One of the largest hospital chains in the Washington, D.C. area was shut down by computer malware Monday that prevented medical staff from even looking up phone numbers. The attack on MedStar Health Inc. forced record systems offline, meaning patients could not book appointments and staff members couldn’t even check emails. The attack comes just weeks after a hospital in California was reported to have paid a bitcoin ransom to malicious hackers to regain control of its system. The FBI said it is assessing whether MedStar is dealing with the same kind of situation. One MedStar employee told a reporter: “We can’t do anything at all. There’s only one system we use, and now it’s just paper.” But company spokeswoman Ann Nickels said patient care was not affected by the attack and that all hospitals were using a paper backup system.