Acute carpal tunnel syndrome (ACTS) is a rare entity, mainly associated with traumatic causes, although patients with predisposing factors such as taking anticoagulants or tendinopathies may debut with an atraumatic ACTS. This case study presents the case of a 77-year-old male patient, anticoagulated, who began with rapidly progressive pain and swelling in the right wrist, radiating towards the medial territory, with no history of traumatic triggering event. Examination showed paraesthesia in the volar aspect of the first to third fingers of the hand and increased pain on passive mobilisation of the fingers. Given the progressive evolution of the condition and the lack of response to both physical and pharmacological measures, the carpal tunnel was opened surgically. During surgery, a significant haematoma was observed secondary to the rupture of the deep flexor tendons of the fourth and fifth fingers inside the canal. Following release of the carpal tunnel, complete recovery of the symptomatology occurred. In conclusion, a high degree of clinical suspicion is necessary in a patient with an examination suggestive of ACTS. The treatment of choice is urgent surgical decompression of the carpal tunnel. Early intervention allows resolution of symptoms and reduces complications.