General characteristics of psychiatric disorders in infections
Psychiatric disorders in various infectious brain lesions do not depend on the specific features of the infectious agent. The clinical picture is identical across a wide variety of infections.
In the acute stage, exogenous-type reactions frequently occur, the most typical of which is delirium. If the disease becomes protracted or causes irreparable damage to brain tissue, a persistent organic defect is formed. Characteristic manifestations of such organic diseases are considered to be memory and intellectual disorders. Personality changes in this case are characterized by specific sluggishness and explosiveness.
General paresis
General paresis is a classic example of a severe infectious CNS disease.
- Clinical presentation: One of the most characteristic neurological manifestations of the pathology is considered to be the Argyll Robertson sign.
- Diagnosis: To confirm the diagnosis, the most important step is to perform a specific laboratory test — the passive hemagglutination assay, which has greater value than instrumental methods (e.g., Doppler ultrasound, MRI, or CT).
- Treatment: Unlike trophic/atrophic processes (Alzheimer's disease or Pick's disease), antibiotic therapy is directly indicated for general paresis.
Infections with atypical pathogens
Among infectious lesions, Creutzfeldt-Jakob disease stands out. Its unique feature is that the infectious agent is not a virus, bacterium, or fungus, but a specific protein (prion). This disease leads to rapid destruction of nervous tissue and severe cognitive disorders, requiring differentiation from other types of dementias.
Differential diagnosis with other pathologies
Psychiatric disorders of infectious origin must be distinguished from disorders caused by other reasons:
- Endocrine disorders: Psychoendocrine syndrome (e.g., in hypothyroidism, Addison's disease, or diabetes mellitus) manifests primarily as affective instability and behavioral disorders. In Addison's disease, acute psychoses of complex structure are possible. The diagnosis is often established solely based on hormonal testing.
- Traumatic brain injuries: As with infections, delirium frequently occurs in the acute phase of head trauma. However, subsequent mental disorders usually follow a regredient course (with gradual improvement).
- Brain tumors: A high risk of an intracranial tumor is indicated by a first-time epileptic seizure in an adult, as well as morning and night headaches accompanied by vomiting.
- Vascular diseases: Vascular dementia is characterized by lacunar dementia and specific “glimmering” (fluctuating) symptoms.
- Atrophic diseases: In Alzheimer's disease, apraxia and dysarthria are observed, but formal insight is preserved at the onset of the disease. Pick's disease manifests at the age of over 50 years.
- Somatogenic and drug-induced factors: Delirium, asthenia, hypochondria, and depression can be the consequence of chronic heart diseases. In addition, psychoses can be triggered by the intake of anticholinergic, antituberculosis, antihypertensive, and antiparkinsonian drugs.
Briefly: answers to topical questions
Which atrophic brain diseases need to be differentiated from infectious lesions, and what are their key features?
Among degenerative (atrophic) brain processes, Alzheimer-type dementias (including Alzheimer's disease and senile dementia) and systemic-organic diseases are distinguished. The latter include Pick's disease, Huntington's chorea, and Parkinson's disease. Chronic, slowly progressive processes, including neurosyphilis, AIDS, Creutzfeldt-Jakob disease, and tuberculous meningitis, require differential diagnosis, as psychiatric disorders in them can act as the first signs of the disease. In Alzheimer's disease, formal insight is preserved at the onset of the disease, and anticholinesterase agents are used in treatment. Pick's disease is characterized by symmetrical local cortical atrophy, the presence of Pick bodies, and "standing" symptoms. In Creutzfeldt-Jakob disease, the infectious agent is a protein.
What forms of delirium can be distinguished in the clinical picture during the severe course of exogenous and somatic disorders?
In the clinical picture of severe delirium, three main forms are distinguished. The first is muttering or whispering delirium, which is characterized by marked exhaustion, decreased blood pressure, small chaotic movements within the bed, senseless muttering, and the inability to establish productive contact. The second form is hyperkinetic delirium, manifested by extreme chaotic agitation, inaccessibility for contact, arterial hypertension, coordination impairment, and hyperthermia. The third form is professional delirium, accompanied by deep clouding of consciousness and the performance of habitual professional movements, such as imitating work with tools or communicating with "subordinates".
What stages are distinguished in the clinical picture of general paresis?
In the clinical picture of general paresis, the following key stages and conditions are distinguished. The initial stage presents with nonspecific pseudoneurasthenic symptomatology, early neurological symptoms in the form of impaired pupillary light reflex and anisocoria, decreased insight, speech disorders, and dysarthria. The phase of full bloom is characterized by gross organic-type personality changes, loss of insight, bizarre behavior, disinhibition, high suggestibility, gullibility, and untidiness. The next stage identified is total dementia, for which the main syndrome is a gross intellectual disorder with a continuous increase in intellectual-mnestic impairments.
What specific psychiatric disorders are characteristic of HIV infection at the AIDS stage?
In HIV-infected patients with a CD4+ cell count of less than 50 cells/µL, the clinical picture manifests as AIDS dementia complex. This condition is characterized by a frequently rapidly progressive course, cranial nerve dysfunction, the development of nystagmus, as well as headaches accompanied by fever. The development of indolent/low-grade encephalopathy is possible, the outcome of which is dementia and polyradiculomyelopathy.
Class and exam questions
Do the symptoms of a psychiatric disorder depend on the type of infection pathogen?
No, psychiatric disorders in various infectious brain lesions are not specific and are identical across a wide variety of infections.
Which exogenous type reaction is most characteristic of acute infections?
Delirium is considered a typical exogenous-type reaction occurring in infectious lesions (as well as in the acute period of traumatic brain injuries).
What diagnostic method is key in progressive paralysis?
To diagnose general paresis, the most important step is to perform the passive hemagglutination assay.
What is the characteristic feature of the Creutzfeldt-Jakob disease causative agent?
Unlike most infectious diseases, in Creutzfeldt-Jakob disease, the infectious agent is a protein.
What else to study on this topic
- Psychoendocrine syndrome and its treatment
- Alzheimer's disease: clinical presentation and therapy with anticholinesterase agents
- Features of the course of psychiatric disorders in traumatic brain injuries
- Drug-induced psychoses and somatogenic disorders
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