What is the initial workup for a patient presenting with night sweats?

Initial Workup for Night Sweats

The initial workup for night sweats should include a complete blood count (CBC), thyroid-stimulating hormone (TSH), erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP), HIV testing, tuberculosis testing (PPD or interferon-gamma release assay), and chest radiography. 1

Comprehensive History Taking

When evaluating a patient with night sweats, focus on:

• Sleep pattern assessment:

  • Frequency and severity of night sweats
  • Association with other sleep disturbances
  • Use of the Epworth Sleepiness Scale to assess daytime sleepiness 1

• Medical conditions screening:

  • Infectious diseases: TB, HIV, fungal infections
  • Endocrine disorders: hyperthyroidism, diabetes
  • Malignancies: lymphoma, other cancers
  • Cardiovascular conditions: heart failure
  • Respiratory disorders: sleep apnea, COPD, asthma
  • Gastrointestinal issues: GERD, inflammatory bowel disease 1, 2

• Medication and substance use:

  • Antidepressants (SSRIs, SNRIs, MAOIs)
  • Cardiovascular drugs (beta-blockers, diuretics)
  • Stimulants and decongestants
  • Alcohol, caffeine, and nicotine 1

Physical Examination

Key elements to assess:

• Vital signs with attention to fever and hypertension
• Lymph node examination for lymphadenopathy
• Thyroid examination for enlargement or nodules
• Cardiopulmonary examination for signs of heart failure or respiratory disease
• Assessment for peripheral edema 3

Laboratory and Diagnostic Testing Algorithm

First-line testing:

1. Complete blood count (CBC) - to screen for infections, anemia, and hematologic malignancies
2. Thyroid-stimulating hormone (TSH) - to evaluate for hyperthyroidism
3. ESR or CRP - to assess for inflammatory conditions
4. HIV testing - especially in at-risk populations
5. Tuberculosis testing (PPD or interferon-gamma release assay) - particularly important in high-risk individuals
6. Chest radiography - to evaluate for pulmonary conditions, including TB and malignancy 1, 2, 4

Second-line testing (based on clinical suspicion):

• CT of chest and/or abdomen - if malignancy or infection is suspected
• Polysomnography - if sleep apnea is suspected
• Bone marrow biopsy - if hematologic malignancy is suspected
• Additional laboratory studies:
  • Ferritin levels - if restless legs syndrome is suspected (values <45-50 ng/mL indicate a treatable cause) 1
  • Electrolytes/renal function - to identify renal or endocrine disease 3
  • Urine albumin:creatinine ratio - potential indicator of chronic kidney disease 3

Common Pitfalls to Avoid

1. Overlooking medication effects - many medications can cause night sweats, including antidepressants, antihypertensives, and antipyretics 1

2. Focusing only on serious causes - while TB and lymphoma are classic causes of night sweats, most patients in primary care settings with night sweats do not have a serious underlying disorder 2

3. Missing common conditions - menopause, mood disorders, GERD, hyperthyroidism, and obesity are commonly associated with night sweats 2

4. Neglecting sleep disorders - conditions like obstructive sleep apnea can present with night sweats 1, 4

5. Failing to consider pulmonary embolism - though uncommon, PE can present with night sweats, especially post-surgery 5

If initial workup is negative and symptoms persist, consider referral to a sleep specialist, especially if the Epworth Sleepiness Scale score is ≥11, indicating high risk for sleep disorders 1.