Case Study: Acute Febrile Illness with Severe GI Symptoms Following Rodent Exposure

Case at a Glance

A 35-year-old male presented to the Emergency Department with high fever, tachycardia, hypertension, and significant gastrointestinal distress, which began approximately ten days after cleaning a rodent-infested garage, prompting concern for a zoonotic infection like Hantavirus.

Patient's Story

The patient is a 35-year-old male residing in a rural area of Central California. About a week and a half prior to seeking medical attention, he undertook an extensive, multi-day cleanup of a garage heavily contaminated with rodent droppings and nests. During the process, he discovered several dead rats. The patient reported using personal protective equipment, including an N95 mask, long-sleeved shirt, and chemical-resistant gloves. Ten days after the initial exposure, he developed an acute onset of chills and a low-grade fever. His condition progressively worsened over the subsequent days.

Initial Assessment

Upon arrival at the Emergency Department, the patient was acutely ill. Vital signs were notable for a fever of 101.2°F, tachycardia with a heart rate of 132 bpm, and severe hypertension at 168/130 mmHg. He complained of an intense headache, diffuse joint pain, neck pain, severe fatigue, abdominal cramps, and profuse, watery diarrhea with an episode of incontinence. The patient explicitly mentioned his recent rodent exposure and expressed concern for Hantavirus. Initial treatment included intravenous fluids and an attempt to manage the fever with ibuprofen, which proved minimally effective.

The Diagnostic Journey

Initial laboratory workup revealed normal blood counts with slightly elevated inflammatory markers. A chest X-ray was clear, showing no signs of pulmonary edema or infiltrates. A rapid COVID-19 test returned negative.

The primary concern, driven by the exposure history and symptom timeline, was Hantavirus Pulmonary Syndrome (HPS). However, the ED staff noted that specific serological testing for Hantavirus was not available at their facility. The patient was advised to contact the local public health department, which he did. The department informed him that Hantavirus was extremely rare in the region, with only four confirmed cases since the 1980s.

The differential diagnosis remained broad. Other zoonotic infections such as leptospirosis were considered, given the GI and systemic symptoms. However, the most likely diagnosis was deemed to be a more common viral pathogen. Clinicians emphasized the principle of "thinking horses, not zebras," suggesting that a severe case of viral gastroenteritis was a more probable cause than a rare disease like Hantavirus.

During his observation, the patient's symptoms evolved. While his blood pressure improved and fever subsided slightly, the diarrhea and headache persisted. He developed a new symptom described as a "menthol feeling" in his chest upon inhalation, which triggered a non-productive cough.

Final Diagnosis

Presumptive Acute Viral Gastroenteritis.

Despite the concerning exposure history, the clinical picture was most consistent with a severe, self-limiting viral illness. The prominence of gastrointestinal symptoms (profuse diarrhea, cramping) and the absence of key HPS indicators like thrombocytopenia or significant respiratory compromise on imaging led to this working diagnosis. The rodent exposure was considered a likely coincidental factor that understandably caused significant patient anxiety.

Treatment Plan

The patient's management was supportive. In the ED, he received intravenous hydration to correct dehydration and electrolyte imbalances from fever and diarrhea. He was discharged with instructions for symptomatic care at home, including:

1. Hydration: Emphasis on maintaining adequate oral fluid intake.
2. Antipyretics: A structured regimen of alternating acetaminophen and ibuprofen for fever and pain management.
3. Rest: Encouraged to rest to allow for recovery.
4. Education and Reassurance: The low statistical probability of Hantavirus was explained to the patient to alleviate his anxiety. He was given strict return precautions, including any worsening shortness of breath, chest pain, confusion, or inability to tolerate oral fluids.

Outcome and Follow-up

Prior to discharge, the patient's blood pressure had normalized to 120/70 mmHg and his fever had reduced to 99.5°F. Tachycardia persisted but had improved to a rate of 90-100 bpm. He was advised to follow up with his primary care physician within a few days for re-evaluation. The case was noted, but further specific testing for zoonotic diseases was deferred pending the clinical course. The patient's condition was expected to resolve with supportive care over the next several days.