The following will change the style of the word 'description' if in upper case or starting a sentence.
Note that the macro calls a character style - here the built-in style 'Strong'. If you call a paragraph style the chances are that the whole paragraph containing the word will be so formatted, so I suggest creating a character style to achieve the formatting you require.
Code:
Sub Macro1()
Dim oRng As Range
Dim vFind As Variant
Dim i As Integer
vFind = Array("DESCRIPTION", "Description")
For i = 0 To UBound(vFind)
Set oRng = ActiveDocument.Range
With oRng.Find
.ClearFormatting
.Text = vFind(i)
Do While .Execute(findText:=vFind(i), MatchWholeWord:=True, MatchCase:=True)
oRng.Style = "Strong" 'Change as appropriate
Loop
End With
Next i
Set oRng = Nothing
End Sub