The “Spiked Helmet Sign”, a Mimic of ST-Elevation Myocardial Infarction in Post-Nephrectomy Ileus

Abstract

There are many causes of ST-elevation on electrocardiogram (ECG). ECG changes in the setting of intra-abdominal pathology is a rare and under characterised and includes the “spiked helmet sign”. We report a rare case of the “spiked helmet sign” that presented with ST-elevation in the precordial leads due to post-operative ileus.

A 64-year-old man who underwent an open left radical nephrectomy for renal cell carcinoma was reviewed on day three post-operatively for dyspnoea (SpO2 85% on room air), tachycardia (120 bpm), nausea, and abdominal distension. He was found to have ST-elevation on bedside ECG (Figure 1). Cardiac investigations, including serum troponins and coronary angiography, were unremarkable.

An upward baseline shift starting prior to the onset of the QRS complex prior to ST-elevation was seen on ECG (Figure 1). This dome and spike morphology has led to the naming of this ECG variant the “spiked helmet sign” (SHS), as it has a similar appearance to the German military spiked helmet, the Pickelhaube [1].

Computed tomography (CT) of the abdomen demonstrated a grossly distended fluid-filled stomach and small bowel, consistent with ileus (Figure 2). Following nasogastric decompression, the patient stabilised, and the ECG changes normalized (Figure 3).

SHS is described as a marker of non-cardiac critical disease [1], with intra-abdominal and intra-thoracic pathology with ST changes found in inferior and precordial ECG, respectively [2,3,4,5,6,7,8,9]. This example shows precordial SHS with an intra-abdominal rather than intra-thoracic cause. Gastric distension, ileus, small bowel obstruction, and bowel perforation are all intra-abdominal pathologies that have been linked to SHS [2,3,4,5,6,7]. Intra-thoracic pathologies associated with SHS include pneumothorax and aortic dissection [7,8,9]. Although the mechanism of SHS is not well understood, intra-thoracic or intra-abdominal pressure resulting in pulsatile epidermal stretch [1] and marked prolongation of the QT interval [10] are both postulated mechanisms of SHS. In all reported cases, SHS changes on ECG resolve upon treatment of the underlying pathology [2,3,4,5,6,7,8,9].

Post-operative patients with ST-elevation on ECG must first undergo cardiac investigation to rule out life-threatening STEMI. Ileus is a common post-operative complication following abdominal surgery and SHS due to ileus demonstrates the importance of considering wide differential diagnoses for ST-elevation in the post-operative setting.