Adrenal hemorrhage

Adrenal haemorrhage can result from a variety of causes (traumatic as well as non traumatic). When unilateral, it is often clinically silent. In contrast, bilateral adrenal haemorrhage can lead to catastrophic adrenal insufficiency.

Clinical presentation

The large majority of patients with unilateral adrenal hemorrhage do not have clinically obvious signs of adrenal insufficiency; and the diagnosis is usually made incidentally at imaging performed for another reason.

Bilateral haemorrhage usually results in an adrenal crisis, with coma and death resulting if replacement steroid therapy is not administered promptly. Despite treatment, overall there is approximately a 15% mortality, and about 50% when in the setting of sepsis.

Pathology

Adrenal haemorrhage can be either unilateral or bilateral. Adrenal gland trauma is a common cause of unilateral adrenal haemorrhage. On the other hand, bilateral adrenal haemorrhage, is rarely due to trauma, and is frequently attributed to adrenal vein spasm or thrombosis. Predisposing risk factors include:

• sepsis, especially menigoccocaemia (a.k.a. Waterhouse-Friderichsen syndrome)
• disseminated intravascular coagulation (DIC)
• primary antiphospholipid syndrome
• heparin-induced thrombocytopaenia
• steroid usage
• anticoagulation
• underlying adrenal tumour

Radiographic features

Ultrasound

The pattern of echogenicity of an adrenal haematoma depends on its age:

• an early-stage haematoma appears solid with diffuse or inhomogeneous echogenicity
• as liquefaction occurs, the mass demonstrates mixed echogenicity with a central hypoechoic region and eventually becomes completely anechoic and cyst-like
• calcification may be seen in the walls of the haematoma as early as 1 - 2 weeks after onset and gradually compact as the blood is absorbed

Colour Doppler and power Doppler imaging allow confirmation of the avascular nature ofconfirm that the mass is avascular.

CT

Adrenal haematomas characteristically appear round or oval often with surrounding stranding of the periadrenal fat evident also.

Attenuation value of adenal hematoma depends on its age:

• acute to subacute hematomas contain areas of high attenuation that usually range from 50-90 HU
• adrenal hematomas decrease in size and attenuation over time, and most resolve completely
• organized chronic adrenal hematoma appears as a mass with a hypoattenuating center with or without calcifications (also known as adrenal pseudocysts)
• adrenal hematomas may calcify after 1 year

MRI

Acute stage (less than 7 days after onset): the hematoma typically appears iso-intense or slightly hypointense on T1 weighted images and markedly hypointense on T2 weighted images.

Subacute stage (7 days to 7 weeks after onset): the hematoma appears hyperintense on T1 and T2 weighted images.

Chronic stage (which typically begins 7 weeks after onset): a hypointense rim is present on T1 and T2 weighted images, which is attributed to haemosiderin deposition and the presence of a fibrous capsule.

See also

• adrenal gland trauma
• adrenal glands
• adrenal lesions
• adrenal calcification
• adrenal adenoma
• adrenal carcinoma
• Cushing syndrome
• fetal adrenal haemorrhage