Abdominal compartment syndrome (ACS) is the life-threatening clinical state of increased intra-abdominal compartment pressure (IAP). Radiological diagnosis is difficult and usually raised when a collection of imaging findings are present in the appropriate clinical setting or if the signs on sequential imaging studies are seen to progress. Diagnosis is usually clinically supported by elevated intravesicular pressure which closely parallels IAP.
ACS is defined as elevated IAP >20 mmHg with dysfunction of at least one thoraco-abdominal organ. It may be known as intra-abdominal hypertension (IAH), but this specifically refers to IAH >12 mmHg without the clinical manifestations.
Patients present with one or many organs failing due to the elevated pressure in the abdomen having direct or indirect effects on the major body systems. Most patients will have abdominal distension. Patients often have multifactorial disease and injuries, and ACS is particularly associated with:
- acute respiratory distress syndrome (ARDS)
- hypovolemic shock
- systemic inflammatory response syndrome (SIRS)
- multiorgan dysfunction syndrome (MODS)
Typically, the severely ill patient is in the intensive care/therapy unit (ICU/ITU) and clinically presents with massive abdominal distention, anuria or progressive oliguria despite adequate cardiac output and/or increasingly difficult mechanical ventilation.
Increased IAP in abdominal compartment syndrome has numerous causes which can be subdivided accordingly:
- primary (abdominopelvic disease or injury)
- secondary (disease or injury outside the abdomen and pelvis)
- rapid fluid resuscitation
There are several overlapping CT and sonographic signs that may support the diagnosis but none are considered specific or sensitive for ACS 2:
- elevated diaphragm
- rounded appearance of the abdominal wall (round belly sign 4)
- flattened inferior vena cava and renal veins
- displacement of solid abdominal viscera
- mosaic liver perfusion
- increased bowel and gastric wall thickening and enhancement
- gastric distention
- increase in ascites over subsequent scans
- bilateral inguinal herniation
- pulmonary basal consolidation, collapse and/or pleural effusion
- reduced diastolic flow in portal, hepatic, and/or renal veins
Treatment and prognosis
Mortality is high in ACS ranging between 60-70% 2. Treatment is aimed at reducing the elevated pressure within the abdomen to correct the reduced perfusion of the affected viscera and prevent irreversible organ failure. This is achieved surgically with decompressive laparotomy but mortality remains high after surgery, reflecting the multifactorial physiological disturbances in these critically ill patients 3. After laparotomy, the abdomen is often left open in those who are at high risk of developing ACS.
Other treatment strategies include drainage of fluid collections with non-operative methods and muscle relaxation.
- 1. Sugrue G, Malbrain MLNG, Pereira B, Wise R, Sugrue M. Modern imaging techniques in intra-abdominal hypertension and abdominal compartment syndrome: a bench to bedside overview. (2018) Anaesthesiology intensive therapy. 50 (3): 234-242. doi:10.5603/AIT.a2017.0076 - Pubmed
- 2. Patel A, Lall CG, Jennings SG, Sandrasegaran K. Abdominal compartment syndrome. (2007) AJR. American journal of roentgenology. 189 (5): 1037-43. doi:10.2214/AJR.07.2092 - Pubmed
- 3. De Waele JJ, Hoste EA, Malbrain ML. Decompressive laparotomy for abdominal compartment syndrome--a critical analysis. (2006) Critical care (London, England). 10 (2): R51. doi:10.1186/cc4870 - Pubmed
- 4. Pickhardt PJ, Shimony JS, Heiken JP, Buchman TG, Fisher AJ. The abdominal compartment syndrome: CT findings. (1999) AJR. American journal of roentgenology. 173 (3): 575-9. doi:10.2214/ajr.173.3.10470882 - Pubmed