The correct answer is C. Deep vein thrombosis (DVT).

This question is testing recognition of classic signs and symptoms of a deep vein thrombosis, which is a blood clot forming in a deep vein, most commonly in the lower extremities.

The patient presents with hallmark findings:

Unilateral calf pain (cramping/soreness)

Swelling (one calf larger than the other)

Redness

Warmth to the touch

These findings strongly indicate DVT.

According to NREMT-aligned EMT educational material:

“Signs of deep vein thrombosis include swelling, pain, warmth, and redness of the affected extremity.”

“DVT most commonly occurs in the legs and may present with unilateral swelling.”

Why the other options are incorrect:

A. Hyperthermia:A systemic condition involving elevated body temperature, not localized calf swelling and pain.

B. Food poisoning:Causes gastrointestinal symptoms such as nausea, vomiting, and diarrhea, not localized extremity findings.

D. Compartment syndrome:Typically presents with severe pain (often out of proportion), decreased pulses, pallor, paresthesia, and paralysis—not primarily redness and warmth. It is usually associated with trauma.

Clinical significance (important NREMT concept):

DVT is dangerous because the clot can dislodge and travel to the lungs, causing a pulmonary embolism, which is life-threatening.

NREMT guidance:

“A thrombus in a deep vein may dislodge and travel to the lungs, causing a pulmonary embolism.”

Exact Extracts:

“Signs of deep vein thrombosis include swelling, pain, warmth, and redness.”

“DVT most often affects the lower extremities.”

“A thrombus can break free and become an embolus, traveling to the lungs.”