Incubation and initial periods
After the microorganism enters the alkaline environment of the small intestine and invades Peyer's patches, the incubation period begins, lasting from 7 to 25 days. As bacteremia develops, the disease transitions into the initial period (the first 5–7 days).
The disease traditionally begins gradually, although acute onset is also encountered in modern practice. The temperature rises stepwise to 39–40°C, accompanied by pronounced intoxication. Patients complain of weakness, headache, and loss of appetite. A specific sign is sleep inversion: the patient is drowsy during the day and suffers from insomnia at night.
Objective examination reveals skin pallor, lethargy, and adynamia. During the first few days, the pulse corresponds to the temperature, but then relative bradycardia and arterial hypotension develop. The tongue is markedly edematous and coated with a dense plaque, while its edges and tip remain clean; dental impressions are clearly visualized along the margins. The abdomen is moderately distended, Padalka's sign is noted (dullness on percussion in the right iliac region), and palpation reveals tenderness, rumbling, or fine-bubble crepitation in the same area. By the end of the first week, the liver and spleen become enlarged.
Period of height
The period of height is characterized by maximal intoxication and hyperpyrexia. The patient may develop status typhosus (typhoid state): stupor, sluggishness, disorientation in space and time, hallucinations, and less commonly, psychomotor agitation or acute psychosis.
The skin remains pale. On the 8th–10th day of illness, a characteristic sparse roseolous rash appears on the skin of the abdomen and chest. An important diagnostic sign is the phenomenon of successive eruptions, in which new elements of the rash appear throughout the entire febrile period, while old ones fade within 2–3 days.
Arterial hypotension persists, heart sounds are muffled, and the pulse may acquire a dicrotic character. Specific necrotic ulcers in the pharyngeal lymphoid ring (Duguet's angina) are occasionally detected. During this same period (corresponding to the second to third weeks of pathomorphological changes—the stage of necrosis and formation of "dirty" ulcers), the risk of fatal specific complications—intestinal perforation and intestinal hemorrhage—increases sharply.
Convalescence period and types of fever
During the convalescence period, the temperature begins to drop. Typhoid fever is characterized by amphibola—significant fluctuations between morning and evening body temperature readings. Intoxication gradually decreases, and the dimensions of parenchymatous organs normalize. However, manifestations of the asthenovegetative syndrome persist for a long time.
Temperature curves in typhoid fever are diverse:
- Trapezoidal (Wunderlich).
- Undulant (Botkin).
- Intermittent or septic (Kyldyushevsky).
- Irregular (most typical for the modern course of the disease).
Classification and severity
Based on the clinical course, typical and atypical forms are distinguished. Atypical forms include abortive (rapid resolution of the disease course and recovery, often in vaccinated individuals) and mild ambulatory forms. The latter occur in modern conditions in almost 50% of cases, accompanied by sparse symptoms, brief low-grade fever, and are diagnosed only by laboratory methods.
The severity of the typical course is determined by the intoxication syndrome:
- Mild: temperature up to subfebrile or febrile levels, no encephalopathy.
- Moderate: fever lasts for at least two weeks, marked neurotoxicosis (lethargy, sluggishness, sleep inversion).
- Severe: hyperpyrexia, early typhoid state, delirium, meningeal signs, hemorrhagic syndrome, or infectious-toxic shock.
Important: Regardless of the level of intoxication, if specific complications develop (perforation, hemorrhage), the patient's condition is automatically classified as severe.
Briefly: answers to topical questions
What stages of pathomorphological changes in the intestinal lymphatic apparatus does typhoid fever undergo?
Pathomorphological changes in the intestine during typhoid fever go through five successive stages corresponding to the weeks of the disease.
- Stage of medullary swelling (1st week) — enlargement of Peyer's patches and solitary follicles with proliferation of macrophages phagocytosing Salmonella typhi.
- Stage of necrosis (2nd week) — necrotization of follicles with the risk of hemorrhage.
- Stage of ulceration (3rd week) — rejection of necrotic masses and formation of "dirty" ulcers.
- Stage of "clean" ulcers (4th week) — ulcers with a smooth base, high risk of intestinal perforation arises.
- Stage of ulcer healing (5th–6th weeks) — formation of delicate scars and restitution of lymphoid tissue.
What specific laboratory diagnostic methods are used to confirm typhoid fever?
Bacteriological and immunological research methods are used for the laboratory confirmation of typhoid fever.
- Bacteriological method — blood culture for hemoculture, stool culture for coproculture, urine culture for urinoculture; also isolation of biliculture when inoculating on diagnostic media. Blood is inoculated into bile broth (Rapoport medium), feces and urine into Ploskirev, Endo, and fat-agar media.
- Immunological methods:
- detection of typhoid bacillus antigens: co-agglutination reaction, ELISA;
- detection of antibodies to typhoid bacillus antigens: Widal test, indirect hemagglutination assay (IHA) with erythrocytic O-, Vi-, H-diagnosticums; serological diagnosis may take into account the rise in the titer of specific antibodies in paired sera.
Which infectious diseases are used for differential diagnosis of typhoid fever?
Differential diagnosis of typhoid fever is carried out with diseases proceeding with prolonged high fever and marked intoxication, as well as a number of similar infections. Sources indicate:
- paratyphoid A and B;
- generalized forms of salmonellosis;
- generalized forms of yersiniosis;
- epidemic typhus;
- influenza;
- malaria;
- tularemia;
- leptospirosis;
- opisthorchiasis;
- sepsis;
- pneumonia;
- pyelonephritis;
- miliary tuberculosis.
In the first week of the disease, typhoid fever is differentiated from influenza, epidemic typhus, malaria, and pneumonia.
Padalka's sign — dullness of the percussion sound in the right iliac region due to enlarged mesenteric lymph nodes.
Class and exam questions
On what day does the rash appear and what does it look like?
Exanthem occurs on the 8th–10th day of illness. This is a sparse roseolous rash located predominantly on the skin of the chest and abdomen. It is characterized by the "phenomenon of successive eruptions".
What is the essence of the sleep inversion phenomenon?
This is a specific sign of neurotoxicosis in the early period: the patient experiences pronounced daytime sleepiness while suffering from insomnia at night or sleeping very superficially.
What does the tongue of a typhoid fever patient look like?
The tongue is significantly edematous and coated with a thick plaque, against which only the edges and tip remain free (clean). Dental impressions are clearly visible along the lateral surfaces.
What does the term typhoid state mean?
This is a manifestation of extreme neurotoxicosis at the peak of the disease. The patient is stunned, lethargic, and disoriented; hallucinations and delirium may occur against the background of hyperpyrexia.
What else to study on this topic
- Pathogenesis of typhoid fever and stages of intestinal morphological changes by weeks.
- Acute and chronic bacterial carriage: persistence of L-forms of the pathogen.
- Specific and non-specific complications: clinical presentation of intestinal hemorrhage and perforation.
- Features of the antigenic structure of Salmonella typhi (O, Vi, and H antigens).
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