Causes of Acute Night Sweats
Night sweats can be caused by a wide range of conditions, with tuberculosis, lymphoma, and other infections being the most serious underlying causes that require prompt evaluation, particularly when accompanied by other constitutional symptoms.
Common Causes of Night Sweats
Infections
- Tuberculosis: Classic presentation includes night sweats, weight loss, and respiratory symptoms 1
- Q fever: Can present with night sweats in both acute and chronic forms 2
- Fungal infections:
Malignancies
- Lymphoma: Particularly Hodgkin lymphoma with B symptoms (fever, night sweats, weight loss) 1, 3
- Neuroendocrine tumors: Can present with flushing, diarrhoea, and night sweats 2
Endocrine Disorders
- Hyperthyroidism: Common hormonal cause of night sweats 4
- Hypoglycemia: Can cause night sweats, particularly in patients with diabetes or insulinoma 2, 3
- Menopause: One of the most frequent hormonal causes for excessive sweating 4
- Male hypogonadism: Less common cause, usually associated with sexual problems 4
Gastrointestinal Disorders
- Gastroesophageal reflux disease (GERD): Often overlooked cause of night sweats 5, 6
- Inflammatory bowel disease: Night sweats may occur during disease flares 2
Other Medical Conditions
- Obstructive sleep apnea: Associated with night sweats 6
- Chronic inflammatory conditions: Can present with night sweats and elevated inflammatory markers 6
- Post-Q fever fatigue syndrome: Characterized by night sweats, fatigue, and other symptoms that persist beyond a year after acute infection 2
Medications and Substances
- Antihypertensives: Can cause night sweats as a side effect 3
- Antipyretics: Paradoxically may cause night sweats 3
- Serotonin reuptake inhibitors: May cause night sweats that can be treated with alpha-adrenergic blockers 7
- Alcohol and heroin: Drugs of abuse that can cause night sweats 3
Diagnostic Approach
Initial Evaluation
- Complete blood count: To evaluate for infections, malignancies 1, 6
- Tuberculosis testing: PPD or interferon-gamma release assay 1, 6
- Thyroid-stimulating hormone (TSH): To rule out hyperthyroidism 1, 6
- HIV testing: Especially in high-risk populations 1, 6
- Inflammatory markers: ESR or CRP to evaluate for inflammatory conditions 1
- Chest radiography: Particularly important for suspected TB or malignancy 1, 6
Additional Testing (Based on Clinical Suspicion)
- CT scans of chest/abdomen: For suspected malignancy or occult infection 6
- Bone marrow biopsy: If hematologic malignancy is suspected 6
- Polysomnography: For suspected sleep disorders 6
- Echocardiogram: If chronic Q fever endocarditis is suspected 2
Important Clinical Pearls
- Night sweats alone do not indicate an increased risk of death in primary care patients 7, 6
- The prevalence of night sweats ranges from 10% in older primary care patients to 60% in women on obstetrics units 7
- Many patients with night sweats in primary care settings do not have serious underlying disorders 6
- If initial evaluation is negative and symptoms persist, consider less common causes or reassure and monitor 6
- Night sweats in combination with weight loss and fever should raise suspicion for tuberculosis or lymphoma 1, 3
- GERD is an often-overlooked cause of night sweats that responds well to anti-reflux treatment 5
Treatment Approach
Treatment should be directed at the underlying cause:
- Appropriate anti-tuberculosis therapy for TB 1
- Referral to oncology for malignancies 1
- Anti-thyroid medications for hyperthyroidism 1
- Acid suppression for GERD 5
- Alpha-adrenergic blockers may help with night sweats caused by serotonin reuptake inhibitors 7
- Thalidomide or thioridazine may benefit terminal cancer patients with night sweats 7
When no specific cause is identified after thorough evaluation, reassurance and continued monitoring are recommended 6.