Episode 5: Renal Colic, Toxicology Update & Body Packers

This Episode is a potpourri of topics –  Renal Colic, Toxicology Update & Body Packers. Dr. Lisa Thurgur and Dr. Paul Rosenberg discuss the common presentation of Renal Colic, with perspectives on the mixed evidence for medical expulsive therapy, the overuse of imaging studies and when we need to worry about the patient who presents with excruciating flank pain. Next, Dr. Thurgur gives us an update on the three most important recent advances in Toxicology for emergency physicians – Lipid Emulsion Therapy, Hydroxocobalamin and Insulin therapy for Calcium Channel Blocker toxicity. Finally, Dr. Rosenberg and Dr. Thurgur discuss the ‘ins and outs’ of body packers. They review the management of both asymptomatic and symptomatic body backers, highlighting common errors and key therapeutic moves to prevent death.

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Written Summary and blog post by Lucas Chartier, edited by Anton Helman June 2010

Cite this podcast as: Thurgur, L, Rosenberg, P, Helman, A. Renal Colic, Toxicology Update & Body Packers. Emergency Medicine Cases. June, 2010. https://emergencymedicinecases.com/episode-5-renal-colic-toxicology-update-body-packers/. Accessed [date].

There are widely varying practices when it comes to managing patients who present to the emergency department with Renal Colic. What is the best practice? How far do we need to go with our workups for renal colic patients? How good are we at diagnosing renal colic clinically? Who requires blood work? Who requires which imaging? Who needs consultation and admission? What determines the probability of a stone passing spontaneously? Who should receive medical expulsive therapy and is their good evidence for it’s use?

What’s new in Toxicology? Lipid emulsion therapy as a last ditch attempt to save the life of certain crashing poisoned patients has had a lot of attention from the Toxicology community recently.

For patients who present to the ED with smoke inhalation injuries, many of them will also suffer from cyanide poisoning. Hydroxocobalamin is a new antidote for cyanide poisoning and may be the preferred choice over traditional cyanide antidote kits.

Finally, to close our Tox Update, while high dose insulin therapy has been used for many years in patients with calcium channel blocker poisoning, it’s use requires finesse. Here, Dr. Thurgur gives us the low down on how to use high dose insulin therapy in CCB poisoning effectively.

With an increase in the number of body packers seen in Emergency Departments in recent years, we need to know how to recognize when these patients can potentially die and how to manage them. Dr. Rosenberg and Dr. Thurgur answer questions like what is the best method of GI decontamination? Is there a role for sending a urine tox screen? How do we know when all the packets are passed? What is the best way to manage seizures, severe hypertension and ventricular dysrhythmias in cocaine overdose? What are the indications for surgery in body packers? and many many more…

RENAL COLIC & NEPHROLITHIASIS

Classic triad of hematuria (absent in 10-15%, and not proportional to size of stone), flank pain and tenderness, yet there is a wide variation in clinical practice, with a propensity to over-image patients

Differential diagnoses of Hematuria

VINDICATE menmonic

• • Vascular (eg, renal vein thrombosis, AAA)
  • Infectious (eg, UTI, pyelonephritis, renal tuberculosis)
  • Neoplastic
  • Intoxicants (eg, sulpha drugs, mercury, blood transfusions)
  • Congenital (eg, Polycystic Kidney Disease – PCKD, medullary sponge kidney)
  • Autoimmune (eg, Goodpasture!s syndrome, Wegener!s granulomatosis, Lupus)
  • Trauma
  • Endocrine/metabolic (eg, nephrolithiasis)

• Also consider alternate diagnoses for renal colic: AAA, appendicitis, diverticulitis, ovarian torsion

Investigations for Renal Colic

• Urine R&M: sensitivity = 85%; sterile pyuria (WBCs alone) is possible in nephrolithiasis, but should mandate further testing if signs of infections are present (eg, bacteruria, fever, general malaise)

• Minimal workup (no blood work, no imaging) might be acceptable in young (<50y.o.) and previously healthy patients if the diagnosis is certain, especially if previously imaged (current study assessing whether this is a safe approach is ongoing)

• More workup is needed in older patients, those with comorbidities, and potentially those with first-time presentations; remember that normal creatinine level does not completely rule out severe unilateral kidney damage if the contralateral kidney is fully functional

Update 2014: Ultrasound comparison to CT for renal colic in NEJM article Abstract

Non-contrast CT scan for Renal Colic

• Very sensitive even for small stones (98%; and 95% for low-radiation protocols), but delivers significant radiation to patient (2 mSv for low-dose protocols, which is 200 times a CXR), especially given that many patients undergo repeated scans over their lifetime; a study quoted a 10% rate of other diagnoses found on CT, such as appendicitis, diverticulitis and ovarian torsion (but also incidental BPH and adenomas) – [Katz et al. Urology 2000;56(1):53-7]

• Should be considered in elderly patients, those in which an alternative diagnosis is suspected, or those with important comorbidities: solitary kidney, renal transplant and septic patients

• Can be considered in all first-time presenters, although a Scandinavian study [Lindqvist et al. Scand J Urol Nephrol 2006;40(2):119-24] showed that no adverse outcomes occurred when imaging was delayed by 2-3 weeks when the patients followed up with urology; some patients even passed their stone in this time interval, thereby avoiding imaging altogether

KUB x-ray

• Reasoning is that a KUB will identify the stones that may be amenable to lithotripsy and medical expulsive therapy (90% of stones have calcium in them and are therefore visualized)

• However, large radiation doses are involved (1/3rd of a CT scan) and the urologist might repeat it anyways before lithotripsy to see whether the stone has passed and the procedure still indicated

Ultrasound for Renal Colic

• Sensitivity is poor for detection of stones, especially in the middle 1/3rd of the ureter, but has good sensitivity to know whether interventions will be needed; consider in women if gynecological diagnoses are considered, and bedside ultrasound to rule out other diagnoses (eg, AAA)

Update 2014: NEJM study shows that ultrasound as first line imaging in renal colic is a viable strategy

Interpretation of the NEJM study on EM Literature of Note

Update 2019: A systematic review of 232 articles showed ultrasound  for suspected renal colic is reasonable for: young patients with new-onset renal colic and controlled pain, prior stones that have passed, and pregnant patients.  CT is best used in: elderly patients (regardless of stone history), those with no stone history, tenderness on exam or uncontrolled pain. A low dose CT protocol should be used.  Abstract

Management of Renal Colic

• Analgesia with NSAIDs (eg, rectal diclofenac or indomethacin, which cause a decrease in ureteric peristalsis and pelvic pressures by their prostaglandin-inhibition mediated decrease in GFR) plus opioids if necessary; patients who cannot be rendered pain-free, or who have abdominal pain or tenderness per se (as opposed to flank or groin pain) might need further investigation for other Dx

• Medical expulsive therapy (alpha-adrenergic blocker like tamsulosin 0.4mg po qd, or calcium-channel blcokers, which block ureteral smooth muscle contraction) may help reduce the time to passage of stone by 40%, especially in moderate-sized stones

• Average passage time for 4-5mm stone is 2wks; the size, location, shape and degree of obstruction of a stone determine whether it will pass (proximal stones >10mm rarely pass spontaneously)

• Patients may be instructed to strain their urine and collect the stone(s), and follow up with their GP, who can analyze the stone and recommend dietary modifications

• Referral to urologist should be considered when significant comorbidities are present, or for large- sized stones; admission should be considered for intractable pain and/or vomiting, if infection/ sepsis is present (urgent surgery may be required), or for solitary kidney or renal transplant

Update 2010: JAMA RCT suggests that tamsulosin might not expedite stone expulsion for distal ureteral stones. Full Article

Update 2015: RCT shows that medical expulsive therapy ineffective at 4 weeks post ED visit Abstract

Update 2017: Recent high-quality RCTs have raised controversy surrounding the efficacy of alpha blockers in renal colic. The latest systematic reviews, including those conducted by Raison et al. (2017) and Hollingsworth et al. (2016), incorporated these recent studies and suggested that alpha blockers may be particularly beneficial in those with larger ureteric stones (6-10 mm). However, the routine use of alpha blockers in all patients with renal colic is not supported by the current literature. Abstract 1  Abstract 2

Update 2018:  A double-blind, placebo randomized controlled trial of 512 patients demonstrated tamsulosin (0.4mg) did not significantly increase the stone passage rate compared to placebo in stones smaller than 9mm, at 28 days post ED visit. Abstract

TOXICOLOGY UPDATE

Intravenous lipid emulsion therapy

• Antidote originally used for local anesthetic toxicity, and now for lipophilic drugs such as TCAs, bupropion, beta-blockers, calcium-channel blockers, and drugs with lipid aqueous partition coefficient >2-3

• Also called TPN (total parenteral nutrition); composed of soybean oil, egg yolk, phospholipid glycerin, aluminum and water; suggested mechanism is that it pulls away the lipophilic drugs from the tissue (thus decreasing damage) and increases the energy supply of free fatty acids to the myocardium

• Indications: when other methods have failed (ACLS, usual antidotes) in setting of lipophilic drug OD

• Practical kit to use in your ED (visit www.lipidrescue.org):
  • 500cc bag of pre-packaged 20% TPN solution (stored at room T°), 50cc syringe and IV tubing
  • Use: IV bolus push of 100cc (or 1.5ml/kg, drawn out and pushed twice with 50cc syringe), then 400cc (the rest of the bag) over 15min (infusion of approximately 0.25ml/kg/min)
  • Safety concerns: no reported adverse events in the literature, but be careful in egg or soybean allergies and disorders of fat metabolism; theoretical concerns of worsening myocardial infarction and risk of fat embolus

For an in-depth review on lipid emulsion therapy check out ALiEM.

Hydroxycobolamine for cyanide treatment

• Vitamin B12 precursor, used in fire victims with smoke-inhalation injury

• Advantage over the “cyanide antidote kit”:
  • The Cyanide (CN) CN-kit contains nitrates as well as sodium thiosulfate, the former of which is dangerous in smoke-inhalation toxicity due to concomitant carbon monoxide (CO) poisoning: nitrates form methemoglobinemia (which will adequately treat CN toxicity), but also carboxyhemoglobin (because of the CO poisoning), causing high levels of abnormal hemoglobins and leading to severe hypoxia that can be life- threatening (on top of the vasodilation and hypotension caused by the nitrates)
• Hydroxycobolamine, however, does not form methemoglobinemia, and therefore is not dangerous in concomitant CN and CO poisoning

When to suspect CN on top of CO poisoning

• Fire victims covered in soot with triad of (1) hypotension, (2) metabolic acidosis (with anion-gap) and (3) elevated lactate level (>8-10) -> such patients should be treated empirically for CO and CN toxicity: hydroxycobolamine is the agent of choice, and nitrates should be avoided (the sodium thiosulfate agent also present in the CN-kit may be used as well)

• Other situations: fumigators, photographers, jewelers, nail polish use, apricot pits ingestion or iatrogenic nitroprusside overdose

• Use: Hydroxycobolamine 5g IV (needs to be diluted) over 15min (both 2.5g vials of the “Hydroxycobolamine kit” need to be given), repeated up to 15g total if necessary Pediatric dose is 70mg/kg per infusion

• Side-effects: chromoturia (red discoloration of urine, and possibly of blood drawn), possible hypertension (due to NO scavenging properties – do not treat the hypertension with nitrates)

High-dose insulin therapy in Calcium-channel blocker overdose

• Old therapy, but people remain reluctant to use in recommended doses:
  • Regular (short-acting) insulin at 1u/kg bolus (ie. 70 units!), followed by 0.5u/kg/hr infusion
• Glucose (1 vial of D50W, or 25g of dextrose) may be given concomitantly, and glucose (and potassium) should be carefully monitored given that a falling glucose level means that the CCB overdose is adequately resolving

• Mechanism: CCBs block the pancreatic insulin-releasing cells (that are calcium dependent), causing hypoinsulinemia and preventing the myocardium from using circulating glucose that it would normally use after the free fatty acids have been depleted in a state of shock

• Indications: “Slow and low” – bradycardic and hypotensive patient (due to CCB, beta-blocker, digoxin or clonidine overdose) with HR of 30-40 and sBP of 70-80; use in conjunction to standard ACLS algorithm (including atropine) and other antidotes (calcium, glucagon, fluids)

BODY PACKERS

Body packers (or internal carriers, drug mules) pre-meditatively insert packets in their rectum, vagina or by swallowing them in order to smuggle drugs across borders, then excrete the drugs and exchange it for money; body stuffers, in contrast, swallow small amounts in an unplanned way to avoid getting caught by police

Cocaine (as well as hashish, heroin, methamphetamines) is usually transported, in doses up to 100 packets of 10g (1g being the lethal dose), in well-sealed packet surrounded by layers of hard wax

Update 2015: Retrospective study suggests that a 6 hour observation period is sufficient for body packers who remain asymptomatic. Abstract

Investigations for Body Packers

• Urine tox screen: not generally recommended to guide management, as sensitivity is only 37%, and active metabolites will be detected up to 4hrs only in acute ingestions (thereby creating false negative), and up to 4-5d in chronic users (false positive); may be useful if initial urine tox screen is negative and subsequent screen becomes positive, indicating a leaking or ruptured packet

• Abdominal x-ray: 85-90% sensitive, and useful to detect bowel obstruction

• Bedside ultrasound: quick and safe, but very operator and patient dependent; consider it’s use in patients presenting in severe, unstable cocaine toxicity with no obvious history of packing

• CT abdomen or barium contrast x-ray: best sensitivity, although not 100%, so may miss some packets; may be used to confirm excretion of all packets

Clinical features of cocaine intoxication

• Cocaine’s mechanisms include re-uptake blockade of norepinephrine, dopamine and serotonin (causing hyperthermia, hypertension and tachycardia, and CNS agitation, seizures or coma), sodium-channel blockade (causing widening of QT interval and potential arrhythmias like VT), as well as endothelin production and nitrous oxide scavenging (causing vasoconstriction and vasospasm, with further hypertension and potential STEMI and aortic dissection)

• Management: Supportive care with benzodiazepines (to calm the patient, reverse the hyperthermia and hypertension, and control seizures) and active cooling of the patient; the hypertension can be treated with nitrates or phentolamine, but “-blockers (even non-selectives like labetolol) should be avoided for fear of unopposed alpha-adrenergic activity; widened QRS (>120ms) should be treated with NaHCO3 (the Na+ treats the Na+-blocking properties); VT should be treated with NaHCO3

Management of cocaine body packers

Asymptomatic patients (90% of patients):

• After patient consent obtained, use whole-body irrigation (WBI) through NG tube, at 250cc of PEGlyte q10min, up to 4L over around 2.5-3hrs

• Multi-dose activated charcoal (1g/kg) may also be considered given that it will adsorb cocaine from possibly leaking packets in the GI tract

• Patients are usually considered to have passed all packets when they have passed 3 packet-free stools (confirmatory CT scan or barium x-ray may be undergone, although not 100% sensitive)

• Patients may be discharged in the hands of RCMP officers (with clear instructions on what symptoms to look for and when to come back) before all packets have passed, after a period of 24hrs

Symptomatic patients:

• Symptomatic patients need aggressive decontamination treatment as above, as well as cocaine- specific detoxification methods (benzodiazepines, cooling, nitrates/phentolamine, NaHCO3)

• Immediate Surgical consult mandated, as symptomatic patients need emergent laparotomy

Indications for surgical consult:

Symptomatic patient, bowel obstruction, failure to pass all packets (possibly due to impaction) either after the 24-hr observation period, or after a 6-day trial while in police’s facilities!

For more on renal colic on EM Cases:
BEEM Cases 2 – Renal Colic Imaging, Analgesia, Fluids & Medical Expulsive Therapy
Journal Jam 3 – Ultrasound vs CT for Renal Colic

For more on toxicology on EM Cases:
Episode 90 – Low and Slow Poisoning

Dr. Helman, Dr. Rosenberg and Dr. Thurgur have no conflicts of interest to declare.