Updated July 2026 · 8 min read
Part of the ICU Emergencies Hub — browse every related guide in one place.
A patient with a vague history of decades-old travel is admitted for something unrelated, started on corticosteroids, and days later spirals into gram-negative sepsis, respiratory failure, and abdominal catastrophe that no one can explain. The culprit is a parasite that has been living quietly in the gut for thirty years, kept in check by a healthy immune system — until the steroids released the brakes and let it multiply and disseminate throughout the body. This is Strongyloides hyperinfection syndrome, a rare but frequently fatal complication that every ICU nurse should recognize, because the trigger is often a treatment we give.
Strongyloides is unusual among worms in that it can complete its life cycle entirely inside one host, re-infecting the same person over and over in a low-grade loop that a competent immune system holds to a trickle. A person can carry it for decades after a single exposure — often in a tropical or subtropical region, in the rural southeastern United States, or through old military or travel history — with few or no symptoms. The danger arrives when that immune restraint is removed. Corticosteroids are the classic and most notorious trigger: they suppress the very responses that kept the parasite in check, and the quiet loop turns into an explosion. The larvae multiply, burrow through the gut wall, and migrate through the lungs and other organs. This is why a careful exposure history matters before starting immunosuppression, and why an unexplained sepsis-plus-respiratory-plus-GI picture in a newly steroid-treated patient should raise the question.
| System | What you may see |
|---|---|
| Bloodstream | Gram-negative or polymicrobial sepsis, recurrent bacteremia, meningitis (gut bacteria carried by larvae) |
| Lungs | Cough, wheeze, hemoptysis, diffuse infiltrates, ARDS-like respiratory failure |
| GI tract | Abdominal pain, ileus, diarrhea, GI bleeding, malabsorption |
| Skin | Rapidly migrating serpiginous rash (larva currens); purpura |
| Labs | Eosinophilia — but often ABSENT/suppressed by steroids (a false reassurance) |
| Setting | Recent steroids/immunosuppression + endemic-area exposure history |
The trap worth underlining is eosinophilia. Blood eosinophils often rise with parasitic infection and can be a clue — but in hyperinfection the triggering steroids frequently suppress the eosinophil count, so a normal eosinophil level does not rule the diagnosis out. Diagnosis rests on finding larvae (in stool, sputum, or other fluids) and serology, but treatment is often started empirically in a deteriorating high-risk patient because delay is deadly.
Because oral absorption can be unreliable in a patient with ileus, getting effective antiparasitic drug into the patient can itself be a challenge the team has to problem-solve. And because the condition is under-recognized, the nurse who connects the dots — recent steroids, endemic exposure, unexplained gram-negative sepsis and lung failure — may be the one who prompts the life-saving question.
Assessment and history-taking matter more here than in most ICU diagnoses: note any recent start of steroids or other immunosuppression and any exposure history (travel, military service, rural residence in endemic regions), and flag the combination to the team. Clinically, monitor for the multi-system picture — respiratory deterioration, hemodynamic instability of sepsis, abdominal distention and ileus, GI bleeding, and any migrating rash. Administer ivermectin and antibiotics promptly and per protocol, and watch for the response. Standard sepsis and ARDS nursing apply: fluid and vasopressor titration, oxygenation and ventilator support, perfusion and urine-output monitoring. Because larvae can be present in stool, sputum, and other body fluids, follow institutional infection-control and body-substance precautions and handle secretions and excreta carefully to protect yourself and others. Support the family through what is often a bewildering, rapidly fatal illness caused by a parasite no one knew the patient carried, and reinforce the systems lesson quietly with the team: screen at-risk patients before immunosuppression whenever possible.
Explore related ICU sepsis and respiratory emergencies: septic shock, lung-protective ventilation in ARDS, disseminated intravascular coagulation (DIC), and adrenal crisis.
Get the ICU Notebook
Free investing strategies built for nurses. One email per week, no fluff.
Yes, send it freeNo spam. Unsubscribe any time.