Abstract:
ST-elevation myocardial infarction (STEMI) seen on electrocardiogram is
not always related to coronary occlusion. Extra cardiac cause must be
considered if symptoms and clinical conditions are not consistent with
acute coronary occlusion. In this case, an elderly woman presented to
the emergency department with nausea, vomiting, abdominal pain, and
tenderness consistent with bowel obstruction. She has had no bowel
movements for many days. ECG showed marked lateral ST-elevation with q
waves but persistently low troponin. Chest X-ray and abdomen/chest CT
scan confirmed the diagnosis of bowel obstruction leading to severe
left-sided diaphragmatic herniation as the cause of Pseudo ST-elevation
seen on her ECG.
Presentation : ST-elevation myocardial infarction (STEMI) seen
on electrocardiogram is not always related to coronary occlusions.
Extracardiac causes need to be considered if symptoms and clinical
conditions are not consistent with acute coronary occlusion. A
98-year-old woman with a history of transient ischemic attack and
hypothyroidism presented to the emergency department with severe
abdominal pain nausea, vomiting, and mild sharp chest pain. She had
severe altered mental status and had a lack of bowel movements for many
days. Her vitals revealed a BP of 181/96 and a heart rate of 91 beats
per minutes (bpm). She was afebrile. She had respiratory distress with a
respiratory rate of 23. Her O2 saturation was 94% on a 2-liter nasal
cannula. Her physical exam was remarkable for abdominal tenderness and
reduced bowel sounds with palpable stool in lower quadrants. The lung
sound of her left side was diminished with a distant heart sound but no
murmur. ECG showed marked lateral ST-elevation consistent STEMI ECG but
had persistently low troponin levels of 0.04. She was also chest
pain-free on arrival at the emergency department. Her labs were
remarkable for normal creatinine, glucose of 182 mg/dl, mildly elevated
liver enzymes, with an elevated white count of 16,000 increasing to
23,000 within a day with the left shift. Her hematocrit was normal. Her
lactic acid level was elevated to 2.6 mmol/l. Her chest X-ray showed a
severe left-sided hiatal hernia with a bowel gas pattern. (figure 1). CT
abdomen revealed bowel obstruction with a large left-sided hiatal hernia
with a loop of colon seen above the diaphragm, distended intrathoracic
stomach, and large fecal impaction (Figures 3 and 4).
Assessment: The patient remained chest pain-free and decided to
be ”do not resuscitate” (DNR). Chest X-ray and abdomen CT scan
confirmed the diagnosis of severe bowel obstruction due to fecal
impaction leading to a giant left-sided diaphragmatic herniation
covering a lateral aspect of cardiac chambers. Due to persistent low
troponin levels, lack of chest pain, and marked left-sided diaphragmatic
herniation, the diagnosis of pseudo-STEMI was made secondary due to
severe diaphragmatic herniation.
Diagnosis: Patients presenting with giant left-sided
diaphragmatic herniation that has displaced the lateral myocardial wall
from the anterior chest that had led to pseudo STEMI ECG pattern.
Clinical presentation with lack of chest pain, multiple imaging
modalities, and laboratory findings were all speaking against the
diagnosis of true STEMI. Furthermore, lack of ST elevation in other
lateral leads such as AVL and I and the absence of reciprocal ST
depressions suggested not a true STEMI. Raising white counts and lactic
acidosis suggested a poor prognosis.
Management : She started on intravenous hydration and
antibiotics. She needed urgent fecal disimpaction to resolve bowel
obstruction and early sepsis. Resolution of bowel obstruction could also
lead to improvement of colonic hernia. However, the patient and family
declined further treatment and the patient was declared comfort care.
She expired the next day.
This case elaborates on the importance of considering clinical
presentation and other diagnostic tools when evaluating patients with an
ECG showing STEMI-like changes in order not to rush to the cardiac
catheterization laboratory for non-cardiac causes of ECG changes. Dr
Kings mentioned a case of pulmonary embolism simulating inferior
myocardial infarction rushed to the cardiac catheterization laboratory
leading to unnecessary percutaneous coronary intervention jeopardizing
the patient by missing the right diagnosis. (1) Diaphgramatic
herniation as a cause of pseudo-ST-elevation myocardial infarction has
been well documented. Sing et al. describe a similar case
of ST-elevation seen on ECG related to extreme abdominal distension and
hemidiaphragm elevation leading to extrinsic cardiac compression
resolution after hernia treatment. (2) in another case, a pseudo
infarction ECG was recorded secondary to a large diaphragmatic hernia
seen during transthoracic echocardiographic study below the inferior
wall simulating a pericardial effusion. (3) Diaphragmatic herniation
depending on the location can simulate various types of ST elevation.
Basir et al. report a case of large diaphragmatic herniation simulation
inferior ST-elevation myocardial infarction with the resolution of ST
changes after treatment. (4) Other cases have documented normal coronary
angiograms performed due to misdiagnosis of ST-elevation myocardial
infarction seen on ECG related to diaphragmatic herniation. (5,6) It is
important that Pseudo ST-elevation myocardial infarction related to
diaphragmatic should be recognized as a not uncommon cause of misleading
diagnosis of ST elevation.