Thanks to Dr. Jeffrey D. Cirillo for his outline and presentation, which was the basis of this post.

The most common lymph node swelling is due to infection (lymphadenitis).

  • Groin, armpit, neck, under jaw/ears
  • Oncological vs. microbiological
    • Acute onset (infection) or gradual onset (cancer)
    • Painful (infection) or painless (cancer -usually)
    • Resolve in a few weeks (viral, self-limiting)
    • Fever, night sweats, weight loss (infection, serious)
    • Red, discolored, black/blue (infection, serious)

      Lymph node
      By KC Panchal – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4360228
    • Continually increasing, no other indicator (cancer)
  • Lymphadenitis –Common Causes
    • Streptococcus, Staphylococcus (local skin)
    • Mononucleosis (cervical)
    • Tuberculosis (mediastinal, hilaradenopathy)
    • Tularemia (regional, cervical)
    • Yersinia (cervical, abdominal)
    • Salmonella (general)
    • Rubella (auricular, posterior cervical, occipital)
    • Atypical mycobacterial infections (submandibular)
    • Histoplasmosis(mediastinal, hilar)
    • Chlamydia (conjunctivitis)
    • Toxoplasmosis (general)
    • Brucella(cervical, rare)
  • Diagnostic Approach
    • History (chronic vs. acute, other indicator).
    • Blood work (liver, kidney, CBC, differential)
      • Lymphocytes, neutrophils (infection, leukemia)
      • Monocytes (infection)
      • Eosinophils(cancer, parasitic infection)
    • Chest X-ray (armpit/neck nodes)
    • Platelet count (certain cancers)
    • Liver-spleen scan
  • Tularemia-F. Tularensis
    • Rabbits, summer, arthropods
    • Gram negative, coccobacilli, facultative intracellular pathogen, survives in phagocytes
    • Tularemia I S/S-regional LAD with ulceration 3-5 days, painless rash
    • Tularemia II S/S-infection of spleen, liver, bone, lung, granulomas
    • Dx-poorly staining, four-fold increase in titers, persistent Ab, ELISA and Cx positive
    • Tx-aminoglycosides
    • Prevention-limited exposure to rabbits, cook meat well, live attenuated vaccine
  • Bubonic Plague-Yerninia Pestis
    • Rats, fleas, human to human (droplets)
    • Gram negative rod, facultative intracellular, anaerobe, capsulated
    • Interaction with host cells via surface adhesins
    • S/S-LAD with buboes, painful (2-6 days after flea bite), fever, confusion, back and limb pain
    • Dx-blood cx, low level bacteremia, bubo aspirate, sputum (pneumonic), direct fluorescent microscopy, serology, blood agar cx
    • Tx-tetracycline or streptomycin, gentamicin/doxy/cipro
    • Prevention-vaccine, rodent control, isolation/quarantine
  • Brucellosis-Brucella spp.
    • Livestock, humans are accidental hosts, ingestion (milk), contact/inhalation
    • Gram negative bacilli
    • Spreads via lymph, disseminated form causes bacteremia (RES), phagocytosis (granulomas)
    • S/S-FUO days to months after exposure (cyclical), malaise, aches, liver dysfunction, granulomas, LAD, osteomyelitis, endocarditis
    • Chronic S/S-(one year of illness) fatigue, aches and pains, depression, anxiety, occasional fever
    • Dx-Cx (blood or tissue), titers >1:160 is presumptive
    • Tx-Doxy and rifampin 6-12 weeks
    • Prevention-cattle vaccination, pasteurization of milk, vaccine high risk population
  • Chlamydia-C. Trachomatis
    • STI/STD, can also cause cervicitis, urethritis, trachoma, conjunctivitis
    • Gram negative cocci/oval, obligate intracellular pathogen
    • S/S-(lymphogranuloma), first stage-small painless vesicular lesion, fever, headache, and myalgia; second stage-LAD, fever, headache, myalgia, buboes, proctitis, ulcers or elephantiasis
    • Dx-Cytology and Cx-iodine staining inclusions, ELISA (LPS), NAT
    • Tx-tetracycline, erythromycin, sulfonamides
    • Prevention-safe sex habits, treat partners too
  • Toxoplasmosis-Toxoplasma gondii
    • Domestic cat, humans accidental hosts
    • Obligate intracellular parasite
    • ⅓ risk of fetal infection with primary maternal infection in pregnancy, death higher in 1st trimester, more infections in 3rd trimester
    • Fetus/newborn infections-70-90% are asymptomatic at birth
    • Classic triad of symptoms: Chorioretinitis, Hydrocephalus, Intracranial calcifications
    • S/S include fever, rash, hepatosplenomegaly, microcephaly, seizures, jaundice, thrombocytopenia, lymphadenopathy
    • Initially asymptomatic infants are still at high risk of developing abnormalities, especially chorioretinitis
    • Dx-maternal IgG testing indicates past infection, cx-placenta umbilical cord, infant serum, newborn serologies with IgM/IgA
    • Tx-adults-sulfadiazine and pyrimethamine plus leucovorin; pregnant women-spiramycin; fetus dx-treat mother spiramycin, pyrimethamine, and sulfadiazine, leucovorin rescue for pyrimethamine; symptomatic newborns-pyrimethamine, leucovorin, and sulfadiazine for 12 months; asymptomatic newborns-same as symptomatic newborns, tx one month
    • Prevention-cook meat completely, freezing meat, washing hands/utensils/dishes contact raw meat; environment don’t drink untreated water, keep away from soil used by cats, wear gloves when changing litter box, keep cats indoors, don’t get a new cat or handle unknown cats while pregnant