Acute cholecystitis is one of the most frequent causes of acute abdomen presented in worldwide emergency departments. General Surgeons are the most prepared doctors to diagnose such disease, because they are well familiarized with its signs and symptoms. Ultrasound (US) is the gold standard for diagnosis of acute cholecystitis, with a gallbladder wall thickening being one of the most important findings. However, imaging findings must be interpreted together with clinical and laboratory findings. Although this is a well known idea inside surgical community, doctors from different areas seem to forget it. It is not uncommon to have patients referred to surgeons with the diagnosis of acute cholecystitis, only because a gallbladder wall thickening was found. A patient can have a gallbladder wall thickening because of many different reasons.
Doctors from the "Department of Imaging Diagnosis of Santa Casa de Misericórdia de Ituverava", Brasil, published an interesting review article about how to interpret gallbladder wall thickening. According to the authors the gallbladder wall thickening was considered highly suggestive of acute cholecystitis in the early 20th century. However, this idea is changing, since other pathologies can also cause gallbladder wall thickening.
A correct interpretation of that thickening is crucial to treatment decision, which may include surgery. So, unnecessary surgeries can be avoid if a correct diagnosis is made.
Gallbladder wall thickening can be mild (4-7 mm) or severe (>7mm), and diffuse or focal. Barbosa et al. present three main groups of diseases responsible for gallbladder wall thickening:
Inflammatory
Acute calculous cholecystitis
Chronic calculous cholecystitis
Acalculous cholecystitis
Adenomyomatosis
Porcelain gallbladder
Neoplasm
Carcinoma of the gallbladder
Metastasis to the gallbladder (lymphoma, breast cancer, melanoma)
Systemic
Congestive heart failure
Hepatitis
Cirrosis
Ascites
Pyelonephritis
Pancreatitis
Diverticulitis
Acute calculous cholecystitis is the most frequent inflammatory cause of gallbladder wall thickening, which is usually < 7mm. However, because an isolated gallbladder wall thickening does not make the diagnosis, additional signs suggestive of acute cholecystitis must be looked for: impacted calculous in main bile duct; calculous in the infundibulum; distended gallbladder with a transversal diameter >4cm; positive sonographic Murphy's sign; pericholecystic fluid. The authors state that a gallbladder wall thickening together with a positive sonographic Murphy's sign has a positive predictive value of 94% for acute cholecystitis.
I must mention the acalculous cholecystitis, which sometimes is diagnosed by some fellow colleagues in patients who resorted to the emergency department by themselves and directly from their homes. Acalculous cholecystitis is found in patients suffering severe trauma and/or burns, and in Intensive Care Unit patients with invasive ventilation. So, patients walking into the emergency department by themselves will most probably not have an acalculous cholecystitis. In that setting, most of the times an acalculous cholecystitis is a misdiagnosis (gallbladder stones are too small to be found or a systemic disease is responsible for gallbladder wall thickening).
Several systemic diseases can cause gallbladder wall thickening. However, a difference can be found. Mucosa will be regular in these disorders, contrasting with mucosa irregularity in acute cholecystitis. Barbosa et al. state that any inflammatory process affecting the upper abdominal quadrant can cause gallbladder wall thickening namely: diverticulitis of ascending/transverse colon, appendicitis with high appendix, pyelonephritis, duodenal ulcer. Additionally, 64% of acute pancreatitis will course with gallbladder wall thickening due to extension of inflammation. This means there is no cholecystitis plus pancreatitis, but an acute pancreatitis with a gallbladder wall thickening secondary to pancreatic inflammation, I think.
The main aim of this post is to highlight some systemic diseases, treated by doctors from different areas, that can cause a gallbladder wall thickening. Hepatitis can cause a regular and diffuse wall thickening. Patients with AIDS can have a gallbladder wall thickening secondary to antiretroviral medications or opportunistic biliary tract infections. Cirrosis and ascitis can promote a gallbladder wall thickening due to hypoalbuminemia. Congestive heart failure will cause high intrahepatic venous pressure (cardiac liver) which will be responsible for a gallbladder wall thickening, a common finding in these cardiac patients.
So, when some colleague comes to you and say - "I have a patient with acute cholecystitis because he has a gallbladder wall thickening in abdominal US" - first thing to do is perform a clinical evaluation. If there is no abdominal pain, an abdominal examination with no tenderness and no Murphy's sign, and normal blood tests, the wall thickening is probably due to a systemic disorder. A gallbladder wall thickening does not mean acute cholecystitis.
The authors concluded that a gallbladder wall thickening does not mean acute cholecystitis.
This review conducted by radiologists is very important so that US findings can be interpreted correctly. For this is very important that all doctors involved in diagnosis process (radiologists included - they are not technicians who perform image exams) take into account signs and symptoms, and laboratory findings. Doctors must keep in mind that imaging is only an adjuvant to diagnosis and treatment decision, and that clinical evaluation is the most important factor in medicine. A correct diagnosis and treatment are only possible if clinical evaluation rules all the process. Imaging and laboratory findings must be interpreted accordingly to clinical evaluation. This interpretation is based on knowledge but is also an art. Medicine is knowledge and art.
Link to Scielo:
Dr. Carlos Eduardo Costa Almeida
General Surgeon