Syndromes in internal medicine

Building a diagnosis: from hypothesis to facts

In the Russian clinical tradition, the path to an accurate diagnosis consists of a strict sequence of steps. The physician begins by gathering facts—interviewing the patient, performing a physical examination, and ordering additional tests. The data are then analyzed and synthesized into clinical syndromes. This makes it possible to put forward a diagnostic hypothesis, perform differential diagnosis, and formulate the final conclusion.

There are two main stages of formulation:

• Preliminary diagnosis. Established based on the initial physical examination and complaints. Its main goal is to determine the plan for applying special instrumental methods.
• Clinical (final) diagnosis. Relies on the generalization of all general clinical and additional studies. This is what determines the patient's treatment plan.

Any clinical diagnosis has a rigid structure: the main disease is placed first, followed by its complications, and finally, comorbidities.

Cavitary lung syndrome and the risk of pneumothorax

The presence of a cavity in the lung (e.g., a drained abscess, tuberculous cavern, or bullous emphysema) carries a hidden threat. If the pathological focus is located subpleurally, the visceral pleura may rupture. As a result, air enters the pleural cavity, and pneumothorax or hydropneumothorax develops—a severe complication causing sudden clinical deterioration.

The clinical presentation of pneumothorax consists of striking symptoms:

• Complaints: sudden acute chest pain on the affected side (at the time of pleural rupture), progressive dyspnea due to compressive collapse (atelectasis) of the lung, and acrocyanosis. If mediastinal emphysema joins, the pain can mimic myocardial infarction.
• Physical examination: the patient is restless and assumes a forced position. The affected hemithorax bulges, intercostal spaces are widened, and noticeable lagging of this side during breathing is observed. In open trauma, a whistling sound of sucked-in air is heard, foamy blood is released from the wound, and subcutaneous emphysema occurs.
• Hemodynamics: mediastinal shift, especially in tension (valvular) pneumothorax, provokes tachycardia, weak pulse, and a sharp drop in blood pressure down to collapse.

Differential diagnosis of pleural fluid collections

To distinguish air accumulation from fluid accumulation during the examination stage, the physician relies on a combination of percussion and auscultation. In both cases, breath sounds decrease, so the percussion sound becomes decisive.

Uremia: pathogenesis and systemic disorders

Uremic syndrome is inextricably linked with the cardiovascular system through two main pathogenetic loops.

First, a vicious cycle is formed with arterial hypertension (AH). Prolonged AH causes arteriosclerosis of renal vessels. Because of this, the concentration function of the kidney drops (hyposthenuria), and protein and red blood cells appear in the urinary sediment. In the terminal stage, waste products are no longer excreted, leading to azotemia and classical uremia.

Second, phosphorus-calcium metabolism is disrupted. Decreased renal function provokes secondary hyperparathyroidism, leading to ectopic tissue calcification (nephrocalcinosis). This further destroys the kidneys and worsens cardiovascular complications.

To assess the condition when uremia is suspected, the following are important:

• Relative urine density (marker of concentration function).
• Creatinine level and glomerular filtration rate (GFR).
• Signs of long-standing renal failure: acid-base balance shifts, hyperkalemia, anemia (due to erythropoietin deficiency), and decreased kidney size on ultrasound.

When managing such patients, extreme caution with medications is required. Low GFR severely slows down their elimination, increasing the risk of cumulative toxicity. Doses of nephrotoxic drugs are adjusted strictly according to creatinine clearance.

Class and exam questions

What else to study on this topic

• Detailed radiological picture of pneumothorax: visceral pleural line sign and mediastinal shift.
• Blood gas changes and CT criteria in modern diagnosis of pneumothorax.
• Differential diagnosis of pain syndrome: mechanisms by which mediastinal emphysema mimics myocardial infarction.
• Pathogenesis of bullae and tuberculous cavities formation as root causes of cavitary lung syndrome.
• In-depth analysis of acid-base balance (ABB) disorders in long-term chronic kidney disease.

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.