Familial Mediterranean fever

What is it?

There is a predominant disease in the Mediterranean region that is characterized by the appearance of fever outbreaks, Joint pain and involvement of one or more serous, such as the peritoneum or pleura. It occurs in members of the same family and is inherited following a recessive pattern. This disease is called Familial Mediterranean fever.

How is it produced?

Family Mediterranean fever is a disease with autosomal recessive inheritance due to a mutation of the most extreme region of the long arm of chromosome 16.

It predominates in the Mediterranean region, hence its name, especially among young men between the ages of 5 and 15. The cause of this mutation is unknown, but several possible triggers such as infectious agents, immunological disorders or catecholamines are considered. In the tissues that are affected, if they are analyzed under a microscope, an infiltrate of polymorphonuclear leukocytes is observed.

Familial Mediterranean fever runs in the form of periodic outbreaks that occur once or twice a month and that they do not follow any type of appearance pattern. Outbreaks usually last 24 to 48 hours. The symptoms that patients present are usually:

• High fever: even up to 40ºC, accompanied by chills and sweating. It tends to give in abruptly.
• Abdominal pain: it occurs in up to 90% of cases. It begins at the level of the right hypochondrium or the right iliac fossa and then spreads to the rest of the abdomen, with abdominal distention and the absence of peristalsis. The pain radiates to the shoulders or back, is accompanied by nausea and vomiting, and is due to irritation of the peritoneum. It reaches its zenith at 6-12 hours and disappears in 24-48 hours.
• Chest pain: secondary to pleurisy, inflammation of the pleura, sometimes accompanied by pleural effusion and friction. It is usually unilateral and associated with peritoneal irritation. It remits in 24-36 hours and is infrequently associated with pericarditis.
• Joint pain: it can present acutely, a fact that is more frequent, with inflammation of a single joint or as asymmetric oligoarthritis, especially in the large joints of the lower extremities. The acute arthritis of familial Mediterranean fever usually lasts between 5 and 6 days, presents an exudative synovitis, and is accompanied by a high fever. Another form of presentation is chronic arthritis, in the form of monoarthritis or oligoarthritis with functional impotence when trying to passively mobilize the patient's joints. It mainly affects the hips and can degenerate into bone necrosis.
• Skin lesions: They occur in a third of patients in the form of localized erythema, especially on the legs and dorsum of the foot. They are erythematous, hot and painful plaques that are accompanied by high fever and joint pain.

Other manifestations: generalized muscle aches, hepatomegaly, splenomegaly, orchitis or hematuria.

The most common complication of familial Mediterranean fever is , which mainly affects the kidneys and can lead to chronic kidney failure. Amyloidosis occurs before age 40. There is no relationship between the number or intensity of flare-ups and the presence of amyloidosis. Amyloidosis is sometimes the only manifestation of familial mediterranean fever, which implies a worse prognosis. In general, the prognosis of familial Mediterranean fever is very good and depends mainly on the presence of amyloidosis.

Diagnosis

The diagnosis of familial Mediterranean fever is based on the patient's symptoms and on a series of diagnostic criteria. In those, an elevation of the acute phase reactants will be appreciated, such as the speed of erythrocyte sedimentation (VSG) and C-reactive protein (PCR). Likewise, an elevation of leukocytes and fibrinogen will be appreciated, a characteristic fact of this disease.

The diagnostic criteria for familial Mediterranean fever are three major (relapsing fever, serosal involvement and skin lesions) and three minor (elevated ESR, increased fibrinogen, and elevated blood leukocytes). In order to establish the diagnosis the fever is needed together with a major and a minor criterion or two minor ones. In those cases in which a sufficient number of criteria for diagnosis are not given, a stimulation test can be performed by intravenous injection of metaraminol; If symptoms consistent with an outbreak of familial Mediterranean fever appear within 48 hours, the test is considered positive.

Treatment

Treatment is based on colchicine, which decreases the number of outbreaks, as well as their intensity. It should be used preventively and continuously, not to treat outbreaks already established. It can be given up to 3 mg a day to control the disease. The main side effects of treatment are nausea, vomiting, and diarrhea.

In case the patient suffers from renal failure secondary to amyloidosis, a kidney transplant can be considered, since the administration of colchicine prevents the appearance of amyloidosis in the graft.

Precautionary measures

Given the it is a hereditary disease, there are no preventive measures to prevent it. People who have family members who suffer from this disease should be advised to be attentive to the possible appearance of it in the early stages of life and if you have any questions, the first thing to do is consult your doctor. They have a large medical staff specialized in rheumatic diseases.