Unexplained somatic symptoms

Unexplained somatic symptoms are physical complaints (pain, fatigue, dizziness, palpitations, gastrointestinal, neurological or other symptoms) for which no sufficient organic cause is found after reasonable assessment, or in which the distress and health related behaviour are out of proportion to the findings. They account for a fifth to a third of primary care consultations, and most are self limiting.

Definitions

• Somatic symptom disorder: one or more distressing somatic symptoms with excessive thoughts, feelings or behaviours about them (disproportionate and persistent concern about seriousness, persistently high anxiety about health, excessive time and energy devoted), persisting typically over 6 months. The symptoms need not be medically unexplained.
• Illness anxiety disorder: preoccupation with having or acquiring a serious illness, with minimal or no somatic symptoms, high health anxiety, and excessive health behaviours (checking, repeated consultations) or avoidance. Subtypes: care seeking and care avoidant.
• Functional neurological symptom disorder (conversion disorder): altered voluntary motor or sensory function (weakness, paralysis, abnormal movements, gait disorder, sensory loss, speech symptoms, functional seizures) with clinical findings showing incompatibility with recognised neurological disease. Positive signs are required.
• Psychological factors affecting other medical conditions, and factitious disorder (deliberate falsification without external reward), differ from malingering (deliberate feigning for external gain).
• Functional somatic syndromes: irritable bowel syndrome, functional dyspepsia, fibromyalgia, chronic fatigue syndrome, chronic widespread pain, tension headache, chronic pelvic pain, noncardiac chest pain, temporomandibular disorder and others. They share overlap and risk factors.
• Bodily distress and persistent physical symptoms are used as descriptive terms.

Classification by cause

• Somatic symptom and related disorders (somatic symptom disorder, illness anxiety, functional neurological disorder, factitious disorder).
• Functional somatic syndromes: irritable bowel syndrome, functional dyspepsia, fibromyalgia, chronic fatigue syndrome, chronic widespread pain, tension headache, chronic pelvic pain, noncardiac chest pain and temporomandibular disorder.
• Psychiatric disorders presenting with physical symptoms: depression (fatigue, pain, sleep and appetite disturbance), anxiety and panic (palpitations, dyspnoea, dizziness, paraesthesia), posttraumatic stress disorder, dissociative disorders, psychosis, and substance use.
• Medical disease with symptoms out of proportion, or early or rare disease that is not yet diagnosed (multiple sclerosis, systemic lupus erythematosus, myasthenia gravis, thyroid disease, malignancy, endocrine disease).
• Drug induced symptoms and withdrawal.
• Physiological responses and normal variants (benign symptoms perceived as threatening).

Epidemiology. Medically unexplained symptoms are present in about 15% to 30% of primary care attenders, and somatic symptom disorder in about 5% to 7% of the general population (more in women). Illness anxiety disorder affects 1% to 5%. Functional neurological disorder is common in neurology clinics (up to 15% of new patients).

Onset is at any age, and women are 2 to 3 times more often affected. Risk factors include childhood adversity and abuse, family illness, prior medical illness, anxiety and depression, and chronic stress.

Mechanisms. Altered central processing of bodily signals (sensitisation, attention to symptoms, predictive processing), stress response and autonomic changes, illness beliefs and anxiety, behavioural avoidance, deconditioning, reinforcement by attention or health systems, and disturbed sleep.

Symptoms are real and not feigned.

Key distinctions. Multiple symptoms across systems, long history, and distress out of proportion suggest somatic symptom disorder. Fear of disease with few symptoms and repeated reassurance seeking suggests illness anxiety disorder. Neurological deficit with positive inconsistency signs suggests functional neurological disorder. Symptoms with deliberate induction suggest factitious disorder.

Symptoms with an obvious external reward suggest malingering. New onset in older age or with weight loss and objective signs needs thorough search for organic disease.

History

• Symptom characterisation: onset, duration, character, severity, pattern, triggers, relieving factors, and associated symptoms for every complaint, as with any organic symptom.
• Number and system distribution: pain in multiple sites, gastrointestinal, sexual, pseudoneurological symptoms, and symptom history across years.
• Functional impact: work, school, family, social life, disability, and sick leave.
• Illness beliefs: what the patient thinks is wrong, what they fear, what they expect, and what they have been told.
• Health behaviour: doctor visits, number of doctors seen, tests, emergency attendances, internet searching, checking, avoidance, drugs, and alternative therapies.
• Psychological: mood, anxiety, panic, trauma and abuse history, bereavement, relationship and work stress, substance use, alcohol, and sleep.
• Previous medical evaluations and results.
• Drugs and withdrawal: opioids, benzodiazepines, analgesic overuse, antidepressants, stimulants, supplements, caffeine, and alcohol.
• Family history of illness, similar symptoms, and psychiatric disorder.
• Suicidal thoughts, self harm, and use of medicines in overdose.
• Red flag symptoms for organic disease for each system (weight loss, fever, night sweats, bleeding, progressive weakness, dysphagia, new headache pattern).

Examination

• A full, careful physical examination relevant to each presenting symptom, repeated as the illness evolves, with explanation to the patient.
• Vital signs, weight and body mass index, and general appearance.
• Neurological examination for positive signs of functional disorder:
  • Hoover sign (hip extension weakness that normalises on contralateral hip flexion).
  • Hip abductor sign, drift without pronation, give way weakness, variable gait with dragging leg and good postural reflexes.
  • Tremor entrainment and distractibility, midline splitting of sensation or vibration, tubular visual fields, and sudden onset non-anatomic sensory loss.
  • Functional seizures: eyes closed during the event, long duration, waxing and waning, pelvic thrusting, side to side head movement, and recall of events.
• Abdominal, cardiovascular, respiratory and musculoskeletal examination including tender points (fibromyalgia: widespread pain for over 3 months).
• Mental state: mood, anxiety, dissociation, thought content about illness, insight, and suicide risk.
• Rating scales: Patient Health Questionnaire-15 (somatic symptom severity, 5 to 9 mild, 10 to 14 moderate, 15 or more severe), Somatic Symptom Scale-8, Whiteley Index and Health Anxiety Inventory, PHQ-9, GAD-7.

Red flags (indications to look harder for organic or psychiatric disease)

• Objective signs: fever, weight loss over 5% in 6 months, anaemia, lymphadenopathy, organomegaly, bleeding, neurological deficit that follows an anatomical pattern, new abnormal reflexes, or abnormal vital signs.
• Age over 50 years with new symptoms, or new onset of multiple symptoms in later life.
• Progressive course, nocturnal symptoms, or symptoms that wake from sleep.
• Chest pain, dyspnoea, syncope, palpitations with exertion, or neurological symptoms with objective deficit.
• Severe depression, suicidal intent, or psychosis.
• Substance dependence, opioid overuse or poisoning.
• Self induced illness (falsified symptoms, tampered samples, unexplained infections or hypoglycaemia) or harm to a dependent (fabricated or induced illness in a child, needing immediate safeguarding action).
• Rapidly progressing disability, dehydration or malnutrition.
• Functional seizures or collapses with injuries, or status like events needing differentiation from epilepsy.
• Sudden loss of vision, speech or limb function (stroke needs to be excluded first).

Special groups

• Children and adolescents: abdominal pain, headache, fatigue, school refusal. Examine for organic disease and assess family illness beliefs, bullying, anxiety, and abuse. Fabricated or induced illness needs urgent safeguarding review.
• Older adults: new somatic symptoms are often organic, depression or drug related. Pain and fatigue require systematic assessment.
• Women: more often diagnosed; also assess for trauma, intimate partner violence, endometriosis (pelvic pain), and perimenopause.
• Pregnancy: assess for physical complications and mental disorder before attributing symptoms to anxiety.
• Patients with intellectual disability: symptoms may signal distress, pain, or abuse.
• Chronic medical illness: symptom burden can exceed pathology, and both coexist.
• Cultural idioms of distress: somatic expression of distress (for example heat in the head, burning sensations, weakness, spirit related illness) is a normal cultural form of communication and is not necessarily a disorder.
• Refugees, trauma survivors and low resource settings: high rates of somatic expression. Screen for trauma, depression and infection.

Psychiatric and functional

• Somatic symptom disorder.
• Illness anxiety disorder.
• Functional neurological symptom disorder (weakness, gait disorder, tremor, seizures, sensory loss).
• Factitious disorder (imposed on self or on another) and malingering.
• Major depressive disorder and persistent depressive disorder.
• Generalised anxiety disorder, panic disorder and social anxiety.
• Posttraumatic stress disorder and dissociative disorders.
• Psychotic disorders with somatic delusions.
• Body dysmorphic disorder and obsessive compulsive disorder.
• Functional syndromes: irritable bowel syndrome, functional dyspepsia, fibromyalgia, chronic fatigue syndrome, tension headache, chronic pelvic pain, noncardiac chest pain, and chronic back pain.
• Substance use disorders, medication overuse headache, and opioid induced hyperalgesia.

Neurological

• Multiple sclerosis, myasthenia gravis, Guillain-Barre syndrome, and periodic paralysis.
• Epilepsy and sleep disorders (cataplexy, parasomnias).
• Parkinson disease and dystonia.
• Stroke and transient ischaemic attack, brain tumour, and spinal cord disease.
• Peripheral neuropathy and radiculopathy.
• Migraine with aura.

Endocrine, metabolic and nutritional

• Hypothyroidism and hyperthyroidism.
• Diabetes mellitus and hypoglycaemia.
• Hypercalcaemia and hyperparathyroidism.
• Adrenal insufficiency and Cushing syndrome.
• Vitamin D, B12, iron and other nutritional deficiencies.
• Phaeochromocytoma.
• Porphyria.

Cardiorespiratory and gastrointestinal

• Arrhythmia and ischaemic heart disease.
• Asthma, chronic obstructive pulmonary disease, pulmonary embolism, and interstitial lung disease.
• Coeliac disease, inflammatory bowel disease, peptic ulcer, gallstone disease, and gastro-oesophageal reflux.
• Chronic pancreatitis and gastroparesis.

Infectious, inflammatory and malignant

• HIV, tuberculosis, hepatitis, syphilis, brucellosis, schistosomiasis, chronic malaria and other chronic infections.
• Systemic lupus erythematosus, rheumatoid arthritis, polymyalgia rheumatica, vasculitis, and sarcoidosis.
• Lymphoma, leukaemia and other occult malignancy; paraneoplastic syndromes.
• Fibromyalgia and chronic fatigue syndrome (functional, not excluded by tests).

Drug and toxin related

• Medication adverse effects (statins, antihypertensives, steroids, antipsychotics, chemotherapy).
• Withdrawal from opioids, benzodiazepines, alcohol or antidepressants.
• Heavy metal poisoning and carbon monoxide.

Step 1. Exclude serious disease and emergencies. Assess vital signs and red flags. Treat urgent causes first. Remember that functional and organic disease coexist.

Step 2. Take a symptom and psychosocial history. Use open questions, allow the patient to tell the story, and ask about life events, mood, anxiety, trauma and beliefs. Use PHQ-15, PHQ-9 and GAD-7.

Review all previous records to avoid duplication.

Step 3. First line tests (limited, directed by the history and examination)

• Full blood count, erythrocyte sedimentation rate or C-reactive protein, urea, creatinine, electrolytes, calcium, glucose or HbA1c, liver tests, thyroid stimulating hormone, ferritin, vitamin B12 and creatine kinase.
• Urine analysis and pregnancy test.
• 12 lead ECG for palpitations, chest pain, or syncope.
• Chest radiograph when respiratory symptoms or constitutional features exist.
• HIV and other infection screening where risk exists.
• Urine or serum toxicology where substance use is possible.

Step 4. Targeted tests (directed by objective signs, not by patient anxiety)

• Imaging (MRI, CT, ultrasound) and endoscopy when focal signs, red flags or age-related risk indicate.
• Antinuclear antibodies and rheumatoid factor only with clinical features of connective tissue disease.
• Coeliac serology and faecal calprotectin for diarrhoea or weight loss.
• Nerve conduction studies and electromyography for objective neuropathy or weakness.
• Video electroencephalography for suspected functional seizures versus epilepsy (the most reliable method of diagnosis).
• Holter monitor or echocardiography for suspected cardiac disease.
• Specialist assessment when a specific disease is possible. Avoid repeating normal tests.

Step 5. Interpretation. Make a positive diagnosis based on typical features (symptom pattern, positive signs, disproportionate distress and behaviour) rather than only the absence of findings. Normal tests are not proof of a psychological cause, and abnormal incidental findings do not explain symptoms unless they match. Diagnose functional neurological disorder on positive signs. Recognise that coexisting organic disease is possible.

Reassess when new features appear, and revisit the diagnosis at follow up. Limits. Tests have false positives that fuel anxiety and further investigation. Repeated testing increases harm and reinforces illness beliefs. Diagnoses of exclusion are unreliable, and misdiagnosis rates are low (about 4%) when positive signs are applied. Cultural and language barriers affect assessment.

Immediate. Treat acute organic causes. Assess suicide risk. Provide a clear explanation that symptoms are real, genuine and common, that the cause is a disturbance in how the nervous system processes signals and not serious structural disease, and that they can improve. Avoid saying "nothing is wrong" or "it is all in your mind". Agree an explanation the patient can accept. Withdraw harmful drugs and stop unnecessary investigation.

General management principles

• Establish a therapeutic relationship, with regular scheduled appointments (every 2 to 4 weeks) with one primary clinician, not symptom driven visits. Visits are brief and include examination of new symptoms.
• Validate symptoms, review results, and explain the link between stress, mood, sleep, attention and physical sensations.
• Set limited goals focused on function and activity, not total symptom removal.
• Reduce unnecessary tests, referrals and polypharmacy. Coordinate care among specialists. Provide a single treatment plan.
• Treat comorbid depression, anxiety, sleep disorder and substance use.
• Graded physical activity and rehabilitation, sleep hygiene, structured daily routine, and return to work and social activity.
• Involve family and carers, and teach them to support without reinforcing disability.
• Document the diagnosis clearly and avoid pejorative labels.

Psychological treatment

• Cognitive behavioural therapy (8 to 16 sessions) adapted for somatic symptoms and health anxiety, which reduces symptoms, distress and health care use.
• Other effective therapies: graded exercise, acceptance and commitment therapy, mindfulness based stress reduction, psychodynamic interpersonal therapy, and behavioural activation.
• Functional neurological disorder: explanation, physiotherapy with specialist neurological rehabilitation (motor retraining), occupational therapy, speech therapy, and psychotherapy. Functional seizures: cognitive behavioural therapy and seizure specific psychoeducation, with withdrawal of unnecessary antiepileptic drugs.
• Illness anxiety disorder: cognitive behavioural therapy with exposure to health related cues and response prevention (reassurance seeking, checking, internet searches).
• Children: family based therapy, school liaison, and graded return to school.

Pharmacological treatment (adjunct, targeted at comorbidity or symptoms)

• Depression and anxiety:
  • Sertraline 25 mg daily for 1 week then 50 mg, increased to 50 to 200 mg (maximum 200 mg).
  • Escitalopram 10 mg increased to 20 mg (10 mg over 65 years).
  • Venlafaxine modified release 75 mg increased to 150 to 225 mg.
  • Duloxetine 30 mg for 1 to 2 weeks then 60 mg daily (maximum 120 mg).
  • Review at 2 and 4 weeks, with full effect over 6 to 8 weeks. Continue for at least 6 to 12 months.
• Neuropathic and widespread pain and fibromyalgia:
  • Amitriptyline 10 mg at night increased by 10 mg weekly to 25 to 75 mg (maximum 75 mg for pain, lower in older adults, with ECG in cardiac disease).
  • Duloxetine 60 mg daily.
  • Pregabalin 75 mg twice daily increased to 150 mg twice daily (maximum 300 mg twice daily; renal dose adjustment at creatinine clearance under 60 mL/min).
  • Gabapentin 300 mg at night increased over 1 to 2 weeks to 900 to 1800 mg daily in 3 divided doses (maximum 3600 mg).
  • Evidence for benefit is modest. Stop if no benefit after 4 to 6 weeks at an adequate dose.
• Irritable bowel syndrome:
  • Antispasmodic (mebeverine 135 mg three times daily before meals, or hyoscine butylbromide 10 to 20 mg three to four times daily).
  • Peppermint oil capsules 0.2 mL one to two capsules three times daily.
  • Loperamide 2 mg after each loose stool (maximum 16 mg daily).
  • Amitriptyline 10 mg at night up to 30 mg, and dietary measures.
• Insomnia: cognitive behavioural therapy for insomnia first, short term zopiclone 3.75 mg (maximum 7.5 mg) for 2 to 4 weeks only if needed.
• Palpitations and anxiety: propranolol 10 to 40 mg two to three times daily as needed (not in asthma).
• Avoid opioids, benzodiazepines (dependence risk), and repeated courses of antibiotics or steroids. Where opioids or benzodiazepines are used, taper slowly: reduce the daily dose by 5% to 10% every 2 to 4 weeks.
• Treat identified medical disease with specific drugs.
• Antipsychotic augmentation (for example quetiapine 25 to 50 mg at night, aripiprazole 2.5 to 5 mg) only for delusional somatic disorder with specialist input.

Special populations

• Pregnancy and breastfeeding: prefer psychological and physical therapies. Sertraline can be used if needed. Avoid benzodiazepines and gabapentinoids unless essential.
• Older adults: lower doses, avoid anticholinergics (amitriptyline), benzodiazepines and falls risk drugs, check sodium on SSRIs, and treat depression.
• Children: psychological therapy first, and drugs only rarely and under specialist care.
• Kidney and liver impairment: halve doses of pregabalin, gabapentin and duloxetine (avoid duloxetine in severe renal or hepatic impairment).
• Fabricated or induced illness: report immediately to child safeguarding services. Factitious disorder in adults: confront gently and supportively, avoid punitive responses, offer psychiatric care, and limit unnecessary tests.

Monitoring. Symptom severity (PHQ-15), function, attendance at work or school, health care use, mood and anxiety scales, suicidal thoughts, drugs and doses, sleep, activity level, weight, and reassessment for new organic signs at each visit.

Referral and escalation. Psychiatry or liaison psychiatry for severe somatic symptom disorder, factitious disorder, comorbid depression with suicidal thoughts, psychosis, or failure to respond. Neurology for functional neurological disorder and seizures. Specialist rehabilitation, pain clinics, and physiotherapy. Gastroenterology, rheumatology or others for specific functional syndromes with objective features. Safeguarding teams when fabricated or induced illness is suspected.

Admission criteria. Suicidal intent, severe depression or psychosis, inability to eat or drink, severe functional disability or immobility needing intensive rehabilitation, unexplained dangerous acute symptoms until organic disease is excluded, and safeguarding emergencies.

Discharge and follow up. Written explanation of the diagnosis and plan, a regular follow up schedule every 2 to 4 weeks at first, and one coordinating clinician. Safety net advice: return for new objective features (fever, weight loss, bleeding, new weakness, chest pain, shortness of breath, fainting, severe headache, or confusion), suicidal thoughts, or worsening function.