Cassandra Hoag v. HHS - DPT, encephalopathy (1998)

On January 12, 1995, John and Patricia Hoag filed a petition under the National Vaccine Injury Compensation Program on behalf of their daughter, Cassandra Hoag, who was born on November 2, 1990. They alleged that Cassandra suffered an encephalopathy following a diphtheria-pertussis-tetanus (DPT) vaccination on February 7, 1991, or a diphtheria-tetanus (DT) vaccination on March 20, 1991.

Alternatively, they argued that the two vaccinations in combination caused her injuries, or that the March 20 DT vaccination significantly aggravated a preexisting encephalopathy that began after the DPT shot. The Chief Special Master denied compensation on all counts, and the petitioners sought review solely on the significant aggravation claim.

The United States Court of Federal Claims, in an opinion by Judge Horn, affirmed the denial of compensation on October 15, 1998. Cassandra was described as developing normally for her first two months.

Ten days after the February 7, 1991 DPT vaccination, her parents took her to Shands Hospital at the University of Florida, where she was diagnosed with apnea, most likely due to seizure activity. Despite a normal EEG, doctors suspected seizures and began phenobarbital.

Over the next month, her episodes included apnea, cyanosis, back arching, stiffness, and jerking. After the March 20, 1991 DT vaccination, Cassandra experienced three seizures on March 22, characterized by shallow breathing, staring, stiffening, trunk arching, and flexion of one or both arms.

A March 25 EEG was highly suggestive of infantile spasms, but a continuous video EEG from March 27 through March 30 showed seizures originating in the right temporal lobe, clinically consistent with complex partial seizures. Dr.

Gilmore saw Cassandra on March 25 and stated she was not encephalopathic. By May 10, 1991, treating physicians noted her seizures had changed into bilateral movements resembling jackknife spasms, leading to a diagnosis of infantile spasm syndrome.

The Chief Special Master rejected the petitioners' claim of an encephalopathy following the February 7 DPT vaccination, finding their testimony about Cassandra's condition immediately after the vaccination contradicted contemporaneous medical records. These records described her as alert, playful, cooing, and neurologically normal, with an abrupt onset of symptoms on February 17, 1991, without a precipitating episode.

The Special Master found the petitioners' experts lacked a reliable factual foundation for their opinions, as these were predicated on the family's rejected testimony. The claim that the DPT vaccination caused the injuries in fact was also denied for the same reason, with experts like Dr.

Sleasman stating there was no direct causal link, Dr. Gilmore noting normal development as of March 25, and Dr.

Schulein finding no encephalopathy. The review proceeding focused on the significant aggravation claim.

Petitioners argued the Special Master improperly required them to prove that infantile spasms could be diagnosed within seventy-two hours, rather than proving the first symptom or manifestation of significant aggravation occurred within that period. The court affirmed the denial, concluding the Special Master correctly applied the Whitecotton significant-aggravation framework.

The court found the Special Master did not make the diagnosis within seventy-two hours the legal test. Instead, based on respondent's expert Dr.

John MacDonald, the Special Master found the March 22 seizures were consistent with Cassandra's evolving preexisting seizure disorder and were not the first symptom or manifestation of a significant aggravation. The court noted that the Special Master found the testimony of Dr.

MacDonald, who had extensive clinical experience and reviewed medical literature, more persuasive than that of petitioners' expert Dr. Marcel Kinsbourne.

The court upheld the denial of compensation.