Makindo Medical Notes

Related Subjects: |Thyrotoxicosis and Hyperthyroidism |Thyroid Storm - Thyrotoxic crisis |Graves Disease (Thyrotoxicosis) |Amiodarone and Thyroid disease |Thyroid Surgery (Thyroidectomy) |Hypothyroidism |Hashimoto's thyroiditis |DeQuervain's thyroiditis |Subacute Thyroiditis |Thyroid nodule |Congenital Hypothyroidism |Thyroid Function Tests and antibodies |Post partum thyroiditis |Sick Euthyroid Syndrome |Thyroid Exam (OSCE) |Thyroid Gland anatomy and Physiology |Thyroid Cancer

Thyroid storm is a rare endocrine emergency but is associated with high mortality. Avoid Aspirin as an anti-pyretic as it can displace thyroxine from its protein binding and increase its biological effects

About

• Endocrine emergency first described in 1926
• Rare and life threatening condition due to excess T3/T4
• Seen in 2% of those with hyperthyroidism and Mortality is quoted as 10-20%

Aetiology

• Graves' disease the commonest pathology
• Thyroiditis , thyroid nodular disease
• Post thyroidectomy for thyrotoxic state

Precipitant

• Recent minor/major illness, infection, MI, Diabetic Ketoacidosis
• Radioactive iodine treatment, Stopping antithyroid treatment e.g. Carbimazole
• Surgery and related stress, childbirth, trauma
• Biological agents such as interleukin-2 and a-interferon have been reported to induce thyroid storm

Clinical

• Tachycardia, sweating, pyrexia > 40°C and agitation
• Delirium - hypo or hyperactive, psychosis
• Symptoms of hyperthyroidism - weight loss, tremor
• Patient may also be lethargic and apathetic especially elderly
• Palpitations AF, High output Heart failure
• Abdominal pain may be seen as "acute abdomen"
• Jaundice, Goitre, Eye signs suggest Graves' disease

Differential

• Hyperactive or any form of delirium
• Septic shock
• Anti cholinergic toxicity
• Delirium tremens
• Acute pulmonary oedema
• Apathetic cases can be subtle

Investigations

• U&E, FBC, ESR/CRP and hypercalcaemia is seen
• Send T3 and T4 and TSH for later analysis
• CXR if infection suspected
• ECG to document AF or other arrhythmias
• Deranged LFTs
• Thyroid autoantibodies can be sent anytime

Key "5 Bs" Issues

• Block synthesis (i.e. antithyroid drugs)
• Block release (i.e. Iodine)
• Block T4 into T3 conversion (i.e. high-dose propylthiouracil [PTU], propranolol, corticosteroid and, rarely, amiodarone)
• Beta-blocker
• Block enterohepatic circulation (i.e. cholestyramine).

Management

• Manage ABC's, IV access, Cool, IV fluids and O₂ if hypoxic. Involving ITU/HDU
• IV fluids ( 1 L N-Saline over 2-4 hrs to start) and correct U&E and dehydration
• IV Paracetamol can be tried but avoid Aspirin.
• Sedate with Chlorpromazine 50-100mg PO/IM every 6 hours as needed, has the additional benefit of reducing body temperature through effects on central thermoregulation. Can also use Diazepam.
• Beta Blockers e.g. Propranolol 60-80 mg 6h IV/PO/NG to rate control tachycardia/AF is useful. Avoid if asthmatic.
• Consider Pabrinex if any nutritional concerns
• Antithyroid therapy
  • Carbimazole 20 mg PO/NG and repeated 6 hourly
  • Propylthiouracil 200 mg TDS PO/NG then 250 mg every 6 hours. It reduces T4 to T3 conversion.
  • 0.3 mls of Potassium Iodide: (100mg/ml) + Iodine (50 mg/ml) given PO TDS. Give 1 hour after anti-thyroid drug.
• IV Steroid e.g. Dexamethasone 2 mg 6 hourly or Hydrocortisone 100 mg 8 hourly to prevent T4 to T3 conversion and may help suppress the autoimmune process
• Plasmapheresis, with the removal of thyroid hormone, has been used successfully both in the thyrotoxic state and to prepare those with thyrotoxicosis for surgery

Complications: Transfer to ITU

• Life threatening shock; treat sepsis, exclude cardiomyopathy, determine aetiology
• Sepsis: Broad spectrum antibiotics
• Disseminated Intravascular coagulation
• Multiple organ failure
• Status epilepticus (Diazepam, Fosphenytoin)
• Congestive cardiac failure (Furosemide, beta blockade, Nitrates, Digoxin, CCB, CPAP)

References

• Endocrine and metabolic emergencies:thyroid storm
• 2016 Guidelines for the management of thyroid storm from The Japan Thyroid Association and Japan Endocrine Society (First edition)