Multisystem Processes & Disorders

Long COVID and post-acute sequelae of SARS-CoV-2

Clinical Overview and When to Suspect Long COVID

— Also called PASC (post-acute sequelae of SARS-CoV-2) or post-COVID condition.

— Can follow asymptomatic, mild, or severe acute infection; vaccination reduces but does not eliminate risk.

— Persistent fatigue, exertional intolerance, "brain fog," dyspnea, palpitations, anosmia, or sleep disturbance >12 weeks after a documented or strongly suspected COVID-19 infection.

— Symptoms that wax and wane, worsen with physical or cognitive exertion (post-exertional malaise, PEM), or follow an orthostatic pattern.

— New-onset POTS, dysautonomia, or unexplained tachycardia in a previously healthy young adult.

— Viral antigen/RNA persistence in tissue reservoirs.

— Immune dysregulation with latent virus reactivation (EBV, HHV-6).

— Microvascular endotheliitis and microclot formation.

— Autonomic dysfunction and small-fiber neuropathy.

— Gut microbiome and vagal nerve disruption.

Board pearl: Long COVID is a clinical diagnosis of inclusion + exclusion — confirm temporal link to SARS-CoV-2, document persistence ≥3 months, and actively rule out treatable mimics (thyroid disease, anemia, OSA, depression, cardiac/pulmonary disease) before labeling. Do not require a positive prior PCR — many patients infected early in the pandemic were never tested.

Definition (NASEM 2024 / WHO / CDC): an infection-associated chronic condition occurring after probable or confirmed SARS-CoV-2 infection, present ≥3 months after acute illness, lasting ≥2 months, not explained by an alternative diagnosis.

Epidemiology: affects roughly 6–10% of US adults post-infection; cumulative US prevalence ~14% ever-experienced. Higher risk with female sex, age 30–60, prior severe acute illness, unvaccinated status, pre-existing autoimmune/atopic disease, obesity, diabetes, and Omicron < Delta < ancestral strains.

When to suspect on Step 3:

Core pathophysiologic hypotheses (overlap, not mutually exclusive):

Presentation Patterns and Key History

— Neurocognitive: brain fog, word-finding difficulty, impaired concentration, headache, insomnia, dysautonomia, paresthesias.

— Cardiopulmonary: dyspnea on exertion, chest tightness, palpitations, orthostatic tachycardia, reduced exercise tolerance.

— Fatigue/PEM phenotype: profound fatigue + delayed symptom worsening 12–72 h after minor exertion (overlaps with ME/CFS criteria).

— Autonomic: POTS-like presentation, lightheadedness on standing, temperature dysregulation, GI dysmotility.

— Sensory: persistent anosmia/parosmia, dysgeusia, tinnitus.

— GI/metabolic: new IBS-like symptoms, post-COVID diabetes, weight changes.

— Dermatologic/MSK: myalgias, arthralgias, hair loss, urticaria.

— Date and severity of acute infection; hospitalization or ICU stay; ECMO/vent use.

— Vaccination history (doses, dates, post-vaccine symptom change — some report improvement).

— Symptom timeline: continuous from acute, or delayed/biphasic onset.

— PEM screening: "Do symptoms worsen 12–48 hours after physical, mental, or emotional effort?" — a yes pivots management away from graded exercise.

— Orthostatic symptoms: lightheadedness, palpitations on standing, relieved by recumbency.

— Functional impact: ADLs, work, school, driving — use a standardized scale (e.g., PROMIS, EQ-5D, DePaul PEM questionnaire).

— Mental health: screen PHQ-9, GAD-7 — but avoid attributing symptoms to psychiatric disease prematurely.

— Medications, supplements, prior similar illnesses (mono, dengue, Lyme).

Key distinction: PEM differentiates the ME/CFS-like Long COVID phenotype from deconditioning. In deconditioning, graded aerobic activity helps; in PEM, the same activity triggers crashes — graded exercise can harm these patients. Use pacing and "energy envelope" counseling instead.

Symptom clusters (often coexist; map to phenotypes that drive workup):

Essential history elements:

Physical Exam Findings and Hemodynamic Assessment

— Perform a 10-minute active stand test or NASA Lean Test in clinic.

— POTS criteria: sustained HR rise ≥30 bpm (≥40 bpm in adolescents) within 10 min of standing, without orthostatic hypotension, with symptoms.

— Orthostatic hypotension: ≥20 mmHg SBP or ≥10 mmHg DBP drop within 3 min standing.

— Inappropriate sinus tachycardia: resting HR >100 with symptoms.

— Usually normal lungs; auscultate for crackles (post-COVID ILD), wheeze (new reactive airway).

— Assess for resting tachycardia, irregular rhythm, pericardial rub.

— SpO2 at rest and with ambulation — desaturation ≥3% with a 1-min sit-to-stand or 6MWT suggests parenchymal/vascular disease.

— Cognitive screen (MoCA) — often normal despite subjective deficits; sensitive to processing speed, not screened well by MoCA.

— Small-fiber assessment: pinprick, temperature, allodynia in stocking distribution.

— Cranial nerve I testing with standardized smell kit (Sniffin' Sticks, UPSIT) for anosmia.

— Thyroid exam, lymph nodes (rule out mimics).

— Joint swelling (post-infectious arthritis differential).

— Skin: livedo reticularis, telogen effluvium, urticaria.

Step 3 management: A documented abnormal 10-min stand test in clinic is the single most actionable bedside finding — it shifts you toward POTS-directed therapy (volume, salt, compression, beta-blocker or ivabradine) and is often missed if you only check supine vitals. Always record both supine and standing HR/BP in the note.

General appearance: often unremarkable, which itself is diagnostically important — the dissociation between subjective disability and normal exam is characteristic and a frequent source of clinician dismissal.

Vital signs and orthostatics (mandatory):

Cardiopulmonary exam:

Neurologic exam:

Other:

Diagnostic Workup — Initial Labs, Imaging, ECG, Biomarkers

— CBC with differential, CMP, TSH (and free T4 if abnormal), HbA1c, fasting lipids.

— Ferritin, iron studies, B12, folate, vitamin D — fatigue mimics.

— ESR, CRP — modestly elevated CRP/D-dimer common but nonspecific.

— CK if myalgia prominent.

— HIV, hepatitis B/C, RPR if risk factors — fatigue + cognitive change differentials.

— Morning cortisol if symptoms suggest adrenal insufficiency (rare post-COVID adrenalitis reported).

— ECG on all with palpitations, chest pain, or dyspnea — look for sinus tach, QT, low voltage, pericarditis pattern.

— Troponin if chest pain or new exercise intolerance.

— NT-proBNP if dyspnea or edema.

— D-dimer if any suspicion of post-COVID VTE (still elevated risk up to 6–12 months post-infection).

— Chest X-ray as first imaging for persistent dyspnea/cough.

— Lyme serology, ANA, RF if arthralgias or rash.

— Sleep study referral if snoring, witnessed apnea, BMI elevated — OSA is a leading missed mimic.

— Consider celiac serology if GI prominent.

Board pearl: A persistently elevated D-dimer >6 months post-COVID in a symptomatic patient warrants imaging evaluation for chronic thromboembolic disease (CTEPH) — order V/Q scan (more sensitive than CTPA for chronic clot), especially with exertional dyspnea and right-heart strain on ECG.

There is no single confirmatory biomarker for Long COVID. Workup is driven by phenotype and aimed at excluding treatable mimics.

Baseline labs for nearly all patients:

Cardiopulmonary phenotype add-ons:

Neuro/autonomic add-ons:

Mental health screening: PHQ-9, GAD-7, PCL-5 — comorbid, not causal.

Diagnostic Workup — Advanced or Confirmatory Studies

— Echocardiogram for persistent dyspnea, chest pain, palpitations, or abnormal ECG — assess EF, RV size/function, pericardial effusion, diastolic dysfunction.

— High-resolution CT chest if abnormal CXR, hypoxia, or persistent cough — look for post-COVID ILD, organizing pneumonia, ground-glass opacities, mosaic attenuation.

— PFTs with DLCO — reduced DLCO is the most common abnormality in post-COVID lung disease.

— Cardiopulmonary exercise testing (CPET): the most informative single test in unexplained exertional intolerance — distinguishes deconditioning, chronotropic incompetence, ventilatory inefficiency (high VE/VCO2), and impaired oxygen extraction (peripheral/mitochondrial pattern, often seen in Long COVID).

— Cardiac MRI if myocarditis suspected (persistent troponin, arrhythmia, regional wall motion abnormality).

— Formal tilt-table testing if POTS suspected but office stand test equivocal or symptoms severe.

— QSART, thermoregulatory sweat test at specialized centers for small-fiber neuropathy.

— Skin punch biopsy for intraepidermal nerve fiber density if SFN suspected.

— Formal neuropsychological testing for objective cognitive impairment documentation (important for disability claims).

— Brain MRI generally normal; order only if focal deficits, headache red flags, or seizure.

— Gastric emptying study if early satiety/nausea suggests post-COVID gastroparesis.

— Endocrine: ACTH stim if cortisol borderline; sex hormones if amenorrhea/ED.

Step 3 management: Reserve advanced testing for patients whose results will change management or qualify them for a specialist clinic / disability documentation. Avoid shotgun testing — it amplifies false positives and patient anxiety.

When initial labs are unrevealing but disability persists, escalate by phenotype:

Cardiopulmonary:

Autonomic:

Neurocognitive:

Other:

Risk Stratification and First-Line Management Logic

— Validate the illness; provide written diagnosis and education.

— Identify and treat comorbid conditions: OSA, anemia, hypothyroidism, depression, deconditioning, orthostatic intolerance.

— Sleep hygiene, hydration (2–3 L/day if no contraindication), increased sodium intake (8–10 g/day) if orthostatic.

— Smoking cessation, alcohol moderation.

— Update vaccinations (COVID booster generally recommended; small subset reports symptom flare — shared decision-making).

— PEM/ME-CFS phenotype: pacing and energy envelope — first-line. Avoid graded exercise therapy. Heart rate–limited activity (stay below anaerobic threshold, often <60% max HR).

— POTS/dysautonomia: volume + salt + compression stockings (waist-high, 20–30 mmHg) → beta-blocker (propranolol low-dose) or ivabradine → midodrine or fludrocortisone if hypotensive subtype.

— Cardiopulmonary deconditioning (no PEM): supervised cardiopulmonary rehab.

— Cognitive: cognitive rehab, speech-language therapy, sleep optimization.

— Anosmia/parosmia: structured olfactory training ×3–6 months.

Key distinction: The PEM screen drives the rehab fork in the road. Deconditioning → exercise reconditioning; PEM-positive → pacing. Mislabeling can produce iatrogenic crashes lasting weeks.

Step 3 framework: stratify by phenotype + functional impact + treatable contributors, not by severity of acute infection.

Tier 1 — universal foundation for every Long COVID patient:

Tier 2 — phenotype-directed therapy:

Tier 3 — refer to multidisciplinary post-COVID clinic when symptoms persist >6 months, multiple systems involved, or unable to work.

Red flags requiring urgent eval: chest pain with troponin rise, syncope, hypoxia, hemoptysis, focal neuro deficit, suicidal ideation.

Pharmacotherapy — First-Line Drug Regimens by Phenotype

— Propranolol 10–20 mg PO TID-QID (low-dose; avoid high doses that worsen fatigue).

— Ivabradine 2.5–5 mg BID — preferred when bronchospasm or fatigue limits beta-blockers; reduces HR without lowering BP.

— Midodrine 2.5–10 mg TID (last dose ≥4 h before bedtime) for hypotensive POTS.

— Fludrocortisone 0.1–0.2 mg daily — monitor K, BP.

— Pyridostigmine 30–60 mg TID — adjunct for refractory POTS.

Step 3 management: Start low, go slow. Long COVID patients are notably drug-sensitive — initiate at half the usual starting dose, titrate weekly. Document baseline orthostatics before and 2 weeks after any cardiovascular drug change.

No FDA-approved drug for Long COVID itself. Treatment targets specific phenotypes; use lowest effective doses and reassess.

POTS / orthostatic tachycardia:

Headache: standard migraine prophylaxis (amitriptyline, topiramate, propranolol, CGRP antagonists for refractory).

Neuropathic pain/SFN: gabapentin, pregabalin, duloxetine, low-dose naltrexone (off-label, growing evidence).

Sleep: sleep hygiene first; trazodone 25–50 mg or low-dose doxepin if insomnia; treat OSA with CPAP.

Mood: SSRI/SNRI when comorbid depression/anxiety — duloxetine and venlafaxine helpful when neuropathic pain coexists.

Cognitive symptoms: no proven drug; avoid stimulants as first-line. Some specialists trial low-dose guanfacine + N-acetylcysteine.

Mast cell activation phenotype (flushing, urticaria, GI, brain fog): H1 (cetirizine, loratadine) + H2 (famotidine) blockade trial.

Anosmia: intranasal corticosteroids only if rhinitis; olfactory training is mainstay.

Expanded Pharmacology, Investigational Therapies, and What NOT to Use

— Nirmatrelvir/ritonavir is FDA-approved only for acute COVID-19; trials (e.g., STOP-PASC, RECOVER-VITAL) of extended courses for Long COVID have so far been negative or inconclusive. Not standard of care.

— Metformin given during acute infection reduced incident Long COVID in COVID-OUT — secondary prevention signal, not treatment.

— Routine empiric anticoagulation for "microclots" is not recommended outside trials.

— Treat documented VTE per standard guidelines; consider extended anticoagulation for unprovoked post-COVID VTE.

Board pearl: A patient asks about a "blood-washing" apheresis clinic abroad. The correct Step 3 response is evidence-based counseling against unproven therapies, screening for financial harm, and offering enrollment in legitimate trials (e.g., NIH RECOVER-TLC).

Antivirals — investigational:

Anticoagulation:

Immunomodulators: IVIG, rituximab, plasmapheresis — investigational, reserved for confirmed autoimmune phenotypes (e.g., autoimmune autonomic ganglionopathy) at specialty centers.

Low-dose naltrexone (1.5–4.5 mg qHS): off-label; small studies suggest fatigue/pain benefit; reasonable trial after standard measures.

Supplements with weak/no evidence: ivermectin, hydroxychloroquine, high-dose vitamin C/D infusions, "stellate ganglion blocks" — avoid recommending; counsel patients against unproven, costly therapies offered by direct-to-consumer clinics.

Hyperbaric oxygen (HBOT): one small RCT showed cognitive benefit; not standard, not typically covered, refer only within research protocols.

Vagal nerve stimulation, breathing retraining (e.g., Stasis, Buteyko): adjuncts for dysautonomia and dysfunctional breathing — low risk, possible benefit.

Drugs to use cautiously: high-dose beta-blockers, anticholinergics, benzodiazepines (worsen cognition), opioids (worsen fatigue and constipation).

Special Populations — Elderly, Renal, and Hepatic Impairment

— Higher risk of post-COVID functional decline, sarcopenia, and incident dementia (cohort data show ~1.7× dementia risk at 12 months).

— Distinguish Long COVID cognitive symptoms from new vascular dementia, delirium, or unmasked Alzheimer's — obtain collateral history, MoCA, B12, TSH, MRI if focal/progressive.

— Polypharmacy review essential before adding POTS or neuropathic agents; check anticholinergic burden.

— Beers criteria: avoid benzos, first-gen antihistamines, tertiary TCAs at high doses.

— Fall risk: midodrine and fludrocortisone increase supine HTN — monitor.

— Physical therapy emphasis on resistance training to combat sarcopenia, with PEM screening still applied.

— COVID accelerates eGFR decline; recheck creatinine 3–6 months post-acute, especially after AKI during hospitalization.

— Dose-adjust gabapentin/pregabalin (gabapentin reduce by ~50% at CrCl 30–60; further at <30).

— Avoid NSAIDs for post-COVID myalgia in CKD.

— Fludrocortisone — monitor K+ closely; risk of hyperkalemia.

— Iodinated contrast: don't withhold if needed (e.g., suspected PE), but optimize hydration.

— Use caution with acetaminophen (≤2 g/day in advanced cirrhosis), duloxetine (avoid in significant liver disease), and tramadol.

— Statin continuation generally safe; monitor LFTs.

— Higher risk of prolonged viral shedding and Long COVID; coordinate antiviral and vaccine timing with transplant team.

— Lower threshold to evaluate persistent symptoms for chronic SARS-CoV-2 replication with repeat PCR/sequencing.

Step 3 management: In any older post-COVID patient with new "brain fog," screen for delirium triggers and depression before attributing cognitive change to Long COVID — these are reversible and frequently missed.

Older adults (≥65):

Chronic kidney disease:

Hepatic impairment:

Post-transplant / immunosuppressed:

Special Populations — Pregnancy, Pediatrics, and Other Subgroups

— Pregnancy itself increased risk of severe acute COVID; Long COVID rates appear similar to nonpregnant women, but symptoms (fatigue, dyspnea, palpitations) overlap with normal pregnancy — high index of suspicion needed.

— Vaccination during pregnancy is recommended and reduces Long COVID risk.

— Safe meds: acetaminophen, low-dose propranolol (category C, generally acceptable), cetirizine/loratadine, famotidine.

— Avoid: ivabradine (limited data), midodrine, fludrocortisone (use only if essential), gabapentin (use lowest effective dose), duloxetine near term.

— Postpartum: differentiate Long COVID fatigue from postpartum thyroiditis, anemia, and PPD — check TSH, CBC, PHQ-9.

— Less common than in adults but real; ~1–3% of infected children develop persistent symptoms.

— Distinct entity: MIS-C (acute, 2–6 weeks post-infection — fever, multisystem inflammation, requires hospitalization) — not Long COVID.

— Adolescent Long COVID often presents as POTS, fatigue, school absenteeism, headache — coordinate school accommodations (504 plan), gradual return-to-learn.

— POTS thresholds in adolescents: HR rise ≥40 bpm.

— Avoid SSRIs as first-line in children without psychiatric indication; involve pediatric subspecialists.

— After any symptomatic COVID, gradual return-to-play protocol; if chest pain, syncope, exertional dyspnea, or arrhythmia → ECG, troponin, echo before clearance to rule out myocarditis.

— Cardiac MRI for confirmed myocarditis → 3–6 months of exercise restriction.

Board pearl: In a child with fever + rash + conjunctivitis + shock 4 weeks after COVID, think MIS-C, not Long COVID — admit, IVIG + steroids, echo for coronary aneurysms.

Pregnancy and postpartum:

Pediatrics and adolescents:

Athletes / return-to-play:

Occupational considerations: healthcare workers, first responders — may qualify for workers' compensation; document exposure and temporal link.

Complications and Adverse Outcomes

— Increased 12-month risk of MI, stroke, heart failure, arrhythmia, pericarditis, and VTE — present even in nonhospitalized patients.

— Post-COVID myocarditis (rare but serious); CTEPH from organized PE.

— POTS and orthostatic syncope → fall injury.

— Post-COVID interstitial lung disease / fibrosis, especially after severe ARDS — reduced DLCO, restrictive PFTs.

— Chronic cough, reactive airway disease, dysfunctional breathing.

— Increased incidence of stroke, seizure, neuropathy, dementia, anxiety, depression, PTSD, substance use disorder in the year following infection.

— Suicidality risk elevated — actively screen.

— New-onset type 2 diabetes (and rarely type 1) — check HbA1c at 3 and 12 months.

— Subacute thyroiditis, adrenal insufficiency (rare).

— Hypogonadism, menstrual irregularities.

— Loss of employment, disability — US estimates 2–4 million working-age adults out of workforce due to Long COVID.

— Insurance denials, school disruption, caregiver burden.

Step 3 management: At the 3-month post-COVID visit, screen all patients for new HTN, dyslipidemia, diabetes, depression, and VTE risk — Long COVID is now framed as a cardiometabolic risk amplifier, and aggressive ASCVD risk factor modification is appropriate.

Cardiovascular:

Pulmonary:

Neurologic / psychiatric:

Endocrine / metabolic:

GI: persistent diarrhea, IBS-like syndrome, gastroparesis, hepatobiliary dysfunction.

Renal: AKI survivors have accelerated CKD progression.

Functional and socioeconomic:

Mortality: modestly increased all-cause mortality in the year post-acute infection, mostly from cardiovascular and thrombotic events.

When to Escalate Care — ICU, Consults, and Inpatient Triage

— Acute chest pain + troponin elevation → rule out MI, myocarditis; admit telemetry.

— Syncope with injury or recurrent syncope → admit, telemetry, tilt as outpatient.

— Hypoxia (SpO2 <92% on room air, or significant exertional desaturation) → CT-PA for PE, evaluate for ILD progression.

— Suspected PE/DVT → ED imaging, anticoagulation.

— Severe dehydration from dysautonomia/gastroparesis → IV fluids, electrolyte correction.

— Acute suicidal ideation → psychiatric evaluation, possible inpatient admission.

— New focal neurologic deficit → stroke workup.

— Cardiology: abnormal ECG/echo, suspected myocarditis, refractory POTS, CTEPH workup.

— Pulmonology: persistent hypoxia, reduced DLCO, abnormal HRCT, suspected fibrosis.

— Neurology: seizures, focal deficits, severe headache, suspected small-fiber neuropathy.

— Autonomic specialist: refractory POTS/dysautonomia.

— Rheumatology: positive autoimmune serologies with clinical correlates.

— Psychiatry: moderate-severe depression, PTSD, suicidality.

— Physiatry / rehab medicine: functional rehab planning, disability documentation.

— Multidisciplinary post-COVID clinic for complex cases.

CCS pearl: If a Long COVID patient presents to the ED with chest pain, dyspnea, and SpO2 91%, your CCS orders should include: IV access, ECG, troponin, BNP, D-dimer, CBC, BMP, CXR, CT-PA, continuous pulse ox, telemetry, and cardiology consult — do not dismiss as "just Long COVID."

Long COVID is overwhelmingly an outpatient diagnosis, but specific scenarios mandate escalation:

Emergency department / inpatient triage:

ICU triggers: respiratory failure (rare post-acute), massive PE, decompensated RV failure from CTEPH, fulminant myocarditis.

Specialty consultation thresholds:

Key Differentials — Same-Category Post-Infectious Syndromes

— Diagnostic overlap is large — many Long COVID patients meet IOM/NASEM ME/CFS criteria (substantial functional reduction ≥6 months, PEM, unrefreshing sleep, plus cognitive impairment or orthostatic intolerance).

— Management principles (pacing, avoidance of GET) are the same.

— Long COVID may be the most common cause of new ME/CFS today.

Key distinction: MIS-C/MIS-A is acute, febrile, inflammatory, and time-limited (2–6 weeks post-infection), requiring hospitalization and immunomodulation. Long COVID is chronic (≥3 months), typically afebrile, and managed outpatient with phenotype-directed care. Mixing these up is a classic Step 3 distractor.

Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS):

Post-treatment Lyme disease syndrome (PTLDS): persistent fatigue, cognitive symptoms, arthralgia after treated Lyme; serology distinguishes.

Post-Ebola syndrome, post-dengue, post-mononucleosis (EBV) fatigue: similar phenotypes; EBV reactivation often coexists with Long COVID.

Post-acute sepsis syndrome (PICS): ICU survivors with cognitive, physical, and psychiatric impairment — overlaps with severe-acute Long COVID; rehab approach similar.

MIS-A / MIS-C: acute hyperinflammatory syndromes 2–6 weeks after infection — fever, multiorgan involvement, elevated inflammatory markers — these are acute, not chronic; require IVIG and steroids.

Vaccine-associated postacute syndromes ("post-vaccine syndrome"): reported but rare; symptomatology overlaps; ongoing NIH research. Approach diagnostically the same as Long COVID.

Reinfection: new acute symptoms in a Long COVID patient may represent a fresh COVID infection (or other viral illness) layered on top — test, don't assume relapse.

Key Differentials — Other-Category Mimics to Exclude

— Hypothyroidism — fatigue, cognitive slowing, weight gain — check TSH.

— Adrenal insufficiency — fatigue, orthostasis, hyperpigmentation — morning cortisol.

— Diabetes (new-onset post-COVID) — fatigue, polyuria — HbA1c.

Step 3 management: Before finalizing a Long COVID diagnosis, document explicit exclusion of TSH, CBC, HbA1c, depression screen, and OSA screen at minimum. Missing OSA is the most common reversible diagnosis hiding under a Long COVID label.

Endocrine:

Hematologic: anemia (iron, B12, folate), occult malignancy.

Sleep: OSA — often unmasked or worsened post-COVID; major reversible cause of fatigue, cognitive symptoms, headache, HTN, palpitations. Low threshold for sleep study, particularly in middle-aged men, postmenopausal women, obese patients.

Cardiopulmonary primary disease: undiagnosed HFpEF, asthma, COPD, pulmonary hypertension, valvular disease.

Rheumatologic: new SLE, RA, Sjögren, fibromyalgia, polymyalgia rheumatica (elderly + high ESR).

Infectious: HIV, hepatitis C, syphilis (neuro), tuberculosis, parasitic — risk-factor based.

Neurologic: MS, normal-pressure hydrocephalus (elderly triad), idiopathic intracranial hypertension (young women with headache + visual symptoms).

Psychiatric: major depression, generalized anxiety, PTSD, somatic symptom disorder — coexist commonly but should not be invoked to dismiss organic workup.

Toxic/medication: beta-blocker fatigue, statin myopathy, anticholinergic cognitive impairment, chronic alcohol use, cannabis.

Functional: dysfunctional breathing pattern (frequent post-COVID — sighing, upper-chest breathing), benign hypermobility-related dysautonomia (hEDS), POTS preceding COVID.

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Vaccination — every dose reduces Long COVID risk by ~15–50%; maintain age-appropriate boosters per ACIP.

— During acute infection: nirmatrelvir/ritonavir in eligible high-risk adults reduces Long COVID incidence in observational data.

— Some observational data suggest metformin during acute infection reduces Long COVID — not yet guideline-endorsed.

— Avoid premature return to strenuous exertion during acute infection (esp. athletes) — possible link to PEM phenotype.

— Aggressive cardiovascular risk modification: BP <130/80, LDL goals per ASCVD risk, HbA1c <7%, smoking cessation.

— Updated COVID booster + annual influenza + pneumococcal + RSV per age/risk.

— Reinfection avoidance counseling: masking in high-risk settings, ventilation, early testing — reinfection can worsen Long COVID.

— VTE prophylaxis during future hospitalizations, surgeries.

— Continue inhaled corticosteroids/bronchodilators only if indicated; deprescribe steroids and antibiotics started empirically.

— Statin and antihypertensive review.

— Anticoagulation duration per VTE guidelines.

— Written care plan with phenotype, active medications, pacing instructions, red flags.

— Disability paperwork — neuropsych testing, CPET, and functional capacity evaluation support claims.

— Vocational rehabilitation referral; school accommodations for students.

— Insurance navigation and patient advocacy resources.

Board pearl: Vaccination remains the single most effective Long COVID prevention strategy — exam answers favoring "update COVID booster" in eligible patients are usually correct.

Primary prevention of Long COVID:

Secondary prevention in established Long COVID:

Discharge medication review after acute hospitalization:

Long-term plan:

Follow-Up, Monitoring Parameters, and Rehab Counseling

— Initial post-acute check-in at 4–12 weeks; if symptomatic, evaluate per phenotype.

— Established Long COVID: every 4–8 weeks until stable, then every 3 months.

— Annual visit minimum once stabilized, with ongoing cardiometabolic surveillance.

— Symptom tracking: validated scales — PROMIS-29, EQ-5D-5L, DePaul PEM, COMPASS-31 (autonomic), Chalder Fatigue Scale.

— Orthostatic vitals at each visit.

— HbA1c, lipids, BP, weight, depression screen every 6–12 months.

— Repeat PFTs/DLCO at 6 and 12 months if abnormal at baseline.

— Repeat echo at 6–12 months if myocarditis or RV dysfunction.

— PEM-positive patients: strict pacing, "stop before you crash," heart-rate–limited activity (HR <60% of max), prolonged rest periods, energy budgeting tools.

— PEM-negative deconditioning: structured cardiopulmonary rehab — start low intensity, increase by ~10%/week, monitor HR/SpO2.

— POTS rehab: Levine protocol (recumbent exercise — rower, recumbent bike, swimming) progressing slowly to upright; combine with leg strengthening.

— Breathing retraining for dysfunctional breathing.

— Cognitive rehab: brief structured sessions, scheduled rest, pomodoro technique, environmental modifications.

— Olfactory training for anosmia: 4 odors × 2×/day × 12+ weeks.

— Validate illness; set expectations — many improve over 6–18 months, some persist longer.

— Sleep, nutrition, hydration, sodium, alcohol/caffeine modulation.

— Support groups, mental health resources.

Step 3 management: Build follow-up around functional outcomes (work hours tolerated, ADL independence, scale scores), not just symptom counts — this drives both clinical decisions and disability documentation.

Visit cadence:

Monitoring parameters:

Rehabilitation principles:

Patient counseling:

Ethical, Legal, and Patient Safety Considerations

— Dismissive language ("it's just anxiety," "you look fine") causes documented patient harm and delays diagnosis.

— Implicit bias: women, minorities, and patients with prior psychiatric history are disproportionately under-diagnosed — be explicit about objective findings.

— Long COVID patients are vulnerable to predatory clinics offering apheresis, stem cells, HBOT, ozone, IV chelation at high out-of-pocket cost.

— Ethical duty: provide balanced evidence review, document the conversation, offer trial enrollment alternatives (RECOVER), and screen for financial harm.

— Provide accurate, evidence-based documentation; do not under- or over-state impairment.

— Long COVID is recognized as a disability under the ADA when it substantially limits major life activities — patients have legal protections including reasonable accommodations.

— Healthcare workers and first responders may qualify for occupational claims; document exposure history.

— Post-ICU/post-hospitalization patients need a scheduled 1–2 week PCP follow-up with medication reconciliation, anticoagulation continuation review, and screening for new diabetes, AKI sequelae, and PICS.

— Use a structured discharge summary including pending labs, follow-up imaging (e.g., repeat CT for residual pneumonia), and specialty referrals.

Board pearl: A patient with cognitive Long COVID continues to drive a commercial vehicle. Step 3 obligation: counsel on driving safety, document the discussion, perform neurocognitive testing, and follow state-specific reporting laws (some require physician reporting of cognitively impaired drivers).

Validating an "invisible" illness:

Informed consent and unproven therapies:

Disability and workers' compensation:

Transitions of care (Step 3 favorite):

Vaccination ethics: respect autonomy; provide balanced counseling about benefits and the small risk of post-vaccine symptom flare.

Confidentiality and reporting: standard rules apply; no mandatory reporting for Long COVID itself, but mandatory reporting if suicidality or driving impairment from cognitive dysfunction (varies by state).

Research participation: offer enrollment in NIH RECOVER or local registries — equitable access is an ethical imperative.

High-Yield Associations and Rapid-Fire Clinical Facts

Key distinction: Deconditioning improves with graded exercise; PEM-positive Long COVID worsens with it — always screen for PEM first.

Long COVID definition: symptoms ≥3 months post-infection, lasting ≥2 months, not otherwise explained.

~6–10% of adults post-infection; women > men; risk falls with each vaccine dose.

PEM = hallmark of ME/CFS-like phenotype; avoid graded exercise in these patients.

POTS criteria: HR rise ≥30 bpm (≥40 in adolescents) within 10 min standing, without OH.

Office 10-min stand test is mandatory at the first Long COVID visit.

Reduced DLCO is the most common PFT abnormality post-COVID.

CPET finding in Long COVID: impaired peripheral O2 extraction, ventilatory inefficiency (high VE/VCO2).

12-month post-COVID cardiovascular risk is elevated (MI, stroke, HF, VTE, arrhythmia) even in nonhospitalized patients.

New-onset diabetes incidence rises after COVID — screen HbA1c at 3 and 12 months.

MIS-C ≠ Long COVID — MIS-C is acute, febrile, multisystem inflammatory, 2–6 weeks post-infection.

Vaccination reduces Long COVID risk by ~15–50% per dose.

Nirmatrelvir/ritonavir in acute illness lowers Long COVID risk in high-risk adults — but is not approved or proven for treating established Long COVID.

Anosmia/parosmia treatment: structured olfactory training (4 odors, 2×/day, ≥12 weeks).

POTS first-line meds: propranolol, ivabradine; midodrine and fludrocortisone for hypotensive subtypes.

Sodium 8–10 g/day + fluids 2–3 L/day + compression stockings for orthostatic intolerance (if no HF/CKD/HTN contraindication).

Long COVID is an ADA-protected disability when it substantially limits major life activities.

EBV reactivation frequently co-occurs and may amplify symptoms.

Drug sensitivity is common — start half-dose, titrate slowly.

Avoid: ivermectin, hydroxychloroquine, empiric anticoagulation, apheresis "blood washing," high-dose benzos.

Board Question Stem Patterns

Step 3 management: The recurring correct-answer themes are phenotype-directed therapy, PEM-aware rehab, cardiometabolic surveillance, vaccination, and avoidance of unproven treatments.

Stem 1 — POTS phenotype: A 28-year-old woman has 5 months of palpitations and lightheadedness since mild COVID. Supine HR 72, standing HR 118 at 8 min, BP unchanged. ECG, echo, TSH normal. Best next step: increase salt and fluids, compression stockings, low-dose propranolol or ivabradine — not SSRI, not anxiolytic.

Stem 2 — PEM-positive ME/CFS-like: A 45-year-old has 8 months of profound fatigue, post-exertional worsening 24–48 hours after light walking. Best management: pacing/energy envelope — not graded exercise therapy. GET is a distractor.

Stem 3 — Post-COVID dyspnea with reduced DLCO and elevated D-dimer: Order V/Q scan or CTPA + echo to evaluate CTEPH.

Stem 4 — Adolescent with fever, rash, conjunctivitis, shock 4 weeks post-COVID: This is MIS-C, not Long COVID — admit, IVIG + glucocorticoids, echo for coronary aneurysms.

Stem 5 — Patient asks about "blood washing" apheresis abroad: Counsel against unproven therapies, offer RECOVER trial enrollment, screen for financial harm — best answer is evidence-based shared decision-making.

Stem 6 — Older patient with new "brain fog" 6 months post-COVID: Before labeling Long COVID, screen TSH, B12, depression, OSA, polypharmacy; obtain neurocognitive testing — reversible mimics first.

Stem 7 — Hospitalized COVID survivor at 3-month follow-up: Order HbA1c, lipids, BP, depression screen, PFTs/DLCO, repeat imaging if prior abnormality — cardiometabolic surveillance is high yield.

Stem 8 — Pregnant patient with persistent post-COVID symptoms: Continue vaccination, use safe meds (acetaminophen, low-dose propranolol), avoid ivabradine and fludrocortisone unless essential.

Stem 9 — Healthcare worker with disabling Long COVID: Document occupational exposure, support workers' comp claim, recognize ADA protections.

Stem 10 — Acute chest pain + troponin rise post-COVID in young athlete: Evaluate for myocarditis — cardiac MRI, exercise restriction 3–6 months.

One-Line Recap

Long COVID is a heterogeneous post-acute condition defined by symptoms persisting ≥3 months after SARS-CoV-2 infection that requires phenotype-directed, multidisciplinary, exclusion-based management built on validation, pacing or appropriate rehab, vaccination, treatment of orthostatic and cognitive symptoms, and aggressive cardiometabolic risk surveillance.

Board pearl: When in doubt on Step 3, the correct answer pairs validation + structured workup to exclude mimics + phenotype-specific therapy + booster vaccination + multidisciplinary follow-up — and never includes ivermectin, empiric anticoagulation, or graded exercise in a PEM-positive patient.

Diagnosis: clinical, inclusion + exclusion — rule out OSA, thyroid disease, anemia, diabetes, depression, and cardiopulmonary disease before labeling.

Phenotype first: identify ME/CFS-like (PEM-positive), POTS/dysautonomia, cardiopulmonary, cognitive, anosmia, or mixed — management diverges sharply, especially around exercise vs. pacing.

Treat what's treatable: POTS → volume/salt/compression + propranolol or ivabradine; anosmia → olfactory training; deconditioning → graded rehab; PEM → strict pacing and energy envelope.

Prevent and protect: vaccinate, treat acute infection with nirmatrelvir/ritonavir in eligible patients, monitor for new diabetes, hypertension, dyslipidemia, VTE, and CV events at 3- and 12-month visits, and avoid unproven therapies.