Imaging Pearls ❯ Adrenal ❯ Shock
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- “The aim of this article is to illustrate the controversial CT hypoperfusion complex in patients with septic shock, characterized by the following imaging features: decreased enhancement of the viscera; increased mucosal enhancement; luminal dilation of the small bowel; mural thickening and fluid-filled loops of the small bowel; the halo sign and flattening of the inferior vena cava; reduced aortic diameter; peripancreatic oedema; abnormal parenchymal perfusion; and other controversial findings that are variably associated with each other and reversible during the early stages. Increasing physicians’ awareness of the significance of these findings could prompt alternative approaches to the early assessment and management of septic shock. In this perspective, CT imaging represents a useful tool for a complete, rapid and detailed diagnosis of clinically suspected septic shock, which can be used to improve patient outcomes.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex".
Di Serafino M, et al.
A pictorial essay. Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. PMID: 34089401; PMCID: PMC8178660. - “The diagnostic accuracy of total-body computed tomography (CT) has been well established for the identification of septic shock, allowing for a rapid and simultaneous study of multiple body areas, generating detailed and panoramic images. The aim of this article is to review the characteristics of septic shock from an imaging perspective, beyond the underlying causes and to highlight how CT can be used to identify a variety of septic shock-related signs that are collectively described as CT hypoperfusion complex. The latter describes a set of widely reported signs and symptoms that are commonly observed during trauma-associated hypovolaemic shock and can be used to identify septic shock. The early recognition, diagnosis, and treatment of septic shock have profound prognostic and therapeutic implications.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex".
Di Serafino M, et al.
A pictorial essay. Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. PMID: 34089401; PMCID: PMC8178660. - “In addition to being used to identify the underlying cause of the septic state, CT is required for the early recognition of shock-associated CT imaging signs, collectively referred to as CT hypoperfusion complex, which can improve patient prognosis and management. The CT hypoperfusion complex is frequently associated with hypotension, which can also present in many no sepsis related clinical conditions, such as trauma-induced hypotensive shock (e.g. severe head or spine injury), cardiac arrest, and diabetic ketoacidosis. The CT hypoperfusion complex has important prognostic and therapeutic implications and must be promptly recognized. However, although the pathogenic mechanisms that underlie hypotensive shock and septic shock are quite different, the CT findings associated with these two syndromes are often comparable to those that have been widely described in previous literature as in post-traumatic hypotensive shock, which can be grouped into vascular, visceral, and parenchymal signs.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex". A pictorial essay.
Di Serafino M, et al.
Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. PMID: 34089401; PMCID: PMC8178660. - “The CT hypoperfusion complex has important prognostic and therapeutic implications and must be promptly recognized. However, although the pathogenic mechanisms that underlie hypotensive shock and septic shock are quite different, the CT findings associated with these two syndromes are often comparable to those that have been widely described in previous literature as in post-traumatic hypotensive shock, which can be grouped into vascular, visceral, and parenchymal signs. These signs include the decreased enhancement of the viscera, the increased mucosal enhancement and luminal dilation of the small bowel, the mural thickening and identification of fluid-filled loops in the small bowel, the halo sign and flattening of the inferior vena cava (IVC), reduced aortic diameter, peripancreatic oedema and other controversial parenchymal and visceral findings and ascites that can occur in varying combinations and are often and reversible during early stages. The presence of 2 or more vascular, visceral, or parenchymal signs is necessary to establish the presence of CT hypoperfusion complex.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex". A pictorial essay.
Di Serafino M, et al.
Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. PMID: 34089401; PMCID: PMC8178660. 
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex".
Di Serafino M, et al.
A pictorial essay. Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. PMID: 34089401; PMCID: PMC8178660.- “Abnormal renal perfusion typically manifests as an increased and prolonged parenchymal enhancement; however, focal and heterogeneous enhancement can also be observed. A fall in systolic pressure causes intense efferent glomerular arteriolar vasoconstriction, which drives glomerular filtration, leading to tubular stasis and the increased resorption of salt and water. Renal parenchymal enhancement is dependent on several factors, including cardiac output and scans timing relative to the injection of contrast agent and, thus, is a non-specific sign. However, kidney enhancement can vary depending on the severity of systemic hypotension. In some cases, unlike hyperenhancement, the decreased enhancement of the renal medulla can be observed in the venous phase, likely due to the impairment of contrast medium outflow from the renal cortex to the medulla, induced by acute renal tubular dysfunction and associated with poor prognosis.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex".
Di Serafino M, et al.
A pictorial essay. Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. PMID: 34089401; PMCID: PMC8178660. - The bilateral hyperenhancement of the adrenal gland is more common in paediatric cases than in adults and can also present in combination with acute adrenal haemorrhage, which most commonly affects the right side unilaterally, with a homogeneous increase in the size of the gland and the associated suffusion of fat around the adrenal gland. Bilateral adrenal hyperenhancement is the manifestation of adrenergic mechanisms that enhance the blood flow to the vital organs. In the arterial phase, the central zone of the adrenal gland shows less intense enhancement than the peripheral zone or presents a mosaic appearance due to the heterogeneous enhancement of the central zone. In both cases, in the venous phase, the whole adrenal gland is homogenously enhanced. This sign highlights the central role played by the adrenal glands in mediating the sympathetic response to hypotensive shock and is associated with poor prognosis.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex". A pictorial essay.
Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5. - “In previously published studies, CT hypoperfusion complex has been almost exclusively focused on trauma-induced hypotensive shock and only few studies correlated these signs with prognosis. Some studies have suggested that flattering of IVC, shock bowel, impaired renal enhancement and splenic hypoperfusion are the most suggestive signs of hypoperfusion complex, strongly correlated with a poor prognosis although in a series of trauma-related hypovolemic shock. In contrast, only adrenal hyperenhancement has been correlated with a poor prognosis in septic shock. Despite these contradictory reports, understanding these findings could prompt the development of alternative approaches for the early assessment and management of septic shock in the emergency setting. Therefore, in addition to the application of CT for determining the underlying cause of the septic state, clinicians should be aware and be able to recognize the various CT findings that are suggestive of the hypotensive state. In this perspective, CT imaging represents a useful tool for a complete, rapid, and detailed diagnosis of clinically suspected septic shock, which can be used to improve patient outcomes.”
Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex".
Di Serafino M, et al.
A pictorial essay. Insights Imaging. 2021 Jun 5;12(1):70. doi: 10.1186/s13244-021-01006-5.
- "Hypovolemic shock may be seen in trauma patients, and reduced blood volume typically prompts increased sympa- thetic activity, which can cause a constellation of findings on CT imaging, also known as the CT hypoperfusion complex. Hyperenhancing mesenteric vessels, decreased aortic caliber, slit-like IVC, intense enhancement of the kidneys, and dilated fluid-filled bowel loops are the findings of this complex . On imaging, shock adrenal glands demonstrate marked enhancement with preserved contours. Persistent, intense adrenal enhancement may be a sign of shock that precedes other imaging features of hypoperfusion, and similar findings were also observed in patients with severe acute pancreatitis.”
Cross‐sectional imaging features of unusual adrenal lesions: a radiopathological correlation
Karaosmanoglu AD et al.
Abdominal Radiology (2021) 46:3974–3994
- "Hypovolemic shock may be seen in trauma patients, and reduced blood volume typically prompts increased sympathetic activity, which can cause a constellation of findings on CT imaging, also known as the CT hypoperfusion complex . Hyperenhancing mesenteric vessels, decreased aortic caliber, slit-like IVC, intense enhancement of the kidneys, and dilated fluid-filled bowel loops are the findings of this complex. On imaging, shock adrenal glands demonstrate marked enhancement with preserved contours. Persistent, intense adrenal enhancement may be a sign of shock that precedes other imaging features of hypoperfusion, and similar findings were also observed in patients with severe acute pancreatitis.”
Cross‐sectional imaging features of unusual adrenal lesions: a radiopathological correlation
Ali Devrim Karaosmanoglu et al.
Abdominal Radiology (2021) 46:3974–3994 - "Addison disease (AD), which refers to adrenal insuffi- ciency caused by a severe deficiency of glucocorticosteroids and mineral corticosteroids, may be potentially fatal. Although the most common cause of AD worldwide is tuberculosis, the primary autoimmune process is the predominant etiology in the developed countries. The diagnosis is difficult and clinical, as the symptoms may be extremely non-specific and insidious, and almost half of the patients are first diagnosed with acute adrenal crisis. Other rare causes of adrenal insufficiency are fungal infections, tuberculosis, hemorrhage, and acquired immunodeficiency syndrome.”
Cross‐sectional imaging features of unusual adrenal lesions: a radiopathological correlation
Ali Devrim Karaosmanoglu et al.
Abdominal Radiology (2021) 46:3974–3994
- "Adrenal infarction is a rare cause of adrenal insufficiency and can be hemorrhagic or non-hemorrhagic, the latter being less common. Most reports have been described in patients with primary antiphospholipid-antibody syndrome (PAPS) and less commonly in pregnancy, heparin- induced thrombocytopenia, myelodysplastic syndrome and Crohn’s disease. Up to 36% of patients with PAPS present with adrenal insufficiency as the first manifestation of the disease.”
CT and MR imaging of acute adrenal disorders
Amar Udare et al.
Abdominal Radiology https://doi.org/10.1007/s00261-020-02580-w - "On CT, the infarcted adrenals are seen as enlarged hypodense glands with absent or poor contrast enhancement. Moschetta et al. described the capsular rim sign in 83% of patients with adrenal infarction, seen as diffusely enlarged hypodense gland with a thin rim of peripheral enhancement, likely due to residual perfusion of the adrenal capsular veins.”
CT and MR imaging of acute adrenal disorders
Amar Udare et al.
Abdominal Radiology https://doi.org/10.1007/s00261-020-02580-w
- “ Finally, it is important to recognize intense adrenal enhancement in morphologically normal-shaped adrenals, especially in unwell patients, because this finding may be an early sign of impending shock, warranting early critical-care management, and may also be a marker of poor prognosis in ill patients.”
Intense Adrenal Enhancement: A Feature of Hypoperfusion Complex
Venkatanarasimha N, Roobottom C
American Journal of Roentgenology. 2010;195: W82-W82 - “We propose that adrenal enhancement may be a sign of hyperperfusion in early stage of shock due to the crucial role of the adrenal glands in this clinical situation. This may not persist with further circulatory compromise due to vasoconstriction. If confirmed, its recognition has potential value of identifying a therapeutic window before irreversible shock set in.”
Persistent adrenal enhancement may be the earliest CT sign of significant hypovolaemic shock.
Cheung SC et al.
Clin Radiol 2003 April 58(4):315-318
- “Intense adrenal gland enhancement is defined as attenuation values equal or greater than those of the IVC . This is symmetrical in the majority of cases. The aetiology of intense adrenal gland enhancement is not known; however, it is likely to be related to a sympathetic response to hypovolaemic shock, along with preservation of perfusion to the adrenal glands as a vital organ. Although useful, intense enhancement of the adrenal gland is not unique to the hypovolaemic shock complex.”
A Pictorial Review of Hypovolaemic Shock in Adults
Tarrant AM et al.
British J Radiol 81(2008), 252-257 - “The aetiology of intense adrenal
gland enhancement is not known; however, it is likely to be related to a sympathetic response to hypovolaemic shock, along with preservation of perfusion to the adrenal glands as a vital organ. Although useful, intense enhancement of the adrenal gland is not unique to the hypovolaemic shock complex. The authors have observed this sign in other situations, e.g. following severe burns or surgery.”
A Pictorial Review of Hypovolaemic Shock in Adults
Tarrant AM et al.
British J Radiol 81(2008), 252-257 - “In 1987, Taylor et al described the CT findings of hypoperfusion in three children with hypovolaemic shock. The CT signs described included diffuse dilatation of the intestine with fluid; abnormal intense contrast enhancement of the bowel wall, mesentery, kidneys and pancreas; decreased calibre of the abdominal aorta and inferior vena cava (IVC); and a moderate to large volume of free peritoneal fluid.”
A Pictorial Review of Hypovolaemic Shock in Adults
Tarrant AM et al.
British J Radiol 81(2008), 252-257