2025 – PAGE 334 – INFECTIOUS DISEASES

INTESTINAL LYMPHANGIECTASIA

Intestinal lymphangiectasia is a protein losing enteropathy. Look for steatorrhea associated with a low serum protein, low serum gammaglobulin level, edema, and possibly lymphopenia.

FAT AND CARBOHYDRATE MALABSORPTION

• FAT MALABSORPTION: If you are concerned about this (possibly due to a clinical vignette describing a fat-soluble vitamin deficiency), obtain fecal fat testing.
• CARBOHYDRATE MALABSORPTION: Look for positive reducing substances on stool testing, or a positive hydrogen breath test.

ACUTE LYMPHADENOPATHY (< 3 WEEKS) IN THE HEAD AND NECK AREA

PEARLS: For all lymphadenopathy evaluations in the head and neck area, always check HOW LONG the lymphadenopathy has been present! For a unilateral lymphadenopathy, consider choosing a BACTERIAL infection as your answer. ALL of the upcoming lymphadenopathy sections are VERY high-yield. For the most part, highlighting has been turned off.

STAPHYLOCOCCUS AUREUS AND STREPTOCOCCUS PYOGENES (AKA GAS or STREP PYOGENES)

• Staphylococcus aureus and Streptococcus pyogenes (AKA GAS or Strep Pyogenes): Look for cervical or submandibular lymphadenopathy in a neonate or infant. This may also present as a breast abscess.
  • PEARL: This is one of the few places where Staph is the correct answer for a neonate. Also, while GBS is a common answer for neonates, GROUP A STREP (GAS) is probably NEVER the answer for a neonate.
• GROUP A STREP (GAS or STREP PYOGENES): Look for an older child with impetigo, pharyngitis, or even a single inflamed lymph node.

PREAURICULAR LYMPHADENOPATHY

Consider adenovirus if you see a patient with conjunctivitis and preauricular lymphadenopathy. Mononucleosis may present with acute or chronic preauricular lymphadenopathy.

EMPIRIC TREATMENT

Empiric treatment for acute lymphadenopathy in the head and neck area should aim to cover beta-lactamase producers. AMOXICILLIN-CLAVULANATE! Other appropriate options include cefazolin, clindamycin, and erythromycin.

CHRONIC CERVICAL LYMPHADENOPATHY (> 3 WEEKS)

(DOUBLE TAKE) BARTONELLA HENSELAE

Bartonella henselae causes CAT SCRATCH DISEASE. Look for DRAINING and TENDER lymphadenopathy and possibly a history of cat (or dog) exposure. It resolves on its own, so there’s no need to treat unless the patient is immunocompromised or has severe symptoms including hepatosplenomegaly. If so, treat with non-penicillin drugs, like macrolides, cephalosporins, doxycycline, or trimethoprim-sulfamethoxazole.

MNEMONIC: Imagine BART Simpson’s cat being a TENDER kitty that’s fine when it’s LEFT ALONE but SCRATCHES you when you try to pet it. The solution is to LEAVE IT ALONE!

• KEY: TENDER = tender lymphadenopathy, LEAVE IT ALONE = no treatment needed.