| Infection | Corticosteroid therapy |
|---|---|
| Acute bacterial meningitis caused by Haemophilus influenzae type B in children or Streptococcus pneumoniae in adults | Dexamethasone 0.15 mg/kg q6h × 4 d |
| Pneumocystis jirovecii pneumonia, P02 ≤70 mm Hg in HIV-infected patients | Prednisone 40 mg BID × 5 d, then 40 mg qd × 5 d, then 20 mg qd for 11 d |
| Acute severe laryngotracheobronchitis (croup) | Dexamethasone >0.3 mg/kg qd × 3–4 d |
| Allergic bronchopulmonary aspergillosis | Prednisone 45–60 mg qd until infiltrate clears then taper |
| Typhoid fever, critically ill with mental status changes or shock | High-dose dexamethasone × 2–3 d |
| Tuberculous pericarditis and meningitis | Prednisone 60–80 mg qd for several weeks followed by taper |
Abbreviations: HIV = human immunodeficiency virus.
Corticosteroids and risk of infection
Myriad pathogens are associated with impaired cellular immunity and corticosteroid use (Table 87.2). Most of the organisms listed rarely cause significant or life-threatening infections in the immunocompetent patient. Some, such as P. jirovecii, cause disease only in immunocompromised individuals.
| Bacteria Legionella pneumophilia Listeria monocytogenes Mycobacterium tuberculosis Nocardia species Salmonella species Rhodococcus equi |
| Fungi Blastomyces dermatitidis Candida species Coccidioides immitis Histoplasma capsulatum Cryptococcus neoformans Aspergillus species |
| Helminths Strongyloides stercoralis Protozoa Cryptosporidium parvum Pneumocystis jirovecii Toxoplasma gondii Plasmodium species |
| Viruses Cytomegalovirus Epstein–Barr Herpes simplex Varicella-zoster Influenza Hepatitis B |
Patients with severe opportunistic infections often have concurrent underlying impairment of cellular immunity separate from the iatrogenic impairment secondary to steroid use. Thus, the risk of infection varies by underlying disease process. For instance, patients with acquired immunodeficiency syndrome (AIDS) or childhood acute lymphocytic leukemia have higher rates of PCP than patients without these diseases but receiving chronic corticosteroid therapy. For patients requiring chronic corticosteroid therapy, the infection rate for many of the pathogens listed in Table 87.2 is actually quite low. Overall, the risk increases with the dose and duration of use and may be increased by concomitant administration of other immunosuppressants. Patients who require ≥15 mg of prednisone or an equivalent dose of other corticosteroids for more than 1 month should receive prophylaxis against PCP and other infections with trimethoprim–sulfamethoxazole. Alternative agents include dapsone, atovaquone, and inhaled pentamidine. Skin induration ≥5 mm after tuberculin skin test is indicative of latent tuberculosis in this population.
Cytotoxic antineoplastic agents
Mechanisms of action
Cancer itself is associated with immune suppression such as neutropenia in acute leukemia or numerical/functional lymphocyte impairment in lymphoma patients. However, clinically significant infections in cancer patients are often related to the effects of cytotoxic antineoplastic agents.
The oldest class of cytotoxic drugs comprises alkylating agents, such as cyclophosphamide, busulfan, melphalan, and chlorambucil. The purine
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