From the Research
The clinical sign characterized by the appearance of a hernia when a patient is standing but not when lying down is called Carnett's sign. This sign is a key diagnostic feature of abdominal wall hernias, particularly inguinal, femoral, and umbilical hernias. When a patient stands, gravity and increased intra-abdominal pressure cause the hernia contents to protrude through the defect in the abdominal wall. When the patient lies down, the hernia contents often return to the abdominal cavity spontaneously or can be manually reduced, making the hernia disappear. This phenomenon occurs because in the supine position, intra-abdominal pressure decreases and gravity no longer pulls the abdominal contents toward the defect.
Key Points to Consider
- Carnett's sign is used to distinguish intrabdominal from abdominal wall diseases, as mentioned in the study by 1.
- The sign is characterized by the appearance of a hernia when a patient is standing, but not when lying down, which is a key diagnostic feature of abdominal wall hernias.
- Reducibility is an important clinical characteristic that helps distinguish uncomplicated hernias from those that are incarcerated or strangulated, which remain protruded regardless of position and represent surgical emergencies.
- During physical examination, having the patient change positions from lying to standing while observing and palpating the suspected hernia site is essential for proper diagnosis, as noted in the study by 2.
- It is sometimes hard to diagnose anterior cutaneous nerve entrapment syndrome without testing for Carnett's sign, as mentioned in the study by 3.
Diagnosis and Treatment
- The diagnosis of abdominal wall hernias can be made using patient history, physical examination, and response to a trigger point injection, as noted in the study by 4.
- The mainstay of treatment consists of reassurance, activity modification, over-the-counter analgesic agent, and trigger point injection, as mentioned in the study by 4.
- In rare cases, treatment with chemical neurolysis or surgical neurectomy may be required, as noted in the study by 4.