The number of cases is underestimated
Since his original case report in May, Dr. Jansen has seen five or so additional cases. But the causal link between the coronavirus and the hematologic symptoms is still undefined. “We don’t know much about platelet counts in COVID-19 at all,” he said. It could be that COVID-19 somehow inhibits platelet production or that it kills existing platelets. Whatever the exact relationship to the virus, Dr. Jansen expects that the true number of COVID-19-related ITP cases is higher than current estimates suggest.
One reason it isn’t coming up more often, Dr. Jansen said, may be that the cause of ITP in COVID-19 patients is hard to pin down. In the case report from May, Dr. Jansen and colleagues wrote: “And there are numerous other factors that can cause thrombocytopenia where COVID is concerned. For instance the coagulation activation by COVID‐19 infection leading to disseminated intravascular coagulation (DIC) and subsequent thrombocytopenia. Also, treatments for COVID‐19, including heparin, azithromycin and hydroxychloroquine, may lead to thrombocytopenia.”
Tracking and understanding COVID-19-associated ITP first requires the extensive process of elimination needed to diagnose it.
In addition, drugs used to treat COVID-19 could be masking COVID-19-related ITP. “Dexamethasone is a mainstay of COVID treatment. And it’s how we treat ITP,” Dr. Johnson said, which means physicians may be treating ITP without even registering it. And that’s one hypothesis for why Dr. Stone and Dr. Johnson didn’t see a case until 9 months into the pandemic.
Treating COVID-19-associated ITP also has its challenges, particularly in patients who develop it during an acute COVID-19 infection and are at risk for both internal bleeding and thrombosis. This was the case for the third patient in Dr. Jansen’s case report. The patient developed a pulmonary embolism and had a falling platelet count. He was given a platelet infusion and then an anticoagulant for the thrombosis. But a retrospective look at the case revealed the transfusion “did not increase numbers at all – which suggests ITP,” Dr. Jansen said. Intracerebral bleeding was the cause of death.
That’s why “it’s important to be aware of this phenomenon,” Dr. Jansen said of COVID-19-associated ITP. If a transfusion is unsuccessful, consider that the patient may have ITP and adjust. Dr. Johnson hasn’t had to treat a patient battling both complications simultaneously but says the ideal course of action would be to raise platelets with steroids and IVIG and then give the anticoagulant once the platelet count is higher. But reality is rarely ideal. Often these two treatments will have to be given concurrently since the patient faces two life-threatening risks, he said. “It’s a very challenging situation,” he said.
The good news is that standard treatments for ITP seem to work for COVID-19-associated ITP. The 30-year-old patient of Dr. Stone and Dr. Johnson responded so well to intravenous steroids that IVIG was unnecessary. She’s now on a slow prednisone taper and maintains platelet counts at 114,000/mm3 at her weekly follow-up appointments with Dr. Johnson.
Meanwhile, Dr. Jansen’s two other patients, now nearly a year out of treatment, require no additional medication. One of the patients is fully recovered and, though the other still has lower than normal platelet counts, she has no bleeding symptoms and her platelet counts remain stable. Still, Dr. Jansen is anxious for more data looking at the platelet counts in every COVID-19 patient and to combine findings from existing COVID-19-associated ITP patients.
For Dr. Stone, she says she’s added one COVID-19-associated complication to her belt. One less aftereffect will catch her off guard. And she wants others to have the same information.
“It’s just a little bit daunting. We don’t know how bad post-COVID will be,” she said. “There’s so many levels to this disease. Some people deal with it for so long and some people just get better and move on – we think ... so far.”
A version of this article first appeared on Medscape.com.