Notes from the Video

What You're Going to Learn from This Video on Diagnosing Appendicitis



As a surgeon one of the most common operations I do every week is a laparoscopic appendectomy...removing a child's appendix.

Whether you are an adult surgeon or a surgeon for children, being able to diagnose appendicitis is a skill you will be expert in.

In this video I go on a deep dive into the following questions about appendicitis:

1.  What is the typical and atypical history for a patient with acute appendicitis?

2.  What are the physical exam findings in acute appendicitis?

3.  What labs are most useful in diagnosing acute appendicitis?

4.  What imaging is important in acute appendicitis?

5.  What clinical prediction rules are helpful for acute appendicitis?

1.  What is the typical and atypical history for a patient with acute appendicitis?

As you are well aware I enjoy using the SRNOPDSARA format for my pain history taking. 

Using this format a typical history may look like the following...

12y male with right lower quadrant pain that is non radiating, it is crampy in nature and began this morning in the central abdomen, it is a constant pain with no pattern or periodicity since onset, reaching a severity of 8/10, aggravated by movement and pressure, relieved with lying still and associated with nausea, vomiting and diarrhea.

Unfortunately not every patient presents typically, some present atypically.

Atypical patients may present with appendicitis due to a number of different reasons:

Retrocecal appendix: In cases where the appendix is positioned behind the cecum (retrocecal appendix), the pain may be located in the right flank or back rather than the lower abdomen. This can lead to confusion and misdiagnosis, as the symptoms may mimic other conditions such as kidney stones or musculoskeletal problems.

Pelvic appendix: If the appendix is located in the pelvis, the pain may be felt in the lower pelvic region rather than the typical right lower quadrant. This can be mistaken for gynecological or urinary tract problems in females.  Often a person with pelvic pain will have painful urination as the inflamed appendix rests against the bladder or have a urine analysis demonstrating many white blood cells.

Appendiceal mass or abscess: In some cases, instead of the typical acute presentation, the inflammation of the appendix may lead to the formation of a localized mass or abscess. This can cause more gradual and persistent abdominal pain with associated symptoms such as a palpable mass, reduced appetite, and weight loss.

Elderly population: Older adults may experience atypical symptoms of appendicitis, including generalized abdominal pain, confusion, altered mental status, or lack of typical signs of inflammation. This can lead to delayed diagnosis and increased risk of complications.

Children: In young children, particularly infants and toddlers, the symptoms of appendicitis may be vague and non-specific. They may present with irritability, poor appetite, diarrhea, or general abdominal discomfort rather than localized pain.

Patients presenting with diarrhea and fever are more likely to have more advanced disease and complicated appendicitis.

2.  What are the physical exam findings in acute appendicitis?

Abdominal tenderness: The presence of localized tenderness in the right lower quadrant of the abdomen is a hallmark finding in acute appendicitis. Palpation of this area may elicit tenderness or discomfort.

Rebound tenderness: When pressure is applied to the abdomen and then suddenly released, the patient experiences increased pain upon release. This is known as rebound tenderness and is a characteristic sign of peritoneal irritation, including in cases of appendicitis.

Guarding and rigidity: In response to abdominal pain, the patient may involuntarily tense the abdominal muscles, resulting in guarding. Rigidity, or a tense and board-like abdomen, may also be present.

McBurney's point tenderness: McBurney's point is located in the right lower quadrant of the abdomen, about two-thirds of the distance from the umbilicus (belly button) to the anterior superior iliac spine (bony prominence in the lower pelvis). Tenderness or pain upon palpation of McBurney's point is a classic finding in appendicitis.

Rovsing's sign: Rovsing's sign is elicited by applying pressure to the left lower quadrant of the abdomen and observing if it causes increased pain in the right lower quadrant. This referred pain can be a positive indication of appendicitis.

Psoas sign: The psoas sign is elicited by asking the patient to lie on their left side and extend their right leg backward against resistance. Pain experienced in the right lower quadrant during this maneuver suggests irritation of the psoas muscle due to inflamed appendix.

Obturator sign: The obturator sign is performed by flexing the patient's right hip and knee and then internally rotating the hip. Pain felt in the right lower quadrant during this maneuver may indicate inflammation of the appendix irritating the obturator muscle.

In patients with a retrocecal tenderness often a patient will have costoverebral angle tenderness or right flank tenderness.

3.  What labs are most useful in diagnosing acute appendicitis?

When I'm evaluating appendicitis I find the following labs most helpful.

Complete Blood Count with a Differential

Increased white blood cell count (leukocytosis): In response to infection or inflammation, the body often produces more white blood cells (WBCs). In acute appendicitis, the WBC count is typically elevated, but it can vary. A WBC count greater than 10,000 to 15,000 cells per microliter is often considered indicative of an inflammatory response.

Shift to the left: In some cases, the CBC may show a left shift, which means an increase in the number of immature forms of white blood cells, such as band neutrophils. This shift suggests an active infection or inflammation.

Elevated neutrophil count: Neutrophils are a type of white blood cell involved in the body's response to infection and inflammation. In acute appendicitis, the neutrophil count is usually increased, reflecting the body's immune response.

C Reactive Protein (CRP)

CRP is a marker of inflammation. In acute appendicitis, CRP levels may be elevated, although this is a nonspecific finding and can be seen in other inflammatory conditions as well.

Basic Metabolic Profile

Electrolyte imbalances: In cases of severe or prolonged inflammation, there may be electrolyte disturbances. These imbalances can include decreased potassium (hypokalemia) or sodium (hyponatremia), which may be caused by factors such as decreased oral intake, vomiting, or dehydration.

Increased blood glucose levels: During times of physiological stress, such as in acute appendicitis, blood glucose levels may be elevated due to the release of stress hormones like cortisol. This response helps provide the body with energy to cope with the stress.

Another test that may be helpful in the septic patient or patient with septic shock would be an arterial blood gas and a better understanding of the acid base balance of the patient.

4.  What imaging is important in acute appendicitis?

Ultrasonography (Ultrasound): Ultrasound uses sound waves to create images of the internal organs. It is a non-invasive and readily available imaging option, particularly useful in children and pregnant women due to its lack of ionizing radiation. Ultrasound can help identify signs of appendicitis, such as an enlarged appendix, fluid collection around the appendix (pericecal fluid), or the presence of an appendicolith (calcified deposit within the appendix). However, the accuracy of ultrasound in diagnosing appendicitis can vary depending on factors such as patient body habitus and the experience of the sonographer.

There are direct signs and indirect signs on ultrasound.

The direct signs include non-compressibility, diameter >6mm, single wall thickness >3mm, appendicolith and hypervascularity. 

The indirect signs of acute appendicitis include free fluid around the appendix, a local abscess, increased echogenicity of the fat, thickened peritoneum and enlarged local lymph nodes.

Computed Tomography (CT) Scan: CT scan provides detailed cross-sectional images of the abdomen and pelvis, allowing for accurate assessment of the appendix and surrounding structures. CT scan is considered the most reliable imaging modality for diagnosing acute appendicitis, especially in adults and has a sensitivity of 99% and specificity of 98%. It can help visualize inflamed appendix, appendiceal abscess, or other complications. However, CT scan involves exposure to ionizing radiation, which is a potential risk, particularly in pregnant women and young individuals. Additionally, the use of intravenous contrast agents can have associated risks, such as allergic reactions or kidney injury in individuals with pre-existing kidney problems.

Magnetic Resonance Imaging (MRI): MRI uses a magnetic field and radio waves to generate detailed images of the body. It can provide excellent visualization of the appendix without exposing the patient to ionizing radiation. MRI is especially useful in pregnant women and individuals with a known contrast allergy. However, MRI is less commonly used for the initial diagnosis of acute appendicitis due to factors such as limited availability, longer scanning times, and higher costs compared to ultrasound or CT scan.

5.  What clinical prediction rules are helpful for acute appendicitis?

Clinical prediction rules for acute appendicitis are tools that use a combination of clinical signs, symptoms, and laboratory findings to assess the probability of an individual having appendicitis.

Two commonly used clinical prediction rules for appendicitis are the Alvarado score and the Pediatric Appendicitis Score (PAS).

Alvarado score: The Alvarado score is primarily used in adults and older children. It assigns points to various clinical features and laboratory findings. The total score helps classify patients into low, moderate, or high probability categories for appendicitis.

The following is a breakdown of the scoring system:

• Migration of pain to the right lower quadrant: 1 point
• Anorexia (loss of appetite): 1 point
• Nausea or vomiting: 1 point
• Tenderness in the right lower quadrant: 2 points
• Rebound tenderness: 1 point
• Elevated body temperature (>37.3°C or 99.1°F): 1 point
• Leukocytosis (WBC count >10,000/mm³): 2 points
• Shift to the left (presence of band cells): 1 point

Score of 0-3 is Low Risk

Score of 4-6 is Medium Risk

Score of > 7 is High Risk.

Pediatric Appendicitis Score (PAS): The PAS is specifically designed for children aged 2 to 18 years. It takes into account clinical features, laboratory values, and imaging findings. Similar to the Alvarado score, it helps categorize patients into low, moderate, or high probability groups.

The PAS includes the following components:

• Migration of pain to the right lower quadrant - 1 point
• Anorexia - 1 point
• Nausea or vomiting - 1 point
• Tenderness in the right lower quadrant - 2 points
• Pain with cough or percussion - 2 points
• Elevated temperature - 1 point
• Elevated white blood cell count - 1 point
• PMN > 75% - 1 point

Score of 0-3 is Low Risk

Score of 4-6 is Medium Risk

Score of > 7 is High Risk.

Each component is assigned a certain number of points, and the total score helps determine the probability of appendicitis.