Human monocytic ehrlichiosis is a rare infectious disease caused by bacteria of the Ehrlichia family. Pathology can be manifested by a sharp increase in body temperature, headache, muscle pain (myalgia), chills, unexplained fatigue, weakness. Symptoms are observed a few weeks after the initial infection. In addition, in many cases, laboratory tests show a decrease in platelet count in the circulating blood (thrombocytopenia) along with a decrease in the number of white blood cells (leukopenia) and an abnormal increase in the level of certain liver enzymes (hepatic transaminases). In some cases, the symptoms progress and are expressed in nausea, vomiting, diarrhea, weight loss, loss of orientation in space. If a patient has monocytic ehrlichiosis of a person, treatment should immediately follow the diagnosis, since in the absence of adequate therapy, the disease leads to dangerous complications such as kidney or respiratory failure. The carriers of infection are ticks.
Signs and Symptoms
Human monocytic ehrlichiosis, the symptoms of which can be easily confused with signs of other infectious diseases, has been discovered and investigated relatively recently. As a rule, pathology manifests itself approximately three weeks after a tick bite - a carrier of bacteria of the Ehrlichia family. Initially, patients suffer from typical signs of infection, including a sharp increase in body temperature and general weakness. In some cases, a skin rash is added to such symptoms. In severe infections, the patient loses his appetite, quickly loses weight and is at risk of anorexia. Rare signs of ehrlichiosis are also sometimes noted - such as coughing, diarrhea, sore throat (pharyngitis) and abdominal pain.
In most cases, when a person’s monocytic ehrlichiosis is suspected, diagnosis involves blood tests. The results of these examinations (a combination of leuko- and thrombocytopenia simultaneously with an abnormal increase in the level of liver enzymes) allow the patient to be correctly diagnosed. In some cases, the patient also suffers from liver inflammation (hepatitis).
In the absence of adequate treatment, severe monocytic human ehrlichiosis develops. Symptoms of the disease in this stage differ from the standard manifestations of infection and can be expressed in the following phenomena and conditions:
- shortness of breath (shortness of breath, dyspnea);
- bleeding disorder (coagulopathy), which can lead to bleeding in the gastrointestinal tract;
- neurological disorders due to infection of the brain and spinal cord (central nervous system).
If the infection has spread to the central nervous system, a patient with a diagnosis of "human monocytic ehrlichiosis" shows pathological changes in the tissue (tumor) in the brain. In addition, in some cases, meningitis develops - inflammation of the protective membrane membranes of the brain and spinal cord. Cerebrospinal fluid may also be affected by infection.
Neurological manifestations
The neurological symptoms of the disease include:
- loss of orientation in space;
- pathological sensitivity to light (photophobia);
- neck stiffness;
- episodes of uncontrolled electrical activity in the brain (convulsions);
- coma.
- In rare cases, there are:
- excessively intense reflex reactions (hyperreflexia);
- impaired coordination of voluntary movements (ataxia);
- partial loss of motor ability of the facial muscles due to damage to one (or more) of the twelve pairs of nerves associated with the brain (cranial nerve palsy).
Monocytic ehrlichiosis and human granulocytic anaplasmosis in the absence of professional treatment become life-threatening diseases.
Causes
All types of the analyzed pathology are caused by bacteria belonging to the family of Erlichia. The causative agent of human monocytic ehrlichiosis is considered gram-negative.
The main cause of infection is believed to be a tick bite. Some of these insects are carriers of pathogens.
Once in the human body through the blood, ehrlichia spread through the blood and lymph vessels. Lymph is a body fluid that carries cells designed to fight infectious diseases. Bacteria settle in some cells (monocytes and macrophages), which play an invaluable role in maintaining the stable functioning of the immune system. These cells absorb and process microorganisms (the process is called phagocytosis), including bacteria and other foreign elements. However, ehrlichia penetrate deep into the natural defenders of immunity and begin to grow in vacuoles - cavities surrounded by a membrane. The disease affects not only monocytes and macrophages in the blood, but also certain types of bodily tissues (including bone marrow, lymph nodes, liver, spleen, kidneys, lungs and cerebrospinal fluid).
Differential diagnosis: granulocytic anaplasmosis
Symptoms of this infectious disease can be easily confused with signs of other pathologies. Most often, differential diagnosis is subject to monocytic ehrlichiosis and human granulocytic anaplasmosis.
Unlike MEP, granulocytic anaplasmosis is caused by a bacterium with the corresponding name anaplasma. A tick-borne microorganism infects certain granular white blood cells - neutrophilic granulocytes. These cells are involved in the process of phagocytosis and are usually responsible for the destruction of harmful microbes. When infected with anaplasma, typical symptoms usually appear a week after a tick bite - a carrier of bacteria. Almost always, the patient suffers from fever, chills, muscle pain (myalgia), general weakness, fatigue, headache. Sometimes coughing, vomiting and / or loss of orientation in space are also observed. In addition, granulocytic anaplasmosis is similar to an infection such as human monocytic ehrlichiosis, and also in the fact that in the results of blood tests an increase in certain liver enzymes (hepatic transaminase) is equally detected. Often diagnosed and anemia caused by a pathological decrease in the level of red bodies in the circulating blood. In the absence of proper treatment, there is a danger of developing renal failure. In the USA, cases of human granulocytic anaplasmosis are most often recorded in the northeastern and western states.
Sennetsu fever
Monocytic human ehrlichiosis (MEC) must also be distinguished from Sennets fever - an extremely poorly understood and very rare infectious disease belonging to the subtype of human ehrlichiosis and caused by bacteria with the corresponding name - Senlets ehrlichia. A few weeks after the initial infection, symptoms develop that are similar to the common signs of MECH: a sharp increase in body temperature, headache, muscle pain (myalgia). Some patients experience nausea, vomiting, or loss of appetite, up to anorexia. In addition, according to the results of blood tests, a decrease in the level of white blood cells (leukopenia) and a pathological increase in the volume of liver enzymes can be judged. The carrier (or carrier) of the fever of the Sennetz has not yet been precisely established; some scientists suggest that it may be ixodid ticks, while other researchers claim that this disease can be infected after eating raw fish. Currently, infections have been observed only in eastern Japan and in Malaysia.
Lyme Borreliosis
Lyme borreliosis is an infectious disease caused by spirochete bacteria from the Borrelia family. Carriers of harmful microbes are black-footed ticks. In most cases, this disease is primarily manifested by the appearance of a red tumor on the skin, which at first resembles an elevated small round spot (papule). Papule begins to grow rapidly and as a result reaches at least five centimeters in diameter. After this, symptoms appear that also characterize monocytic human ehrlichiosis. The likelihood of contracting Lyme borreliosis is much lower than the risk of catching MECH, however, differential diagnosis remains a necessary step in determining the infection. Lyme borreliosis patients also often complain of fever (not as sharp and dangerous as with MEP), chills, muscle and headaches, weakness, fatigue, and pain or stiffness in large joints (infectious arthritis), most often in knees. Symptoms may take the form of recurring cycles. In severe cases, in the absence of timely treatment, neurological disorders and pathologies of the heart muscle are observed. According to statistics, Lyme borreliosis is most often found in the northeastern states of the United States. However, cases of infection are also known in other countries, including China, Japan, Australia and some European countries.
Human pyroplasmosis
Human monocytic ehrlichiosis, the probability of infection of which is relatively higher than the risk of infection with other bacteria, is not the only potentially dangerous infectious disease transmitted by ticks. Human pyroplasmosis (in other terminology - babesiosis) is an infection caused by unicellular microorganisms from the Babesian family. Most often, this disease affects animals, but from time to time there are cases of infection of people with it. In particular, it is believed that ixodid ticks are carriers of babesia that can parasitize the human body. Pyroplasmosis is similar to human monocytic ehrlichiosis in the first place with symptoms: patients complain of fever, chills, headaches and muscle pain, nausea, and vomiting. In addition, pathological phenomena such as premature destruction of red bodies in the circulating blood (hemolytic anemia), an abnormal decrease in their number (thrombocytopenia), a decrease in the total volume of white blood cells (leukopenia), and an increase in the spleen (splenomegaly) are also observed. In people with satisfactory overall health, the symptoms of the disease may be mild or completely absent. Severe cases of human pyroplasmosis are observed in patients who have previously undergone a spleen removal surgery (splenectomy) or who have a weak immune system. Most often, human babesiosis is diagnosed in the north of the USA, however, cases of its detection in European countries are known.
Tick-borne rickettsiosis
Human monocytic ehrlichiosis should be distinguished from American tick-borne rickettsiosis , a rare infectious disease caused by bacteria from the Rickettsia family. The carriers of infection are the same insects that can infect a person with monocytic ehrlichiosis. With rickettsiosis, severe headaches and muscle pains, fever, chills, loss of orientation in space are observed. In most cases, after two to six days after a tick bite, a skin rash appears, primarily covering the palms, wrists, soles of the feet, ankles and forearms. Later, the rash spreads to the face, trunk and lower legs. Nausea, vomiting, and abdominal pain are sometimes observed. In some cases, when the disease is not diagnosed on time or in the absence of adequate treatment, the symptoms of American tick-borne rickettsiosis can be life-threatening. Epidemic outbreaks of this disease are recorded in various regions of the United States.
Diagnostics
To diagnose a person’s monocytic ehrlichiosis, the infection of which can lead to potentially dangerous symptoms, is necessary with the help of a thorough medical examination, analysis of the signs of the disease and specialized laboratory tests. Blood tests often indicate typical manifestations of human monocytic ehrlichiosis: a decrease in the volume of red blood cells (thrombocytopenia), a decrease in the number of some white bodies (leukopenia), and a simultaneous increase in the level of certain liver enzymes (for example, serum aspartate aminotransferase and alanine aminotransferase). In some cases, as a result of laboratory examinations, pathologies of cerebrospinal fluid are detected. In addition, chest x-ray may reveal abnormal changes in the lungs (for example, pulmonary infiltrates or accumulation of excess fluid).
Examination of a blood smear under an electron beam microscope allows you to detect accumulations of bacteria in the vacuoles of some cells (in particular, monocytes), however, at the early stage of an infectious disease, such accumulations are not always visible. In some cases, additional specialized laboratory tests are required to determine the specific type of infection or confirm the diagnosis.
Such specialized tests include, for example, an indirect immunofluorescence method for detecting pathologies, which consists in examining serum based on the patient’s blood. Antibodies - proteins produced by certain white blood cells - help the body fight toxins and harmful microorganisms. When using the indirect immunofluorescence method, human antibodies are labeled with special fluorescent dyes, the serum is placed under ultraviolet radiation and examined under a microscope to determine the antibody response to specific microorganisms.
Treatment
If the diagnosis of human monocytic ehrlichiosis is confirmed, how can this disease be treated? Most often, doctors prescribe a standard dosage of tetracycline antibiotics. As an alternative, doxycycline therapy is sometimes used. In severe cases, the patient may need professional supervision in a hospital setting. In addition to antibiotics, you can take any medications allowed by your doctor to relieve typical symptoms of infection.
Prevention
If you live in a geographic area inhabited by ticks of potentially dangerous species, including carriers of bacteria from the Erlichia family, it is advisable to take appropriate precautions. If you go outdoors, remember that you thereby increase the risk of contracting such a serious illness as monocytic human ehrlichiosis. Photos of ticks that are confirmed bacteria carriers can help you stay alert, but knowing a potential enemy by sight is not enough. Wear long pants, shirts, and long-sleeved T-shirts. It is important to wear hats, best of all - wide-brimmed hats, as many mites live on trees. Choose clothes in light shades, as it is easiest to see an insect on it. Use special repellents and be sure to inspect your skin and clothing as often as possible. Most tick bites occur on the scalp and neck.