Critical Care

The Obtunded Patient

The Case

52 y/o male with HTN, hyperlipidemia, chronic back pain, and recent depression came back from a walk and per family was ataxic, dysarthric and confused, so his family drove him to the ED. On the way, he began vomiting repeatedly and became increasing obtunded.  As he entered the ED went into apparent cardiovascular and respiratory collapse. Given 2mg of Naloxone without response and intubated by RSI for further evaluation.

Examination

Vitals on arrival in the ED:  Temp: 36, RR:-no spontaneous breaths noted after entering the ED O2: 88% on bag valve mask, HR: 68 BP: 88/64. Glucose 104.  GCS 3 (non verbal, no motor movement, pupils 2mm and fixed). No corneal or occulacephalic reflexes noted, no cough or gag elicited. All extremities were flaccid and areflexic. EKG show sinus rhythm, no obvious conduction abnormalities.

Medication hx: Simvastatin 40 mg daily, amlodipine 10 mg daily, Baclofen 20 mg TID, Vicodin 5-300 1 tablet q6 hrs

Labs: ETOH: 150. CBC, lactic acid, chemistry, venous blood gas (on ventilator), CPK, LFT’s, troponin asa, acetaminophen, UA, UDS all WNL

Imaging: CTA pan scan negative except for mild aspiration in the R lung base.

 

So what happened…..?

Baclofen Toxicity

What is it?

Baclofen is a synthetic derivative of the naturally occurring inhibitory neurotransmitter GABA.

Acts principally on the GABA-B receptor at the spinal level and reduce the post-synaptic potentials along motor neurons, thus relaxing the skeletal muscles.

Baclofen is primarily used for the treatment of spastic movement disorders and now more ubiquitously for the treatment of chronic back pain.

 

How is it given?

Oral: Until the past 10 years, the primary method of administration of Baclofen was oral.

  • Peak concentration in 2 hours and half life of 3.5hours
  • Dosage 40-80mg daily dosed q8 hrs
  • Centrally acting but crosses the blood brain barrier ineffectively, limiting its bioavailability
  • Very low toxic range with severe toxicity from oral baclofen, necessitating ICU level care occurring fairly consistently with baclofen overdoses of over 200mg (a 3 day supply for most people)
Figure 2: Baclofen pump concept

Figure 2: Baclofen pump concept

Intrathecal: Intrathecal baclofen is administered through the implantation of a pump subcutaneously with a catheter from the pump inserted directly into the CSF fluid.

  • Dosage: 90 mcg to 800 mcg daily
  • Intrathecal baclofen allows for 4x the amount of baclofen to be delivered to the spinal cord with just 1% of the oral dose.

Intrathecal Baclofen Pumps: The pump is surgically implanted under the skin in the abdomen and the catheter is tunneled under the skin and inserted into the intrathecal space usually between the 1st and 2nd lumbar vertebrae.

Currently SynchroMed is the only pump currently being used in the US for intrathecal baclofen, hydromorphone and morphine

  • The catheter holds 3-4ml
  • The reservoir holds 20-40ml
  • Pump battery lasts for 5-7 years
Figure 3: Synchromed Baclofen pump

Figure 3: Synchromed Baclofen pump

Toxicities 

Baclofen has the potential for both overdose and withdrawal, which can both present with a wide array of symptoms.

Overdose Symptoms

Most commonly include CNS depression, lethargy, somnolence, hallucinations, agitation, mydriasis/miosis, nausea and vomiting

Severe toxicity is associated with bradycardia, hypotension (more common) or hypertension, respiratory failure, hypothermia, seizures, coma and death.

Rarely, rhabdomyolysis and conduction disturbances may occur

Causes

Oral Baclofen overdoses:

  • Usually intentional overdoses-either for recreational or self harm

Intrathecal baclofen overdoses:

  • Wrong dose is manually programmed into the pump
  • Wrong concentration is placed in the pump
  • Wrong bolus is given when starting the pump
  • Wrong port is accessed or wrong port filled

Treatment

Patients are usually treated by supportive methods only.

In severe overdoses, this often means supporting blood pressure with fluids and pressors and often-mechanical ventilation for respiratory failure until drug toxicity subsides.

Generally overdose symptoms will resolve in approximately 24-48 hours

For Intrathecal baclofen overdoses:

Most are correctable by emptying the pump reservoir:

  • Turn off pump-programmer (need external device programmer to do this)
  • Empty reservoir: Use a 22 gauge needle to stick the middle of the pump and pull out all the drug
Figure 4: Emptying the reservoir

Figure 4: Emptying the reservoir

Remove the CSF- Use a 24-25 gauge needle to stick the side port and aspirate 30-100 ml of CSF

In severe cases performing a lumbar puncture to reduce circulating baclofen in the CSF while performing all normal supportive strategies (small case reports- this involves replacing entire circulating volume of CSF with saline and has been used successfully in a few cases of massive overdose)

Withdrawal Symptoms

Similar to withdrawal from alcohol or benzodiazepines, with the loss of gaba-mediated inhibition: hyper metabolic states, spasticity/rigidity, hallucinations/seizures, tachycardia, hyperthermia, and hypertension are more commonly observed.

Mild: pruritus, agitation, diaphoresis and increased tone

Moderate: fever, tachycardia, spontaneous clonus and painful muscle spasm

Severe: worsening of above along with seizures, delirium, hallucinations, rhabdomyolysis and death.

Remember the mnemonic, "ITCHY, TWITCHY, BITCHY."

Causes of Withdrawal

Oral Baclofen Withdrawal:

  • Oral Baclofen withdrawal can occur when a person is abruptly stops taking baclofen or weans off to fast.
  • Of note oral baclofen diffuses through the blood brain barrier deep into the brain whereas- intrathecal baclofen stays almost exclusively in the CSF with a penetration of only approximately 1-2 inches into the brain. Therefore, a person who is being switched to intrathecal baclofen must still be tapered off their oral baclofen or they will withdraw.

Intrathecal Baclofen Withdrawal:

  • Intrathecal Pump Malfunction
    • Intrinsic pump malfunction is exceedingly rare.
  • Pocket Refill
    • Rather than an overdose this results in acute withdrawal as intrathecal dosing is 1/100th of oral dosing/subcutaneous dosing.
  • Battery failure
    • Expected to die at 84 months.
    • Will alarm 3 months prior. 

Medication Changes or interactions:

  • SSRI’s especially known for decreasing effect

Catheter malfunctions: (kink, micro/macroleaks, scarring, migration)

  • Most common cause of pump failure
  • KUB and AP/lateral spine first step to look for catheter fracture or migration
Figure 6: KUB demonstrating Baclofen pump

Figure 6: KUB demonstrating Baclofen pump

Treatment

Oral Baclofen withdrawal is usually easily treatable by restarting baclofen and introducing a slow tapered wean if discontinuation is desired.

Intrathecal Baclofen Withdrawal presents more of a challenge in both recognition and treatment.  It can be tricky to recognize baclofen withdrawal as it often masquerades as sepsis (ex-tachycardia, hyperthermia, altered mental status). It is important to recognize that many of these patients have severe spasticity and may have limited verbalization skills. Often they come from long term care facilities without much information, along with the fact that many times the baclofen will not be listed on their daily facility medication list, making it extremely important to look for a pump every time.

Recognizing that a patient’s symptoms may be secondary to intrathecal baclofen and interrogating the pump and obtaining pump series imaging to evaluate for catheter related malfunctions is a key first step

Essentially intrathecal baclofen withdrawal requires intrathecal baclofen. The key is finding the reason for the withdrawal and fixing the primary cause. Everything else is a temporizing measure.

To help with symptoms while attempting to fix the primary cause of pump failure treatment can include:

  • High Dose Oral Baclofen
    • Treating intrathecal baclofen withdrawal with oral baclofen is often unsuccessful as the vast difference in bioavailability of oral doses and intrathecal doses.
  • Benzodiazepine treatment
  • Propofol low dose
  • Experimentation with Dexamedetomidine and cyproheptadine
  • CSF infusion of Baclofen

So what happened to our patient?

After approximately 18 hours intubated, our patient began waking up, became agitated and self-extubated himself. He admitted to taking approximately 900 mg of baclofen in a suicide attempt the day of admission. He was discharged to inpatient psychiatry without any further medical sequela on hospital day 3. 

Take Home Points

  • Overdose: variable presentation, CNS depression is often involved, good supportive care is key.
  • Withdrawal: variable presentation, Itchy/twitchy/bitchy. Will have increased muscle tone from baseline.
  • Always remember the pump is there.
  • Overdose: For intrathecal overdose-2 ports from which you can draw drug and CSF back out.
  • Withdrawal: Look for the cause and treat supportively with oral baclofen, benzos, and propofol.

Faculty Reviewer: Dr. Kristina McAteer

References

Image 1: “Spasticity2” by Bill Connelly- Own Work

https://commons.wikimedia.org/wiki/File:Spasticity2.svg

Image 2: http://www.gablofen.com/patients/intrathecal-baclofen-therapy

Image 3: http://www.ajnr.org/content/32/7/1158

Image 4: http://www.rch.org.au/kidsinfo/fact_sheets/Intrathecal_baclofen_3_the_ITB_pump/

Image 5: http://www.cliparthut.com/clip-arts/175/people-clip-art-175256.gif

Image 6: https://emcow.files.wordpress.com/2014/01/baclofen-3.jpg

 

 

 

 

 

Ultrasound Case of the Month

Case: submitted by Dr. Paul Cohen

This is a 30-year-old female, who presented to the ED with lower abdominal pain. She received a FAST exam in the urgent area of the ED for abdominal pain, which was positive, and she was then transferred to the critical care area for further evaluation. The patient reports having intercourse earlier in the evening and developed 9/10, sharp, non-radiating, suprapubic pain and NBNB emesis. Her LMP was ~6 weeks prior and she endorses using condoms. Her HCG was negative.

Whats the diagnosis?

Ruptured ovarian cyst with hemoperitoneum

Discussion:

The image was taken with the curvilinear probe in the suprapubic area, with the probe marker facing the patient’s right side in the transverse plane. This is the pelvic view in the FAST exam. Typically, one would see the bladder most anteriorly, followed by the uterus and then pouch of Douglas. The adnexa can be seen lateral to the uterus on either side.  The image shows, from anterior to posterior: the bladder, the uterus and a 5.7 cm cyst.

The next ultrasound was the RUQ view from the FAST exam of the same patient. The curvilinear probe was placed in the mid-axillary line, at the level of the xiphoid process with the probe marker pointing to the patient’s head to obtain a coronal plain. Free fluid is evident in Morrison’s pouch. Recall that there are four areas that need to be thoroughly interrogated in a FAST exam:

1. RUQ: Fan through to visualize above and below the diaphragm, Morrison’s pouch, and the inferior pole of the kidney

2. LUQ: Fan through to view above and below the diaphragm as well as the splenorenal recess and the inferior pole of the kidney. It is very important to visualize underneath the diaphragm on the LUQ view as this is where fluid often collects first on this side

3. Pelvic view: Fan through to visualize rectovesicle pouch (men) or rectouterine pouch (female)

4. Cardiac subxiphoid

Ovarian cyst rupture is a relatively common occurrence in women of child-bearing age. They are more common in conditions that promote ovulation induction and are less common with the use of OCPs. Additionally, vaginal intercourse has been noted to be a risk factor for ovarian cyst rupture. Pelvic ultrasound is the test of choice for diagnosis given that it is sensitive and relatively inexpensive. Most women with ovarian cyst rupture have an uncomplicated case and are managed expectantly. Initial evaluation should look for signs of hemodynamic instability, significant bleeding and ongoing blood loss (serial Hgb), signs of infection, and signs of malignancy. In terms of management of cysts, the single most important factor for malignancy is the sonographic appearance of the mass (solid, nodular, thick septations). For simple cysts in the premenopausal female, < 5 cm cysts do not require follow-up; 5-7 cm cysts are considered likely benign and should be followed annually; and cysts > 7 cm, may require an MRI or surgery depending on the clinical situation.

This patient was admitted for hemodynamic monitoring and pain control and discharged the next day. She was started on OCPs for ovarian suppression and reported significant improvement in her pain and nausea at her one-week follow-up appointment.

Faculty Reviewer: Dr. Kristin Dwyer

Additional Resources:

1. Alcázar, J. L., Castillo, G., Jurado, M. & García, G. L. Is expectant management of sonographically benign adnexal cysts an option in selected asymptomatic premenopausal women? Hum. Reprod. 20, 3231–3234 (2005).

2. Bottomley, C. & Bourne, T. Diagnosis and management of ovarian cyst accidents. Best Pract Res Clin Obstet Gynaecol 23, 711–724 (2009).

Clinical Image 22: The Stuck Sub

WELCOME BACK TO ANOTHER CLINICAL IMAGE FROM THE CASE FILES OF THE BROWN EM RESIDENCY!

Case:

HPI: A 27 year-old male with no significant past medical history presents to the ED with chest pain. The patient states about 30 minutes prior to arrival he was eating a meatball sub and got the feeling “like something was stuck in my chest”. He drank water in an attempt to push the food into his stomach but it did not help.  He then tried to self induce vomiting multiple times when he developed acute chest pain. Over the course of several minutes his chest pain worsened and was now associated with shortness of breath, nausea and dry heaving, dysphagia, and odynophagia. He also feels as though his voice sounds hoarse.  He denies dizziness, syncope, palpitations, or abdominal pain. He’s been otherwise well leading up to this.   

Vitals: T: 99.4 BP: 138/68 P: 86 R: 16 SpO2: 100% on room air

Physical examination: Patient found sitting up in the stretcher and appears extremely uncomfortable. He is cool and clammy. He has diminished breath sounds bilaterally. He is noted to have right facial and neck swelling as well as underlying crepitus. Heart sounds are regular rate and rhythm without murmur, rub, or gallop. He has no abdominal tenderness, guarding, rebound, or distention. No other pertinent exam findings.

Chest X-ray imaging was obtained:

Figure 1: Chest x-ray imaging on patient arrival

Figure 1: Chest x-ray imaging on patient arrival

What does the chest x-ray show and what is the presumptive diagnosis?

Pneumomediastinum concerning for esophageal rupture (Boerhaave’s Syndrome)

In the chest x-ray above we can see air tracking along the mediastinum (red arrows), as well as extensive subcutaneous emphysema tracking into the neck (green arrows).

Figure 2: Pneumomediastinum. Air can be seen tracking along the mediastinum (red arrows), and into the subcutaneous tissues of the neck (green arrows).

Figure 2: Pneumomediastinum. Air can be seen tracking along the mediastinum (red arrows), and into the subcutaneous tissues of the neck (green arrows).

The patient’s respiratory distress worsened and he became hypoxic requiring oxygen by NRB. Repeat chest x-ray demonstrated a left sided pneumothorax, as identified by a pleural line (arrows).

Figure 3: Left sided pneumothorax as identified by a pleural line (arrows)

Figure 3: Left sided pneumothorax as identified by a pleural line (arrows)

Some quick facts about Boerhaave’s Syndrome:

  • Full thickness perforation of the esophagus after a sudden increase in intraesophageal pressure, typically in the setting of forceful emesis.
  • Foreign body ingestion and food impaction may also result in perforation either directly or indirectly (forceful vomiting).
  • Blunt or penetrating neck trauma can also cause perforation, as well as instrumentation (endoscopy).
  • Most perforations are left sided and distal, although proximal perforations are more commonly seen with instrumentation.
  • Classic presentation is sudden onset, severe chest pain following forceful emesis. It often radiates into the back, abdomen, neck, and shoulders.
  • Patients are typically ill appearing, diaphoretic, dyspneic, and/or tachycardic.
  • On examination patients may have subcutaneous crepitus appreciated in the chest and neck. Hamman’s crunch, an audible crepitus appreciated on heart auscultation, is sometimes heard in the setting of pneumomediastinum.
  • Chest x-ray imaging may reveal pneumomediastinum, pneumoperitoneum, pneumothorax, subcutaneous air, or pleural effusions (typically left sided), although a normal x-ray does not rule out the diagnosis as mediastinal emphysema takes time to develop.
  • Patients can develop mediastinitis, pneumonitis, or peritonitis from the leakage of esophageal contents, which can rapidly develop into septic shock.
  • ED management includes resuscitation in the setting of septic shock, administration of broad spectrum antibiotics (consider anti-fungals as well), and surgical consultation.
  • Delay in diagnosis and treatment > 24 hours is associated with an increased rate in mortality.
  • Definitive management ranges from conservative for smaller tears with a more indolent clinical course, to surgical management for more severe perforations.

Pneumomediastinum versus Pneumopericardium: Does the distinction matter?  

Of course! The main importance is that pneumopericardium can develop tension physiology, whereas as pneumomediastinum typically does not. With pneumomediastinum, in addition to air tracking along the mediastinum, you can also see a pleural edge along the upper heart border. In this case, the pleural reflection is very thin, versus pneumopericardium in which there is a much thicker edge given the thickness of the pericardium. In pneumopericardium the air is confined to the pericardial space, where in pneumomediastinum it often decompresses into the subcutaneous tissue.

Case Conclusion:

Our patient underwent a left sided chest tube insertion for management of his pneumothorax followed by barium swallow to assess the severity of his perforation. He was found to have a small, focal, contained perforation in the distal esophagus.

Figure 4: Barium swallow demonstrating distal esophageal perforation (arrows).

Figure 4: Barium swallow demonstrating distal esophageal perforation (arrows).

He received broad spectrum antibiotics and was admitted to the cardiothoracic surgery service where he underwent successful conservative management.

Faculty Reviewers: Dr. Alyson McGregor and Dr. Robert Tubbs

More Reading:

https://lifeinthefastlane.com/pulmonary-puzzle-003/

https://radiopaedia.org/articles/pneumomediastinum

https://radiopaedia.org/articles/pneumothorax

References:

1: Gorrochategui, M., et. al. Pneumothorax. Radiopaedia. 2017 <https://radiopaedia.org/articles/pneumothorax>.

2: Gorrochategui, M., et. al. Pneumomediastinum. Radiopaedia. 2017. <https://radiopaedia.org/articles/pneumomediastinum>.

3: Raymond, D., Jones, C. Surgical Management of Esophageal Perforation. UptoDate. 2017.

4: Tintinalli, et. al. Emergency Medicine. 8th Edition. 2016. 328; 511-512.