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Altered LOC – a case of thyroid storm; EM Reflections

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Altered LOC – a case of thyroid storm; EM Reflections February 2022

Authored and Copyedited by Dr. Mandy Peach

Thanks to Dr. Joanna Middleton for leading the discussion

All cases are imaginary but highlight important learning points

Case

An elderly male is brought to the ED by EMS after being found wandering the streets downtown. A local resident was concerned and called 911. He looks disheveled and is dressed in light clothing despite the cold weather. He has no identification. He is agitated but not aggressive. He is speaking short sentences, with recognizable words, but is nonsensical. He can give no identifying information.

His vitals are 90/62 HR 132 RR 22 O2 93% RA T – 40.1°C.  Gluc 12

On exam he has no obvious neurological deficits but will not follow command for strength or coordination testing. He walked unaided into the department. His pupils are 3mm and reactive bilaterally. He will not follow your finger for oculomotor testing. He does have some dried blood on his right ear –  there appears to be a scalp laceration superior to the ear. There are no other signs of head injury. His neck appears to be supple as you draw his attention to things in the room. Cardiac, abdominal and skin exam are non-contributory. You hear expiratory crackles to the right lung base.

Patients with an altered level of consciousness, especially in the geriatric population, are becoming increasingly more common. What is an easy mnemonic to remember the differential1?

You order a broad scope of investigations including a tox screen, TSH, LFT’s and coags, VBG, blood and urine cultures and CXR.

Is a CT head always a requirement6?

No, CT brain scan should not be used routinely but should be considered in patients with the following indications:

New focal neurological signs
Reduced level of consciousness not adequately explained by another cause
History of recent falls
Head injury
Anticoagulation therapy.

While that is pending, what is your approach to management?

From an airway perspective they are talking, they are maintaining their oxygen saturations. There is borderline hypotensive and tachycardia with a fever.

Initially you decide to cover for sepsis, potentially a respiratory source given your findings on exam. You obtain bilateral IV access, start fluids and antibiotics post cultures. Tylenol is given for fever. You apply oxygen as saturations are low 90’s.

Although infectious causes are common there are a vast number of presentations to consider with a febrile, altered patient2.

  • Heat stroke
  • CNS causes other than infectious: ICH, Stroke, Status Epilepticus
  • Thyroid storm
  • Lithium toxicity
  • Salicylate toxicity
  • Anticholinergic toxicity
  • Alcohol and Benzo Withdrawal
  • Malignant Hyperthermia
  • Neuroleptic Malignant Syndrome
  • Serotonin Syndrome

Chances are this is sepsis so you initiate your therapy and cognitively unload yourself.

Portable CXR is done showing potentially a slight haziness in the right lower lobe. No pulmonary edema. It’s not a slam dunk infiltrate, but common things being common you still suspect sepsis.

The VBG comes back first – its normal. WBC is also back and it is upper end of normal – unexpected given how febrile this patient was. Now you’re starting to question your diagnosis – you go back to your differential for a febrile, altered patient. You decide to add lithium level to your work up as well LFT’s and extended lytes.  Heat stroke is unlikely given the cool weather ongoing this week. Otherwise, you can consider CT head for CNS causes but the remainder will require some sort of collateral history.

While you are mulling this over there is a call from the lab – they are giving a verbal for a critically low TSH level and critically high T4 levels.

You are worried this patient is in thyroid storm.

What are signs/symptoms of thyroid storm3,5?

  • High fever
  • Altered mentation: ranges from agitation and delirium to stupor and coma
  • Cardiovascular instability: tachycardia (often exceeding 140 bpm), hypotension and potentially arrythmia and cardiovascular collapse
  • GI/hepatic symptoms – nausea/vomiting, abdominal pain

 

Physical exam can reveal the following:

  • Goiter
  • Lid lag
  • Tremor
  • Warm, moist skin
  • Ophthalmopathy4 (in presence of Grave’s disease)

Does the degree of hyperthyroidism matter? Ie. The severity of the lab disturbance3?

No, the levels of TSH and and T4/T3 are typically similar to those seen in uncomplicated thyrotoxicosis.

Are there any other lab derangements that would help point in the direction of thyroid storm3?

  • mild hyperglycemia due to catecholamine-induced inhabitation of insulin release and increased breakdown of glucose stores
  • mild hypercalcemia due to hemoconcentration and increased bone resorption.
  • abnormal liver function tests as thyroid hormones are metabolized in the liver
  • leukocytosis or leukopenia

Given that lab values can be similar to thyrotoxicosis are there any criteria to diagnose thyroid storm vs impeding thyroid storm?

No validated criteria exist, however there are scoring systems in circulation similar to this one3.

A value > 45 confirms thyroid storm, a value between 25-45 is concerning for impeding thyroid storm.

You score your patient at 65, assuming that the pneumonia is the precipitating factor. You feel confident thyroid storm is the diagnosis.

Where you wrong to initiate treatment for sepsis5?

Typically for thyroid storm the patient has a history of hyperthyroidism but is tipped into instability with a precipitating factor. Given your clinical findings and CXR this patient potentially has pneumonia that precipitated his presentation. However, if infection doesn’t seem to be the most likely trigger it is not necessary to cover with antibiotics. Consider others causes.

Other than infection what are other risk factors for thyroid storm3,5?

  • Recent surgery
  • Trauma
  • Iodine load ie. Initiating amiodarone treatment
  • Pregnancy/toxemia of pregnancy
  • PE
  • Acute MI
  • DKA
  • Hyperemesis
  • CVA

Your patient is becoming increasingly agitated – what is the management plan5?

Benzos are the drug of choice to manage agitation in this patient. Other supportive therapies include fluids, cooling and monitoring and treating electrolyte/glucose disturbance as needed. However now that the diagnosis is confirmed, treating the cause of the agitation can now be initiated.

What is the treatment for thyroid storm? And the order given?

You reassess your patient after the tylenol, fluid bolus, benzos and antibiotics.

BP 102/62 HR 120, RR20 O2 98% on 1L NC, 39.9°C

You commence cooling and begin beta-blockade with propranolol. You continue fluids and plan to treat with methimazole as currently the patient is not in cardiovascular collapse. You treat with potassium iodide 1 hour later. ICU are now there to do a consult and admit.

Take home points –

  • Consider a broad differential with any altered patient, remember AEIOU
  • A febrile, altered patient isn’t always sepsis! See this great algorithm for differential as well as treatment

  • Untreated thyroid storm has a high mortality – add TSH to your investigations and remember the order of treatment matters to prevent worsening thyrotoxicosis.

 

References & further reading

  1. Morgenstern, J. 2016. First10EM AEIOU TIPS mnemonic for altered mental status. Accessed June 21, 2022 from https://first10em.com/unconscious/first10em-aeiou-tips-mnemonic-for-altered-mental-status/
  2. Helman, A. Long, B. Khatib, N. Strayer, R. Hensley, J. Foohey, S. Petrosoniak, A. EM Quick Hits 36 – Surviving Sepsis, Angle Closure Glaucoma, Bougies, Frostbite, Hot/Altered Patient, Central Cord Syndrome. Emergency Medicine Cases. March 2022. https://emergencymedicinecases.com/em-quick-hits-march-2022/. Accessed [June 21, 2022].
  3. Ross, D (2021). Thyroid Storm. UptoDate. Accessed June 21 2022 from https://www.uptodate.com/contents/thyroid-storm?search=thyroid%20storm&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H57436952
  4. Image from https://www.mayoclinic.org/diseases-conditions/graves-disease/symptoms-causes/syc-20356240
  5. 2017. Thyroid and Adrenal Disorders. CRACKCase E128. CanadiEM. Assessed July 6, 2022 from https://canadiem.org/crackcast-e128-thyroid-adrenal-disorders/
  6. Altered Mental Status – Delirium. Chang A, Marsden J. 2020. Point of Care Emergency Summary, BC Emergency Medicine Network.Assessed July 6, 2022 from https://www.bcemergencynetwork.ca/clinical_resource/altered-mental-status-delirium/
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