What are the causes and treatment options for night sweats?

Night Sweats: Causes and Treatment

Initial Diagnostic Approach

Begin by ruling out serious underlying conditions through targeted history and basic investigations, then proceed to symptomatic management based on the most likely etiology. 1, 2

Key Historical Features to Elicit

• Duration and pattern: Episodic vs. persistent, frequency per week 2
• Associated symptoms: Weight loss >10%, fever, cough >2 weeks, hemoptysis, lymphadenopathy 3
• Medication review: Antihypertensives, antipyretics, SSRIs, alcohol, heroin 4
• Menopausal status: Age, last menstrual period, other vasomotor symptoms 1
• Risk factors: TB exposure, HIV risk, travel to endemic areas, immunosuppression 3

Essential Initial Investigations

Order these tests for all patients with persistent night sweats of unclear etiology: 4, 2

• Complete blood count with differential 3, 2
• Thyroid-stimulating hormone 1, 2
• Fasting glucose 1
• HIV testing 4, 2
• Tuberculosis testing (PPD or interferon-gamma release assay) 4, 2
• C-reactive protein or ESR 3, 2
• Chest radiograph 3, 2

Major Causes by Category

Infectious Causes

Tuberculosis remains a critical diagnosis not to miss, particularly in high-risk populations. 3

• TB screening threshold: Cough >2 weeks with fever, night sweats, hemoptysis, and/or weight loss warrants immediate investigation 3
• High-risk populations: HIV-positive patients, recent immigrants, homeless, incarcerated 3
• Diagnostic approach: XpertMTB/RIF testing preferred over sputum microscopy when available; chest x-ray should be performed 3

Other infectious considerations: 3

• HIV infection (obtain HIV test in all cases) 4, 2
• Endemic mycoses (histoplasmosis, coccidioidomycosis, blastomycosis) in patients with travel to endemic areas 3
• Lymphatic filariasis presenting with tropical pulmonary eosinophilia 3

Malignancies

Lymphoma is the classic malignancy associated with night sweats, but represents only ~2% of cases in primary care. 3, 4

• Hodgkin lymphoma: Night sweats with weight loss, fever, and lymphadenopathy 3
• Polycythemia vera: Consider when elevated hemoglobin/hematocrit with night sweats; check JAK2 V617F mutation 3
• Cutaneous T-cell lymphoma: May present with pruritus and erythroderma 3
• Evaluation: If lymphadenopathy present, refer for excision or ultrasound-guided core biopsy 3

Hormonal/Metabolic Causes

Menopausal vasomotor symptoms are the most common hormonal cause in postmenopausal women. 1, 5

• Hyperthyroidism: Check TSH in all patients 1, 2, 5
• Hypoglycemia: Check fasting glucose, particularly in diabetics on insulin or sulfonylureas 1, 4
• Male hypogonadism: Rare cause; must be associated with sexual dysfunction and low morning testosterone 5

Other Common Causes

• Gastroesophageal reflux disease 4, 2
• Obstructive sleep apnea (consider polysomnography if suspected) 4, 2
• Mood disorders (anxiety, panic attacks) 2, 5
• Medications: SSRIs, antihypertensives, antipyretics 4
• Obesity 2

Treatment Approach

For Menopausal Vasomotor Symptoms

Start with venlafaxine 37.5-75 mg daily (extended-release) as first-line therapy due to its rapid onset and 40-65% reduction in hot flash frequency. 1, 6

Alternative first-line options: 1, 6

• Paroxetine (controlled-release) 7.5-12.5 mg daily (avoid if taking tamoxifen due to CYP2D6 inhibition) 1
• Gabapentin 300-900 mg daily, particularly useful for sleep-disrupting night sweats 1

Treatment algorithm: 1

1. Rule out secondary causes (thyroid disease, diabetes) 1
2. Start venlafaxine or gabapentin 1
3. Titrate dose after 1-2 weeks 1
4. Reassess at 4-6 weeks 1
5. If inadequate response, switch to alternative non-hormonal agent or consider acupuncture 1, 6

Hormone therapy considerations: 1

• Generally contraindicated at age 74 and in patients with history of breast cancer, endometrial cancer, venous thromboembolism, stroke, coronary heart disease, or active liver disease 1
• Not recommended for prevention of chronic conditions due to increased cardiovascular and dementia risk 1

Non-pharmacologic interventions: 1, 6

• Acupuncture (equivalent or better efficacy compared to venlafaxine or gabapentin in some studies) 1
• Cognitive behavioral therapy 1, 6
• Weight loss if overweight (≥10% may eliminate symptoms) 1, 6
• Smoking cessation 1, 6
• Avoid triggers: hot beverages, spicy foods, alcohol, warm environments 1, 6

For Medication-Induced Night Sweats

Alpha-adrenergic blockers may reduce night sweats in patients taking serotonin reuptake inhibitors. 7

For Terminal Cancer Patients

Thalidomide and thioridazine may benefit some terminal cancer patients with night sweats. 7

When to Pursue Advanced Testing

If initial workup is negative and symptoms persist, consider: 2

• CT chest and/or abdomen 2
• Bone marrow biopsy (if hematologic malignancy suspected) 3, 2
• Polysomnography (if sleep apnea suspected) 2

Prognosis

Reassuringly, the presence of night sweats alone does not indicate increased risk of death in primary care patients. 7, 2 Life expectancy appears normal when serious underlying conditions are excluded 7. If all investigations are normal and no additional disorders are suspected, reassurance and continued monitoring are appropriate 2.