haematomas of the superficial abdominal wall occur infrequently in the hospital setting . though uncommon the well - described complications of an abdominal wall haematoma include uncontrolled haemorrhage requiring blood product transfusion and death . a number of factors are known to predispose to the development of an abdominal wall haematoma . these include older age , female sex and the use of anti - platelet or anti - coagulant agents . obesity is an additional factor that may complicate the formation of an abdominal wall haematoma . compared with the non - obese , the sub - cutaneous tissue of the obese is considered dysfunctional and has a different vascular structure and extra - cellular matrix composition . the self tamponade effect that limits the extension of an abdominal wall haematoma may be deficient in the obese . here we report the case of a 59-year - old obese female who developed an abdominal wall haematoma and haemodynamic instability during admission in our hospital . a 59-year - old obese female was admitted to the hospital with fever on the background of poorly controlled type 2 diabetes ( hba1c 9.5% ) . the patient 's background included ischaemic heart disease , chronic kidney disease , peripheral vascular disease and a right - side , below - knee amputation . on examination , the patient 's weight was 125 kg , height 154 cm and body mass index was 53 . two weeks later , the patient remained hospitalized for the management of an infected diabetic foot ulcer and awoke one morning with acute abdominal pain and shortness of breath . the patient was haemodynamically compromised with a pulse rate of 120 and blood pressure 90/60 lying . the haemoglobin fell overnight from 126 to 90 g / l and a few hours later there was a further fall to 79 platelet count was 242 , international normalized ratio ( inr ) 1.0 , activated partial thromboplastin time ( aptt ) 33 and anti - factor xa level 0.41 in keeping with prophylactic clexane administration . a ct scan was performed , which demonstrated a large abdominal wall haematoma ( see fig .  1 ) . figure  1:ct abdomen of a 59-year - old obese female with an abdominal wall haematoma . ct abdomen of a 59-year - old obese female with an abdominal wall haematoma . there are limited data on the relationship between weight or body mass index ( bmi ) and the development of an abdominal wall haematoma . in the case series we reviewed , the weight or bmi of the patient is rarely mentioned . yet , where a photographic image is published , the patient 's weight and abdominal girth often appear excessive . it has been recognized that women are more prone to haematoma formation owing to the relative lack of abdominal wall muscle mass compared with men . the effects of pregnancy are also known to contribute to haematoma formation . despite a paucity of evidence , it has been suggested that the obese are at risk of developing complicated abdominal wall haematomas and the presence of increased abdominal fat may predispose to an increased risk of haemorrhage . the adipose tissue of the obese differs from those with a normal bmi and obesity - associated adipose tissue dysfunction is an entity thought to be caused by a combination of inappropriate angiogenesis , localized inflammatory reaction and hypoxia . specifically , the vascularity of subcutaneous tissue in the obese is abnormal when compared with controls . there is an increase in the number and size of blood vessels in the abdominal wall and there are structural alterations in the small arteries . these processes are driven by an increase in local vascular endothelial growth factors and angiopoietins . change in the subcutaneous tissue of the obese is not limited to the vasculature and there are differences in the extra - cellular matrix when compared with the non - obese with the structure of both elastin and collagen affected . quantification of elastin in one trial showed that adipose tissue from obese individuals had < 6% total elastin content compared with 12% in lean individuals . as in the elderly where vascular fragility and changes to the subcutaneous tissue environment limit the external compression of an abdominal wall haematoma , the same may be said of the obese . for this reason the tamponade effect that contributes to the cessation of haemorrhage may be attenuated in obese patients . to summarize , although abdominal wall haematomas are not common , they are potentially fatal . the literature makes little reference to the weight or body mass index of this group of patients . it has been shown that there are changes in the vascularity and the extra - cellular matrix in the subcutaneous tissue of the obese . it is thought that the lack of external compression of an abdominal wall haematoma makes bleeding more likely . for this reason , the obese appear at greater risk from this relatively uncommon phenomenon and vigilance is required in this group of patients to ensure their haemodynamic stability and safety .
we report the case of a 59-year - old obese female who developed an abdominal wall haematoma during administration of prophylactic clexane . compared with 
 the non - obese , the subcutaneous tissue of the obese is considered dysfunctional and has a different vascular structure and extra - cellular matrix composition . 
 while the development of an abdominal wall haematoma is relatively uncommon , when they occur they can have fatal consequences . 
 the altered subcutaneous tissue environment in the obese attenuates the normal external compression of an abdominal wall haematoma and as a result the obese are at greater risk of haemorrhage .