Lacunar strokes occur when a branch of a large cerebral artery is blocked. The thalamus is often affected, causing uncontrollable motions.

A 72-year-old previously healthy man presented with involuntary motions in the right limbs, which were present at rest, and exacerbated during voluntary actions. He had received the first dose of the adenoviral vector-based coronavirus disease 2019 vaccine (ChAdOx1 nCoV-19) 9 days ago.

Severe thrombocytopenia and elevated levels of lactate dehydrogenase, ferritin, C-reactive protein, and D-dimer were found, without any evidence of connective tissue disease. Electromyography demonstrated typical choreiform movements, and the brain magnetic resonance imaging indicated a small high signal lesion on the left side of the thalamus.

Detection of the immunoglobulin G antibodies against platelet factor 4 in the blood, negative heparin-induced platelet activation (HIPA) test, and positive modified HIPA test confirmed the thalamic stroke due to the vaccine-induced prothrombotic immune thrombocytopenia (VIPIT).

He was admitted to the intensive care unit and received nadroparin, sodium ozagrel, edaravone, methylprednisolone, and haloperidol. His hemi-chorea improved gradually over 2 weeks, and he was discharged after 21 days with rehabilitation advice. VIPIT due to the ChAdOx1 nCoV-19 is a novel immune-mediated response that needs clinicians’ awareness and further investigations.


COVID-19 mainly affects the respiratory system, ranging from mild flu-like symptoms to severe acute respiratory syndrome. In a subset of patients with yet unknown causes, COVID-19 has a particularly tempestuous course characterized by inflammatory cytokine response (storm) and multi-organ failure and may be potentially fatal. Extra respiratory multi-systemic complications such as neurologic, thrombotic, hematologic, cardiovascular, renal, liver, musculoskeletal, dermatologic, psychological, and gastrointestinal have all been reported in the medical literature. The risk of both venous and arterial thromboembolism is significantly increased in COVID-19 patients. Even after discharge, recovery, or vaccination, thromboembolism is one of the most common causes of sudden or undetected morbidity or mortality. The mechanisms leading to these complications are increasingly being studied. However, there is a lack of data about the disease course once the patient has had clinical and/microbiological recovery [567].

The safe implementation of vaccines is very important, and now many cases of unusual thrombotic or hemorrhagic or both events, especially following the ChAdOx1 nCoV-19 vaccine, have been reported. Concern about neurological complications from COVID-19 vaccines escalated in the fall of 2020 when many cases of transverse myelitis and Guillain-Barré syndrome manifested after receiving the Oxford/AstraZeneca vaccine [28] After that, many European countries (such as Austria, Norway, and Denmark) reported unusual thrombotic or hemorrhagic or both events in healthy persons following vaccination with the ChAdOx1 nCoV-19 vaccines. These unpredictable complications led to a temporary or permanent cease in using these vaccines in many countries [89]. The Society of Thrombosis and Haemostasis Research (Gesellschaft für Thrombose und Hämostaseforschung e.V.) presented an essential pathomechanism that 4 to 16 days after vaccination with the ChAdOx1 nCoV-19 vaccine, the formation of antibodies against platelet antigens (against the platelet factor 4) occur as an inflammatory reaction and immune stimulation. Without heparin involvement, these antibodies (IgG PF-4) subsequently cause massive platelet activation via the Fc receptor, thrombus formation, and severe thrombocytopenia like heparin-induced thrombocytopenia (HIT). A HIT mimicry mechanism, named VIPIT, was demonstrated in four patients with a sinus/cerebral vein thrombosis after vaccination with AstraZeneca COVID-19 vaccine. There have been reports of unusual thrombotic or hemorrhagic or both events following the ChAdOx1 nCoV-19 vaccine and the possibility of specific immune-mediated thrombocytopenia in the literature. However, it is unclear as to why this immunogenic thrombosis mainly manifests in cerebral vessels [589].

In this case, clinical presentations, neurological examinations, surface electromyography, and diffusion-weighted MRI demonstrated thromboembolic thalamic stroke in a 72-year-old previously healthy man, 9 days after receiving the first dose of the ChAdOx1 nCoV-19. Severe thrombocytopenia in a patient with a thromboembolic thalamic stroke was a significant finding. We managed this case based on the diagnostic and therapeutic algorithm in patients with thrombocytopenia/thrombosis following the AstraZeneca COVID-19 vaccine. Detecting the IgG PF-4 in the blood, negative HIPA test, and positive modified HIPA test presented the VIPIT as a predisposing or main case of the thromboembolic thalamic stroke. We admitted the patient to the ICU and treated him immediately with nadroparin, sodium ozagrel, edaravone, methylprednisolone, and haloperidol. His hemi-chorea improved gradually during 2 weeks, but on the follow-up brain MRI, he had a chronic lesion with deficiency of cerebral blood flow in the bilateral basal ganglia and remarkable brain atrophy in the bilateral frontotemporal lobes. Warfarin was started in replace of nadroparin and was titrated by monitoring PT levels for the next 3 months. Finally, we discharged him after 21 days with advice to rehabilitation exercise and follow-up [5].

In conclusion, thromboembolic thalamic stroke with severe thrombocytopenia, presence of the IgG PF-4 in the blood, negative HIPA test, and positive modified HIPA, 4–16 days after receiving the first dose of the ChAdOx1 nCoV-19 vaccine, represent the novel immune-mediated responses to the vaccine similar HIT mimicry mechanism, named VIPIT [5, 8, 9]. Our patient may be immunized against severe acute respiratory syndrome coronavirus 2, but he lost some of his best motor and cognitive functions. We believe that VIPIT due to the ChAdOx1 nCoV-19 needs more extensive investigations in the future and has great importance for clinicians worldwide for rapid identification, diagnosis, and treatment of similar cases.

Source – https://ecevr.org/DOIx.php?id=10.7774/cevr.2022.11.2.217