a left lateral tilt position.

However, it is difficult to perform good quality chest compressions when the patient is in a titled position.

Therefore, the optimal position for chest compressions on the patient in cardiac arrest in the second half of pregnancy is to have the patient in a supine position; and have another rescuer manually deflect the uterus to the patient's left side. This provides optimal compressions + optimal venous return.

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Chief complaint: “Posterior heel pain”

http://www.aidmybursa.com/_img/ankle-retrocalcaneal-subcutaneous-bursitis.jpg

Retrocalcaneal bursitis

The retrocalcaneal bursa is located between the Achilles tendon and the posterior superior border of the calcaneus.

H&P: Inflammation and pain may follow repetitive dorsi/plantar flexion of the ankle (excessive running, jumping activities). Tenderness anterior and superior to the Achilles insertion on the heel.

Treatment: Minimize weight bearing. ½ inch elevation. NSAIDs.

Posterior calcaneal bursitis

This bursa is subcutaneous, just superficial to the insertion of the Achilles tendon.

H&P: Inflammation and pain may follow irritation from the upper border of the heel counter of a shoe. Posterior heel pain. Tender “bump” (the inflamed and swollen bursa) on the back of the heel.

http://podiatry.files.wordpress.com/2006/12/patient2.jpg

Treatment: Opened-heeled shoes, sandals, or placement of a “U-shaped” pad between the heel and the counter. NSAIDs. Advance to shoes with soft or less convex heel counters.

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• occurs in 1/1000 live births, but found in 15% of neonatal autopsies
• usually weigh <2500 grams at birth with prematurity the most common risk factor
• present with bleeding from the nose and mouth with severe respiratory distress
• immediate treatment with tracheal suctioning, oxygen, and positive-pressure ventilation
• ventilation goal is to maintain a high, positive expiratory pressure of at least 6-10cm H20
• also check for and correct any underlying bleeding disorders
• extremely high mortality, but no long-term pulmonary deficits if the infant survives

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As we eat our turkey today and the myth that we are tired because of the tryptophan content is propagated further - nothing to do with the 2000kcals that we just ate - I would like to share an interesting and controversial study. 

Use of stimulants and and sedatives by EM residents. Incidence is as follows:

In a study of 485 residents with 47% response rate:

Prescription Stimulants: 3.1%

Sleep Aids (all):  89%

Use of Nonbenzodiazepines (zolpidem): 14%

Use of Melatonin: 10%

Benzodiazepines: 9%

Difficult job with difficult hours. What is the appropriate medication or is there a medication that truly assists with performance? Are they doing harm to themselves? to patients?

Disrupted circadian rhythm, addiction tendencies and the hardship of a stressful nightshifts are the price we pay for this specialty. Awareness and education are needed for the residents as well as the attendings.

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• Any patient presenting with an acute onset of dizziness described as a spinning sensation should be thoroughly assessed for cerebellar stroke, as these often present in such a manner, prior to assuming that the source is simple vertigo.

• Cerebellar strokes, whether due to infarct or hemorrhage, typically present with ataxic gait, abnormal Rhomberg, dysmetria with finger-to-nose and heel-to-shin testing, and nystagmus.

• In addition, the dizziness associated with cerebellar strokes should be less reproducible and extinguishable than that due to simple vertigo.

• In terms of imaging, remember that CT scanning is not the preferred radiologic modality for evaluating the cerebellum and posterior aspects of the brain; the thickness of the posterior skull tends to create significant artifact and distortion. If suspicion warrants, MRI should therefore be pursued.

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Non-Convulsive Status Epilepticus (NCSE) is generally under reported. An ICU study found 10% admissions for altered mental status (AMS) were eventually diagnosed as NCSE.

Pearls:

- Include NCSE in the AMS differential

- NCSE may occur with or without convulsive seizures

- Difficult to distinguish from a post-ictal state (14% of convulsive seizures convert to  

  NCSE)

- Reported mortality is up to 44%

Consider NCSE when:

- Seizure history / recent seizures

- Post-ictal period >1 hour

- Odd behaviors (e.g., chewing, blinking, personality change) and abnormal eye 

  movements (86% specific)

- AMS without structural, metabolic or traumatic etiology

- Patient intubated for status epilepticus 

If you are unsure but suspicious of NCSE order a STAT EEG.  Treat NCSE like a convulsive status.

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We mentioned atropine's elimination from the cardiac arrest (asystole, PEA) protocols last week. Atropine (0.5 mg) is still indicated in unstable bradycardias that appear to be vagally-mediated, such as sinus bradycardia and Mobitz I bradycardia.

Beware, however, that atropine is not recommended in patients with transplanted hearts. These hearts lack vagal innervation, and in fact there's one small study suggesting that atropine may be associated with paradoxical slowing of the heart rate and worsening AV block. Go straight to pacing with these patients.

 

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Evaluation of Potential Intra-Articular Joint Lacerations

Skin and soft tissue injuries in proximity to a joint often prompt concern of whether the injury violated the joint space.  Joint Space involvement is important to exclude as it can lead to septic joints and long term disability.

One easy way to determine if the joint capsule has been violated is to inject methylene blue into the joint and watch to see if any of the methylene blue extravasates through the soft tissue.

Indications for a methylene blue injection include:

1. Periarticular fracture
2. Visible joint capsule
3. Proximity to a joint

There are no absolute contraindications.  Though clearly the procedure does not need to be done when the injury  highly suggests an open joint injury and the patient will require operative debridement and exploration.

To watch a video of a injection head to eMedicine by clicking http://emedicine.medscape.com/article/114453-overview

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In the setting of a patient suffering from an anticholinergic overdose with hallucinations/agitation, it may be beneficial to administer the antidote: Physostigmine. Many hesitate simply because they have never administered before or there may be doubt in the diagnosis. Here is the skinny:

1) Anticholinergic OD seen in following meds: diphenhydramine (Benadryl), dimenhydrinate (Dramamine), scopolamine, benztropine (Cogentin), some plants like datura stromonium (thorn apple)

2) Physostigmine 1mg IV slowly over a REAL 5 min. Administer to fast and patient may seize. Maximum dose of 2mg IV.

3) Contraindications: suspicion of TCA OD (anectdotal and from old case report) - screening EKG should be done prior to administration of physostigmine. Also glaucoma, closed angle, obstructive uropathy.

Remember your clinical endpoint needs to be measurable, thus hallucinations and agitation should be reversed. No indication if the patient is only experiencing dry mouth or other more mild anticholinergic symptoms.

• Idiopathic Intracranial Hypertension, previously known as pseudotumor cerebri, can be treated with medications such as carbonic anhydrase inhibitors (i.e. acetazolamide), corticosteroids, indomethicin, loop diuretics, and analgesics used to treat migraine headaches.

• While removing excess cerebrospinal fluid (CSF) via lumbar puncture (LP) is sometimes considered to be an appropriate therapeutic intervention for IIH in the emergency department, it is generally not recommended for the following reasons:

             -- CSF reforms within 6 hours, making its removal short-term, unless there is a CSF leak.

             -- LP can be challenging in obese patients and uncomfortable for patients, in general.

             -- LP complications such as low pressure headaches, CSF leak, CSF infection, and intraspinal epidermoid tumors.

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