Appendicitis: Clinical sciences

Appendicitis refers to inflammation of the appendix, which is usually caused by obstruction of the appendiceal lumen by tumors, fecaliths, or hard fecal masses, and lymphoid hyperplasia. When the appendix is obstructed, the pressure inside it increases. This causes local stasis of lymphatic flow, occlusion of small vessels, and bacterial overgrowth, which can eventually lead to ischemia and necrosis of the appendix.

Now, appendicitis can be classified as uncomplicated or complicated. In uncomplicated appendicitis, the appendix is only inflamed; while in complicated appendicitis, it may develop perforation, phlegmon, or abscess.

If you suspect appendicitis the first thing you should do is an ABCDE assessment, to determine if your patient is unstable or stable. If the patient is unstable, which usually results from sepsis, you should first stabilize their airway, breathing, and circulation. This means that you may need to intubate the patient, establish IV access, or administer fluids before continuing with your assessment.

However, if your patient is stable, your next step is to obtain a focused history and physical examination, as well as labs such as a CBC and CRP. Now, history typically reveals abdominal pain, which starts around the umbilicus and migrates to the right lower quadrant. Additionally, the patient might report fever, nausea, vomiting, and anorexia.

On physical examination, individuals usually present with tenderness in the affected area, most commonly the right lower quadrant, especially at a region called McBurney point, located one-third of the distance from the anterior superior iliac spine to the umbilicus. Some additional physical exam findings that can help you recognize appendicitis include the Rovsing, psoas, and obturator signs.

A Rovsing sign is positive when you palpate your patient’s left lower quadrant and your patient feels pain in the right lower quadrant. This indicates peritoneal irritation of the right side of the abdomen. On the other hand, a psoas sign is positive when passive extension of the patient’s right hip causes right lower quadrant pain. This indicates an inflammation of an appendix that is retrocecal, or situated behind the cecum. Finally, the obturator sign is positive if internal rotation of the hip with the knee and hip flexed causes pain in the patient’s right lower quadrant. This may indicate an appendix located in the pelvis. Lastly, it’s extremely important to evaluate for peritoneal signs, such as local or diffuse rebound tenderness, as well as rigidity, and guarding.

Now, when it comes to labs, you might see leukocytosis with a left shift, and an elevated CRP. These lab findings are not specific for acute appendicitis but may support the diagnosis. Alright, if you suspect acute appendicitis based on the history, physical examination, and lab findings, make sure to initiate acute management. This includes starting IV fluids as well as administering antiemetics and pain medications as needed. Additionally, you should keep the patient NPO.

After initiating the acute management, your next step is to confirm the diagnosis. To do this, order a CT scan of the abdomen and pelvis with IV contrast to assess the appendiceal diameter and wall thickness, and whether any fat stranding is present. A high yield fact to remember is that some institutions prefer starting with an ultrasound because it’s quicker, more cost efficient, and avoids radiation exposure. This is especially important in the pediatric population. If the imaging reveals an appendiceal diameter of less than 6 mm; appendiceal wall thickness of less than 3 mm; and no fat stranding around the appendix, then appendicitis is unlikely, so you should consider other diagnoses, such as mesenteric adenitis.