Wednesday, December 18, 2013

Myasthenia gravis

Today we had pharmacist round in the medical ward. We had reviewed 2 patients in the medical ward. The first patient is a 78 years old Malay female who was admited for myasthenia gravis (MG) and later progress to myasthenia crisis. Patient was presented with dysphagia, ptosis, diplopia and fatigue. She was also diagnosed with new onset of atrial fibrillation, with existing hypertension and hyperlipidemia.
 
Patient was treated with tab pyridostigmine 30mg TDS for MG. and later the dose was increased to 60mg TDS. At the same time she was also given IVIG infusion 20g OD for 5 days. (0.4g/kg/day). Patient responded to the treatment. However, she still has dysphagia upon review. After IVIG infusion was completed, Tab prednisolone 50mg OD (1mg/kg) was later started for MG and there is plan to initiate immunosuppressant such as Azathioprine or cyclosporine in this patient. These medications are usually required for lifelong unless the culprit organ of secreting antibody has been removed. In the ward, patient's hypertension was also treated with tab amlodipine 10mg OD and her lipid profile showed that total cholesterol was 6 and the LDL was 5.01, as a result, tab simvastatin 20mg was later increased to 40mg ON.
 
Important point of myasthenia gravis include this is an autoimmune disease. Usually affecting voluntary muscle and may cause severe fatigue and respiratory distress. The common cause influde hyperactive thymus. Thymus is an organ that we used during childhood to produce T-lymphocytes, but the organ became dormant in adulthood. However in MG, the thymus gland is hyperactive and this required removal of thymus if the condition was severe.
 
Questions raised during the round included why treatment was not initiated for atrial fibrillation. Suggestions was made to score the patient according to CHA2DS2-VASc score and assess the bleeding risk according to HAS-BLED. I score the patient myself. Total CHA2DS2-VASc score: 4, patient is a candidate for anticoagulation and should be counselled on starting warfarin.
 
C-Chronic heart failure history - 0/1
H-Hypertension history - 1/1
A-Age>75 - 2/2
D-Diabetes mellitus - 0/1
S-Stroke history - 0/2
V-Vascular disease history - 0/1
A-Age 65 to 74 - 0/1
Sex-Female - 1
 
H-Hypertension history
A-Age>65, alcohol usage history
S-Stroke history
B-Prior major bleeding history
L-Labile INR
E-Medication usage predispose to bleeding.
D-Renal / liver disease
 
HAS-BLED score was 2: hypertension and age. The risk is low. If AF is confirmed, suggestion should be made to start warfarin.
 
Questions raised also include should the simvastatin be discontinued as simvastatin may cause muscle weakness and further worsen patient's condition. I suggested that simvastatin may be continued for short period of time and to monitor her condition and only discontinued when patient showed symptoms of muscle weakness again.
 
A list of drugs which should be used cautiously in patient with MG as these medications may worsen patient's symptoms upon using was also mentioned. This include phenytoin, beta blocker, loperamide, aminoglycoside, tetracycline, sulfonamide, fluoroquinolone, colistin, Quinidine, CCB. Further list can refer to
 
 
 
 
We then proceed to the next patient in the ward next door. 
 
 
 

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