Low red cell count I would suppose.
Depends on the organism.
Acute mycoplasma can cause a severe hemolytic anemia, I have seen a Hgb of 2.
There is as also Mycoplasma (Hemoplasma) (PubMed).
Mycoplasma causes cold hemagglutinin disease has also been seen with mumps, cytomegalovirus, Legionnaires’ disease, and visceral leishmaniasis
Warm agglutinin anemia includes HIV, hepatitis C and mononucleosis.
Then there is Hemolytic Uremic Syndrome, usually from toxigenic E. coli but reported with other organisms.
Parvovirus B19, which kills red cell precursors. If the patient relies of increased output to maintain their HCT (ex: sickle cell) they can become acutely anemic. Treatment is supportive. AIDS patients can get severe refractory anemia with a parvovirus infection as they do not make antibody against the virus. AIDS patients are seronegative and the diagnosis is made by bone marrow biopsy that shows giant pronormoblasts or blood for PCR for parvovirus. The treatment for AIDS is monthly IVIG.
Acute Clostridia infections can cause a severe hemolytic anemia, by the time you make the diagnosis the patient is dead.
Rare in the US, anemia can be caused by worms that cause bleeding, by eating your food for you or malabsorption (Whipples).
Most patients with infection will get anemia of chronic disease.
Many antibiotics will cause anemia, but usually part of a pancytopenia. The big exception is patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency have an increased risk hemolysis with primaquine. Also quinolones and sulfa are a risk (PubMed).
Besides transfusion (duh), depends in the cause.
Last Update: 05/06/18.