2025 – PAGE 335 – INFECTIOUS DISEASES

FRANCISELLA TULARENSIS

Francisella tularensis causes GLANDULAR or ULCEROGLANDULAR DISEASE (AKA TULAREMIA) due to pleomorphic gram-negative organisms. Look for fever, hepatosplenomegaly, lymphadenopathy, ULCERS, and a history of exposure to deer or rabbits. It’s a tick-borne illness. Treat mild/moderate disease with GENTAMICIN or ciprofloxacin. Treat severe disease with GENTAMICIN or streptomycin.

MNEMONIC: Instead of Tularemia, say t-ULCER-emia.

MYCOBACTERIUM TUBERCULOSIS (MTB or TB)

If a patient has been diagnosed with typical mycobacterium tuberculosis (MTB or TB) and is found to have lymphadenopathy, treat with medications alone. Do NOT excise the lesion UNLESS it turns into a draining abscess. Lymphadenopathy tends to be painless.

ATYPICAL MYCOBACTERIA

Atypical mycobacteria include Mycobacterium avium-intracellulare (MAC) and Mycobacterium scrofulaceum. Look for a freely movable node without many other symptoms. First place a PPD. The result will show some induration, but it will NOT be large enough to diagnose TB. Once the induration is noted, surgical excision is curative, and no antibiotics are required. Lymphadenopathy tends to be painless.

BRUCELLOSIS

Brucellosis is caused by Brucella, a gram-negative organism. Look for fever, chronic cervical lymphadenopathy, myalgias, and hepatosplenomegaly. There may also be mention of a farm or exposure to unpasteurized milk products.

PEARL: For brucellosis WITHOUT focal disease from spondylitis, neurobrucellosis, or endocarditis:

• If >8 years use Doxycycline + either Rifampin OR Streptomycin OR Gentamicin.
• If <8 years use TMP-SMX + Rifampin. (Prolonged courses of doxycycline >21 days not recommended for <8 years old due to risk of dental staining.)

PEARL: For brucellosis WITH focal disease, there are different regimens based on whether the disease is due to spondylitis, neurobrucellosis, or endocarditis. So, here are some key points to remember:

• If >8 years use Doxycycline + Rifampin + “a 3rd medication” (an aminoglycoside for spondylitis or endocarditis, and ceftriaxone for neurobrucellosis).
• If <8 years use TMP-SMX + Rifampin + Streptomycin OR Gentamicin.

OTHER: Also consider Epstein-Barr Virus (EBV), Cytomegalovirus (CMV), and Toxoplasma gondii as causes of chronic lymphadenopathy.

LYMPHADENOPATHY IN OTHER AREAS

(DOUBLE TAKE) LYMPHOGRANULOMA VENEREUM SEROVAR

Lymphogranuloma Venereum Serovar is an STD caused by Chlamydia trachomatis. It is rare in the U.S. but more common in tropical areas. It starts as small nontender papules or shallow ulcers that resolve. Eventually, a TENDER UNILATERAL INGUINAL lymph node appears. Pain is relieved when it ruptures. The node can continue to drain for months. Treat with DOXYCYCLINE or erythromycin.

• PEARL: In general, when you think the diagnosis is due to a Chlamydia species, choose doxycycline or a macrolide (usually erythromycin). Also, this is an intracellular organism. Look for the phrase “intracytoplasmic inclusions.”