ANAESTHETIC MANAGEMENT OF A PATIENT WITH MYSTHENIA GRAVIS POSTED

FOR THYMECTOMY- A CASE REPORT

Dr. Aradhana Behare P.G.Student Dept Of Anaesthesia, Critical Care &

Pain. Tata Memorial Hospital, Mumbai.

History• A 28 year old (54 Kg) female presented to outpatient department

with

H/o - Rapid worsening features of Nasal regurgitation of liquid and food . Drooping of eyelids . Difficulty in swallowing Weakness of both upper limbs and Difficulty in speech ( Nasal twang) No history of difficulty in breathing.

• H/o LSCS 1 month back under GA 1.5 months back. Recovery uneventful.

Investigation• X Ray chest -> S/o mediastinal widening

• CT neck -> Normal study

• CT chest-> Heterogeneously enhancing right mediastinal mass

• causing encasement of vasculature structure and abutting rt atrium and invasion of fat planes.F/s/o- Ant mediastinal neoplasm like germ cell tumour or thymoma.

• CT brain -> Two foci of calcification along the tentorium cerebelli on the right side

Investigation

• Ach receptor antibody titre-> 21.20 nmol/ l ( Negative - <0.25)

( equivocal -.25-0.40 )

( positive - >0.40 )

• Nerve conduction Study( NCS ) -> The NCS in both upper and lower limbs were normal.

• Repetitive nerve stimulation test revealed a myasthenic response in right orbicularis oculi and to lesser extent in the right trapezius muscle.

Diagnosis of mysthenia gravis with thymoma was confirmed.

Treatment• Antibiotic – Inj Monocef 2 gm IV Inj Metrogyl 200 mg 8 hrly

• Steroids - Inj Solumedrol 1gm iv over 4 hrs OD Tab Prednisolone 10 mg 2-1-0

• Achese inhibitor – Tab Pyridostigmine 60 mg 1-1-1-1-1

• Antacids - Tab Pantoprazol 40 mg od orally

• Saline Nebulisation

The patient showed improvement within 10 days with improved facial

muscle weakness.

• Patient was referred to Tata Memorial Hospital for Thymectomy.

• She received 3 # Adriamycine, endoxan, VCR and inj cisplatin.

• Post Chemotherapy – CT chest revealed residual right anterior mediastinal mass.

• CT neck- Normal

• PFT 4 hours after pyridostigmine dose - Mild obstructive with restrictive disease.

• 2-D ECHO- Normal.

• Routine laboratory test –Normal

• Patient was scheduled for trans-sternal thymectomy and pre-anaesthetic check up was done.

• Routine laboratory studies were within normal limits .

• Routine medications were continued till day of surgery.

• Premedication – Inj Glycopyrrolate 0.4 mg im 45 min before surgery

Inj Rantac 50 mg iv

Inj Metoclopromide

Inj Hydrocortisone 100 mg iv

Induction

• I.V. line was secured with 16 G cannula.

• Monitors- Pulseoxymeter

- Cardio scope

Invasive blood pressure monitor in left radial artery

Capnoneter

Temperature probe

• Epidural -

16 G epidural catheter -T5-T6 interspace -lateral position - paramedian approach, using loss of resistance technique and test dose of inj lignocaine with 1: 200000 adrenaline 3 cc given .

Induction• Preoxygenated with 100% oxygen for three minutes .

• Induction- Inj fentanyl 50 mcg iv and Sevoflurane gradually increased to 7% .

• Neuromuscular monitoring till there was loss of 3 rd and 4th twitches on TOF.

• Inj Propofol 1% 2 mg /kg iv was given after which there was loss of all four responses on TOF.

• Larynx was spread with 10% xylocaine.

• Patient was intubated with 7mm cuffed ETT without use of muscle relaxant.

• Nasogastric tube 16 G was inserted and pyridostigmine 60 mg through NG tube was given.

• No haemodynamic response to laryngoscopy and intubating condition were excellent. (jaw relaxation complete, laryngoscopy easy, vocal cords open, no coughing, no movement).

Intraoperative period

• Neuromuscular monitoring was done throughout the procedure to maintain presence of one count on TOF.

• Throughout the surgical procedure, heart rate, blood pressure and oxygen saturation did not vary from the baseline value

• Anaesthesia was maintained with N20 :02( 50 %:50% ), sevoflurane (2-2.5 %) , inj fentanyl 50 mcg ,inj propofol boluses given intermittently and thoracic epidural infusion of 0.125 % bupivacaine 5-7 ml/hr.

• Controlled ventilation was adjusted to maintain normocapnia.

• Thymectomy was done under mid-sternotomy and lasted 180 min.

• The intraoperative period was uneventful.

• At the completion of surgery, when all the four responses in TOF reappeared and no fade occurred on DBS, sevoflurane was switched off.

• 100 % oxygen given.

• Patient regained consciousness and was breathing spontaneously.

• The pt belonged to Modified Osserman classification -3, not extubated.

• Shifted in ICU on ventilator on pressure support mode and electively ventilated overnight.

• Epidural infusion of inj bupivacaine 0.125% started at the rate of 6 ml/hr and inj fentanyl 50 mcg IV given.

Extubation• CBC, Serum electrolytes, ABG –normal.

• Pt was haemodyanmically stable throughout the night.

• After fulfilling the weaning criteria, patient was extubated next day at 8:00 Am.

• O2 by mask @ 4L/Min given.

• The patient was comfortable, analgesia was excellent.

• Breathing exercise and incentive spirometry were started.

• Her post extubation ABG and X-ray chest showed no abnormality.

• The patient was discharged to ward on 3rd postoperative day and from the ward after uneventful 10 days stay.