Hi and welcome to another video of Medic Notes. This video will be on Myelodosis. It is an infectious disease caused by a gram-negative bacteria.
Bacchodura pseudomallei. It is often fulminant and it is a fetal disease, endemic in Southeast Asia, the Caribbean and Northern Australia. The bacteria causing meleidosis are found in contaminated water and soil and are transmitted to humans and animals through direct contact with the contaminated sources.
Incubation period is around 2 days and can be up to many years. The predisposing factors to melioidosis include those who are immunosuppressed like diabetes mellitus patients, chronic renal failure, retroviral infections, those that have hematological malignancies, connective tissue disease, long-term stereotherapy, alcoholism and also trauma. And because the source is from contaminated water and soil, farmers are at a risk of myeloidosis as well.
So when we take history, we have to ask carefully what are their occupations and whether they are taking care of any cattle or any animals. So for clinical features, the range of presentation varies from localised abscess to severe community-acquired pneumonia to acute fulminant septicemia with multiple abscesses and can often lead to death. There are a few groups of presentation.
The range is very wide. So the first one is some may present with acute localised infection where there is a nodule with acute lymphagitis or lymphadenitis where inflammation of the... the lymph nodes. And these patients may present with fever and generalized malaise. So if a patient present with fever and malaise, there are a lot of differential diagnosis that we can think of.
So because melidosis, the incubation period is very long, can be up to a few years, we have to have a constant reminder of this disease. So those with fever and malaise, we have to always have melidosis as a differential diagnosis. the other infectious diseases. So another range of presentation is those with pulmonary infection and this may range from mild bronchitis to severe fulminating pneumonia.
The symptoms include high grade fever, headache, anorexia, myalgia, chest pain and coughing either non-productive or productive. And for radiological findings the chest x-ray it can can see bilateral disseminated nodules or can also see diffuse fluffy alveolar infiltrates. The range is very big.
The third group are those who are more severe with acute septicemia and this is commonly seen especially in those patients with some debilitating illness or comorbidities. So they will often present with a history of septicemia. fever with no evidence of any focus of infection and the onset may be sudden and usually rapidly progress to disseminated bacteremia involving multi organ and then later causing septicemic shock So the dominant symptoms depend on the site of the septicemic shock, depends on the site of involvement. So if it includes the lung, it can cause respiratory distress and other systems may have severe headaches.
fever and diarrhea, multiple boils, muscle tenderness and even confusion. Whereas for those with chronic separative infection, it is a chronic form of mellidosis and it typically involves these areas such as the joints, viscera and others. For investigation, so the key to diagnosis is a constant reminder and remembrance of the existence of this disease.
So we have to always put in mind myeloidosis if the patient presents with fever or looks like infection. And myelodorsis can be diagnosed by culturing Brachylderia pseudomallei, the bacteria, from blood, urine, sputum, skin lesion or even pus from any abscess or wound. And we can also do tissue biopsy to diagnose as well, as it is the gold standard in diagnosing myelodorsis.
Culture from non-steroid sites like sputum, skin ulcer or lesions can be problematic. and will need special incubation method or a specimen medium called ashdowns for selective growth of the bacteria. And whereas for serological tests, there are a few that are helpful in diagnosis of mellitus.
For example, indirect hemagglutination test, the IHAT, immunofluorescent antibody test, IFAT, IgG and IgM ELISA, and also rapid immunochromatographic tests. So in endemic areas, the most rapid, most sensitive and specific form of mellitus is the endemic. for current infection will be the IFAT, immunofluorescent antibody test.
For treatment of melidosis, the main treatment is antibiotics. And it is usually sensitive to doxycycline, chloramphenicol, chlortrimoxazole, ceftazidime, amoxicillin, clavulanic acid, imipenem and meropenem. And treatment should be started promptly.
So it's divided into intensive therapy and maintenance therapy. So for intensive therapy, it is given at least two weeks. It depends on whether it's severe myelodosis and bacteremia or it is localized.
So for severe myelodosis and bacteremia, we give ceftazidime, imipenem, meropenem, with or without col-trimoxazole. For localized myelodosis, we can give col-trimoxazole plus doxycycline. So intensive therapy is continued for at least 2 weeks. Waste maintenance therapy includes drugs like quatrimoxazole or amoxicillin clavulanic acid and this is given at least three months. This is considered necessary for preventing later relapse of myelodosis.
So this is all for this video, thank you.