Secondary thrombocytosis

    Secondary thrombocytosis, or reactive thrombocytosis, occurs as a result of a physiologic reaction to a primary event. Primary thrombocytosis in pediatric patients is very rare, while reactive thrombocytosis is very common. It is associated with a diversity of clinical conditions, such as infection or malignant disease. Infections of the central nervous system are the most common cause of an elevated platelet count in children. In addition, several studies have shown that pediatric patients with lower respiratory tract infections often present with thrombocytosis. In these cases, platelet count can be used as a valuable clinical marker to assess the severity of the infection. Malignant diseases are scarcely associated with extreme cases of thrombocytosis.
     The degree of reactive thrombocytosis is related to the child’s age, and increase in platelet count is proportional to hospitalization duration. The degree of thrombocytosis is negatively related to hemoglobin value and positively related to white cell count.
      Usually when the patient is treated and the condition that is stimulating thrombocytosis has ceased, platelet count returns to normal level. Even though the platelet count is highly elevated, complications associated with it are very rare. Physicians should concentrate on the underlying cause of reactive thrombocytosis.

Rhinoscleroma

I found this disease state to be intriguing, therefore I wanted to discuss it in this post, and learn a new topic for this week.  

            Rhinoscleroma (or Scelroma) is a chronic granulomatous bacterial disease of the nose that infects the upper respiratory tract. In rare cases, it can also affect the nasopharynx, larynx, trachea, and bronchi. Scleroma is a tropical disease and is mostly endemic to Africa and Central America, and it slightly affects more females than males.

Scelroma is caused by Klebsiella rhinoscleromatis, which is a subspecie of Klebsiella pneumoniae. Rhinoscleroma is a member of the Enterobacteriaceae family; it is an encapsulated gram-negative, nonmotile, diplobacillus that is sometimes referred to as the "Frisch bacillus," named for Anton von Frisch who has identified the organism. It is contracted directly by droplets or by contamination of food/objects that are subsequently inhaled.

The presentation is often nonspecific and is often unrecognized due to its resemblence for cold symptoms. It should be taken into consideration in cases of chronic rhinitis, even in developed countries. Nasal obstruction is the main complain, and the disease can be divided into 3 stages: catarrhal/atrophic, granulomatous, and sclerotic stages; only the granulomatous stage has diagnostic changes. Cellular immunity is impaired in patients infected with rhinoscleroma but the humoral immunity is preserved. CD4–CD8 ratio within the lesion is altered, showing decreased CD4 lymphocytes and increased CD8 lymphocytes, with a diminished T-cell response. A positive culture in MacConkey agar is diagnostic of rhinoscleroma, but cultures are positive in only 50% to 60% of cases.
Treatment should include long-term antimicrobial for 2 to 3 months with tetracycline being the drug of choice, and surgical intervention in patients with symptoms of obstruction. 

                                                                                     http://www.artandmedicine.com/biblio/authors/Wolkowitsch.html

IMMUNOCOMPROMISED: NO higher risk for UTI!

This week we have discussed urinary tract infection and the different bacteria involved. And I would love to discuss with you the risk of UTI in immunocompromised patients.

In contrary to common believe that immunocompromised patients are at higher risk for urinary tract infection, several studies have shown that the defect in humoral or cellular immunity in immunocompromised patients do not seem to predispose to higher risk for UTI but it affects the clinical symptoms, severity, microbiology, and complications of the infection once the patient has a urinary tract infection.

The frequency of urinary tract infections in immunosuppressed patients other than diabetics or renal transplant recipients is not superior to the frequency of urinary tract infections in non-immunosuppressed patients. The higher incidence of infection seen in renal transplant patients is more related to the period of invasive bladder catheterization rather than to the patient immunocompromised condition.

Because of Neutropenia, urinary tract infection predisposes the patient to bacteremia. Thus, broad-spectrum antibiotics have to be used, which leads to modifications in normal flora, further promoting urinary tract infections with resistant nosocomial pathogens, and can also predispose to fungal infection in the urinary tract.

In urinary tract infection, a functionally and anatomically intact urinary tract and kidney are the main host defenses, with immune mechanisms and phagocytic function playing an important role to LIMIT THE CONSEQUENCES of those infections.

 Diagnostic approach to UTI:

                                           http://www.aafp.org/afp/1999/0301/p1225.html

Primary Thrombocytosis in Babies

I would like to introduce my graduate project “Thrombocytosis in babies” by giving a definition of thrombocytosis and explaining primary thrombocytosis. And then, in later posts I will be focusing more on causes, clinical presentation, pathophysiology, and diagnosis of thrombocytosis in children and babies.

Thrombocytosis in babies

Platelet counts physiologic reference range is 150-400 X 10⁹/L. Thrombocytosis is when platelet count exceed the upper limit. It can be primary or secondary.

 

This is a blood smear of a patient with thrombocytosis: 

                            http://www.thailabonline.com/blood/thrombocytosis1.jpg

Primary thrombocytosis:

There are 2 types of primary thrombocytosis or essential thrombocytosis. Classical primary thrombocytosis is the first type. It is caused by continuous production of platelets, which in this case is not regulated by the physiologic negative feedback mechanism that usually maintains platelet count within the reference range. It can be due to a myeloproliferative disorder such as polycythemia vera, essential thrombocythemia, chronic myelocytic, myelofibrosis with myeloid metaplasia or, very rarely, it can be due to an acute myelocytic leukemia. These patients represent a monoclonal hematopoiesis. Endogenous erythroid colony growth is the main characteristic of their hematopoiesis, with an increase in the expression of granulocyte polycythemia rubra vera-1 (PRV-1) RNA, and is associated by JAK2^V617Fmutation in nearly 30% of the pediatric cases.

However, the second type of primary thrombocytosis is classified as familial thrombocytosis and is due to a mutation of either thrombopoietin receptor gene (mpl) or thrombopoietin (TPO) gene.  Hematopoiesis in familial thrombocytosis is polyclonal.

Welcome To Reina's Bug Blog!!

First of all I want to welcome everyone to Reina’s bug blog. 

I am very excited about this new learning experience. This is a place where we can all share interesting facts, articles, pictures and videos related to the infectious disease class.  In addition, I will be posting information related to my graduate project “thrombocytosis in babies”. Hope my blog will be very informative and useful. Please feel free to leave any comments!  Enjoy :-)