01Approach to the Critical Patient/attcp52

Immediate life threats

›Myocarditis recognition

›Chest pain with fever and myalgia in trichinosis context

›Leading cause of death in severe trichinosis

›ST-T wave changes, arrhythmias, conduction block

›Hemodynamic instability

›SBP < 90 mmHg

›MAP < 65 mmHg

›If cardiogenic shock, initiate resuscitation and ICU transfer

›Cardiology consultation

›Avoid aggressive fluid loading in low-EF state

›Neurotrichinosis recognition

›Encephalopathy, seizures, focal neurologic deficits

›Mortality up to 5% with CNS involvement

›Hemiparesis, ataxia as presenting features

›If seizures, benzodiazepine first-line

›Lorazepam 0.1 mg/kg IV

›Neurology consultation

›Respiratory failure

›Diaphragm involvement causing dyspnea

›Decreasing respiratory reserve

›Aspiration risk from dysphagia

›Pulmonary infiltrates from trichinella pneumonitis

›SpO2 < 92% on room air as escalation trigger

›If progressive dyspnea, early airway planning

Monitoring and targets

›Monitoring bundle

›Continuous cardiac monitoring for arrhythmias

02History/hx46

Exposure and onset

›Meat exposure history

›Raw or undercooked pork, wild boar, bear, deer, walrus, horse

›Timing typically 1-4 weeks prior to symptom onset

›Home-slaughtered or uninspected meat highest risk

›Shared meal exposure — common source outbreak pattern

›Other symptomatic household members or co-diners

›Source of meat: backyard-raised pigs fed scraps or offal

›Biphasic illness timeline

›Enteral phase: GI symptoms within 1-7 days of ingestion

›Nausea, diarrhea, abdominal pain, vomiting

›Parenteral phase: systemic symptoms at 2-6 weeks

›Fever, myalgia, periorbital edema

Symptom characterization

›Classic triad

›Fever — reported in 61% of cases (global meta-analysis)

›High-grade fever pattern

›Chills and rigors

›Myalgia — reported in 63% of cases

›Degree of muscle pain and weakness

›Difficulty with ambulation or movement

›Periorbital or facial edema — reported in 59% of cases

›Bilateral distribution

›Onset timing relative to exposure

›Alarm symptoms

›Chest pain and palpitations — myocarditis

›Dyspnea at rest

›Syncope or presyncope

03Physical Exam/exam46

Vital signs and general

›Hemodynamic assessment

›Temperature — often high-grade fever

›Tachycardia as myocarditis marker

›Hypotension as cardiogenic or distributive shock marker

›Respiratory rate

›Elevated rate with diaphragm or pulmonary involvement

›SpO2 on room air

›General appearance

›Toxicity and distress level

›Muscle weakness affecting gait

Head, eyes, and skin

›Hallmark findings

›Periorbital and facial edema — classic sign

›Bilateral versus unilateral distribution

›Associated conjunctival injection

›Subconjunctival hemorrhages

›Splinter hemorrhages of nails

›Maculopapular or urticarial rash

›Ocular findings

›Extraocular muscle tenderness on movement

›Diplopia or ophthalmoplegia in severe cases

›Periorbital pain on palpation

Musculoskeletal exam

›Muscle tenderness

›Diffuse myalgia with palpation

›Masseter tenderness — trismus possible

›Diaphragm involvement — paradoxical breathing

04Differential Diagnosis/ddx48

Life-threatening mimics

›Myocarditis etiologies

›Viral myocarditis (Coxsackie B, CMV, influenza)

›ICD-10 I40.0

›No eosinophilia; different exposure history

›Eosinophilic myocarditis (hypereosinophilic syndrome)

›ICD-10 I41

›Bone marrow biopsy distinguishes

›CNS inflammatory conditions

›Viral encephalitis

›ICD-10 A86

›CSF analysis, no muscle involvement

›Bacterial meningitis

›ICD-10 G00.9

›CSF pleocytosis, no eosinophilia

Muscle and rheumatologic mimics

›Inflammatory myopathies

›Dermatomyositis

›ICD-10 M33.1

›Elevated CPK but no eosinophilia or exposure history

›Polymyositis

›ICD-10 M33.2

›Anti-Jo-1 antibodies, EMG changes

›Polyarteritis nodosa

›Fever, myalgias, eosinophilia — requires angiography or biopsy to distinguish

›Other parasitic infections

›Toxocariasis — visceral larva migrans

›ICD-10 B83.0

05Laboratory Tests/lt44

Core diagnostic labs

›Complete blood count with differential

›Eosinophilia present in approximately 97% of cases

›Hallmark finding — absolute eosinophil count

›Leukocytosis in approximately 71% of cases

›Falling eosinophil count paradoxically associated with poor prognosis

›Monitor trend serially

Muscle enzyme markers

›Creatine phosphokinase

›Elevated in approximately 82-85% of cases — reflects muscle invasion

›Serial CPK trending to monitor disease course

›Normalization correlates with treatment response

›Lactate dehydrogenase

›Elevated in active muscle disease

›Aldolase elevation consistent with myositis

›Liver and inflammatory markers

›AST and ALT

›Mild elevation possible

›Significant elevation suggests hepatic involvement

›Erythrocyte sedimentation rate

›Elevated in approximately 98% of cases

›Non-specific but supports inflammatory state

Serology and cardiac markers

›Anti-Trichinella serology

›Anti-Trichinella IgG by ELISA — sensitivity approximately 94%, specificity approximately 94%

›Often negative in first 3 weeks of illness

›Paired sera drawn several weeks apart recommended

›IDSA recommends EIA through CDC or reference laboratory as main diagnostic test

06Diagnostic Tests/dt55

Scoring Systems

›Clinical diagnosis triad

›No validated scoring system specific to trichinosis

›Diagnosis relies on clinical triad: periorbital edema + myalgia + eosinophilia

›Must be in context of appropriate exposure history

›Severity classification

›Mild: GI symptoms only, self-limited

›Moderate: Systemic symptoms without organ complications

›Severe: Myocarditis, neurotrichinosis, pneumonitis, thromboembolic events

MRI

›Brain MRI for neurotrichinosis

›Indication: Encephalopathy, seizures, focal neurologic deficits

›Superior to CT for white matter and cortical lesion detection

›Multifocal white matter and cortical lesions characteristic

›MRI findings in neurotrichinosis

›T2/FLAIR hyperintensities in cortex and subcortical white matter

›May show ring-enhancing lesions mimicking metastatic disease

›Cardiac MRI

›Indicated when echocardiography equivocal for myocarditis

›Late gadolinium enhancement pattern of myocarditis

CT

›Brain CT

›Indication: Acute seizure or focal deficit when MRI not immediately available

›Multifocal hypodensities in cortex and white matter

›Less sensitive than MRI for early or subtle lesions

›Chest CT

›Indication: Progressive pulmonary symptoms or infiltrates on CXR

›Patchy ground-glass opacities or consolidations

07Disposition/dispo36

Admission criteria

›Indications for hospitalization

›Myocarditis — any troponin elevation with ECG changes

›Cardiac monitoring required

›ICU if hemodynamic compromise

›Neurotrichinosis — any encephalopathy, seizure, or focal deficit

›Neurology consultation

›ICU level care for status epilepticus

›Severe myalgias with inability to ambulate

›High-grade fever with hemodynamic instability

›Dysphagia or dyspnea from muscle involvement

›Observation indications

›Moderate symptoms with significant eosinophilia and elevated CPK pending workup

›Awaiting serology results

›Unable to tolerate oral medications reliably

Discharge criteria

›Safe discharge requirements

›Mild GI symptoms only without systemic features

›Stable vital signs throughout observation period

›Able to tolerate oral medications and fluids

›Reliable follow-up confirmed

›Infectious disease within 1-2 weeks

›Repeat serology planned in 2-4 weeks if initial testing negative

Consultations and reporting

›Mandatory consultations

›Infectious disease for all confirmed or strongly suspected cases

›CDC Parasitic Diseases Hotline if outbreak suspected

›Cardiology if myocarditis features present

08Treatment/t61

Anthelmintic therapy

›Albendazole — preferred agent

›Dosing

›400 mg PO twice daily (15 mg/kg/day in divided doses) for 10-15 days

›Must be taken with fatty meals to improve absorption and bioavailability

›Efficacy considerations

›Most effective during enteral (intestinal) phase

›Efficacy decreases once larvae have encysted in muscle

›Contraindications

›Contraindicated in pregnancy — Category D

›Not recommended in children under 2 years

›Mebendazole — alternative agent

›Dosing

›200-400 mg three times daily for 3 days

›Then 400-500 mg three times daily for 10 days

›Alternative weight-based: 5 mg/kg/day up to 20-25 mg/kg/day for 10-15 days

›Contraindications

›Contraindicated in pregnancy

›Not recommended in children under 2 years

›Mild disease considerations

›Mild disease with clinical suspicion alone may not require antiparasitic treatment

›Symptomatic therapy with close monitoring may be appropriate

›Reassess if symptoms progress

Corticosteroids

›Prednisolone for severe or complicated disease

›Dosing

›30-60 mg/day orally for 10-15 days

›Taper as symptoms improve

09Special Populations/sp47

Pregnancy

›Anthelmintic safety

›Albendazole and mebendazole are contraindicated in pregnancy

›Both agents are teratogenic (Category D / Pregnancy Category X)

›Avoid in first trimester especially

›Management approach in pregnancy

›Supportive therapy only if feasible — analgesics, antipyretics

›Acetaminophen preferred antipyretic

›Specialist consultation: maternal-fetal medicine and infectious disease

›Corticosteroid use

›Prednisolone generally acceptable in pregnancy for severe complications

›Weigh benefit-risk for myocarditis or neurotrichinosis

›Monitor for gestational diabetes and preterm labor

›Fetal considerations

›Potential for placental transmission — limited evidence

›Serial obstetric ultrasound monitoring

›Neonatal serology if maternal infection confirmed

Geriatric

›Altered presentation

›Blunted fever response — may present without high-grade fever

›Occult myocarditis risk higher with pre-existing heart disease

›Falls risk from profound myalgia and weakness

›Cognitive changes

›Delirium may be the predominant CNS manifestation

›Baseline cognitive assessment required for comparison

›Medication considerations

›Renal function for anthelmintic dosing adjustment

›Avoid NSAIDs in renal impairment or cardiovascular disease

10Background/b66

Epidemiology

›Global burden

›Parasitic zoonosis caused by nematodes of the genus Trichinella

›Most common species: Trichinella spiralis

›Over 12 species and genotypes recognized

›Military personnel have highest pooled prevalence — 41.5% in exposed populations (Acta Tropica, 2026)

›Geographic hot spots: Thailand, Germany, Turkey, Eastern Europe

›Regions with inadequate meat inspection programs at highest risk

›Transmission and seasonality

›Ingestion of raw or undercooked meat containing encysted larvae

›Pork, wild boar, bear, deer, walrus, horse implicated

›Backyard-raised pigs fed scraps or offal carry highest risk

›Outbreak pattern common — multiple cases from single shared meal

›Indoor or outdoor gatherings featuring wild game

›Not seasonally restricted but correlates with hunting seasons

›Chronic sequelae

›52% of patients reported myalgias and fatigue at 6 months post-treatment in one cohort

›Fatigue and reduced muscle strength may persist for years

›Thromboembolic complications described as long-term sequelae

Pathophysiology

›Biphasic disease mechanism

›Enteral phase — intestinal invasion

›Ingested encysted larvae excysted by gastric acid

›Larvae penetrate small intestinal epithelium within hours

›Mature to adult worms in 2-3 days

›Parenteral phase — systemic larval migration

›Newborn larvae enter lymphatics and bloodstream

›Hematogenous dissemination to striated muscle and organs

›Larvae penetrate muscle fibers and encyst (nurse cell complex)

›Organ-specific pathology

›Skeletal muscle — most common target

›Intense inflammatory infiltrate around encysted larvae

›Myofiber degeneration and CPK release

›Myocardium — leading cause of death

›Larvae migrate but cannot complete encystment in cardiac muscle

›Intense eosinophilic myocarditis results

›CNS

›Direct larval invasion of cerebral vasculature

›Inflammatory vasculitis and microhemorrhages

›Lung — pneumonitis from larval passage

›Eosinophilic infiltration of alveolar walls

›Patchy consolidations on imaging

›Immune response

›Massive eosinophil recruitment in response to larval antigens

›IgE-mediated hypersensitivity contributes to urticaria and edema

›Paradoxical eosinophil fall — worse prognosis signifier

›Hypergammaglobulinemia reflects immune activation

Therapeutic Considerations

›Anthelmintic timing principle

›Treatment most effective during enteral phase — first 1-2 weeks

›Once larvae encysted in muscle, anthelmintic penetration reduced

›Albendazole preferred over mebendazole for systemic bioavailability

›Albendazole bioavailability optimization

›Fat-rich meal significantly improves absorption

›Peak plasma concentration occurs 2-5 hours after ingestion

›Corticosteroid rationale

›Anti-inflammatory effect reduces immune-mediated organ damage

›Does not kill larvae — must combine with anthelmintics

›Indicated for myocarditis, CNS involvement, severe inflammatory response

›Potential paradoxical effect of steroids alone

›Immunosuppression without anthelmintics may worsen larval burden

›Combination therapy is the standard approach

›Evidence base

›Albendazole superior to thiabendazole (CID 1996 retrospective study)

›Better tolerability and comparable or superior efficacy

›Thiabendazole no longer recommended due to side effect profile

›No randomized controlled trials for optimal anthelmintic duration

›10-15 day course based on expert consensus and clinical experience

›Expert Opinion on Pharmacotherapy 2002 consensus recommendations

11Patient Discharge Instructions/pdi33

copy discharge instructions

›Diagnosis and expected course

›Diagnosed with trichinosis (trichinellosis) — a parasitic infection from undercooked meat

›Caused by a roundworm called Trichinella

›Symptoms typically improve within 2-3 weeks of treatment

›Chronic fatigue and muscle aches may persist for several months

›Muscle strength returns gradually

›Most patients recover fully with proper treatment

›Medications — take as prescribed

›Albendazole — take with a fatty meal (e.g., peanut butter, full-fat yogurt, avocado)

›Take every dose as directed for the full course (10-15 days)

›Do not stop early even if feeling better

›If prescribed prednisone — do not stop abruptly

›Follow taper schedule as written

›Monitor for blood sugar elevation if diabetic

›Diet and activity

›Discard all remaining suspect meat — do not share with others or animals

›Ensure all future pork and wild game is cooked to internal temperature of 71 degrees Celsius (160 degrees Fahrenheit)

›Freezing does not reliably kill all Trichinella species — cooking required

›Rest and limit strenuous activity until muscle symptoms resolve

›Maintain adequate hydration

›Follow-up instructions

›Infectious disease appointment within 1-2 weeks

›Repeat blood test (serology) in 2-4 weeks — first test may be negative early

›Repeat CPK and eosinophil count to track treatment response

›This infection is reportable — public health may contact you for investigation

›Inform household members and others who shared the meal to seek medical evaluation

›Return to emergency department immediately for

12References/r42

Guidelines and key sources

›IDSA/ASM Microbiology Laboratory Diagnostic Guidelines 2024

›Miller JM, Binnicker MJ, Campbell S, et al. Clinical Infectious Diseases 2024

›Recommends EIA serology through CDC or reference laboratory as primary diagnostic test

›https://academic.oup.com/cid/article-lookup/doi/10.1093/cid/ciae104

›Expert Opinion on Diagnosis and Treatment of Human Trichinellosis

›Dupouy-Camet J, Kociecka W, Bruschi F, et al. Expert Opinion on Pharmacotherapy 2002

›Consensus recommendations on albendazole and mebendazole dosing

›https://pubmed.ncbi.nlm.nih.gov/12150691

›CDC Yellow Book — Post-Travel Parasitic Disease 2025

›Wendt EM, Kamb ML, Montgomery SP. CDC Yellow Book 2025

›Exposure sources, alarm features, diagnostic approach

›https://www.cdc.gov/yellow-book/hcp/post-travel-evaluation/post-travel-parasitic-disease.html

Epidemiology and clinical studies

›Global Prevalence and Risk Factors of Human Trichinellosis

›Wei W, Jiao D, Zhang X, et al. Acta Tropica 2026

›Systematic review and meta-analysis — myalgia 63%, fever 61%, facial edema 59%

›Military personnel highest pooled prevalence 41.5%

›https://pubmed.ncbi.nlm.nih.gov/42070613

›Trichinellosis: A Zoonosis That Still Requires Vigilance

›Mitic I, Vasilev S, Gruden-Movsesijan A. PLoS Neglected Tropical Diseases 2026

›52% of patients reported myalgias and fatigue at 6 months

›https://pubmed.ncbi.nlm.nih.gov/41615911

›Clinical and Epidemiological Descriptions From Trichinellosis Outbreaks in Bulgaria

›Vutova K, Velev V, Chipeva R, et al. Experimental Parasitology 2020

›Outbreak pattern data; initial misdiagnosis common

›https://pubmed.ncbi.nlm.nih.gov/32179068

Evidence & Review

Evidence & Review