What is the workup for night sweats?

Workup for Night Sweats

Begin with thyroid-stimulating hormone (TSH) and free T4 testing, followed by a complete blood count, tuberculosis testing, HIV testing, C-reactive protein, and chest radiography if initial evaluation is unrevealing. 1, 2

Initial Clinical Assessment

Key Historical Features to Elicit

• Menopause status in women, as this is the most common cause of night sweats in older women 3
• Frequency and severity of episodes, including impact on quality of life 3
• Associated symptoms including:
  • Weight loss, fever, or fatigue (suggesting infection or malignancy) 3, 2
  • Cold intolerance, dry skin, constipation, hoarseness (hypothyroidism) 1
  • Heat intolerance, nervousness, tremulousness, insomnia, weight loss, diarrhea (hyperthyroidism) 1
  • Paroxysmal hypertension, headache, palpitations, pallor (pheochromocytoma) 1
  • Prolonged cough with sputum production, hemoptysis (tuberculosis) 4
• Medication review for antihypertensives, antipyretics, serotonin reuptake inhibitors, and drugs of abuse 5
• Risk factors for tuberculosis (immigration from high-prevalence areas, HIV infection, homelessness, incarceration) 4

Physical Examination Findings

• Thyroid examination for goiter, periorbital puffiness, coarse/cold skin, slow movement, delayed ankle reflexes 1
• Lymphadenopathy (suggesting lymphoma) 2, 5
• Cardiovascular and respiratory examination 2

First-Line Laboratory and Imaging Studies

Order these tests systematically if history and physical examination do not reveal a specific diagnosis: 2, 5

1. TSH and free T4 - Primary screening for thyroid dysfunction 1, 2
2. Complete blood count - Evaluate for hematologic malignancies or infection 2, 5
3. Tuberculosis testing (purified protein derivative or interferon-gamma release assay) 2, 5
4. HIV testing 2, 5
5. C-reactive protein - Nonspecific inflammatory marker 2
6. Chest radiography - Screen for tuberculosis, lymphoma, or other pulmonary pathology 2, 5

Second-Line Testing (If Initial Workup Normal)

Consider these studies selectively based on clinical suspicion: 2, 5

• 24-hour urinary fractionated metanephrines or plasma metanephrines if episodic symptoms with hypertension suggest pheochromocytoma 1
• CT chest and/or abdomen if malignancy suspected despite normal chest radiograph 2, 5
• Polysomnography if obstructive sleep apnea suspected (present in 25-50% of cases with night sweats) 1, 2
• Bone marrow biopsy if hematologic malignancy suspected with abnormal CBC 2, 5
• Erythrocyte sedimentation rate for inflammatory or autoimmune conditions 5

Specific Clinical Scenarios

When Thyroid Dysfunction is Suspected

• No additional confirmatory tests needed beyond abnormal TSH and free T4 for diagnosis 1
• Refer to endocrinology if symptoms persist despite normal initial thyroid testing 1

When Menopause is Suspected

• Use standardized scales like the Greene Scale to establish severity 1
• Evaluate contraindications to hormone replacement therapy (breast cancer history, coronary heart disease, venous thromboembolism, stroke, active liver disease) 3
• Consider non-hormonal approaches first in women with contraindications 3

When Tuberculosis is Suspected

• Obtain respiratory cultures via sputum or throat swab if cough present for >2-3 weeks 4
• Classic presentation includes upper lobe infiltrates with cavitation on chest radiograph 4

Management if All Testing is Normal

If comprehensive workup is unrevealing and no additional disorders are suspected: 2, 6

• Provide reassurance - night sweats alone do not indicate increased risk of death 2, 6
• Implement non-pharmacological measures: improve sleep hygiene, avoid triggers, consider relaxation techniques 3
• Continue monitoring with periodic follow-up 2
• Consider trial of specific treatment for 4-8 weeks if clinical diagnosis is suspected despite negative testing 2

Important Caveats

• Most patients in primary care with night sweats do not have serious underlying disorders 2, 6
• Common benign causes include menopause, mood disorders, gastroesophageal reflux disease, hyperthyroidism, and obesity 2
• The combination of night sweats and cold intolerance strongly suggests thyroid dysfunction as the most likely diagnosis 1
• Avoid algorithmic approaches as they are not evidence-based; use clinical judgment 6