Symptoms and signs of leptospirosis – is an infectious disease transmitted from animals to humans

Symptoms and signs of leptospirosis

Symptoms and signs of leptospirosisSymptoms and signs of leptospirosis – is an infectious disease transmitted from animals to humans.

The incubation period, that is to say, the time from when the leptospira enters the blood and the appearance of symptoms of leptospirosis is usually from 7 to 12 days (but can range from 2 to 20 days). The infection can be shown in three ways:

  • In most cases, approximately 90%, there is a mild disease, without jaundice (yellowing of the skin and mucous membranes due to the deposit of bilirubin in them, caused by the elevated presence of bilirubin in the blood).
  • In some cases, approximately 15%, the infection goes unnoticed – subclinical infection – and can only be diagnosed by analyzing the antibodies: the person goes from having no antibodies to leptospires to having them (seroconversion).
  • In a minority of cases – less than 5% – a severe form of the disease develops, which can even cause death, called icteric leptospirosis or Weil’s disease.

The typical form of leptospirosis has two phases that, in turn, coincide with two phases of fever: the first phase or septicemia (when leptospira can be detected in the blood) lasts between 4 and 7 days; then, between days 7 and 10, the fever virtually disappears, and then the fever reappears in the second phase or immune phase, which can last between 4 and 30 days.

Sometimes, these two phases are indistinguishable: in the mild form, because the second phase is very brief or does not exist; and in the severe form, because the two phases, septicaemic and immune, merge, showing symptoms and very serious signs in a continuous manner. From the clinical point of view, two forms of the disease caused by leptospires are considered: anicteric leptospirosis (without jaundice) and icteric leptospirosis or Weil’s disease.

Anicteric leptospirosis

In anicteric leptospirosis, the febrile phase or leptospiremia is the stage in which the leptospires are in all tissues and therefore the symptoms affect the whole body. It usually starts suddenly with a high fever (39 ºC-40 ºC), with muscle aches and a very intense headache. Appetite loss is common and sometimes nausea, vomiting, abdominal pain and diarrhea occur  . In some patients, there are pulmonary symptoms such as chest pain, cough, bloody expectoration and much difficulty breathing (adult respiratory distress syndrome).

Less frequently, neurological alterations occur such as delusions, hallucinations or paralysis of some nerves. A very rare but very serious complication is inflammation of the gallbladder without obstruction due to bile duct stones (acalculous cholecystitis). A very frequent and characteristic sign is that the patient has conjunctivitis with red eyes (due to congestion and even haemorrhage in the conjunctiva of the eye). This phase usually lasts from 4 to 9 days, which is when the antibodies against leptospira are produced and the appearance of Leptospira in the urine (immune phase).

After this first phase, 35% of patients recover completely. In the rest of the patients, after a few days without symptoms, they reappear, beginning the second phase of the disease or immune phase. In her, the fever, the muscular pains and the digestive symptoms are milder than in the first phase.

In many patients (80% -90%)  aseptic meningitis occurs, which means that in the patient’s cerebrospinal fluid the bacterium is not detected, but there is inflammation of the meninges; this meningeal reaction may last a few days, up to two weeks. Rarely, there may be more serious conditions of the nervous system. In this phase may appear redness of the legs, specifically at the height of the shins, which is called “pretibial fever” and also myocarditis (inflammation of the heart muscle), which in general has no significance.

Icteric leptospirosis or Weil’s disease

The other clinical form, the severe form, is icteric leptospirosis or Weil’s disease, which can be caused by different serotypes – leptospira with different antigens – but the most frequent is the  Leptospira interrogans serotype icterohaemorrhagie . It begins similarly to the mild form, but after 4-7 days the severe symptoms begin fever continues, jaundice, haemorrhages, renal failure, myocarditis, altered consciousness, anaemia (decreased amount of red blood cells in the blood) and thrombocytopenia (decrease in the number of platelets in the blood).

Jaundice is the fact that alerts the serious form of the disease because, without jaundice, the disease is not fatal, but jaundice can be. Jaundice is accompanied by increased size and, sometimes, liver pain; there may also be an increase in the spleen. In patients with severe jaundice, renal alterations, cardiovascular collapse and haemorrhages are more frequent. The latter is presented as nosebleeds (epistaxis), lung (hemoptysis), gastrointestinal and skin (purpuric lesions), among others.

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