2025 – PAGE 336 – INFECTIOUS DISEASES

YERSINIA PESTIS

Yersinia pestis causes the PLAGUE. This is still found in the Southwestern U.S. Look for a fever associated with painful and swollen lymphadenopathy. Lymphadenopathy in the inguinal and axillary regions is especially common. Aspirate the lymph nodes to get a diagnosis and then treat with streptomycin.

PEARL: Look for a history of being in or near the woods, for example, a teenager who went hunting. Also, “bubo” means swollen lymph node. Hence the name, Bubonic Plague.

MNEMONIC: “PESTI” Plague.

NONTENDER LYMPHADENOPATHY

NOTE: Please do not assume that all of the lymphadenopathies discussed outside of this section are tender lymphadenopathies.

SPOROTRICHOSIS (AKA ROSE PICKER’S DISEASE)

For sporotrichosis (AKA rose picker’s disease), look for a single, PAINLESS, movable nodular lesion that enlarged, became fluctuant, and then ulcerated. This is a slowly progressive disease and is caused by Sporothrix schenckii. After that additional painless, movable nodules appear along the lymphatic system. The primary treatment is itraconazole, or amphotericin B for those who are severely ill. Other treatments include terbinafine, fluconazole, and potassium iodide (“saturated solution of potassium iodide,” “SSKI”).

PEARL: This used to be called rose-picker’s disease. Look for a history that includes a garden.

MYCOBACTERIUM TUBERCULOSIS

The lymphadenopathy of Mycobacterium tuberculosis tends to be painless.

ATYPICAL MYCOBACTERIA

The lymphadenopathy of atypical mycobacteria tends to be painless.

(DOUBLE TAKE) HODGKIN’S LYMPHOMA

Hodgkin’s lymphoma accounts for almost HALF of lymphoma cases and has a GOOD prognosis with GOOD cure rates. Signs and symptoms progress in a stepwise fashion. Look for a TEENAGE patient with NONTENDER CERVICAL or SUPRACLAVICULAR lymphadenopathy. It always starts this way! That will then be accompanied by fevers, fatigue, night sweats, and weight loss. Later in the course, there is also generalized lymphadenopathy. On labs, the patient may have a normal or high LEUKOcyte count (WBC), but must have either high or low LYMPHOcytes. DIAGNOSE with an excisional node biopsy and note REED STERNBERG CELLS, which are usually of B-cell origin.

PEARL: Your differential may include TB or Atypical Mycobacteria. For a NEGATIVE PPD, choose Hodgkin’s. For a slightly positive PPD (5-10 mm), choose Atypical Mycobacteria. For a PPD that is > 15 mm, choose MTB.

IMAGE: www.pbrlinks.com/HODGKINS1 = RS Cells

MNEMONIC: REED Sternberg cells kind of look like OWLS’ EYES, so imagine a STERN OWL wearing glasses and REEDing a book on a farm. The farmer comes outside and takes a shot at the OWL. He misses the OWL but hits the book. The OWL flies away SAFELY (high cure rate). Whew! That owl really “HODGED” a bullet.