Adrenergic storm

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Adrenergic storm
Other namesSympathomimetic toxicity
Sympathomimetic toxidrome
Complications Tachycardia, hypertension
Causes Cocaine, stimulant abuse, subarachnoid hemorrhage, methamphetamine, foods high in tyramine, rabies
Treatment diazepam, benzodiazepines, beta blockers, anti-hypertensives

An adrenergic storm is a sudden and dramatic increase in serum levels of the catecholamines adrenaline and noradrenaline (also known as epinephrine and norepinephrine respectively), with a less significant increase in dopamine transmission. It is a life-threatening condition because of extreme tachycardia and hypertension, and is especially dire for those with prior heart problems. If treatment is prompt, prognosis is good; typically large amounts of diazepam or other benzodiazepines are administered alongside beta blockers. Beta blockers are contraindicated in some patients, so other anti-hypertensive medication such as clonidine may be used. [1] Antipsychotics are also used to treat the most severe psychiatric reactions such as psychosis, paranoia or terror, after their use was formerly discouraged because of their potential to prolong the QT interval; however, more recent research performed since 2019 has revealed that this and other severe side effects are rare and their occurrence does not warrant banning antipsychotics from the treatment of adrenergic crises for which they can be extremely useful. [2] [3] [4] [5] [6] [7] [8]

Contents

Adrenergic storms are usually caused by overdoses of stimulants, especially cocaine or methamphetamine, or eating foods high in tyramine while taking monoamine oxidase inhibitors. [9] A subarachnoid hemorrhage can also cause an adrenergic storm. [9] A catecholamine storm is part of the normal course of rabies infection, and is responsible for the severe feelings of agitation, terror, and dysautonomia present in the pre-coma stage of the disease. [10]

Signs and symptoms

The behavioral symptoms are similar to those of an amphetamine, cocaine or caffeine overdose. Overstimulation of the central nervous system results in a state of hyperkinetic movement and unpredictable mental status including mania, rage and suicidal behavior; hyperthermia is also prominently present. [11] Delirium can also be present but rarely. [12]

Physical symptoms are more serious and include heart arrhythmias as well as outright heart attack or stroke in people who are at risk of coronary disease. Breathing is rapid and shallow while both pulse and blood pressure are dangerously elevated. [13]

Other complications would include rhabdomyolysis, a breakdown of the voluntary muscles because of the excessive physical movement, causing the components of the muscle, most notably myoglobin, to be released into the bloodstream and then clog the kidneys, causing renal failure. [14] In all, rhabdomyolysis is especially common in adrenergic storms caused by the use of stimulant drugs, most notably those of the phenethylamines such as cathinones or amphetamines. [15]

Causes

There are several known causes of adrenergic storms; in the United States, cocaine overdose is the leading cause. [16] Any stimulant drug has the capacity to cause this syndrome if taken in sufficient doses, but even non-psychotropic drugs can very rarely provoke a reaction. [17]

Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the enzyme monoamine oxidase. This enzyme is responsible for breaking down many compounds; basically, anything with a primary amine moiety is likely to be oxidized by monoamine oxidase. An important substrate of the enzyme MAO is tyramine. MAOIs inhibit the enzyme either reversibly, in which MAO is inhibited only until the drug is cleared from the system, or irreversibly, in which the substrate binds permanently to the enzyme, rendering it inactive and effectively destroying it. Irreversible MAOIs are potentially more dangerous, because the body takes about two weeks to regenerate MAO enzymes to functional levels. [18] Two subtypes of MAO exist: MAO-A and MAO-B; this is relevant to adrenergic storms, as there are significant differences between the two types, such as their differential expression throughout the body, and range of substrates. While both MAO-A and MAO-B metabolize tyramine, only MAO-A is present in the gastrointestinal tract and singularly metabolizes the majority of consumed tyramine. [9] (The small portion normally passing into circulation is mostly degraded in the liver where both MAO types act. [9] )

Subarachnoid hemorrhage is an extremely serious condition in which a neural membrane is breached and the brain itself is compromised. The onset is sudden, described as "the worst headache of one's life," and many grave symptoms follow. Adrenergic storm is often present among these symptoms, and is responsible for some of the dangers, both long-term and short, of subarachnoid hemorrhage adrenergic storm, through a complex cascade of processes starting with the movement of subarachnoid blood into the brain. Apparently, as the intracranial pressure increases, the brain is squeezed and catecholamines are forced out of their vesicles into the synapses and extracellular space. [19]

Rare causes

Rarely, a pheochromocytoma (tumor of the medullar tissue of the adrenal glands, which are located anterior to the kidney), may result in an adrenergic storm. [20] This type of tumor is not common to begin with, and furthermore, the subtype that can cause massive adrenaline release is rarer still. Patients with pheochromocytoma can unexpectedly fly into a rage or sink into trembling fear, possibly dangerous to themselves and others as their judgment is impaired, their senses and pain threshold are heightened, and the level of the adrenaline in their bloodstream is more than most people ever experience; pheochromocytoma can, very rarely, kill by internal adrenaline overdose. [21] But overall, adrenergic storm is an uncommon but certainly not rare phenomenon associated with the also uncommon condition of pheochromocytoma. [22]

Diagnosis

Differential diagnosis

Because the adrenergic storm overlaps with so many other similar conditions, such as hypertensive crises, stimulant intoxication or overdose, or even panic attack, and because the treatments for these overlapping conditions are largely alike, it is not necessary to obtain a differential and definitive diagnosis before initiating treatment. However, analysis of the patient's medical history, checked against the possible causes of the adrenergic storm such as those above, should be done, because some adrenergic storms can be caused by serious underlying conditions. [10] If a patient has an adrenergic storm and all or most of the other factors are ruled out, the adrenergic storm could lead to the discovery of a pheochromocytoma, which can become malignant. However, not all cases of adrenergic storm have an identifiable cause. Like a seizure, sometimes a patient has a single one, or perhaps a few, and then does not for the rest of their life. [23] The mechanisms of idiopathic adrenergic storm are very poorly understood.

Serotonin syndrome, in which an excess of serotonin in the synapses causes a similar crisis of hypertension and mental confusion, could be confused with an adrenergic storm. Serotonin, being a tryptamine (non-catecholamine) involved in higher brain functions, can cause dangerous hypertension and tachycardia from its effects on the sympathetic nervous system. [23] Symptoms caused by excessive adrenergic signalling can occur alongside those of serotonergic signalling. One example would be: overdose of drug(s) influencing multiple targets including serotonin, and adrenergic systems, with concurrent MAOI use). Abnormal echocardiograms, or chest pain are indicative of adrenergic crisis. [23] On the other hand, uncontrollable slow, rhythmic, and/or jerky movements, contractions and tension-often in every part of the body, dangerously high fever, eye rolling, and bruxism are more indicative of serotonin syndrome. [10] [24]

Treatment

If there is evidence of overdose or it is suspected, the patient should be given gastric lavage, activated charcoal, or both; this could make the difference between life and death in a close situation. [25] It can however aggravate the patient which should be taken into account. [10]

The first line treatments are diazepam and a non-selective beta blocker; other antihypertensive drugs may also be used. It is important to note that not all benzodiazepines and beta blockers are safe to use in an adrenergic storm; for instance, alprazolam and propranolol; [10] alprazolam weakly agonizes dopamine receptors and causes catecholamine release while propranolol mildly promotes some catecholamine release - each worsening the condition. [23]

Antipsychotics are also used to treat the psychiatric symptoms such as aggression, agitation, psychosis, paranoia or anxiety. Originally, the use of antipsychotics was discouraged because of their potential to prolong the QT interval; [3] however, newer research has revealed that their careful use does not carry the potential for any significant side effects and today their judicious use is encouraged. [3] [2] [4] [26]

Adrenergic storms are often idiopathic in nature; however if there is an underlying condition, then that must be addressed after bringing the heart rate and blood pressure down. [1]

See also

Related Research Articles

<span class="mw-page-title-main">Monoamine oxidase inhibitor</span> Type of medication

Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as effective antidepressants, especially for treatment-resistant depression and atypical depression. They are also used to treat panic disorder, social anxiety disorder, Parkinson's disease, and several other disorders.

<span class="mw-page-title-main">Monoamine oxidase</span> Family of enzymes

Monoamine oxidases (MAO) are a family of enzymes that catalyze the oxidation of monoamines, employing oxygen to clip off their amine group. They are found bound to the outer membrane of mitochondria in most cell types of the body. The first such enzyme was discovered in 1928 by Mary Bernheim in the liver and was named tyramine oxidase. The MAOs belong to the protein family of flavin-containing amine oxidoreductases.

<span class="mw-page-title-main">Serotonin syndrome</span> Symptoms caused by an excess of serotonin in the central nervous system

Serotonin syndrome (SS) is a group of symptoms that may occur with the use of certain serotonergic medications or drugs. The symptoms can range from mild to severe, and are potentially fatal. Symptoms in mild cases include high blood pressure and a fast heart rate; usually without a fever. Symptoms in moderate cases include high body temperature, agitation, increased reflexes, tremor, sweating, dilated pupils, and diarrhea. In severe cases, body temperature can increase to greater than 41.1 °C (106.0 °F). Complications may include seizures and extensive muscle breakdown.

A psychiatric or psychotropic medication is a psychoactive drug taken to exert an effect on the chemical makeup of the brain and nervous system. Thus, these medications are used to treat mental illnesses. These medications are typically made of synthetic chemical compounds and are usually prescribed in psychiatric settings, potentially involuntarily during commitment. Since the mid-20th century, such medications have been leading treatments for a broad range of mental disorders and have decreased the need for long-term hospitalization, thereby lowering the cost of mental health care. The recidivism or rehospitalization of the mentally ill is at a high rate in many countries, and the reasons for the relapses are under research.

<span class="mw-page-title-main">Catecholamine</span> Class of chemical compounds

A catecholamine is a monoamine neurotransmitter, an organic compound that has a catechol and a side-chain amine.

<span class="mw-page-title-main">Phenelzine</span> Antidepressant

Phenelzine, sold under the brand name Nardil, among others, is a non-selective and irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine family which is primarily used as an antidepressant and anxiolytic to treat depression and anxiety. Along with tranylcypromine and isocarboxazid, phenelzine is one of the few non-selective and irreversible MAOIs still in widespread clinical use.

<span class="mw-page-title-main">Phenethylamine</span> Organic compound, a stimulant in humans

Phenethylamine (PEA) is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain, phenethylamine regulates monoamine neurotransmission by binding to trace amine-associated receptor 1 (TAAR1) and inhibiting vesicular monoamine transporter 2 (VMAT2) in monoamine neurons. To a lesser extent, it also acts as a neurotransmitter in the human central nervous system. In mammals, phenethylamine is produced from the amino acid L-phenylalanine by the enzyme aromatic L-amino acid decarboxylase via enzymatic decarboxylation. In addition to its presence in mammals, phenethylamine is found in many other organisms and foods, such as chocolate, especially after microbial fermentation.

<span class="mw-page-title-main">Tranylcypromine</span> Irreversible non-selective MAO inhibitor Antidepressant drug

Tranylcypromine, sold under the brand name Parnate among others, is a monoamine oxidase inhibitor (MAOI). More specifically, tranylcypromine acts as nonselective and irreversible inhibitor of the enzyme monoamine oxidase (MAO). It is used as an antidepressant and anxiolytic agent in the clinical treatment of mood and anxiety disorders, respectively. It is also effective in the treatment of ADHD.

<span class="mw-page-title-main">Tyramine</span> Chemical compound

Tyramine, also known under several other names, is a naturally occurring trace amine derived from the amino acid tyrosine. Tyramine acts as a catecholamine releasing agent. Notably, it is unable to cross the blood-brain barrier, resulting in only non-psychoactive peripheral sympathomimetic effects following ingestion. A hypertensive crisis can result, however, from ingestion of tyramine-rich foods in conjunction with the use of monoamine oxidase inhibitors (MAOIs).

Atenolol is a beta blocker medication primarily used to treat high blood pressure and heart-associated chest pain. Although used to treat high blood pressure, it does not seem to improve mortality in those with the condition. Other uses include the prevention of migraines and treatment of certain irregular heart beats. It is taken orally or by intravenous injection. It can also be used with other blood pressure medications.

<span class="mw-page-title-main">Sympathomimetic drug</span> Substance that mimics effects of catecholamines

Sympathomimetic drugs are stimulant compounds which mimic the effects of endogenous agonists of the sympathetic nervous system. Examples of sympathomimetic effects include increases in heart rate, force of cardiac contraction, and blood pressure. The primary endogenous agonists of the sympathetic nervous system are the catecholamines, which function as both neurotransmitters and hormones. Sympathomimetic drugs are used to treat cardiac arrest and low blood pressure, or even delay premature labor, among other things.

<span class="mw-page-title-main">Selegiline</span> Monoamine oxidase inhibitor

Selegiline, also known as L-deprenyl and sold under the brand names Eldepryl, Zelapar, and Emsam among others, is a medication which is used in the treatment of Parkinson's disease and major depressive disorder. It has also been studied for a variety of other indications, but has not been formally approved for any other use. The medication in the form licensed for depression has modest effectiveness for this condition that is similar to that of other antidepressants. Selegiline is provided as a swallowed tablet or capsule or an orally disintegrating tablet (ODT) for Parkinson's disease and as a patch applied to skin for depression.

<span class="mw-page-title-main">Isocarboxazid</span> Antidepressant

Isocarboxazid is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class used as an antidepressant. Along with phenelzine and tranylcypromine, it is one of only three classical MAOIs still available for clinical use in the treatment of psychiatric disorders in the United States, though it is not as commonly employed in comparison to the others.

<span class="mw-page-title-main">Moclobemide</span> Antidepressant

Moclobemide, sold under the brand names Amira, Aurorix, Clobemix, Depnil and Manerix among others, is a reversible inhibitor of monoamine oxidase A (RIMA) drug primarily used to treat depression and social anxiety. It is not approved for use in the United States, but is approved in other Western countries such as Canada, the UK and Australia. It is produced by affiliates of the Hoffmann–La Roche pharmaceutical company. Initially, Aurorix was also marketed by Roche in South Africa, but was withdrawn after its patent rights expired and Cipla Medpro's Depnil and Pharma Dynamic's Clorix became available at half the cost.

<span class="mw-page-title-main">Rasagiline</span> Chemical compound

Rasagiline, sold under the brand name Azilect among others, is a medication which is used in the treatment of Parkinson's disease. It is used as a monotherapy to treat symptoms in early Parkinson's disease or as an adjunct therapy in more advanced cases. The drug is taken by mouth.

<span class="mw-page-title-main">Pargyline</span> Chemical compound

Pargyline, sold under the brand name Eutonyl among others, is a monoamine oxidase inhibitor (MAOI) medication which has been used to treat hypertension but is no longer marketed. It has also been studied as an antidepressant, but was never licensed for use in the treatment of depression. The drug is taken by mouth.

<span class="mw-page-title-main">Monoamine oxidase B</span> Protein-coding gene in the species Homo sapiens

Monoamine oxidase B, also known as MAO-B, is an enzyme that in humans is encoded by the MAOB gene.

Mary Lilias Christian Bernheim was a British biochemist best known for her discovery of the enzyme tyramine oxidase, which was later renamed as monoamine oxidase. Bernheim discovered the enzyme system of tyramine oxidase during her doctorate research at the University of Cambridge in 1928, and her research has been referred to as "one of the seminal discoveries in twentieth century neurobiology".

Peripherally selective drugs have their primary mechanism of action outside of the central nervous system (CNS), usually because they are excluded from the CNS by the blood–brain barrier. By being excluded from the CNS, drugs may act on the rest of the body without producing side-effects related to their effects on the brain or spinal cord. For example, most opioids cause sedation when given at a sufficiently high dose, but peripherally selective opioids can act on the rest of the body without entering the brain and are less likely to cause sedation. These peripherally selective opioids can be used as antidiarrheals, for instance loperamide (Imodium).

References

  1. 1 2 King, Andrew; Dimovska, Mirjana; Bisoski, Luke (January 2018). "Sympathomimetic Toxidromes and Other Pharmacological Causes of Acute Hypertension". Current Hypertension Reports. 20 (1): 8. doi: 10.1007/s11906-018-0807-9 . PMID   29478133. S2CID   3530495.
  2. 1 2 Malashock, Hannah R.; Yeung, Claudia; Roberts, Alexa R.; Snow, Jerry W.; Gerkin, Richard D.; O’Connor, Ayrn D. (April 2021). "Pediatric Methamphetamine Toxicity: Clinical Manifestations and Therapeutic Use of Antipsychotics—One Institution's Experience". Journal of Medical Toxicology. 17 (2): 168–175. doi:10.1007/s13181-020-00821-4. PMC   8017059 . PMID   33442836.
  3. 1 2 3 Connors, Nicholas J.; Alsakha, Ahmed; Larocque, Alexandre; Hoffman, Robert S.; Landry, Tara; Gosselin, Sophie (October 2019). "Antipsychotics for the treatment of sympathomimetic toxicity: A systematic review". The American Journal of Emergency Medicine. 37 (10): 1880–1890. doi:10.1016/j.ajem.2019.01.001. PMID   30639129. S2CID   58631990.
  4. 1 2 Richards, John R.; Derlet, Robert W. (December 2019). "Another dogma dispelled? Antipsychotic treatment of sympathomimetic toxicity". The American Journal of Emergency Medicine. 37 (12): 2256–2257. doi:10.1016/j.ajem.2019.05.013. PMID   31088749. S2CID   155090660.
  5. Goldstein, Scott; Richards, John R. (1 January 2020). Richards, John R. (ed.). Sympathomimetic Toxicity. Treasure Island, Florida, United States of America: StatPearls Publishing. PMID   28613508 . Retrieved 28 July 2021 via NCBI (National Center for Biotechnology Information)/NLM (United States National Library of Medicine).
  6. Connors, Nicholas J.; Alsakha, Ahmed; Larocque, Alexandre; Hoffman, Robert S.; Landry, Tara; Gosselin, Sophie (December 2019). "Evidence over dogma and anecdotes". The American Journal of Emergency Medicine. 37 (12): 2257. doi:10.1016/j.ajem.2019.05.014. PMID   31128936. S2CID   167206288.
  7. Lam, Vivian; Shaffer, Robert W. (2017). "8. Management of Sympathomimetic Overdose Including Designer Drugs". In Hyzy, Robert C.; McSparron, Jakob (eds.). Evidence-Based Critical Care: A Case Study Approach (2nd ed.). Cham, Switzerland: Springer Nature. p. 65. doi:10.1007/978-3-030-26710-0. ISBN   978-3030267094. S2CID   202810365 via Google Books.
  8. Roberts, James R. (1 January 2016). Roberts, James R.; Hoffman, Lisa; Nace, Lynn; Gibson, Grace (eds.). "InFocus: Treating Sympathomimetic Toxicity". Emergency Medicine News. 38 (1). Wolters Kluwer Health, Inc. (Lippincott Williams & Wilkins): 10–12. doi:10.1097/01.EEM.0000476273.56614.28. Archived from the original on 10 January 2016. Retrieved 28 July 2021.
  9. 1 2 3 4 Finberg, John P.M.; Gillman, Ken (2011). "Selective inhibitors of monoamine oxidase type B and the "cheese effect"". Monoamine Oxidase and their Inhibitors. International Review of Neurobiology. Vol. 100. pp. 169–190. doi:10.1016/B978-0-12-386467-3.00009-1. ISBN   978-0-12-386467-3. PMID   21971008.
  10. 1 2 3 4 5 Holstege, Christopher P.; Borek, Heather A. (October 2012). "Toxidromes". Critical Care Clinics. 28 (4): 479–498. doi:10.1016/j.ccc.2012.07.008. PMID   22998986.
  11. Suchard, Jeffrey R. (August 2007). "Recovery from Severe Hyperthermia (45 degrees C) and Rhabdomyolysis Induced by Methamphetamine Body-Stuffing". The Western Journal of Emergency Medicine. 8 (3): 93–95. PMC   2672216 . PMID   19561691.
  12. von Braun, Amrei; Bühler, Annette; Yuen, Bernd (May 2012). "Severe thyrotoxicosis: a rare cause of acute delirium". Internal and Emergency Medicine. 7 (S1): 27–28. doi:10.1007/s11739-011-0572-0. PMID   21451989.
  13. Mayersohn, Michael; Guentert, Theodor W. (November 1995). "Clinical Pharmacokinetics of the Monoamine Oxidase-A Inhibitor Moclobemide*". Clinical Pharmacokinetics. 29 (5): 292–332. doi:10.2165/00003088-199529050-00002. PMID   8582117.
  14. Lombard, J.; Wong, B.; Young, J. H. (April 1988). "Acute renal failure due to rhabdomyolysis associated with cocaine toxicity". The Western Journal of Medicine. 148 (4): 466–468. PMC   1026152 . PMID   3388853.
  15. O’Connor, Ayrn D.; Padilla-Jones, Angie; Gerkin, Richard D.; Levine, Michael (June 2015). "Prevalence of Rhabdomyolysis in Sympathomimetic Toxicity: a Comparison of Stimulants". Journal of Medical Toxicology. 11 (2): 195–200. doi:10.1007/s13181-014-0451-y. PMC   4469713 . PMID   25468315.
  16. Jones, Chris; Owens, Dave (June 1996). "The recreational drug user in the intensive care unit: a review". Intensive and Critical Care Nursing. 12 (3): 126–130. doi:10.1016/s0964-3397(96)80418-6. PMID   8717812.
  17. Gupta, Anish; Omender, Singh; et al. (Foreword by Fahrad N. Kapadia) (31 May 2019). "Chapter 8: Sympathomimetic Drugs". In Singh, Omender; Juneja, Deven (eds.). Principles and Practice of Critical Care Toxicology. New Delhi, India: Jaypee Brothers Medical Publishers. p. 84. ISBN   9789352706747 via Google Books.
  18. Yamada, M (January 2004). "Clinical Pharmacology of MAO Inhibitors: Safety and Future". NeuroToxicology. 25 (1–2): 215–221. Bibcode:2004NeuTx..25..215Y. doi:10.1016/S0161-813X(03)00097-4. PMID   14697896.
  19. Rodman, Karen A.; Awad, Issam A. (1993). "CHAPTER 2: Clinical Presentation". In Awad, Isam A.; Barrow, Daniel L.; Miller, Linda S. (eds.). Cuerrent Management of Cerebral Aneurysms. Neurosurgical Topics. Vol. 15. Rolling Meadows, Illinois, United States of America: AANS Publications Committee (American Association of Neurological Surgeons (AANS)). pp. 21–43. ISBN   9781879284425 via Google Books.
  20. Tevosian, Sergei G.; Ghayee, Hans K. (December 2019). "Pheochromocytomas and Paragangliomas". Endocrinology and Metabolism Clinics of North America. 48 (4): 727–750. doi:10.1016/j.ecl.2019.08.006. PMID   31655773.
  21. Whalen, Raymond K.; Althausen, Alex F.; Daniels, Gilbert H. (January 1992). "Extra-Adrenal Pheochromocytoma". Journal of Urology. 147 (1): 1–10. doi:10.1016/s0022-5347(17)37119-7. PMID   1729490.
  22. Manger, William M. (August 2006). "An Overview of Pheochromocytoma: History, Current Concepts, Vagaries, and Diagnostic Challenges". Annals of the New York Academy of Sciences. 1073 (1): 1–20. Bibcode:2006NYASA1073....1M. doi:10.1196/annals.1353.001. PMID   17102067. S2CID   21423113.
  23. 1 2 3 4 Williams, Robert H.; Erickson, Timothy; Broussard, Larry A. (1 September 2000). Bertholf, Roger L. (ed.). "Evaluating sympathomimetic intoxication in an emergency setting". Laboratory Medicine. 31 (9). Chicago, Illinois, United States of America: American Society for Clinical Pathology (ASCP)/Oxford University Press: 497–508. doi: 10.1309/WVX1-6FPV-E2LC-B6YG . OCLC   423776763.
  24. Vizcaychipi, M.P.; Walker, S.; Palazzo, M. (December 2007). "Serotonin syndrome triggered by tramadol". British Journal of Anaesthesia. 99 (6): 919. doi:10.1093/bja/aem325. PMID   18006535.
  25. Hughes, Joshua D.; Rabinstein, Alejandro A. (June 2014). "Early Diagnosis of Paroxysmal Sympathetic Hyperactivity in the ICU". Neurocritical Care. 20 (3): 454–459. doi:10.1007/s12028-013-9877-3. PMID   23884511. S2CID   6433256.
  26. Jerry, Jason; Collins, Gregory; Streem, David (April 2012). "Synthetic legal intoxicating drugs: The emerging 'incense' and 'bath salt' phenomenon". Cleveland Clinic Journal of Medicine. 79 (4): 258–264. doi:10.3949/ccjm.79a.11147. PMID   22473725.