Clinical application of infrared thermography in the diagnosis of appendicitis

Signs and symptoms of serious illness in adults with acute abdominal pain presenting to ambulatory care: a systematic review

BACKGROUND

Acute abdominal pain is a common complaint, caused by a variety of conditions, ranging from acutely life-threatening to benign and self-limiting, with symptom overlap complicating diagnosis. Signs and symptoms may be valuable when assessing a patient to guide clinical work.

AIM

Summarising evidence on the accuracy of signs and symptoms for diagnosing serious illness in adults with acute abdominal pain in an ambulatory care setting.

DESIGN & SETTING

We performed a systematic review, searching for prospective diagnostic accuracy studies that included adults presenting with acute abdominal pain to an ambulatory care setting.

METHOD

Six databases and guideline registers were searched, using a comprehensive search strategy. We assessed the risk of bias, and calculated descriptive statistics and measures of diagnostic accuracy. Results were pooled when at least four studies were available.

RESULTS

Out of 18 923 unique studies, 16 studies with moderate to high-risk bias were included. Fourteen clinical features met our criteria, including systolic blood pressure <100 mmHg (positive likelihood ratio [LR+]7.01), shock index >0.85, uterine cervical motion tenderness (LR+5.62 and negative likelihood ratio [LR-]8.60), and a self-assessment questionnaire score >70 (LR+12.20) or <25 (LR-0.19). Clinical diagnosis made by the clinician had the best rule-in ability (LR+24.6).

CONCLUSIONS

We identified 14 signs and symptoms that can influence the likelihood of a serious illness, including pain characteristics, systemic signs, gynaecological signs, and clinician's overall assessment. The risk of bias was moderate to high, leading to uncertainty and preventing us from making firm conclusions. This highlights the need for better research in this setting.

Abdominal pain in children

Abdominal pain and gastrointestinal symptoms such as vomiting or diarrhea are common chief complaints in young children who present in emergency departments. It is the emergency physician's role to differentiate between a self-limited process such as viral gastroenteritis or constipation and more life-threatening surgical emergencies. Considering the difficulties inherent in the pediatric examination, it is not surprising that appendicitis, intussusception, and malrotation with volvulus continue to be among the most elusive diagnoses. This article reviews both the self-limited and more life-threatening gastrointestinal conditions that may present in the emergency department.

Meta-analysis of the clinical and laboratory diagnosis of appendicitis

BACKGROUND

The importance of specific elements in the clinical diagnosis of appendicitis is controversial. This review analyses the diagnostic value of elements of disease history, clinical findings and laboratory test results in suspected appendicitis.

METHODS

A systematic Medline search was made of all published studies on the clinical and laboratory diagnosis of appendicitis in patients admitted to hospital with suspected disease. Meta-analyses of receiver-operator characteristic (ROC) areas, and positive and negative likelihood ratios, of 28 diagnostic variables described in 24 studies are presented.

RESULTS

Inflammatory response variables (granulocyte count, proportion of polymorphonuclear blood cells, white blood cell count and C-reactive protein concentration), descriptors of peritoneal irritation (rebound and percussion tenderness, guarding and rigidity) and migration of pain were the strongest discriminators, with ROC areas of 0.78 to 0.68. The discriminatory power of the inflammatory variables was particularly strong for perforated appendicitis, with ROC areas of 0.85 to 0.87. Appendicitis was likely when two or more inflammatory variables were increased and unlikely when all were normal.

CONCLUSION

Although all clinical and laboratory variables are weak discriminators individually, they achieve a high discriminatory power when combined. Laboratory examination of the inflammatory response, clinical descriptors of peritoneal irritation, and a history of migration of pain yield the most important diagnostic information and should be included in any diagnostic assessment.

Abdominal surgical emergencies in infants and young children

Surgical emergencies can be missed easily in children, who are not always able to volunteer relevant information. Awareness of the entities discussed in this review might help the EP uncover subtle clues to early diagnoses that might not be initially apparent. Ill-appearing children who have abdominal pain and vomiting should be considered to have ischemic or necrotic bowel until proven otherwise. Possible diagnoses include volvulus, intussusception, and necrotizing enterocolitis. Bilious vomiting, especially in a young infant, should be considered to be an indication of a high bowel obstruction such as midgut volvulus, which warrants immediate surgical consultation. Significant rectal bleeding with abdominal pain can result from intussusception, volvulus, or an inflamed Meckel's diverticulum. Rectal bleeding with unstable vital signs can result from an upper GI bleed (eg, peptic ulcer disease). Painless rectal bleeding can result from a Meckel's diverticulum, polyps, arteriovenous malformation, or a tumor. Examination of the genitalia is imperative, especially in boys, to exclude the possibility of an incarcerated hernia or testicular torsion.

Timing of the thermographic assessment of burns

The thermographic assessment of burns using infrared imaging has previously been shown to be a useful aid in the estimation of burn depth. In this study, thermographic images of burns, obtained from 65 patients over a 4-year period, were reviewed. An infrared transparent, water-impermeable membrane was used as a wound cover to abolish evaporative cooling artefacts. Single images were obtained from patients with burns to various parts of the body, excluding the hands. A significant change in the temperature of deep burns was observed between days 2 and 3 after injury (chi-square, P < 0.01; Fisher exact probability test between days 2 and 3, P < 0.01). The results of this study suggest that thermography of burns, to assess depth, should be performed within 3 days following the injury.

Accuracy of serum C-reactive protein measurements in diagnosis of acute appendicitis compared with surgeon's clinical impression

Diagnosis of acute appendicitis is established generally by the surgeon's clinical impression. Today, negative laparotomy rate because of clinical diagnosis is still 15 to 25 percent.

PURPOSE

This study was designed to determine the accuracy of C-reactive protein (CRP) measurements in the diagnosis of acute appendicitis and to compare it with the surgeon's clinical diagnosis.

METHODS

One hundred eight consecutive patients were studied prospectively. Depending on results of the examination by a surgeon, patients underwent surgery for acute appendicitis. Serum CRP measurements were performed before the operations but were not taken into account for the decision of laparotomy to compare it with the surgeon's clinical diagnosis.

RESULTS

Histopathologic findings confirmed acute appendicitis in 90 patients. Normal appendixes were removed in the remaining 18 patients. Mean serum CRP value was 5 (range, 0-12.6) mg/l in patients with normal appendix, 33.8 (range, 5-85.1) mg/l in patients with nonperforated appendicitis, and 128.5 (range, 79.2-230) mg/l in patients with perforated appendixes. These differences were highly significant (P < 10(-6)). Serum CRP levels were normal in three patients with acute appendicitis. Thus, the false-negative rate of CRP was 3 percent. Of 18 patients with normal appendectomy serum CRP levels were slightly elevated in two patients. We determined, therefore, a false-positive rate of CRP as 11 percent. CRP levels were false-negative in three patients and false-positive in two patients. Thus, CRP levels were true (positive or negative) in the remaining 103 patients. On the other hand, the diagnosis depending on surgeon's clinical impression was true in 90 patients and false in 18 patients. This difference was statistically significant (P = 0.0035). In the present study the sensitivity, specificity, and accuracy of serum CRP measurements were calculated as 93.5, 80, and 91 percent, respectively.

CONCLUSION

We found that elevated serum CRP levels support surgeon's clinical diagnosis. We recommend CRP measurement as a routine laboratory test in patients with suspected diagnosis of acute appendicitis.