Case:
A 66-year-old male, a known case of hypertension, diabetes mellitus,
heart failure with preserved ejection fraction (HFpEF), chronic
obstructive pulmonary disease (COPD), and having metastatic non-small
cell lung cancer (NSCLC) (TTF-1 positive, PDL1>50%
positive) presented to the emergency department with the complaint of
mild chest pain and shortness of breath on exertion for 5 days. The
patient was in the usual state of health when he gradually started
experiencing mild chest pain, suggesting musculoskeletal pain due to
chronic cough predominantly accompanied by shortness of breath. He
denied fever, nausea, vomiting, orthopnea, paroxysmal nocturnal dyspnea
or leg swelling. The patient was diagnosed with lung cancer 2 months
back, for which he was started on pembrolizumab infusion therapy with 3
doses over 6 weeks. He did not have any prior cardiac history. His
previous echocardiogram showed a 50-55 percent ejection fraction with
grade I diastolic dysfunction 4 months prior to the current
presentation.
On examination, the patient was tachycardiac with a heart rate of 134
beats/min and blood pressure of 144/84 mm of Hg with oxygen saturation
of 88%, requiring 4 liters of supplemental oxygen. On laboratory
evaluation, his NT-proBNP level was 2585 pg/ml, while other vital
laboratory parameters (WBC=4.4 B/L, Chloride=98 mmol/L, Co2=30 mmol/L,
BUN=21 mg/dL, Anion-gap=13 mmol/L, Calcium=9.6 mg/dL, Magnesium=1.6
mmol/L, Protein Total=7.5 g/dL, Albumin= 4.2 g/dL, Bilirubin=0.7 mg/dL,
Hb=8.6 gm/dL, ALT=43 IU/L, AST=37 IU/L, ALP=166 IU/L, Glucose=142 mg/dL,
eGFR=67, Cholesterol Total=218 mg/dL, HDL=55 mg/dL, LDL=124 mg/dL,
Triglycerides=194 mg/dL and PSA=0.4 ng/mL) were also checked. His EKG
revealed sinus tachycardia, Q waves in leads V2 and V3 (anteroseptal
infarct), and a low voltage QRS complex that did not differ from the
prior one (Figure 1). His CXR showed pulmonary vascular congestion. In
addition, his CT scan revealed no pulmonary emboli. His echocardiography
revealed an EF of 10-15%, global hypokinesis, reduced RV function, and
a moderately enlarged left atrium (Figure 2). He underwent coronary
angiography, which revealed no obstructive lesions. A viral etiology of
myocarditis was also ruled out in the laboratory workup. Cardiologists
and oncologists identified the patient with pembrolizumab-induced
cardiomyopathy due to the length of time since starting anti-tumor
medication and the reduction in LV function.
The patient was initially treated with, IV methylprednisolone 125 mg
daily for 3 days, IV Lasix 40 mg twice daily for 5 days, resulting in an
8-litre diuresis, before being released on oral prednisone 60 mg daily,
furosemide 40 mg oral, metoprolol succinate 50 mg daily, and lisinopril
40 mg daily. He was advised to see cardiology and oncology on an
outpatient basis. After two weeks of outpatient follow-up, he was
started on spironolactone 25mg daily.