Delirium could signal Covid-19 infection in older adults, study finds

Delirium may be an early warning sign of Covid-19 infection in older adults, a new study has found. In some cases, it was the only symptom in patients who tested positive for the virus.

More than one-fourth of older patients in the study arrived at hospital emergency rooms with delirium, and 37% of these patients had no typical Covid-19 signs, such as fever or shortness or breath.

Delirium — confusion, inattention, disorientation, and other cognitive change — is a common sign of any infection in older people, whose immune systems respond differently to viral or bacterial illnesses than younger adults’. Patients hospitalized for Covid-19, especially if they need ventilators to help them breathe in intensive care units, are known to be vulnerable to delirium, a risk that research has shown can be augmented by the isolation imposed to limit coronavirus spread. 

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Identifying delirium as a Covid-19 symptom in patients before they are admitted to a hospital could be important to protect others from infection. It could also be critical for their care because in general, patients with delirium from any cause are more likely to fare worse than other patients. They suffer more severe disease, they stay in the hospital longer, and they are more likely to die. If they survive, they are more likely to need care in a rehabilitation facility or a nursing home after their hospitalization. 

“Delirium is a great barometer,” said Wes Ely, a pulmonologist and critical care physician at Vanderbilt University, who was not involved in the study. “The message to get to the lay public and to the medical personnel is, if people are confused, pay attention, because right now they could have Covid.”

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For their study, published Thursday in JAMA Network Open, researchers analyzed the medical records of 817 patients seen at seven hospitals in five states as the pandemic first surged in March. Their mean age was 77 years old and all were at least 65; 62% were white, 27% were Black, and 7% were Hispanic or Latino. All tested positive for SARS-CoV-2, the virus that causes Covid-19.

More than a quarter, 28%, were diagnosed with delirium, the sixth most common symptom after fever, shortness of breath, low oxygen, cough, and weakness. But more than a third of patients with delirium had none of those more typical signs of Covid-19. Delirium was their sole symptom.

“One of our main messages, especially right now, is to really try to screen everyone, older adults especially,” said Benjamin Helfand, a study co-author and an M.D.-Ph.D. candidate at the University of Massachusetts Medical School. “People coming in with even these atypical symptoms still should be screened and tested for Covid.”

In the study, patients with delirium were more likely to be over 75, live in a nursing home or assisted living facility, have taken psychoactive drugs in the past, have Parkinson’s disease, and have vision or hearing problems. 

When they came to hospital emergency departments, less than half were screened and diagnosed using a test such as the Confusion Assessment Method, a tool developed by a team including Vanderbilt’s Ely and Sharon Inouye of Harvard Medical School, who is a co-author of the current study. The remaining patients’ symptoms were compared to checklists from the Centers for Disease Control and Prevention and the World Health Organization to confirm the delirium diagnosis.

Ely thinks if more patients were assessed with some version of a delirium tool, more cases would have been detected. “If you don’t use a delirium tool, you miss about 75% of delirium,” Ely said. “There’s no question that the number they put forth is lower than the actual delirium number. It’ll be bigger than that.”

The study authors acknowledge that limitation, recognizing that most emergency departments do not routinely screen patients for delirium.

Delirium is a serious problem that Ely compares to other conditions that can also occur in Covid-19 patients.

“If you’re not breathing well, you have low oxygen. If your heart is failing, you have low blood pressure,” Ely said. “If your brain is failing, you have delirium.”

The study authors hope their work will help delirium be spotted and treated earlier.

“Adding delirium as a common presenting symptom of Covid-19 will keep important cases from being missed and allow earlier identification and management of vulnerable patients at high risk for poor outcomes,” they wrote.

Source: STAT