South Dakota inmate Daniel Hanic appeals the District Court’s 1 adverse grant of summary judgment in his 42 U.S.C. § 1983 action. As relevant to this appeal, Hanic sued Dr. James Schaeffer, the physician who treated him after he sustained an ankle injury in February 1996. He claimed Dr. Schaeffer had been deliberately indifferent to his serious medical need because Dr. Schaeffer should have recognized, and initiated appropriate treatment for, deep vein thrombosis (DVT). 2 Having carefully reviewed the record, see Beck v. Skon, 253 F.3d 330, 332-33 (8th Cir. 2001), we affirm.

We agree with the District Court that Hanic failed to create a triable issue as to whether Dr. Schaeffer knew he had DVT, or was developing DVT, yet ignored it. See Roberson v. Bradshaw, 198 F.3d 645, 647 (8th Cir. 1999) (stating elements of deliberate-indifference claim). According to Hanic’s affidavit, when Dr. Schaeffer last saw him on March 14, 1996, for his ankle, it was discolored but the swelling had decreased somewhat. At that point, because Hanic’s symptoms had not entirely resolved since his original ankle injury, Dr. Schaeffer referred him to the medical director for approval of an orthopedic consult. Hanic further attested that on March 17, three days later, his entire leg became severely swollen and blue, and that a nurse (not Dr. Schaeffer) observed, but ignored the change in his condition.

In resisting summary judgment, Hanic offered only his opinion that he exhibited obvious signs of DVT when Dr. Schaeffer last assessed him. Hanic did not offer any expert testimony that he had or was developing DVT when he last saw Dr. Schaeffer. Therefore, we agree with the District Court that Hanic’s opinion was an inadequate response to Dr. Schaeffer’s testimony and attestations about the causes, symptoms, and diagnosis of DVT, and what he observed when he last saw Hanic on March 14, 1996. See Robinson v. Hager, 292 F.3d 560, 564 (8th Cir. 2002) (holding reasonable juror could not infer from evidence whether inmate’s lapse in being prescribed hypertension medication caused stroke; when injury is sophisticated, cau *667 sation generally must be shown by expert testimony). As a matter of law, Hanic has failed to create a prima facie case of deliberate indifference to a serious medical need, and summary judgment was correctly granted in favor of Dr. Schaeffer.

Accordingly, we affirm.