Lyme Disease and Related Tick-Borne Infections - Ehrlichiosis

Outlook and Complications of Ehrlichiosis

Some experts estimate that only about 10% of people infected with ehrlichiosis develop symptoms, which are often so mild and flu-like that probably many people recover without seeking either a diagnosis or treatment. In symptomatic patients, however, ehrlichiosis can be more severe than Lyme disease. In studies of reported cases of both HME and HGE, 57 - 62% percent of patients required hospitalization, and estimated morality rates were 5% for HME and 10% for HGE. These percentages, however, probably reflect an overrepresentation of serious cases, and there is some evidence that they are significantly lower (2.7% for HME and 0.7% for HGE). The accuracy of any figures relating to ehrlichiosis is uncertain because there are so few cases.

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In general, it is important to initiate treatment for ehrlichiosis as soon as possible. The longer a patient is untreated, the worse the outcome will be. The disease is more severe in the elderly, those with anemia, and people with impaired immune systems such as those with AIDS. HME may be more severe in children because initial symptoms are often mild and even doctors are often unaware of it. The following are severe complications associated with ehrlichiosis when left untreated:

Either form of ehrlichiosis can damage white-blood cells to the point where a patient can die from serious infections such as fungal pneumonia.
HGE may infect young white blood cells in the bone marrow, which are then released into general circulation. Infected white blood cells can affect in the spleen, liver, lymph nodes, bone marrow, lung, kidney, and cerebrospinal fluid.
Signs of central nervous system abnormalities, such as changes in mental state, are indicators of a very dangerous condition.

Ehrlichiosis does not appear to have a chronic phase as Lyme disease does, although blood tests of patients previously treated indicates that the infection persists in many cases. At this time not enough is known about ehrlichiosis to come to any confident conclusions about long-term effects.

Diagnosing Ehrlichiosis

A diagnosis of HME or HGE is based on observation of the patient's symptoms, usually supported by immunofluorescence assay or polymerase chain reaction tests. Few doctors, however, are aware of ehrlichiosis, and even the knowledgeable ones are unable to diagnose ehrlichiosis simply on the basis of symptoms. Experts suggest that doctors consider a diagnosis for ehrlichiosis in the following patients:

Those with fever and flu-like symptoms who report being bitten by a tick
Those whose blood tests indicate lower amounts of white blood cells and platelets and elevated liver enzyme levels