Hematuria as a Predictor of Abdominal Injury After Blunt Trauma M. Margaret Knudson, Mo, Jack W. MeAninch, MD,=Reyna!do Gomez, MD, Peter Lee, as. Harrison A. Stubbs, PhD, San Francisco,Californm
Among the 1,484 patients included in the Renal Trauma Project with evidence of blunt trauma and hematuria, 160 patients were found to have both hematuria and a significant intra-abdominal injury not related to the genitourinary system. The incidence o f abdominal injury generally increased with the degree of hematuria, approaching 24% in patients with gross hematuria. For each category of degree of hematuria, patients with shock had a significantly higher incidence of abdominal injury (p < 0 . 0 5 ) than patients without shock. The incidence of abdominal injury in patients with microscopic hematuria and shock was 29%, and it was 65% for patients with both gross hematuria and shock. All patients with gross hematuria after blunt abdominal trauma and all patients with microscopic hematuria and a history of shock should be evaluated for both urologic and extra-renal abdominal injuries.
" ematuria has long been recognized as the most reliH . able sign of injury to the urinary system. More recently, hematuria has been regarded as a marker of abdominal injury in children after blunt trauma [1,2], but this association has not been studied extensively in adults. The presence of hematuria has also been an indication for radiologic imaging of the genitourinary system after trauma. Since abdominal computed tomographic (CT) scanning has largely replaced intravenous pyelography for the Staging of genitourinary injuries in stable patients, we have observed that extra-renal abdominal injuries are often detected by the imaging procedure and that many of these injuries are clinically occult. Detection of abdominal injuries after blunt trauma remains a challenge for the trauma surgeon. Physical examination alone has an overall accuracy of only about 65% for its ability to detect intra-abdominal injuries and is even less reliable in the presence of alcohol, drugs, or central nervous system injury . Physical examination is also less accurate in pediatric patients with multiple injuries. A recent review from a highly organized trauma system revealed that the most common error that contributed to the morbidity and mortality in trauma patients was failure to adequately evaluate the abdomen for the presence of injuries , We postulated that hematuria was a marker of abdominal injury in both adults and children and that the presence of hematuria should be added to the list of objective clinical criteria that prompt early diagnostic evaluation of the abdomen after blunt trauma.
PATIENTS AND METHODS The Renal Trauma Project at San Francisco General Hospital, which was instituted in 1977, contains extensive data on all patients entering the hospital with hematuria after either penetrating or blunt trauma. From a total of 1,484 patients who had both hematuria and blunt trauma entered into this registry, 160 patients were identified with extra-renal abdominal injuries detected either at the time of laparotomy or by abdominal CT scanning. The medical records of these 160 patients were reviewed extensively by the authors andare the focus of this report. The data gathered for this review included the followFromthe Departmentsof Surgery (MMK) and Urology(JWM, RG, ing factors: demographic data (age/sex/mechanism of PL), UniversityofCalifornia,San Francisco,and San FranciscoGener- injury); the presence or absence of shock in the prehospial Hospital,and San FranciscoCenter for InjuryPreventionand Research (HAS),San Francisco,California.Thisworkwas supportedby tal setting or during the resuscitative phase of the pathe San FranciscoCenter for InjuryPreventionand Researchand by tient's evaluation (shock defined as a systolic blood presGrant R49/CCR 903697-02 fromthe Centersfor DiseaseControl. sure of less than 90 mm Hg in adults and less than 80 mm Requests for reprints shouldbe addressedto MI Margaret Knud- Hg in children); the quantitative degree of hematuria; the son, MD, Department of Surgery, Ward 3A, San FranciscoGeneral objective findings on the initial physical examination of Hospital, 1001PotreroAvenue,San Francisco,California94110. Presentedat the 44th AnnualMeetingof the SouthwesternSurgi- the abdomen; the findings on abdominal CT scanning if it was performed; the nature and type of abdominal organ cal Congress,Scottsdale,Arizona,Apri! 26-29, 1992. 482
THE AMERICAN JOURNAL OF SURGERY VOLUME164 NOVEMBER1992
HEMATURiA AND ABDOMINAL TRAUMA
and renal injuries detected and the treatment of these injuries; the presence or absence of an altered level of consciousness at the time of the initial examination (i.e., the presence of head injury or use of alcohol or drugs); and the presence of any associated major injuries to the chest or extremities. For purposes of analysis, these data were entered into computer files. Statistical methods: The relationship between the degree of hematuria and the percentage of patients with significant intra-abdominal injury was tested using Spearman's rho correlation coefficient and comparing its value to a table of exact significant probabilities . All other statistical significance results were based on the X2 test, with a significance level of 0.05.
TABLE I E x t r a - R e n a l A b d o m i n a l I n j u r i e s Associated With Hematuria* Organ Injured
No. of Injuries
Spleen Liver Pancreas Small bowel Colon Mesentery Stomach Diaphragm Adrenal gland
81 66 17 16 11 8 6 6 !
*There were 212 involvedorgans in 160 patients.
RESULTS The 160 patients with blunt trauma, hematuria, and significant extra-renal abdominal injury included 113 in Table H. As can be seen, the likelihood of abdominal males and 47 females. Twenty-three pediatric patients injury generally increased with the degree of hematuria were included (age less than 18 years). The major mecha- present on the microscopic examination of the urine, nism of injury was related to motor vehicular trauma reaching 17% in the case in which red cells were too (53%), followed by pedestrian injuries (25%), falls (12%), numerous to count and 24% in the case in which gross and assaults (10%). Forty-two patients (26%) had a histo- hematuria was present. The presence of abdominal injury ry of shock in the field or became hypotensive during their was also strongly correlated with the presence of shock. early resuscitative phase. Fifty patients (31%) had no Statistical analysis of these data revealed that abdominal evidence of abdominal tenderness on the initial physical injury is significantly associated with increasing degrees examination. Fourteen patients had abdominal distension of hematuria regardless of the presence of shock (p as their only objective finding on examination of the