Called to a rural residence for a male with high blood pressure, a headache and a "Cath" that wasn't working. Dispatch was prompted for additional information. They provided that the "Cath" was a foley catheter, and that the patient was a quadriplegic. I suspected autonomic hyperreflexia. Neat. On arrival patient had a BP of 180/110 (normally below 100 due to condition), was profusely diaphoretic and complaining of a headache. Catheter was indeed fully obstructed for at least 6 hours. The catheter was flushed, and symptoms resolved. Transported for a new catheter placement (old was was quite filthy).