What are the possible causes of night sweats in individuals, considering factors such as hormonal changes, infections, medications, and underlying medical conditions like cancer, tuberculosis, and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS)?

Causes of Night Sweats

Night sweats have numerous potential causes ranging from benign conditions like menopause and gastroesophageal reflux to life-threatening diseases like tuberculosis and lymphoma, though serious causes are infrequently found in modern primary care practice. 1, 2

Infectious Causes

Tuberculosis

• Classic presentation includes persistent cough (>2-3 weeks), fever, night sweats (present in 35% of cases), and weight loss (25%) 3, 4
• Maintain high suspicion in patients with risk factors: HIV infection, immigration from high-prevalence areas, homelessness, previous incarceration, or known TB exposure 4
• Night sweats occur alongside other constitutional symptoms rather than in isolation 3

HIV/AIDS and Opportunistic Infections

• Disseminated nontuberculous mycobacterial (NTM) disease in AIDS patients presents with fever (80%), night sweats (35%), and weight loss (25%) 3
• Occurs only in severely immunocompromised patients with CD4 counts <50 cells/μL, typically <25 cells/μL 3
• Consider HIV testing as part of the diagnostic workup for unexplained night sweats 1, 2

Other Infections

• Various infectious processes can cause night sweats, though specific pathogens are less commonly identified in primary care 1, 2

Endocrine and Hormonal Causes

Menopause and Hormonal Changes

• Menopause is the most frequent hormonal cause of excessive sweating and night sweats 5
• Obtain menstrual history in women of relevant age as part of the review of systems 6
• Pregnancy can cause night sweats in approximately 60% of women 7

Thyroid Disorders

• Hyperthyroidism is a common hormonal cause of excessive sweating 1, 2, 5
• Both overactive and profoundly underactive thyroid can contribute to night sweats 3
• Obtain thyroid-stimulating hormone (TSH) testing in the diagnostic workup 1, 2

Other Endocrine Disorders

• Hypoglycemia can cause night sweats 1
• Diabetes insipidus may present with night sweats 3
• Testosterone deficiency in males (though rare) can cause excessive sweating when associated with sexual problems and low morning testosterone 5

Cardiovascular and Renal Causes

Heart Failure

• Congestive heart failure (CHF) is associated with night sweats 3
• Look for accompanying symptoms: ankle swelling, shortness of breath on exertion, orthopnea 3

Hypertension

• Hypertension itself can be associated with night sweats 3

Chronic Kidney Disease

• CKD can cause night sweats and xerostomia (dry mouth) leading to increased fluid intake 3

Gastrointestinal Causes

Gastroesophageal Reflux Disease (GERD)

• GERD is a commonly associated condition with night sweats in primary care 1, 2
• Two case reports demonstrated excellent response to anti-reflux treatment in patients with night sweats after excluding systemic diseases 7
• Consider a therapeutic trial of GERD treatment for 4-8 weeks when clinical diagnosis is apparent 2

Sleep Disorders

Obstructive Sleep Apnea (OSA)

• OSA increases arousals and light sleep, raising the likelihood of waking and subsequent sweating 8
• Screen with specific questions: gasping/stopping breathing at night, daytime sleepiness, non-refreshing sleep 3, 8
• Consider OSA in patients with night sweats who don't respond to conventional treatments 8

Other Sleep Disorders

• Insomnia, restless legs syndrome (RLS), periodic limb movements of sleep (PLMS), and parasomnias can all contribute 3

Psychiatric Causes

Mood Disorders

• Depression and anxiety are commonly associated with night sweats 2
• Panic attacks should be considered, especially when night sweats are the presenting symptom 5, 7
• Depression screening should be performed as part of the psychiatric assessment 6

Malignancies

Lymphoma and Other Cancers

• Lymphoma is a disease where night sweats are a dominant symptom, though infrequently found in modern practice 1
• Cancer remains an important diagnostic consideration despite low prevalence 1, 2
• Consider chest and abdominal CT scans and bone marrow biopsy if initial workup is unrevealing and suspicion remains high 1, 2

Medication-Related Causes

Common Culprits

• Antihypertensives (especially calcium channel blockers) can cause night sweats 3
• Antipyretics may paradoxically cause night sweats 1
• SSRIs and SNRIs used for depression can cause or exacerbate night sweats 3
• Alpha-adrenergic blockers may reduce night sweats in patients taking serotonin reuptake inhibitors 9

Other Medications

• Corticosteroids, bronchodilators, decongestants, diuretics 3
• Lithium and NSAIDs 3
• Over-the-counter preparations containing pseudoephedrine, phenylpropanolamine, or caffeine 3

Substances of Abuse

• Alcohol and heroin can cause night sweats 1
• Nicotine (cigarettes, gum, transdermal patches) can impair sleep and cause sweating 3

Neurological Causes

Various Neurological Diseases

• Most neurological diseases are potentially relevant to night sweats 3
• Assess for problems controlling legs, slowness of movement, tremor in hands 3

Autoimmune and Inflammatory Conditions

Autoimmune Diseases

• Autoimmune diseases affecting salivary glands can cause xerostomia, prompting increased fluid intake and subsequent night sweats 3
• Obtain erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) if inflammatory conditions are suspected 1, 2

Diagnostic Approach

Initial Evaluation

• Obtain thorough history focusing on: duration, severity, associated symptoms (fever, weight loss, cough), medication review, and risk factors 6, 1, 2
• Perform focused physical examination looking for: lymphadenopathy, reduced salivation, peripheral edema, neurological abnormalities 3, 6

First-Line Laboratory Testing

• Complete blood count (CBC), tuberculosis testing (PPD or IGRA), TSH, HIV test, ESR or CRP, chest radiograph 1, 2
• Additional baseline tests: electrolytes/renal function, calcium, HbA1c, urine dipstick 3

When Initial Workup is Negative

• If clinical diagnosis is apparent, offer specific treatment for 4-8 weeks 2
• If no diagnosis is apparent after initial workup, consider: chest/abdominal CT, bone marrow biopsy, polysomnography 1, 2
• If all testing is normal and no additional disorders are suspected, provide reassurance and continued monitoring—the presence of night sweats alone does not indicate increased risk of death 2, 9

Clinical Pitfalls

• Most patients reporting persistent night sweats in primary care do not have a serious underlying disorder 2
• Night sweats are nonspecific and prevalence ranges from 10% in older primary care patients to 60% in obstetric inpatients 9
• Life expectancy of primary care patients reporting night sweats does not appear to be reduced 9
• Many patients experience night sweats but rarely discuss them without prompting 2, 5