Читать книгу Point-of-Care Ultrasound Techniques for the Small Animal Practitioner - Группа авторов - Страница 271

Evaluation of the gallbladder wall is generally easily accomplished due to the contact between the anechoic bile and the more echogenic gallbladder wall and surrounding hepatic parenchyma. The normal gallbladder wall appears as an echogenic (white) line surrounding the luminal contents (see Figure 8.4A–C). Diffuse gallbladder wall thickening may occur with a wide range of conditions such as acute or chronic cholecystitis, hepatitis, canine anaphylaxis (Quantz et al. 2009), right‐sided heart failure, iatrogenic volume overload (Nelson et al. 2010), and hypoalbuminemia (Nyland et al. 2002) (see Chapters 7, 20, 26, and 36). Therefore, the finding must be interpreted in conjunction with additional ultrasound findings as well as clinical signs and biochemical alterations (Figure 8.11; see also Figures 7.11, 7.12, 18.22, and 39.6).

Generally, gallbladder wall thickening is nonspecific for any of the above conditions and thickening is typically associated with wall edema with similar sonographic features despite the underlying pathologic cause (see Figure 8.11 and Table 7.5). Most commonly, the gallbladder wall appears diffusely hypoechoic with parallel hyperechoic lines on either side, referred to as a “double rim effect” or “halo effect” (Nyland et al. 2002; Quantz et al. 2009) (see Figures 7.11, 7.12, 18.22, and 39.6). This change needs to be distinguished from small‐volume fluid external to the gallbladder, where effusion within the gallbladder fossa can mimic the double rim or halo effect. Focal and/or irregular thickening of the gallbladder wall is less common, and may be consistent with chronic cholecystitis or neoplastic change. A flaccid or undulating gallbladder wall may be consistent with wall rupture and warrants correlation to the index of suspicion for biliary peritonitis as well as clinical and biochemical assessment of the patient.

Pearl: In patients in which peritonitis is suspected (ruptured gallbladder, perforated bowel, low‐grade bleed), especially in dehydration, fluid resuscitation and reevaluation (serial exam within the next 2–4 hours) with AFAST and an abdominal fluid score often prove most helpful because once rehydrated, peritoneal effusion develops or progresses (higher abdominal fluid score) and sampling for fluid characterization becomes possible.