Corticosteroids

Core Concepts

Airway inflammation: the disease inside the disease

In asthma, chronic inflammation of the airway wall — driven by eosinophils, mast cells, T-helper cells, and their chemical messengers (cytokines, leukotrienes) — causes swelling, increased mucus production, and airway hyperresponsiveness (twitchy airways that constrict in response to triggers like allergens, cold air, or exercise). Bronchodilators treat the constriction; corticosteroids treat the inflammation that makes the airways constrict so easily. This is why the two classes are complementary: one rescues, the other prevents.

How corticosteroids work: the genomic mechanism

Corticosteroids are lipophilic, so they cross cell membranes easily. Inside the cell, they bind the glucocorticoid receptor; the drug–receptor complex moves into the nucleus and changes gene transcription:

• Down-regulates the genes for pro-inflammatory cytokines, adhesion molecules, and enzymes (e.g., COX-2, inducible nitric oxide synthase).
• Up-regulates anti-inflammatory proteins (e.g., lipocortin/annexin, which inhibits phospholipase A2 and thereby reduces prostaglandin and leukotriene production).
• Reduces the recruitment and survival of inflammatory cells — eosinophil apoptosis increases, mast cell numbers fall.

The net effect: less swelling, less mucus, fewer inflammatory cells, and a higher threshold for bronchoconstriction. But transcription and protein synthesis take hours, which is why corticosteroids are controllers (prevention), not rescue drugs — a SABA remains the rescue agent.

Inhaled vs. systemic: same drug, different risk

• Inhaled corticosteroids (ICS) — e.g., fluticasone, budesonide, beclomethasone — are designed for high local lung activity with low systemic absorption. They are the foundational daily controller for persistent asthma and are often combined with a LABA in a single inhaler (recall the previous topic: LABA + ICS combination is the standard way a LABA is used in asthma). Local adverse effects include oropharyngeal candidiasis (thrush) and dysphonia (hoarseness), both largely preventable by rinsing the mouth and gargling after use (and using a spacer). Systemic effects are dose-dependent and matter most at high doses or with long-term use — children's growth is monitored, and high-dose ICS may affect adrenal function in susceptible people.
• Systemic corticosteroids — e.g., oral prednisone, IV methylprednisolone — are used for short courses in asthma or COPD exacerbations and for severe disease. The price is systemic exposure: HPA axis suppression (the body's own cortisol production shuts down), hyperglycemia (relevant in diabetes), fluid retention, mood changes, insomnia, increased infection risk, and with long-term use, osteoporosis, muscle wasting, and skin changes. The critical rule: after significant use, steroids must be tapered, never stopped abruptly, because the adrenal glands need time to resume producing cortisol — abrupt withdrawal risks adrenal insufficiency/crisis under stress.

Nursing considerations

• Assessment: for exacerbation treatment, baseline and post-treatment respiratory status; for long-term ICS users, watch for thrush, hoarseness, and (in children) growth concerns; for systemic therapy, monitor blood glucose, blood pressure, and mood.
• Technique and sequence: teach correct inhaler use; if both a bronchodilator and a corticosteroid inhaler are ordered, the bronchodilator generally goes first to open the airway, then the corticosteroid — always following the prescriber's explicit orders and product instructions.
• Rinse after ICS: rinsing the mouth and gargling (then spitting) after each ICS dose reduces thrush and hoarseness.
• Taper teaching: explain why systemic corticosteroids must not be stopped abruptly, and teach signs of adrenal insufficiency (weakness, fatigue, dizziness, nausea) and when to seek help; verify the taper schedule against orders.
• Adherence support: people stop controllers when they feel well; the nurse explains that ICS prevents attacks even between symptoms and explores barriers (cost, technique, forgetting).
• Scope: administration, tapering, and monitoring follow prescriber orders, the formulary, and institutional policy; verify everything against current references.

Common Confusions