Meningitis without fever: symptoms, treatment

The temperature in the inflammatory process - in particular, with meningitis - is a typical reaction, thanks to which you can pay attention to the problem in time, take measures and prevent the development of complications. However, in rare cases, meningitis develops without fever, which greatly complicates the diagnosis and may indicate disorders of the immune system. The features of this phenomenon should be discussed in more detail.

Can there be meningitis without fever?

All infectious and inflammatory pathologies are potentially dangerous, and even more so - infections that affect the brain. Meningitis of any origin poses a considerable danger to the health and life of the patient. Therefore, it is extremely important to notice the disease in a timely manner and consult a doctor for diagnosis and treatment. But, unfortunately, in some cases the clinical picture is atypical, the symptoms are erased. Indeed, there are cases when meningitis occurs without fever.

Experts explain: normally, the infectious process should be accompanied by an increase in temperature, because with the help of such a reaction the body fights the disease. But the opposite situation, when infection and inflammation are present, and temperature indicators are in the range of 36.6-36.9 ° C, may indicate that the mechanism of immune defense and thermoregulation is impaired, and there are several reasons for this.

Epidemiology

It is estimated that more than 1.2 million cases of bacterial meningitis occur each year worldwide. [1]The most common signs of pathology are fever and headache, although over the past decade the number of atypical cases of the disease has increased significantly.

Meningitis without fever is more common in the elderly, although its development is not excluded in children: approximately one in five children's inflammation of the meninges ends with a lethal outcome. In the most dangerous risk zone are infants under one year old.

Causes of the meningitis without fever

Body temperature is a kind of marker, or a complex indicator that reflects all the thermal processes occurring in the body. This indicator is constant if there is a balance of heat generation and heat loss. Thermoregulation is directly controlled by the nervous system, using temperature receptors and a neuroendocrine regulator - the hypothalamus.

With the start of infectious and inflammatory processes, an increase in temperature above 37 ° C is observed. The lack of such an increase may be due to several reasons:

• state of immunity. It is considered normal that any inflammatory reaction should be accompanied by the production of antibodies and an increase in temperature. If there is a clear immunodeficiency, then this process may be disrupted. [2]
• type of infection. To date, hundreds of thousands of different viruses and bacteria with varying degrees of virulence are known. The immune defense of a person does not always react in the same way to a particular pathogen. She may consider one "stranger" dangerous and quickly respond to its invasion (in particular, with the help of a temperature reaction), and in relation to another pathogen, the reaction may be rather weak.
• Regular intake of medications. If the patient constantly or very often takes non-steroidal anti-inflammatory drugs, then this can lead to inhibition of the synthesis of prostaglandins and cyclooxygenase - components that are actively involved in the mechanism of inflammation and fever. [3]
• Chemotherapy. If a person recently underwent chemotherapy for oncological pathologies, then his immune system can be greatly weakened. As a result, the rapid spread of infection and latent symptoms. [4]

Risk factors

The incorrect course of internal biological and chemical processes can be observed in patients with immunodeficiency states, oncology, and chronic complicated pathologies. These disorders can cause a failure of the immune response or metabolism, and thereby upset the construction of the inflammatory response in the body.

Often, meningitis without fever develops in senile patients, which is due to the dominance of metabolic decay processes over the formation and synthesis of substances. It is noticed that in old age the production of pro-inflammatory components is significantly reduced. Also, elderly patients are often unable to elicit a strong inflammatory response to infection and disease because their temperature does not reach the temperature range traditionally considered to be the fever temperature range. [5]

In rare cases, meningitis without fever is associated with a congenital disorder of the pituitary gland. So, some people have a corresponding developmental defect, and sometimes such a defect is the result of intrauterine infection.

Pathogenesis

Meningitis without fever is a kind of deviation from the norm. The basic thermoregulatory centers that coordinate all processes associated with the preservation or increase in temperature during meningitis are localized in the hypothalamus. [6] Additionally, the endocrine glands are also involved in the mechanism - in particular, the adrenal glands and the thyroid gland.

Among the etiological factors that cause an increase in temperature in meningitis, they most often talk about bacteria and viruses, their decay products, as well as the components that act as "targets" of phagocytosis and pinocytosis.

Pyrogens are substances that trigger a temperature reaction. They are exogenous (microbial, non-microbial) or endogenous (leukocyte). [7]When pyrogens enter the body, the thermoregulation mechanism is activated, the temperature rises:

• pyrogens enter the central nervous system, affect the nerve cells of the anterior region of the hypothalamus;
• these nerve cells have specific membrane receptors, due to which the adenylate cyclase system is stimulated;
• the intracellular amount of cyclic adenosine monophosphate increases, which changes the sensitivity of the nerve cells of the thermoregulatory center. [8]

Meningitis without fever is most often the result of a violation in any of the stages of the process induced by pyrogens.

Symptoms of the meningitis without fever

In patients who suffer from meningitis without fever, an infectious and inflammatory pathology can be suspected for other characteristic symptoms:

• severe pain in the head;
• neck muscle tension, inability to tilt the head to the chest (specific meningeal signs);
• nausea to vomiting (after vomiting, relief does not occur);
• disorders of consciousness (fogging, drowsiness, loss of consciousness);
• increased reaction to light and loud sounds, high skin sensitivity;
• tachycardia;
• convulsive muscle twitching;
• stellate eruptions.

In severe cases, with meningitis without fever, hallucinations, delusions, agitation, anxiety, or vice versa, apathy may occur. 

First signs

In many cases, an acute respiratory viral infection becomes a harbinger of inflammatory pathology, which is treated for a long time and to no avail, although in reality the disease has already been complicated by meningitis without fever. It is important to suspect such a complication in a timely manner, since meningitis, if not properly treated, can cause serious adverse effects that will bother the patient for many more months, or even a lifetime.

The first signs that require special attention and quick response to them:

• frequent pain in the head, which can not be eliminated by taking the usual medications;
• sharply increasing deterioration in visual and / or auditory function;
• regular convulsions, unexpected attacks of epilepsy;
• the appearance of problems with cardiac activity;
• signs of pulmonary edema (frequent shallow breathing, dry cough with wheezing, severe shortness of breath, swelling in the face and neck, foam from the mouth);
• signs of cerebral edema (increased pain in the head, vomiting, convulsions, shortness of breath, depression of consciousness up to coma);
• paralysis.

Signs of meningitis in an adult without fever

The most common symptoms of meningitis without fever are:

• severe pain in the head, which cannot be eliminated by taking the usual analgesics;
• tension of the neck muscles up to numbness;
• impaired consciousness (from slight drowsiness to coma);
• increased susceptibility to light and sound stimuli.

The patient feels sick, vomits, which, even after repeated episodes, does not bring relief. Severe weakness is noted, the heartbeat quickens, pain in the muscles appears.

Meningeal syndrome is expressed in the appearance of symptoms of Kernig and Brudzinsky: the patient is unable to bend the neck and bring the chin to the chest. Simultaneously with such attempts, the legs are bent at the knee joints. Hypersensitivity is expressed: loud sounds, bright light become painful. Even touching the body causes a hypertrophied reaction.

Meningitis without temperature is dangerous because, with apparent well-being, the pathological process continues to progress, so it can rapidly develop into a coma. The main diagnostic moment in such a situation is the study of cerebrospinal fluid taken during a lumbar puncture.

Can a child have meningitis without fever?

Congenital vulnerabilities of immunity, imperfection of immune function can lead to the fact that meningitis in a child will not be accompanied by a pronounced rise in temperature. In such a situation, it is important to pay attention to other symptoms in a timely manner:

• the baby becomes lethargic, whiny, capricious;
• the skin turns pale (especially on the limbs);
• there is vomiting, drowsiness;
• possible appearance of reddish dots on the body. 

The child refuses to eat, constantly cries. There may be convulsive muscle twitches, protrusion and pulsation of the large fontanel, tension of the occipital muscles. The kid screams sharply when he hears a loud sound, turns away from the window, throws his head back and bends his legs at the knee joints, does not allow himself to be touched. If the cranial nerves are affected, the infant may experience strabismus. [9]

If these signs are found, it is necessary to urgently send the child to the hospital. Treatment of this condition at home is impossible and can be fatal.

Complications and consequences

Regardless of what type of meningitis occurs without fever (viral, bacterial or fungal), the risk of complications is always present. In most patients, even with successful treatment, the so-called asthenic syndrome is observed for a long time, which is characterized by general weakness, apathy, and depression. The average duration of the syndrome is from three months to one year.

Approximately every third person who has had meningitis without fever develops more severe complications:

• paresis and paralysis;
• hearing impairment up to its complete loss;
• hydrocephalus;
• ischemic stroke (more typical for adult patients);
• intellectual impairment - in particular, memory impairment, learning difficulties, etc.;
• convulsions, epilepsy;
• deterioration of visual function, up to blindness;
• change in gait, coordination disorders.

Overall, up to 1 in 10 cases of bacterial meningitis is estimated to be fatal. [10]

Predicting the consequences of meningitis without temperature is almost impossible. Therefore, it is extremely important to identify the disease in a timely manner and begin its treatment.

Diagnostics of the meningitis without fever

Meningitis without fever is a condition that requires particularly careful diagnosis. The examination begins with an examination of the patient, an assessment of meningeal symptoms. Next, instrumental diagnostics and analyzes are prescribed, while the main point is lumbar puncture. Indicators of cerebrospinal fluid, confirming meningitis, are: cytosis (increased number of cells), changes in cellular composition, increased protein content. In general, the doctor may prescribe the following procedures:

• microbiological examination of the cerebrospinal fluid (bacterioscopy of smears with Gram and Romanovsky-Giemsa stain, inoculation on nutrient media (is the "gold standard" for the diagnosis of bacterial meningitis, and obtaining  in vitro results  is mandatory));
• virological examination of cerebrospinal fluid (PCR, ELISA, IFM, RTGA);
• parasitological examination (liquor microscopy, PCR, ELISA);
• polymerase chain reaction to determine the DNA or RNA of the pathogen;
• general and biochemical blood tests;
• electroencephalography;
• electromyography;
• radiography;
• serodiagnosis;
• computed and magnetic resonance imaging;
• electrocardiography;
• general urinalysis.

It is also possible to evaluate the blood coagulation system.[11]

As the patient recovers from meningitis without fever, the patient must pass control tests and receive a consultation from a neurologist.

Differential diagnosis

Differential diagnosis of meningitis without temperature is reduced to the identification of:

• individual diseases with signs of primary meningitis;
• pathologies in which meningitis can become a secondary disease (for example, focal bacteriosis or viral infection);
• purulent-septic pathologies with a picture of secondary bacterial meningitis;
• other, mainly neurological pathologies - for example, intracranial hematoma, acute cerebrovascular accident, malignant brain tumors, etc.

Most often, meningitis without fever has to be distinguished from such pathologies:

• Hemorrhagic stroke - it is characterized by an acute onset associated with physical or stressful overexertion and high blood pressure.
• Ischemic stroke - occurs with a predominance of focal neurological symptoms over meningeal syndrome.
• Volumetric brain pathologies (abscesses, intratumoral hemorrhages) are accompanied by a subacute development of the cerebral syndrome, they are distinguished by the absence of an infectious and epidemiological factor. CT images, fundus examination data, and the absence of an infectious component become diagnostically significant.
• Thrombosis of the cerebral veins is characterized by an acute onset and the development of focal and cerebral neurological signs along with a general infectious syndrome and / or intoxication. Neurological symptoms correspond to the location of the venous sinus.
• Neurotoxicosis - accompanied by normal parameters of the analysis of cerebrospinal fluid.
• Migraine - characterized by the absence of somatic disorders, infectious and meningeal syndrome.
• Anemia, which usually causes headaches and weakness.
• Exposure to carbon monoxide.
• Child abuse.
• Tick-borne diseases.
• Tuberculosis. [12]

Treatment of the meningitis without fever

Meningitis without fever is potentially life threatening and should always be considered a medical emergency. The patient is admitted to the hospital and antibiotic therapy is started as early as possible - immediately after the lumbar puncture is performed.

The infectious-inflammatory process is being treated with antibiotics such as penicillin, ampicillin, ceftriaxone. To enhance the effect of drugs, pyrazinamide and rifampicin are prescribed. [13], [14]

In order to detoxify, it is appropriate to use atoxil, enterosgel.

If we are talking about a fungal infection, amphotericin, 5-flucytosine is prescribed.

As symptomatic agents, it is possible to prescribe antihistamines, anti-inflammatory drugs, diuretics and analgesics.

An example treatment regimen might look like this:

• Abundant fluid intake, nasogastric intubation and tube feeding with the likelihood of aspiration and depressed consciousness, an elevated head position with a turn of the head to one side.
• Benzylpenicillin sodium salt every 3-4 hours intramuscularly in combination with ceftriaxone (1-2 times), or with cefotaxime (every 6 hours). If the initial antibiotic therapy is ineffective, then for 2-3 days antibiotics are replaced according to the identified bacterial sensitivity.
• As an immunoreplacement treatment, intravenous administration of human normal immunoglobulin is possible.
• In herpetic meningitis, acyclovir is used intravenously every 8 hours for 2 weeks.
• With cytomegalovirus, ganciclovir is successfully used intravenously for 2-3 weeks.
• With convulsions, increased intracranial pressure, cerebral edema, dexamethasone (2-7 days), mannitol (15-20%), furosemide, diacarb, magnesium sulfate are prescribed.
• For the purpose of detoxification, 15% mannitol with lasix, saline solution, 10% glucose solution, rheopolyglucin, solution of gelatin succinate and hydroxyethyl starch are administered intravenously.

If necessary, perform tracheal intubation and artificial ventilation of the lungs.

Throughout the entire period of treatment, the dynamics of symptoms from the central nervous system is noted, the size of pupils and body temperature, hemodynamic parameters and hourly diuresis, levels of potassium, sodium in plasma, and acid-base balance of the blood are monitored.

Sanitation of the cerebrospinal fluid is considered the main criterion for improvement in meningitis without fever. Control lumbar puncture is performed after elimination of meningeal syndrome, with stabilization of general blood counts. Treatment is stopped when the number of cells in 1 μl of cerebrospinal fluid does not exceed 50 cells due to lymphocytes (70%).

Prevention

The formation of a person's immune defense occurs even in the womb, and much depends on the hereditary factor. But just as important as immunity is the way of life, which we can and should influence. Strengthening the body is a guarantee that the immune system will work correctly, the temperature regulation mechanism will not be disturbed, and the likelihood of getting meningitis will decrease significantly.

Vaccination

Vaccines are the most effective way to protect against certain types of bacterial meningitis. There are vaccines against 4 types of bacteria that can cause meningitis:

• Meningococcal vaccines help protect against N. Meningitidis. [15]
• Pneumococcal vaccines help protect against S. Pneumoniae.
• Haemophilus influenzae serotype b (Hib) vaccines help protect against Hib.
• Bacillus Calmette-Guérin vaccine helps protect against tuberculosis. [16]

Vaccines can protect against certain diseases, such as measles, mumps, chickenpox, and influenza, which can lead to viral meningitis. [17]

The main points of strengthening immunity are as follows:

• The immune system needs regular training - for example, hardening. It should be tempered not only regularly, but also moderately and gradually. Do not immediately, without preparation, practice cold douche. To begin with, you should be more in the fresh air, ventilate the room more often, walk barefoot, wipe your body with a damp towel, and wash your face with cool water. And only at the second stage, when the body gets used to a slight change in temperature, you can try a contrast shower. Procedures should be carried out regularly, avoiding long breaks. The only condition under which you need to skip the procedure is a disease (cold, acute respiratory infections, SARS, etc.).
• The quality of immune protection largely depends on our diet: how balanced it is, rich in minerals and vitamins. It is desirable that the diet was extremely varied. The menu should include dairy products, vegetables and fruits, cereals, protein (meat, fish, eggs, legumes or nuts). The body must receive a sufficient amount of fat - of course, not margarine and trans fats, but natural vegetable oil, fish oil. Useful in this regard, nuts and avocados.
• If there are not enough vitamins in the diet, they may need additional intake - in the form of multivitamin and complex vitamin-mineral preparations. It is especially important to take such funds during a surge in seasonal morbidity, with severe and frequent stress, depression, excessive stress, pregnancy, chronic diseases, and also after prolonged antibiotic therapy. Taking drugs can last from 30 to 90 days, and the course is recommended to be repeated 2 times a year. In addition to vitamins, probiotics will bring no less benefit - biologically active components that positively affect the intestinal microflora and human health in general. The benefits of probiotics are no longer limited to the quality of the microflora: these drugs are used to treat and prevent immunodeficiency states and pathologies caused by dysbacteriosis.
• For the normal functioning of the immune system, a regimen is needed, since its absence brings the body a lot of additional stress. It is important to wake up and go to bed at the same time, get enough sleep, walk more (in any weather), and maintain physical activity. Even ordinary morning exercises have a positive effect on immune defense, increase body tone, enrich blood with oxygen, improve sleep and appetite, and relieve the effects of stress.
• Bad habits in the form of smoking, alcohol and drug abuse block the immune system, negatively affect the function of most organs, worsen the quality of blood vessels, and increase the risk of developing many pathologies. By the way, some medications can also weaken the immune system, especially if they are used uncontrollably and inappropriately without consulting a doctor.

Meningitis without fever is a pathology that is difficult to diagnose in a timely manner. Therefore, you should take care in advance and take all measures in order to prevent the development of the disease and strengthen the immune system.