Clinical Triads for the Physician Assistant Exam
The Physician Assistant Exam (PANCE) question-makers love clinical triads because they are a great resource for test questions. When you understand common triads, you’re one step ahead of everyone else.
Virchow’s Triad: Thrombosis
Virchow’s triad of stasis, hypercoagulable state, and endothelial dysfunction are thought to be components of or causes of thrombosis. When you’re reading questions concerning a deep venous thrombosis (DVT) or hypercoagulable state, you may well be dealing with some abnormality of this triad.
Scenarios you encounter on an exam typically include a person who’s been on a long plane trip or car ride who develops a lower extremity DVT. In other scenarios, the person may have had a prolonged surgery or have been immobilized for a long period of time. You may need to determine the duration of anticoagulation. All these scenarios concern issues of stasis predisposing to a DVT.
Charcot’s Two Triads: Ascending Cholangitis or Multiple Sclerosis
Jean-Martin Charcot actually came up with two different triads. The first Charcot’s triad concerns the triad of ascending cholangitis, and the second is related to the triad of multiple sclerosis (MS).
Ascending cholangitis is an infection of the biliary tract and is a medical emergency. Charcot’s triad concerning the biliary tract is right upper-quadrant (RUQ) pain, fever, and jaundice. Here’s a high-yield fact: The most common medical condition associated with ascending cholangitis is inflammatory bowel disease (IBD).
Charcot’s triad concerning MS is nystagmus, intention tremor, and dysarthria. These symptoms can clue you in that MS may be present. Another big symptom for MS is optic neuritis.
Don’t confuse Charcot’s triad as it pertains to MS with the triad of Wernicke’s encephalopathy. Wernicke’s is caused by a thiamine deficiency, usually secondary to alcoholism and poor nutritional status. The immediate treatment is thiamine; the longer term treatment is to stop drinking.
Beck’s Triad: Cardiac Tamponade
You don’t want to miss Beck’s triad, either clinically or on the test. The triad consists of three important signs of cardiac tamponade. The signs are jugular venous distention (JVD), shock, and distant or muffled heart sounds. Cardiac tamponade is a surgical emergency requiring emergent pericardiocentesis.
On the PANCE, you’ll be given a patient scenario and asked about managing a patient in shock.
Saint’s Triad: Gallstones, Hiatal Hernia, Diverticular Disease
Saint’s triad consists of gallstones, hiatal hernia, and diverticular disease. This triad teaches an important lesson, both in test-taking and in clinical medicine. Although many people have all three of these separate conditions, there isn’t one unifying diagnosis that explains them.
Whipple’s Triad: Insulinoma
Whipple’s triad consists of three criteria that alert the clinician that a person’s diaphoresis, tremulousness, and shakiness may be due to hypoglycemia. If symptoms are present and the following happens, insulinoma may be present. The procedure goes like this:
The patient demonstrates diaphoresis, tremulousness, and shakiness.
While the person is having the symptoms, the clinician checks the blood glucose level to be certain that hypoglycemia is present at the same time as the symptoms.
Normalizing the blood glucose normalizes the person’s symptoms.
Don’t confuse Whipple’s triad with Whipple’s disease, which is a malabsorption syndrome caused by the Tropheryma whipplei bacterium. Whipple’s disease, which is also referred to as tropical sprue, involves two big-ticket points:
Recognition of the disease by means of a positive periodic acid-Schiff stain as found on intestinal biopsy
Treatment for 1 year with trimethoprim/sulfamethoxazole (Bactrim)
Dieulafoy’s Triad: Acute Appendicitis
Dieulafoy’s triad deals with acute appendicitis. This is a big-payoff surgical test question, and it’s easy to grasp.
Dieulafoy’s triad consists of abdominal tenderness, skin hypersensitivity, and contraction of the muscle at McBurney’s point. McBurney’s point is a point on the right side of the abdomen, one-third the distance from the anterior superior iliac spine (ASIS) to the umbilical area.
Sampter’s Triad: Aspirin Sensitivity
Sampter’s triad, also known as the aspirin triad, is a medical condition consisting of asthma, sensitivity to aspirin, and nasal polyps. This is one of those medical syndromes where you either recognize the clinical presentation or you don’t. It usually occurs in young people in their late twenties and early thirties. They have significant sensitivity to acetylsalicylic acid; however, people with this syndrome are able to tolerate acetaminophen.
The treatment is to desensitize the person to aspirin. Steroids and leukotriene agonists may be needed.
Waddell’s Triad: High-Impact Childhood Trauma
Waddell’s triad is a recurrent topic. The triad is associated with childhood trauma, specifically in a child hit by a motor vehicle. With this triad, it refers to high impact trauma. The triad consists of femur fracture, traumatic injuries to the chest or abdomen, and injuries to the opposite side of the head. Waddell’s triad isn’t very common, but it is something to be aware of for the PANCE.
Cushing’s Triad: Head Trauma
If you see test questions about any type of head trauma, remember Cushing’s triad. This triad consists of a decreased heart rate, altered respiratory pattern, and increased systolic blood pressure. These three changes are a consequence of increased intracranial pressure associated with head trauma.
Don’t confuse Cushing’s triad with Cushing’s syndrome or Cushing’s disease. Any medical condition that causes the adrenal gland to secrete excess cortisol is called Cushing’s syndrome. If the cause of the excess cortisol is a tumor in the pituitary gland (making excess ACTH), then the condition is called Cushing’s disease. In other words, Cushing’s disease is one of myriad causes of Cushing’s syndrome.
Bergmann’s Triad: Fat Embolism
Bergmann’s triad is often seen in the context of a fat embolism. This triad consists of abrupt onset of shortness of breath, change in mental status, and petechial lesions along the chest and axillary area. Fat embolism is an emergent medical condition.
Fat embolism is a common occurrence after many orthopedic procedures. It’s also described after a trauma, usually if there are fractures of the long bones. In addition to the triad, note that fat embolism can cause bilateral pulmonary infiltrates consistent with acute respiratory distress syndrome (ARDS).