Meningitis without fever: symptoms, treatment

Temperature during an inflammatory process – in particular, during 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 temperature, which significantly complicates diagnosis and may indicate disorders of the immune system. The features of this phenomenon should be discussed in more detail.

Is it possible to have meningitis without fever?

All infectious and inflammatory pathologies are potentially dangerous, and even more so – infections affecting 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, an 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 the temperature indicators are within 36.6-36.9 ° C, may indicate that the mechanism of immune protection 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 worldwide each year. The most common symptoms are fever and headache, although the number of atypical cases has increased significantly in the last decade.

Meningitis without fever is more common in old age, although its development is not excluded in children: approximately every fifth childhood inflammation of the meninges ends in death. Infants under one year old are in the most dangerous risk zone.

Causes meningitis without fever

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

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

• Immunity status. It is considered normal that any inflammatory reaction should be accompanied by the production of antibodies and an increase in temperature. If there is an obvious immunodeficiency, this process may be disrupted. [ 1 ]
• Type of infection. Today, hundreds of thousands of different viruses and bacteria are known, each with varying degrees of virulence. The human immune system does not always react to a particular pathogen in the same way. It may consider one “stranger” dangerous and quickly react to its invasion (in particular, with a temperature reaction), while in relation to another pathogen, the reaction may be quite weak.
• Regular intake of medications. If a patient takes non-steroidal anti-inflammatory drugs constantly or very often, this can lead to inhibition of the synthesis of prostaglandins and cyclooxygenase – components that actively participate in the mechanism of inflammation and temperature increase. [ 2 ]
• Chemotherapy. If a person has recently undergone chemotherapy for oncological pathologies, then their immune system may be greatly weakened. As a result, the infection spreads rapidly and symptoms become hidden. [ 3 ]

Risk factors

Incorrect internal biological and chemical processes can be observed in patients with immunodeficiency, oncology, and chronic complicated pathologies. These disorders can cause a failure of the immune response or metabolism, and thus disrupt the formation of an inflammatory response in the body.

Often, meningitis without fever develops in elderly patients, which is due to the dominance of metabolic breakdown processes over the formation and synthesis of substances. It has been noted that in old age, the production of proinflammatory components is significantly reduced. Also, elderly patients are often unable to cause a strong inflammatory response to infection and disease, since their temperature does not reach the temperature range that is traditionally considered the temperature range of fever. [ 4 ]

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

Pathogenesis

Meningitis without fever is a specific deviation from the norm. The basic thermoregulatory centers that coordinate all processes associated with maintaining or increasing the temperature during meningitis are localized in the hypothalamus. [ 5 ] 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, the most common are bacteria and viruses, their decay products, as well as components that act as “targets” of phagocytosis and pinocytosis.

Pyrogens are substances that trigger a temperature reaction. They can be exogenous (microbial, non-microbial) or endogenous (leukocyte). [ 6 ] When pyrogens enter the body, the thermoregulation mechanism is activated, the temperature rises:

• pyrogens enter the central nervous system and affect the nerve cells of the anterior 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, changing the sensitivity of the nerve cells of the thermoregulatory center. [ 7 ]

Meningitis without fever is most often a consequence of a disturbance in one of the stages of the process induced by pyrogens.

Symptoms meningitis without fever

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

• severe headache;
• tension in the neck muscles, inability to tilt the head toward the chest (specific meningeal signs);
• nausea to the point of vomiting (no relief after vomiting);
• disturbances of consciousness (clouding, drowsiness, loss of consciousness);
• increased reaction to light and loud sounds, high skin sensitivity;
• tachycardia;
• convulsive muscle twitching;
• star-shaped rash.

In severe cases of meningitis without fever, hallucinations, delusional state, agitation, anxiety, or, conversely, apathy may occur.

First signs

In many cases, the precursor to inflammatory pathology is an acute respiratory viral infection, which is treated for a long time and without result, 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 treated incorrectly, can cause serious adverse effects that will bother the patient for many months or even for life.

The first signs that require special attention and a quick response:

• increased headaches that cannot be relieved by taking conventional medications;
• a sharply increasing deterioration in visual and/or auditory function;
• regular convulsions, unexpected epileptic seizures;
• the emergence 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 at the mouth);
• signs of cerebral edema (increased headaches, vomiting, convulsions, shortness of breath, decreased consciousness up to and including coma);
• paralysis.

Signs of meningitis in an adult without fever

The most common signs of meningitis without fever are:

• severe headache that cannot be relieved by taking conventional analgesics;
• tension in the neck muscles to the point of numbness;
• impaired consciousness (from slight drowsiness to a comatose state);
• increased sensitivity to light and sound stimuli.

The patient feels sick, wants to vomit, which does not bring relief even after multiple episodes. Severe weakness is noted, the heart rate increases, and muscle pain appears.

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

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

Meningitis without fever can occur in a child

Congenital vulnerabilities of the immune system, imperfection of the 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 timely attention to other symptoms:

• the baby becomes lethargic, whiny, capricious;
• the skin turns pale (especially on the limbs);
• vomiting and drowsiness appear;
• reddish spots may appear on the body.

The child refuses to eat and cries constantly. Convulsive muscle twitching, bulging and pulsation of the large fontanelle, and tension in the occipital muscles may be observed. The baby screams sharply when hearing a loud sound, turns away from the window, throws his head back and bends his legs at the knee joints, and does not allow himself to be touched. If the cranial nerves are damaged, the baby may have strabismus. [ 8 ]

If these signs are detected, the child must be urgently sent to hospital. Treatment of such a condition at home is impossible and can be fatal.

Complications and consequences

Regardless of the type of meningitis that occurs without fever (viral, bacterial or fungal), the risk of complications is always present. Most patients, even with successful treatment, experience the so-called asthenic syndrome for a long time, 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 and including complete hearing loss;
• hydrocephalus;
• ischemic stroke (more common in adult patients);
• intellectual disabilities – in particular, memory loss, learning difficulties, etc.;
• convulsions, epilepsy;
• deterioration of visual function, even to the point of blindness;
• changes in gait, coordination disorders.

Overall, it is estimated that up to 1 in 10 cases of bacterial meningitis is fatal.[ 9 ]

It is almost impossible to predict the consequences of meningitis without fever in advance. Therefore, it is extremely important to promptly identify the disease and begin its treatment.

Diagnostics meningitis without fever

Meningitis without fever is a condition that requires particularly careful diagnostics. The examination begins with an examination of the patient, an assessment of meningeal symptoms. Then instrumental diagnostics and tests are prescribed, with the main point being a lumbar puncture. Cerebrospinal fluid indicators confirming meningitis are: cytosis (increased cell count), changes in cellular composition, increased protein content. In general, the doctor may prescribe the following procedures:

• microbiological examination of cerebrospinal fluid (bacterioscopy of smears with Gram and Romanovsky-Giemsa staining, culture on nutrient media (is the “gold standard” for diagnosing bacterial meningitis, and obtaining in vitro results is mandatory));
• virological examination of cerebrospinal fluid (PCR, ELISA, IFM, RTGA);
• parasitological examination (cerebrospinal fluid microscopy, PCR, ELISA);
• polymerase chain reaction to detect DNA or RNA of the pathogen;
• general and biochemical blood tests;
• electroencephalography;
• electromyography;
• radiography;
• serodiagnostics;
• computed tomography and magnetic resonance imaging;
• electrocardiography;
• General urine test.

It is also possible to conduct an assessment of the blood coagulation system. [ 10 ]

As the patient recovers from meningitis without fever, he or she must undergo follow-up tests and receive a consultation with a neurologist.

Differential diagnosis

Differential diagnosis of meningitis without fever comes down to identifying:

• certain diseases that have signs of primary meningitis;
• pathologies in which meningitis can become a secondary disease (for example, focal bacteriosis or viral infection);
• purulent-septic pathologies that have 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 must be distinguished from the following pathologies:

• Hemorrhagic stroke 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, intratumor hemorrhages) are accompanied by subacute development of general brain syndrome, are characterized by the absence of infectious and epidemiological factors. CT images, fundus examination data, and the absence of an infectious component become diagnostically significant.
• Cerebral vein thrombosis is characterized by an acute onset and 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 cerebrospinal fluid analysis results.
• Migraine is characterized by the absence of somatic disorders, infectious and meningeal syndrome.
• Anemias, which usually cause headaches and weakness.
• Exposure to carbon monoxide.
• Child abuse.
• Tick-borne diseases.
• Tuberculosis. [ 11 ]

Treatment meningitis without fever

Meningitis without fever is potentially life-threatening for the patient, so it should always be considered a medical emergency. The patient is hospitalized and antibiotic therapy is started as soon as possible - immediately after performing a spinal puncture.

The infectious and inflammatory process begins to be treated with antibiotics such as penicillin, ampicillin, ceftriaxone. To enhance the effect of the drugs, pyrazinamide and rifampicin are prescribed. [ 12 ], [ 13 ]

For detoxification purposes, it is appropriate to use atoxil and enterosgel.

If it is a fungal infection, amphotericin and 5-flucytosine are prescribed.

As symptomatic treatment, antihistamines, anti-inflammatory drugs, diuretics and analgesics may be prescribed.

An approximate treatment plan might look like this:

• Abundant fluid intake, nasogastric intubation and tube feeding in case of possible aspiration and depressed consciousness, elevated head position with head turned to the 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 within 2-3 days the antibiotics are replaced according to the identified bacterial sensitivity.
• Intravenous administration of human normal immunoglobulin is possible as an immunoreplacement therapy.
• For herpetic meningitis, acyclovir is used intravenously every 8 hours for 2 weeks.
• For cytomegalovirus, ganciclovir is successfully used intravenously for 2-3 weeks.
• For seizures, increased intracranial pressure, and cerebral edema, dexamethasone (2-7 days), mannitol (15-20%), furosemide, diacarb, and magnesium sulfate are prescribed.
• For the purpose of detoxification, 15% mannitol with lasix, saline solution, 10% glucose solution, rheopolyglucin, gelatin succinate solution and hydroxyethyl starch are administered intravenously.

If necessary, tracheal intubation and artificial ventilation are performed.

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

The main criterion for improving the condition in meningitis without fever is considered to be the sanitation of the cerebrospinal fluid. Control lumbar puncture is performed after the elimination of the meningeal syndrome, with the stabilization of general blood indices. 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 in the mother's womb, and much depends on the hereditary factor. But no less important in the quality of immunity is the lifestyle, 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 disrupted, and the likelihood of getting meningitis will be significantly reduced.

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.[ 14 ]
• Pneumococcal vaccines help protect against S. pneumoniae.
• Haemophilus influenzae serotype b (Hib) vaccines help protect against Hib.
• Bacillus Calmette-Guerin vaccine helps protect against tuberculosis. [ 15 ]

Vaccines can protect against some diseases, such as measles, mumps, chickenpox, and influenza, which can lead to viral meningitis.[ 16 ]

The main points of strengthening the immune system are as follows:

• The immune system requires regular training, such as hardening. Hardening should be done not only regularly, but also moderately and gradually. You should not immediately, without preparation, practice cold dousing. To begin with, you should spend more time outdoors, ventilate the room more often, walk barefoot, wipe your body with a damp towel, wash with cool water. And only at the second stage, when the body gets used to a small change in temperature, you can try a contrast shower. The procedures should be carried out regularly, avoiding long breaks. The only condition under which you need to skip a procedure is an illness (cold, acute respiratory infection, acute respiratory viral infection, etc.).
• The quality of immune protection largely depends on our diet: how balanced it is, how rich in minerals and vitamins it is. It is desirable that the diet be as varied as possible. The menu should include dairy products, vegetables and fruits, cereals, protein (meat, fish, eggs, legumes or nuts). The body should receive a sufficient amount of fats - of course, not margarine and trans fats, but natural vegetable oil, fish oil. Nuts and avocados are useful in this regard.
• If there are not enough vitamins in the diet, you may need to take additional vitamins in the form of multivitamin and complex vitamin-mineral preparations. It is especially important to take such products during periods of seasonal illness, severe and frequent stress, depression, excessive stress, pregnancy, chronic diseases, and after prolonged antibiotic therapy. Taking the 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 are no less beneficial - biologically active components that have a positive effect on the intestinal microflora and human health in general. The benefits of probiotics have long been limited to the quality of microflora: these drugs are used to treat and prevent immunodeficiency conditions and pathologies caused by dysbacteriosis.
• For normal functioning of the immune system, a routine is needed, since its absence brings a lot of additional stress to the body. 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 regular morning exercises have a positive effect on immune protection, increase the body's tone, enrich the blood with oxygen, improve sleep and appetite, and eliminate the effects of stress.
• Bad habits such as 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 used uncontrolled 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 to prevent the development of the disease and strengthen the immune system.