How can I differentiate between biliary colic and acute cholecystitis in a primary care setting?

Differentiating between biliary colic and acute cholecystitis in a primary care setting primarily hinges on the presence of systemic unwellness and the nature of the pain ¹,².

• Systemic Unwellnes: This is the most crucial differentiator. People with biliary colic typically present with a self-limiting attack of pain that lasts for hours and are generally not systemically unwell ¹. In contrast, if acute cholecystitis is suspected, the person is likely systemically unwell and requires emergency admission ¹,².
• Pain Characteristics: Biliary colic usually presents as a self-limiting attack of pain lasting for hours, which can often be controlled with appropriate analgesia in primary care ¹. Nonsteroidal anti-inflammatory drugs (NSAIDs) like diclofenac are effective for biliary colic pain and may reduce the risk of developing acute cholecystitis ¹. Acute cholecystitis pain may be more persistent and is often associated with systemic signs ².
• Management and Referral Urgency:
  • For biliary colic, initial management in primary care involves pain relief (e.g., diclofenac 75 mg intramuscularly, or an opioid if NSAIDs are unsuitable or ineffective) and advice on a low-fat diet to help prevent further episodes ¹. Emergency referral to hospital is indicated only if the pain cannot be managed in primary care or if the person becomes systemically unwell ¹.
  • For acute cholecystitis, immediate hospital admission is required for confirmation of diagnosis, monitoring, treatment (including intravenous fluids, antibiotics, and analgesia), and surgical assessment ². This is an emergency referral ¹,². Early laparoscopic cholecystectomy (within 1 week of diagnosis) is recommended for people with acute cholecystitis ³.
• Complications and Prognosis: Acute cholecystitis carries a significant risk of complications such as gallbladder necrosis, abscess formation, or perforation, and has a higher mortality rate compared to biliary colic ². About 25–30% of people with acute cholecystitis will require surgery or develop complications ². Biliary colic, while painful, is generally self-limiting and less prone to these severe complications unless it progresses to cholecystitis ¹.
• Diagnostic Confirmation: While both conditions may involve gallstones, the definitive diagnosis of acute cholecystitis requires a combination of detailed history, complete clinical examination, laboratory tests (such as a white blood cell count, C-reactive protein, and serum amylase), and imaging (such as abdominal ultrasound) in secondary care ²,³. There is no single feature or test with sufficient diagnostic power to establish or exclude acute cholecystitis in primary care ².