Internal bleeding.
http://www.kcom.edu/faculty/chamberlain/bioterror/hemorrhagic.htm
Early signs typically include
fever, low blood pressure, a low heart rate, a high respiration
rate, conjunctivitis and sore throat. Most diseases are associated
with the skin becoming red or a skin rash, but the specific
characteristics of the rash vary with each disease. Later, patients
may show signs of progressive bleeding, such as skin petechiae,
petechiae in the mouth, and bleeding in the conjunctiva; blood in
the urine; vomiting blood; and dark black stools indicating
bleeding in the intestines (melena). Due to the blood loss the
patient may develop extremely low blood pressure and go into shock.
Infection of the brain may present with delirium, convulsions, or
coma. Patients with infection of the brain more commonly result in
death.
