Patient condition assessment and paradoxes of well-being
Before prescribing additional examinations, the physician assesses the patient's general condition, classifying it as satisfactory, moderate, or severe.
It is important to remember the possible dissociation between subjective well-being and actual objective status. A patient may feel completely normal while being in a critical condition. Classical examples of such a situation are the acute stage of myocardial infarction (when changes are recorded only on the ECG) or life-threatening changes in blood composition (e.g., pronounced hyperkalemia) occurring without any immediate complaints.
Laboratory diagnostics: from screening to microbiology
Laboratory tests complement physical findings. Basic screening invariably includes complete blood counts and urinalysis.
- Hematological studies: A complete blood count allows for the assessment of quantitative parameters (hemoglobin, erythrocytes, leukocytes, ESR) and qualitative parameters (differential leukocyte count). Detailed study of cell morphology is necessary to detect hemoblastoses.
- Biochemistry and immunology: Analysis of plasma and serum helps track disease dynamics, such as the escalation or resolution of an inflammatory process.
- Microbiology: Bacteriological culture of feces, cerebrospinal fluid (CSF), or pleural fluid aims to precisely identify the etiological factor—the specific infectious agent.
Note: Some classical methods, such as the examination of gastric juice or duodenal contents, are losing their relevance today and are rarely used.
Radiological and tomographic imaging methods
Instrumental methods range from routine to complex invasive procedures. Basic radiology is used to examine the bones, lungs, heart, kidneys, and gastrointestinal tract. To increase diagnostic value, contrast agents are used: barium suspension for the gastrointestinal tract and iodine-containing preparations for blood vessels.
Computed tomography (CT) significantly surpasses classical radiography. Scanning with a thin X-ray beam yields clear cross-sectional slices reconstructed by a computer based on differences in radiation absorption. This makes it possible to distinguish tissues with similar densities without contrast. For maximum detail, high-resolution CT (HRCT) is used.
Magnetic resonance imaging (MRI) is based on the phenomenon of nuclear magnetic resonance. It provides even higher slice detail compared to CT; however, its widespread use is limited by the high cost of the equipment and the procedure itself.
Ultrasound, radioisotopes, and electrophysiology
To assess not only structure but also organ function, methods based on different physical principles are used:
- Ultrasound examination (Ultrasound): Operates on the principle of echolocation (reflection of waves from boundaries of media with different densities). This is a safe and non-invasive method for studying the anatomy of the heart and abdominal organs (liver, kidneys, gallbladder). A variation of the method—Doppler ultrasound—allows for the assessment of hemodynamics: velocity, direction, and nature of blood flow (laminar or turbulent).
- Radioisotope study: A substance labeled with a radioactive isotope that is tropic to a specific organ (thyroid gland, kidneys, liver, bones) is introduced into the body. Detection of radiation from the accumulated isotope reveals functional and morphological defects.
- Electrophysiology: Recording electrical activity to assess function. Includes ECG (heart), electroencephalography (brain), and electromyography (muscles).
Endoscopy and morphological verification
Examination of the mucous membrane of hollow organs (bronchi, gastrointestinal tract, urinary tract) is performed using flexible endoscopes with computer image processing. The method is highly informative and is frequently supplemented by tissue sampling.
Tissue biopsy is necessary for a definitive morphological diagnosis (assessing tumor malignancy grade or the nature of inflammation). Methods for obtaining material:
- During an endoscopic examination.
- Aspiration biopsy: cell sampling via a needle.
- Incisional biopsy: surgical excision of a tissue fragment.
- Sternal puncture or trephine biopsy: bone marrow sampling.
Briefly: answers to topical questions
What are the absolute and relative contraindications for magnetic resonance imaging (MRI)?
Absolute and relative contraindications for magnetic resonance imaging (MRI) are due to the effect of a powerful magnetic field on foreign objects in the patient's body, as well as psychological discomfort.
- Relative contraindications — claustrophobia (fear of enclosed spaces).
- Absolute contraindications — the presence of electronic implantable devices (pacemakers, middle ear implant systems, insulin pumps) and ferromagnetic foreign bodies (metal fragments in organs, inside or near the eyeball, cerebral vessel clips).
If modern models of electronic devices specifically designed and tested for strong magnetic fields are present, performing an MRI scan is possible.
What specific biochemical markers are used to confirm acute myocardial infarction?
To confirm acute myocardial infarction, biochemical evaluation of cardiospecific blood markers is used dynamically.
- Myoglobin — the earliest marker: rises sharply in the first hours, peaks up to 12 hours, and rapidly normalizes within the first day.
- Creatine phosphokinase (CPK) and CK-MB — begin to rise in the first hours, peak activity occurs at approximately 24 hours, and return to normal by day 3.
- Aspartate aminotransferase (AST) — follows the dynamics of CPK, but with a smaller amplitude and a smoother decline.
- Lactate dehydrogenase (LDH) — a late marker: peak activity occurs on days 2–4, activity persists longer and declines by day 8.
- Troponins T and I — key markers of myocardial necrosis; for troponin I, the onset of elevation is noted in the first hours with prolonged persistence of elevated levels up to 7–8 days and longer.
To understand the essence of the methods, divide them into two groups: those visualizing structure (X-ray, CT, MRI, classical ultrasound, endoscopy) and those assessing function (ECG, EEG, Doppler ultrasound). Radioisotope scanning is a universal method that shows both.
Class and exam questions
What is the main advantage of computed tomography over conventional X-ray?
CT scans an object with a thin beam of rays and creates a cross-sectional image. This allows for high-clarity differentiation of tissues that have only a minor difference in density, even without the administration of contrast agents.
What does dopplerography allow to evaluate in contrast to standard ultrasound?
While standard ultrasound assesses organ size and structure, Doppler ultrasound demonstrates hemodynamics: the direction, velocity, and nature of blood flow (whether it is turbulent or laminar).
What else to study on this topic
- Principles of interpreting the differential leukocyte count in various pathologies.
- Diagnosis of hemoblastoses: the role of cell morphology and bone marrow biopsy.
- Types of contrast agents (barium suspension, iodine-containing preparations) and indications for them.
- Differences between aspiration biopsy and incisional biopsy: indications and sampling technique.
- Radioisotope diagnostics: mechanisms of radiopharmaceutical accumulation in target tissues.
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