2025 – PAGE 310 – INFECTIOUS DISEASES

(DOUBLE TAKE) ASPERGILLUS

In immunocompetent patients, Aspergillus may cause a hypersensitivity reaction called Allergic Bronchopulmonary Aspergillosis (ABPA). This is especially true in asthmatics and patients with cystic fibro­sis. Asthmatics seem to have an exacerbation that WORSENS despite “appropriate” treatment with steroids. Look for increased eosinophilia and lung infiltrates. Treat with itraconazole and steroids. In an immuno­compromised patient, Aspergillus can cause INVASIVE pulmonary disease resulting in nodular infiltrates on imaging. Aspergillus can also be an etiology of Chronic Eosinophilic Pneumonia (peripheral infiltrates on X-ray). Treat invasive Aspergillus with either voriconazole or isavuconazole. Both invasive and noninvasive infections may require long-term steroids. All Aspergillus patients should be in a negative pressure room (as with MTB).

PEARL: Aspergillus is fairly ubiquitous in the world and may be found on cultures as a contaminate. Only choose amphotericin if there is laboratory data supporting Aspergillus infection and it seems that the Asper­gillus is the likely cause of the patient’s symptoms.

MYCOBACTERIUM TUBERCULOSIS (AKA MTB or TB)

Mycobacterium tuberculosis (AKA MTB or TB) is a bacterium (not a fungus) that does not allow for Gram staining (that’s why acid-fast detection is used). It’s presented here due to overlapping symptoms with the fungal infections. For newborns and young children, look for a prolonged illness with fever and cough. For older kids, look for fevers, chills, night sweats, weight loss, immigrant status, travel to an endemic area, hilar lymphadenopathy, an apical infiltrate, a pleural effusion, and/or a supraclavicular lymph node. Diagnose by AFB smears of sputum/secretions, a positive PPD, or a Quantiferon Gold. The BCG vaccine protects against TB, is given in TB-endemic areas, and can cause a false positive PPD result. Therefore, use the Quantiferon test as the initial test or to make the diagnosis of TB after a positive PPD in children who have received the BCG vaccine.

PPD READINGS

• PEARL: The PPD and treatment information is a little overwhelming. I have tried to simplify it, but if it’s too much, MOVE ON. At the most, it would be worth one question. Other areas are MUCH more high yield.
• < 5 MM INDURATION: Negative for MTB
  • PEARL: If +induration and < 5 mm, consider an infection with ATYPICAL mycobacteria.
• 5–9 MM INDURATION: Positive IF there are X-ray findings or there is a history of “close contact” with someone who recently got diagnosed with TB (newly +PPD), or the patient is immunocompromised. If none of the above conditions exist, a 5–9 mm induration in an otherwise healthy child is considered NEGATIVE for tuberculosis.
• 10-14 MM INDURATION: POSITIVE if there is ANY risk factor.
• > 15 MM is used as a POSITIVE only for the lowest-risk patients with ZERO risk factors.
• TREATMENT AFTER A +PPD SCREEN:
  • NORMAL CHEST X-RAY: Single therapy with INH for 9 months.
  • POSITIVE CHEST X-RAY: Positive means the presence of hilar lymphadenopathy, an infiltrate, or a pleural effusion. The patient gets 3- to 4-drug therapy.
    • TRIPLE THERAPY: Rifampin, isoniazid, and pyrazinamide.
      MNEMONIC: You must treat, or the patient will have to Rest In Peace!
• • • QUADRUPLE THERAPY: Ethambutol is added to the regimen. The ethambutol is stopped after 2 months.
• TREATMENT FOR NEWBORNS WITH +PPD MOMS
  • If mom is asymptomatic AND has a negative chest X-ray, check a PPD in the baby every 3 months. If it turns positive, the baby will need treatment with INH for a year if the chest X-ray is negative, and triple to quadruple therapy if it is positive.
  • If mom has active disease OR a positive chest X-ray, the baby is considered positive as well and gets full treatment (triple to quadruple drug regimen).
• TREATMENT FOR OLDER KIDS WITH ACTIVE TB IN A HOUSEHOLD CONTACT
  • PPD NEGATIVE & CXR NEGATIVE CHILD = INH prophylaxis for 12 weeks.
  • PPD POSITIVE & CXR NEGATIVE CHILD = INH prophylaxis for 9 months.
  • PPD POSITIVE & CXR POSITIVE CHILD = TRIPLE or QUADRUPLE therapy
  • TREATMENT FOR TB MENINGITIS: Same meds + STEROIDS + STREPTOMYCIN
• PEARLS: The right supraclavicular nodes drain the mediastinum and the lungs and are therefore more likely to show adenopathy in lung infections. The left side drains the thorax and the abdomen (lymphadeno­pathy is more likely to be lymphoma on the exam).
• PEARL: To check for how infectious a patient is, do NOT get a chest X-ray. Obtain sputum samples or gastric aspirates for AFB smear.
• PEARL: Don’t worry about the duration of treatment since it varies based on the type of TB they have (e.g., pulmonary, osteoarticular, meningitis, etc.).