Rheumatic fever

Rheumatic fever. It can produce cardiac sequelae due to valve involvement, hence the famous metaphor that Rheumatic Fever. “It licks the joints, but it bites the heart.”

Summary

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  • 1 Definition
  • 2 Etiology
  • 3 Epidemiology
  • 4 Pathophysiology
  • 5 Clinical picture
  • 6 Diagnosis
  • 7 Complementary exams
  • 8 Differential diagnosis
  • 9 Complications
  • 10 Evolution and prognosis
  • 11 Prevention
  • 12 External links
  • 13 Sources

Definition

It is a systemic disease that affects almost the entire organism, especially the joints, heart , nervous system , skin and subcutaneous cell tissue that appears as a late complication of an infection of the upper respiratory system, caused by group A beta-hemolytic streptococcus. .

It can appear at any age but it manifests itself in children older than 5 years and in young adults, exceptionally before 4 years.

Etiology

There is a close relationship between rheumatic fever and group A beta-haemolytic streptococcus. Acute outbreaks of the disease occur as a post-strep sequela of tonsillitis, everything seems to indicate that for this to occur, a host response to the germ is required. That is, their immunological reactions against streptococcus or its products are extremely intense. It is also established that streptococci that cause skin infections do not cause the disease.

epidemiology

Given the causal relationship between rheumatic fever and group A strep throat, the epidemiology of the two diseases is very similar. Initial attacks of rheumatic fever occur rather between the ages of 6 and 15; the risk increases in certain populations: people in overcrowding and people in continuous contact (such as schoolchildren and the military).

The strain of rheumatogenic streptococci containing M proteins and powerful capsules of hyaluronic acid favor the great virulence of the germ making it resistant to phagocytosis, in contrast to the non-rheumatogenic strains of streptococci. The incidence of rheumatic fever, especially in underdeveloped countries, becomes a public health problem, since it is the most common cause of heart disease in people between the ages of 5 and 30, and is therefore the main cause of death from heart disease in people under 45 years of age.

Pathophysiology

Group A beta hemolytic streptococcus represents antigenic stimulation through some membrane proteins (Protein M) that, when contacting monocytes or macrophages, activates them by fixing on their membrane. The activated cell becomes an activated monocyte capable of presenting the antigen to which B lymphocytes (humoral immunity) react, which are responsible for the production of antibodies against the microorganism (anti-streptolysins).

In tissues, the monocyte becomes a macrophage and presents the antigen attached to the T lymphocyte (cellular immunity) on its membrane. Activated macrophages are likely to become giant Aschoff cells, which will be part of the formation of granulomatous lesions; These are pathognomonic of rheumatic carditis and are known as Aschoff’s nodules, which can remain for many years after a rheumatic attack.

Activated T lymphocytes have been found in large numbers in the heart valves of subjects with active rheumatic fever, mostly T4, which are capable of generating lymphokines capable of activating proinflammatory systems, which appear to be the cause of valve inflammation. (valvulitis) during the acute attack. The acute phase of the disease is characterized by exudative and proliferative inflammatory reactions that affect connective tissue and collagen.

The pathological process is diffuse, but mainly attacks the heart, brain, joints, skin and subcutaneous tissues; A generalized small vessel vasculitis is usually recorded. Other streptococci like those in group C and G are capable of eliciting an immune response, but not rheumatic fever.

Clinical picture

The classic clinical picture is preceded, 2-3 weeks before, by strep throat, with tonsil redness, with or without exudate, petechiae on the palate, submaxillary or laterocervical lymphadenopathy, dysphagia, high or moderate fever, abdominal pain and sometimes scarlet fever rash, later appearing the own symptoms of the disease.

Symptoms start with general malaise, asthenia, adynamia, myalgia, arthralgia, hyporexia and fever. Any of the following manifestations can be associated with this table:

  • Arthritis. Present in 75% of cases. It is the main sign, but the least specific. It almost always affects large joints (knees, elbows, wrists and ankles) in an asymmetric and migratory way, but it can affect small joints such as those of the hands, feet and spine. When the acute outbreak disappears, the inflammation disappears without sequelae. In cases where no treatment is received, the condition may last 2 to 3 weeks.
  • Carditis. It can be seen in 40-50% of cases. It is appreciated in the 3rd week. It is the most serious manifestation of rheumatic fever since it can produce from mild manifestations to the death of the patient during the acute attack or leave sequelae that will later affect the functioning of the heart. The acute heart attack affects its three layers constituting a pancarditis (pericarditis, myocarditis and endocarditis). If carditis does not appear within 2 or 3 weeks after the attack, it is rare that it occurs.
  • Sydenham’s Korea. It occurs in 2% of patients. It is considered a late manifestation, usually appearing between 2 and 3 months after the onset of streptococcal infection. The manifestation of acute attack in the central nervous system is injury to the basal ganglia and the caudate nucleus (extrapyramidal system), a late phenomenon in rheumatic fever. It is characterized by involuntary movements, lack of coordination and muscle weakness as well as emotional lability. It mainly affects the muscles of the face and extremities; speech can become explosive and difficult. They disappear during sleep, but can occur at rest and interfere with voluntary activity. The emotional changes are mainly crying and restlessness, the patients despair when they cannot control the movements of their hands or face.
  • Subcutaneous nodules (Meynet’s nodules). They are observed in 10% of cases. They usually appear after the first few weeks of the disease and almost always appear in patients with carditis. They are firm, painless, move easily and can measure up to 2cm; Although they rarely appear, their presence should make carditis suspicious. They usually occur on the extensor face of the joints, particularly the elbows, knees, and wrists. They last from 1 to 2 weeks.
  • Marginal erythema. It is seen in less than 5% of patients. It is a non-pruritic, macular, evanescent eruption, with a pale and circular center, with serpiginous edges, fleeting, of short duration and migratory. Its location occurs in the trunk, buttocks and the proximal region of the extremities, but not in the face. It is also more common in cases with carditis. Duration of the rheumatic attack It fluctuates between 3 weeks to 6 months, as long as there is no new streptococcal infection that prolongs the picture.

Diagnosis

It is based on the Jones criteria, modified by the American Heart association in 1992 that stipulates the major and minor criteria.

Major criteria

  • Sydenham’s Korea.
  • Subcutaneous nodules.
  • Marginal erythema.

Minor criteria

  • Arthralgia
  • Fever greater than 38 C.

Paraclinical.

  • Elevation of acute phase reactants: erythrocyte sedimentation and elevated C-reactive protein
  • Leukocytosis; alpha-2 and increased gamma globulins.
  • Prolongation of the PR interval.
  • Evidence of Streptococcal infection (Group A)

Increased antibodies against streptococcus: antisptreptolysins (more than 333
U Todd) and other streptococcal antigens.

  • Pharyngeal culture positive for group A streptococcus

The existence of two major signs or one major and two minor signs supported by previous infection with group A streptococcus strongly indicate the probability of Rheumatic Fever. The absence casts doubt on the diagnosis, except that it is Sydenham’s Chorea, with a long period of previous infection.

Complementary exams

It should be noted that there is no specific laboratory test for the diagnosis of rheumatic fever, although they can guide us towards the diagnosis of this entity.

  • Pharyngeal culture: it only shows positivity in 10% of cases.
  • Antistreptolysin O titre: its elevation above 200 U only indicates that the patient contacted the streptococcus.
  • Blood count: leukocytosis, neutrophilia, polynucleosis, and moderate anemia.
  • Erythrosedimentation: accelerated above 50mm in almost all patients.
  • C reactive protein: high.
  • Sinus tachycardia.
  • Long PR interval greater than 0.16 seconds and long Qt interval.
  • Disorders of repolarization of the ST segment.

Differential diagnosis

  • Juvenile rheumatoid arthritis.
  • Reactive arthritis.
  • Septic arthritis.
  • Postinfectious arthritis.
  • Sickle cell anemia.
  • Serum sickness.
  • Drop .
  • Systemic lupus erythematosus.
  • Still’s disease.
  • From the point of view heart, you should think of the endocarditis , myocarditis, the cardiomyopathies and Kawasaki disease.
  • The differential diagnosis should also be made with skin lesions that present with various nodules and eruptions, as well as with choreic syndromes of non-rheumatic cause.

Complications

  • Pericarditis .
  • Heart failure .
  • Atrial fibrillation.
  • Subacute bacterial endocarditis or slow endocarditis.
  • Venous thrombosis.

Evolution and prognosis

The disease is considered cyclical, evolving due to outbreaks with spontaneous cyclical regression between 8 and 10 weeks after the outbreak. 80% of patients reach adulthood, and of these approximately 65% ​​can lead a normal life. Recurrences are more frequent during the 5 years after the initial outbreak and decrease progressively as time passes without rheumatic activity.

They are signs of active rheumatic activity. The fever, tachycardia, leukocytosis, elevated ESR, C – reactive protein positive, weight loss.

The prognosis is determined by the degree of residual cardiac involvement, which can be excellent if relapses are prevented.

Prevention

The best way to prevent rheumatic fever is to get prompt treatment for strep throat and scarlet fever.

 

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