Self-medication With Thyroxin – Hyperthyroid State

PERI-OPERATIVE

Chapter 15

vidyasagaran

Dr. Vasanthi Vidyasagaran*

Department of Anaesthesiology, Kauvery Hospital, Chennai, Tamilnadu, India

*Correspondence: Vasanthi.vidyasagaran@gmail.com

A 55-year-old woman was posted for removal of a thrombus from her left upper limb as an emergency. She was very anxious and complained of severe pain due to acute ischemia. On examination, her resting heart rate was 130/min, BP=140/80 and ECG showed sinus tachycardia. Other basic investigations were normal. She was too distressed to discuss any detailed history. Relatives were not able to provide any relevant information either.

The options for anaesthesia included local infiltration with monitored anaesthesia care, regional, or general anaesthesia. She did not consent to regional anaesthesia. Since she had just recovered from fever and still had respiratory infection, we chose not to give general anaesthesia. The procedure was planned under local anaesthesia with monitored care. Standard monitors were placed.

Midazolam 1mg, and Fentanyl 50 mcg were given intravenously. The surgeons infiltrated the area to be operated, and started the procedure. Her heart rate went up to 160/min, but continued to be in sinus rhythm. Further 2 mg Midazolam was given. An incremental dose of Metoprolol, up to 10 mg was given. However, the heart rate remained around 120/min. She complained of precordial discomfort. Intravenous Morphine 5mg was administered, after which the surgery was completed.

At the end of the procedure she mentioned that she was on regular tablets, and on examining the prescription, we found it to be 200 mcg Eltroxine. Blood samples were taken to check for thyroid function tests. Results revealed a TSH value < 0.01, and T4=15 mcg/dl. She further gave a history of having been diagnosed with hypothyroidism 16 years ago, for which she was prescribed 200 mcg Thyroxine at that time. She had continued taking the drug without any follow up! It was quite surprising that she did not suffer any major complication due to her hyperthyroid state. She was referred to the physician for further management.

Discussion

Unresponsive tachycardia may give a clue to hyperthyroidism but this will be difficult to diagnose in conditions of anxiety and pain, particularly in the peri-operative setting. The usual differential diagnoses of tachycardia include cardiac disease, electrolyte abnormalities, anxiety, or depleted volume status. Endocrine causes such as hyperthyroidism, and Pheochromocytoma must be borne in mind. A number of cases of subclinical hyperthyroidism as well as hypothyroidism are seen especially in women coming up for surgery. Whether or not to perform a thyroid function test routinely before surgery is worth contemplating.

 

References

 

  1. Jay G. Watsky & Mark A. Koeniger, Prevalence of hyperthyroidism in community hospital. JABFP May-June 1998 Vol. 11 No.3
  2. Brams, E. O. (2005). Thyroid disease: A case-based and practical guide for primary care. Totowa, N.J: Humana Press.
  3. Mittra et al. Uncommon Causes of Thyrotoxicosis; Journal of Nuclear Medicine Vol. 49, No. 2, February 2008

PERI-OPERATIVE

Chapter 16

Surgical Procedure for a Patient With recent Myocardial Infarction

Case 1

A 76-year-old man was admitted to the coronary care unit for acute antero-septal STEMI and was recovering after having received thrombolytic therapy. He was shifted to intermediary care after 5 days. On day 7 post MI, he was allowed to walk up to the rest room as he had difficulty in using the bed pan. He sustained a fall in the restroom and injured his right hip. Prior to the fall, he did not experience any giddiness, chest pain or hypoglycaemic event predisposing to the fall.

On examination he was conscious, very anxious and in pain. He was administered oxygen and pain relief. Vital signs were HR=110/min, BP=180/90 mm Hg, SpO2=98%. X-ray of hip showed fracture neck of femur. Patient refused conservative management. He insisted on undergoing immediate definitive surgery as he did not want to be bedridden. In his original words to the anesthesiologist, “I am an old rich orphan, both my children live abroad and I have no one to help. I need to be independent if I am alive. Please do not refuse anaesthesia.

Discussion with the patient regarding the surgery and the high risk of morbidity and mortality involved in perioperative period due to his age, nature of surgery and all the more due to the very recent cardiac event was done in detail. The patient had a good understanding of the situation and was insisting on taking the risk as otherwise the consequences may be worse. The patient’s request was recorded and signed by him. His sons were contacted over the phone and their consent was sent by email. We took signature from two witnesses, who were the patient’s friends, one being a lawyer.

Preoperative investigations showed Hb=10 g%, all other blood investigations including RFT were within normal limits. ECG showed sinus rhythm, ST elevation, occasional ventricular premature complexes. His cardiac enzymes were still elevated. He was on Metoprolol, Aspirin, Atorvastatin, and ISDN. Patient was also on low molecular weight Heparin. However due to the cardiac risk, we did not stop the medication. Anticipating excess blood loss, blood products were reserved.

Right hip hemiarthroplasty was scheduled the next day. It was planned to be performed under general anaesthesia. Emergency trolley with defibrillator was kept ready. Antiarrhythmic and other resuscitation drugs were readily available inside theatre. The cardiologist was notified and requested to remain within the hospital premises to be able to attend to the patient without delay, if a need were to arise. He was induced with Thiopentone 200 mg and intubated with Vecuronium 6 mg. preservative free lignocaine 60 mg was used to attenuate the stress response to intubation. Morphine 5 mg was given, and he was maintained with Oxygen/Nitrous Oxide and Isoflurane. He was carefully monitored throughout surgery.

Invasive blood pressure monitoring and CVP were helpful in maintaining haemodynamics. Surgery was performed by a skilled surgeon who completed the procedure in 40 minutes with minimal blood loss. At the end of the procedure he recovered smoothly without any difficulty. No vasopressors were required. Fluids were titrated carefully. A total of one litre – 500 ml of half Normal Saline, and 500 ml of Ringer Lactate was used. Urine output was maintained at 50 ml/hour. Postoperatively, patient was shifted back to the ICCU for intensive monitoring and was discharged home uneventfully after 10 days.

Case 2

A 56-year-old patient, presented to the emergency room at 5 pm with profuse per rectal bleeding for over the last 2 hours. He gave history of chest pain and admission into hospital 7 days ago and had undergone coronary stenting. He had drug eluting stents in situ and was on beta blockers, nitrates and antiplatelet. He developed constipation over the preceding 2 days after discharge from hospital and he started bleeding from his haemorrhoids.

Surgeons tried rectal pack. But due to profuse bleeding, it was decided to bring the patient to operating theatre and secure haemostasis. The urgent need and potential risk involved was discussed with the patient and relatives. He was given platelets and PRBS on the table as he had lost nearly a litre of blood and his Hb was only 6 gms percent.

Stent re-thrombosis and relapse of coronary event was the dreaded risk, as the patient had the procedure done just 7 days ago. Risks and benefits of the surgery were explained and informed consent was obtained. The risks to keep in mind were:

  1. Coronary event unresponsive to thrombolysis, requiring repeat PCI
  2. Arrhythmias
  3. Sudden death if either of the above become untreatable, as the myocardium had sustained recent injury

The plan was to perform the surgery under general anaesthesia to achieve haemostasis. PRBCs and platelets were available before commencing the anaesthesia. Cardiologist was informed and he was available in hospital for emergency situation. Defibrillator and emergency drugs were kept ready to use.

Platelets were transfused even prior to induction. Anaesthesia was induced with Sevoflurane gas induction and Fentanyl 1 mcg/kg. Laryngeal mask airway was used to secure airway. Surgery was completed in 20 minutes uneventfully. Haemostasis was achieved. No intraoperative cardiac complications were observed. Patient recovered well and was observed in coronary unit overnight. He recovered with no additional problems.

Discussion

Challenges in management of an elderly patient, with history of myocardial infarction in the preceding week, for emergency femur surgery:

  1. Worsening of myocardial function with risk of cardiac failure
  2. Risk of another myocardial infarction in the perioperative period
  3. Risk of arrhythmias
  4. Anticoagulants and risk of bleeding intraoperatively
  5. Maintaining homeostasis and not overshooting targets in hemodynamic and respiratory parameters
  6. Monitoring and maintaining urine output
  7. Delayed recovery from anaesthesia and need for postoperative intensive care
  8. Perioperative DVT prophylaxis, ensured by the low molecular weight heparin patient was already on
  9. Skilled and efficient surgeon who can minimize the duration of surgery and blood loss maximizes the chances of recovery. As an anaesthesiologist, this is an important factor, while taking up high risk patients.

Challenges in anaesthesia for a patient with coronary stent and recent MI for emergency surgery:

  1. Patient with reduced cardiac reserve
  2. Patient on dual antiplatelets, no time to stop them and give bridge therapy
  3. Patient at risk of bleeding haemorrhoids

Role of prophylactic platelet transfusion is emerging, but one should be wary of compromised cardiac function and large volumes should be avoided.

In emergency situations like in our patient, risks and benefits have to be weighed and explained to the patient and relatives. Risk of re-thrombosis is high and thrombolysis may be ineffective in these patients. They will require percutaneous coronary intervention. Newer antiplaletet drugs like Prasugrel have higher risk of bleeding compared to Clopidogrel and Aspirin, whereas Ticagrelor is said to have relatively less serious bleeding. Tirofiban and Eptifibatide have longer lasting actions and hence bleeding may be a significant issue.

Performing neuraxial anaesthesia on patients receiving these newer drugs is contraindicated as their duration of action is not clearly predictable. ASRA recommendations can be referred to. Smooth and safe general anaesthesia with care regarding haemodynamics and prophylactic platelets will help save the patient.

The key to the successful management of any patient, high risk category in particular, is the efficient planning and execution of care plan in perfect order without any lapses in the chain involved.

A recent MI remains a significant risk factor for postoperative MI and mortality following surgery. Delaying elective operations for at least 8 weeks and providing interim medical optimization is recommended. Risk of a catastrophic myocardial event increases from 6% when surgery is performed later than 6 months, to 33% when surgery is performed within the first month of a myocardial event. The time allowed for cardiac tissue to recover and gain cardiopulmonary reserve capacity to compensate for the surgical stress makes all the difference.

References

  1. Livhits M1, Ko CY, Leonardi MJ, Zingmond DS, Gibbons MM, de Virgilio C Risk of surgery following recent myocardial infarction. Ann Surg. 2011 May; 253(5):857-64.
  2. Semark A1, Rodseth RN, Biccard BM. When is the risk acceptable to proceed to no cardiac surgery following an acute myocardial infarction? Minerva Anestesiol. 2011 Jan; 77(1):64- 73.
  3. Fleisher LA, et al. 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery, Journal of the American College of Cardiology (2014)
  4. Ford MK, Beattie WS, Wijeysundera DN. Systematic review: prediction of perioperative cardiac complications and mortality by the revised cardiac risk index. Ann Intern Med. 2010; 152:26-35.

Documentation is very important in anaesthesia practice

Only documents speak in a court of law.

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