Approach to Common Symptoms (Fever, Pain, Fatigue)

Fever - Burning Questions

• Definition: Core body temp > 38.3°C (101°F) or sustained > 38°C (100.4°F) over 1 hour.
• Mechanism: Pyrogens (exogenous/endogenous) → Hypothalamic PGE2 ↑ → ↑ thermoregulatory set point.
• Key Patterns (Clinical clues, not diagnostic):
  • Continuous: Typhoid, lobar pneumonia. Fluctuates < 1°C/24h.
  • Remittent: Infective endocarditis. Fluctuates > 1°C/24h, always above normal.
  • Intermittent: Malaria, pyemia. Fever spikes with return to normal.
  • Pel-Ebstein: Hodgkin's lymphoma. Cyclical fever for days/weeks.
• Fever of Unknown Origin (FUO): Temp > 38.3°C for ≥ 3 weeks; no diagnosis after 1 week inpatient workup (classic definition).
  • Common causes: Infections (e.g., TB, endocarditis), Malignancies (e.g., lymphoma), Autoimmune (e.g., Still's disease).
  • Other types: Nosocomial, Neutropenic (ANC < 500/µL), HIV-associated.
• Initial Workup Approach:

• Red Flags: Immunocompromise, new cardiac murmur, petechiae/purpura, altered sensorium, severe headache.

⭐ Pel-Ebstein fever, a cyclical pattern of fever lasting for days to weeks followed by afebrile periods, is classically associated with Hodgkin's lymphoma.

Pain - Agony Aunt

Pain: Unpleasant sensory & emotional experience associated with actual or potential tissue damage. Often considered the fifth vital sign.

• Assessment: 📌 SOCRATES

  • Site: Where? Localized/diffuse?
  • Onset: When? Sudden/gradual?
  • Character: What type? (e.g., Sharp, dull, burning, throbbing)
  • Radiation: Does it spread?
  • Associated symptoms: Nausea, vomiting, fever, neurological deficits?
  • Timing/Duration: Constant/intermittent? Pattern?
  • Exacerbating/Relieving factors: What makes it better/worse?
  • Severity: Pain scales (e.g., Visual Analog Scale 0-10, Numeric Rating Scale 0-10, Wong-Baker FACES for children).

• Types of Pain:

  • Nociceptive: Due to tissue injury.
    • Somatic: Musculoskeletal (well-localized, aching, throbbing).
    • Visceral: Internal organs (poorly localized, deep, cramping, squeezing).
  • Neuropathic: Due to nerve lesion/dysfunction (burning, tingling, shooting, electric shock-like).
  • Nociplastic: Altered nociception without clear evidence of actual or threatened tissue damage (e.g., fibromyalgia).

• Management Principles (WHO Analgesic Ladder):

  • Step 1: Non-opioid (e.g., Paracetamol, NSAIDs) ± Adjuvant.
  • Step 2: Weak opioid (e.g., Codeine, Tramadol) ± Non-opioid ± Adjuvant.
  • Step 3: Strong opioid (e.g., Morphine, Fentanyl) ± Non-opioid ± Adjuvant.
  • Address underlying cause; consider non-pharmacological therapies (physio, TENS, CBT).

⭐ Neuropathic pain often responds poorly to traditional analgesics but may improve with anticonvulsants (e.g., gabapentin, pregabalin) or tricyclic antidepressants (e.g., amitriptyline).

Fatigue - Energy Crisis

• Definition: Subjective lack of physical and/or mental energy, distinct from weakness or somnolence.
• Duration Criteria:
  • Acute: < 1 month
  • Chronic: > 6 months (significant impact on daily life)
• Etiology: Broad differential.
  • Medical: Anemia, hypothyroidism, Diabetes Mellitus, infections (e.g., TB, HIV, EBV), malignancy, autoimmune (SLE, RA), cardiac/pulmonary/renal insufficiency.
  • Psychiatric: Depression, anxiety disorders.
  • Lifestyle/Medications: Poor sleep, deconditioning, stress, alcohol/substance abuse, beta-blockers, antihistamines.
  • Chronic Fatigue Syndrome (CFS/ME).
• Red Flags: Unexplained weight loss (>5% body weight), persistent fever (>38.3°C), generalized lymphadenopathy (>2cm), focal neurological signs, unexplained bleeding, drenching night sweats.
• Initial Workup: Detailed history (including psychosocial), physical exam, CBC with differential, ESR/CRP, TSH, random blood sugar, electrolytes, LFTs, RFTs, urinalysis. Consider HIV, CXR based on risk factors/symptoms.

⭐ A hallmark of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is post-exertional malaise (PEM), where symptoms worsen significantly after minimal physical or mental exertion, typically lasting >24 hours and being disproportionate to the activity.

High‑Yield Points - ⚡ Biggest Takeaways

• Fever of Unknown Origin (FUO): Temperature >38.3°C for >3 weeks, undiagnosed after 1 week of inpatient evaluation.
• Pain Assessment: Systematically use OPQRST (Onset, Palliative/Provocative, Quality, Radiation, Severity, Timing) or SOCRATES for comprehensive characterization.
• Fatigue Red Flags: Unexplained weight loss, lymphadenopathy, and focal neurological deficits warrant urgent investigation.
• Drug Fever: Often presents with rash and eosinophilia; common culprits include beta-lactams and sulfonamides.
• Key Fever Patterns: Continuous (typhoid), intermittent (malaria), Pel-Ebstein (Hodgkin's lymphoma) are diagnostically crucial.