Prof. Sadqa Aftab Consultant anesthetist cardiac surgery dept CHK Thyroid storm/crisis Prof. Sadqa Aftab Consultant anesthetist cardiac surgery dept CHK

A 18 yr old women 78 Kg was diagnosed as Graves disease and treated with propylthiouracil 250mg and propranolol 40mg twice daily. After one year she was planned for elective thyroidectomy, she had also history of asthma with occasional use of Inhaled Albuterol. On examination Thyroid was slightly enlarged and Her labs were within normal limit

On morning of surgery vitals and labs were BP 134/74 mmHg HR 100/min Temp 37 C Hb 11.4gm/dl ECG sinus tachycardia No history of previous anesthesia or surgery All medication were withheld in morning on advice of surgeon and tachycardia attributed to anxiety before surgery Premedication's midazolam,

Induction Propofol, fentanyl and Rocuronium Maintenance O2/N2O/isoflurane Thirty mins after incision during dissection around thyroid gland HR increases to 110 to 120/min Additional bolus of fentanyl was given Sweating started with temp of 39 but end tidal tidal CO2 was 30mmHg and soda lime absorber does not indicate undue warmth

Management Metopropolol 1mg given while proponolol avoided because of asthma Cooling measures with cooling and cold IV fluids started & urinary catheter was inserted Then Temp decrease to 38 C, SPO2 97%, BP 105-120/40-50 mmHg, HR 110/min

Metopropolol was repeated on interval and total of 10 mg was administered along with repeated doses of fentanyl and Rocuronium during surgery Subtotal thyroidectomy completed with minimum blood loss Patient transferred to ICU

ICU management One hr later with vitals BP 145/65 mmHg, HR 108/min, Temp 37 C, R/R 23/ min, SPO2 98%, ABG PH 7.28, PaO2 209 mmHg , PCO2 48 mmHg, HCO3 22, BD -5 with 40% Fio2 on spontaneous mode Reversal done with neostigmine and glycopyrolate Patient was responsive to verbal command and extubated after T piece trail Propylthiouracil was started HR came down to 100/min, patient was discharge to ward on next day

Discussion Thyroid storm/crisis in surgical patients Surgery Infection Trauma Overdose of thyroid replacement medication Usually occur 6-18 hrs postoperatively in unprepared or inadequately prepared patients But can happen intraoperatively mimicking malignant hyperthermia

Clinical presentation fever, tachycardia, profuse sweating, systolic hypertension and widened pulse pressure, atrial fibrillation. Restlessness and agitation, CCF Differential diagnosis include anaphylactic reaction, malignant hyperthermia, pheochromocytoma, neuroleptic malignant syndrome (Unlike MH, not associated with muscle rigidity, elevated CPK, or marked degree or lactic or respiratory acidosis)

Treatment if crisis occurs ABC’s General supportive measures cooling, cold IV fluid, treatment of hypovolemia IV propanolol (.5mg increments)/esmolol to control heart rate until less than 100. (Diminish metabolic effect of thyroid hormones Proponolol drug of choice) Propylthiouracil 250mg Q6 hours orally or by NG tube Reducing secretion and production of thyroid hormone Sodium Iodide 1 gram over 12 hours

6. Treat underlying illness e 6. Treat underlying illness e.g correction of any precipitating events (infection) 7. Cortisol is recommended if there is any coexisting adrenal gland suppression 8. Treatment of possible thyroid crisis should not await the arrival of confirmatory thyroid function test 9. Mortality rate is approximately 20%

In Our case Preoperatively Possibly patient was undertreated because of absence of obvious sign and symptoms Antithyroid medications and beta-blockers should be continued through the morning of surgery. On day of surgery BP 134/74 mmHg, HR 100/min, Temp 37 C, Hb 11.4gm/dl Monitor shows ECG sinus tachycardia

Crisis precipitated With stress of anesthesia and surgery To Differentiate from malignant hyperthermia (normal End tidal CO2, absence of arrhythmias, skin flushing, ABG with normal PaCO2, and absence of Hypoxemia Crisis managed Early intervention with B blocker prevented disaster

Lesson to learn Thyroid storm is uncommon but occur in unprepared and inadequately treated patients Be careful especially in day case surgery for hyperthyroid patient undergoing non thyroid surgery Brief period to assess and formulate plan of anesthesia does not serve the patient well Anesthetist should meticulously assess euthyroid state of patient