Try like this
Create a hidden button in the Page and on the click event on the server, call the page load.
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<script src="jquery-1.10.2.js" type="text/javascript"></script>
<script type="text/javascript">
function ReloadPatientDemo(PatID) {
document.getElementsByName('HiddenField1')[0].value = PatID;
document.getElementById('btnHidden').click();
}
</script>
</head>
<body>
<form id="frm" runat="server">
<asp:Button ID="btnHidden" runat="server" Style="visibility: hidden" OnClick="btnHidden_Click" />
</form>
</body>
</html>
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnHidden_Click_Click(object sender, EventArgs e)
{
Page_Load(null, null);
}