These days medical students are just flooded with a huge amount of information –different description of diseases, fresher and fresher publications – all available online. It is really difficult to pick the clinically relevant data, especially when you do not have those years of practice behind your back. In our blog series You will find short and straightforward lists of clinical signs, symptoms which are the most typical and pathognomonic in certain diseases.
Tuberculosis – you may think this disease belongs to the past… but you are wrong! In 2015, it was the 9th leading cause of death worldwide, and the leading from a single infectious agent, ranking above HIV/AIDS. The tricky thing about this disease is that it does not give any or gives only mild symptoms for months. Yet, how could you figure out whether your patient has TB? Let’s see!
Why? Bacterial infection activates macrophages which release different cytokines: TNF-α, IL-6, IL-1, IFN-γ. These (among others) are responsible for acute phase reaction. Lower, remittent fever due to altered thermoregulation, fatigue and consequent sweating are the main outcomes of this reaction.
Why? Inflammatory cytokines TNF-α and CRP seem to have important roles in the process of weight loss. Both of them are inversely associated with leptin concentration, which is responsible for hunger and also important for cell-mediated immunity.
Why? Typical signs of lung infection. In active TB with granulomas and caverns, sputum appears in a big amount and contains lots of bacteria. Hemoptysis appears in 50% of the cases; much more often than in pulmonary embolism, for instance.
Why? It can be just a typical sign of lung infection, indicating pleural involvement. But in TB patients, it can also result from tuberculous acute pericarditis. Pericardial TB can lead to cardiac tamponade or constriction!
Why? If your patient shows some of the mild symptoms listed abover AND also has a condition including a compromised immune system, you should definitely check if they have been infected with TB. List of risk factors:
Severe kidney disease
Visit in Africa (particularly Sub-Saharan-Africa), India, Afghanistan, Southeast-Asia (including Indonesia)
Low socioeconomic status
Why? During the delayed type hypersensitivity reaction, monocytes form epitheloid granulomas around bacteria and macrophages full with bacteria. These granulomas and cavities can be seen as nodules, round infiltrates or cavities, mostly in the upper lobes.
Why? Especially in immune-compromised conditions, mycobacteria can spread throughout the circulation causing miliary tuberculosis. Bone marrow is the most often affected extrapulmonary organ, but any sites may be involved.
Back pain or stiffness
Anemia, thrombocytopenia (bone marrow involvement)
Altered mental status, neurological deficit
Lymphadenopathy (usually bilateral and around the neck or in the supraclavicular nodes)
Robbins: Basic Pathology (Vinay Kumar, Abul K. Abbas, Jon C. Aster)