factitious disorder

**Definition (DSM-5-TR):** Falsification of physical or psychological signs or symptoms, or induction of injury or disease, associated with identified deception. The person presents as ill, impaired, or injured. The behavior is evident even without obvious external rewards (e.g., money, avoiding work or legal trouble). It is not better explained by another mental disorder such as delusional disorder. Specify: single episode vs. recurrent episodes.

**Types:** - **Imposed on self** (Munchausen syndrome): The patient fabricates or induces their own illness. Examples include surreptitious insulin or sulfonylurea use (hypoglycemia with LOW C-peptide with exogenous insulin, but HIGH C-peptide with sulfonylureas), thyroid hormone ingestion (thyrotoxicosis with low thyroglobulin), contaminating urine or blood samples, self-injecting feces or saliva to cause infection, warfarin ingestion (elevated INR), and heating a thermometer to simulate fever. - **Imposed on another** (formerly Munchausen by proxy): A caregiver (most often the mother) falsifies or induces illness in a child or other dependent. The *perpetrator* receives the diagnosis, not the victim. This is a form of child abuse, so clinicians must report to child protective services. The child may be diagnosed with child physical abuse or medical child abuse.

**Epidemiology and risk factors:** Often young adult women, frequently with healthcare backgrounds (nurses, allied health). Associated with personality disorders (especially borderline), childhood abuse or neglect, and prior significant illness or hospitalization.

**Clinical clues:** - Dramatic but inconsistent history - Symptoms that do not fit known disease patterns - Many hospitalizations, often at multiple hospitals ("hospital hopping") - Extensive medical knowledge - Eagerness to undergo invasive procedures - Multiple surgical scars - Symptoms that occur only when the patient is unobserved, or that resolve when the patient is observed - Lab findings that do not match the clinical picture

**Differentiating from related disorders (high-yield):**

| Disorder | Symptom production | Motivation | |---|---|---| | Factitious disorder | Intentional | Unconscious/internal need for sick role (no external gain) | | Malingering | Intentional | External gain (money, drugs, avoiding jail or work) | | Somatic symptom disorder | Not intentional | Excessive thoughts, feelings, or behaviors about real symptoms | | Conversion disorder (functional neurologic symptom disorder) | Not intentional | Neurologic deficits incompatible with known disease | | Illness anxiety disorder | Not intentional | Preoccupation with having a serious illness, with minimal or no symptoms |

**Management:** - Maintain a high index of suspicion and review records from prior hospitalizations. - Coordinate care through a single primary physician. - Avoid unnecessary tests and procedures. - Confront the patient in a **non-punitive, non-accusatory, supportive** manner, allowing the patient to save face. - Offer psychiatric referral and psychotherapy (CBT). There is no specific pharmacotherapy. Treat comorbid conditions. - Patients often deny the behavior and leave against medical advice, then seek care elsewhere. - For imposed on another: protect the victim first, report to child protective services, and consider separating the child from the perpetrator. The perpetrator needs psychiatric evaluation.

**Boards pearls:** - "Intentional production, no obvious external gain" = factitious disorder. - "Intentional production, external gain" = malingering. - Exogenous insulin: high insulin, low C-peptide. Sulfonylurea: high insulin, high C-peptide, and a positive sulfonylurea screen. - A parent who repeatedly brings a child in with unexplained symptoms that occur only in the parent's presence suggests factitious disorder imposed on another. - Best next step with a suspected diagnosis: usually review records and discuss with the patient non-confrontationally. In suspected child abuse, report to protective services.