Night sweats

Infectious Causes

Tuberculosis: Common cause of night sweats, especially in patients with a history of travel to endemic areas, chronic cough, haemoptysis, and weight loss.
Endocarditis: Associated with night sweats, fever, and a new heart murmur; consider in patients with a history of valve disease, intravenous drug use, or prosthetic valves.
HIV/AIDS: Presents with night sweats, weight loss, and opportunistic infections; consider in patients with risk factors such as unprotected sex or intravenous drug use.
Malaria: Associated with cyclic fevers, night sweats, and history of travel to endemic regions; presents with chills, headache, and splenomegaly.
Abscesses: Deep-seated infections like liver or lung abscesses can cause night sweats, fever, and localised pain.

Malignancies

Lymphoma: Both Hodgkin and non-Hodgkin lymphomas commonly present with night sweats, unexplained weight loss, and lymphadenopathy.
Leukaemia: Can present with night sweats, fatigue, frequent infections, and easy bruising or bleeding; often associated with pancytopenia on blood tests.
Solid Tumours: Advanced malignancies (e.g., renal cell carcinoma, gastrointestinal malignancies) may cause night sweats, particularly if there is metastatic disease.
Carcinoid Syndrome: Rare cause of night sweats associated with flushing, diarrhoea, and bronchospasm; typically seen with neuroendocrine tumours.

Endocrine Causes

Hyperthyroidism: Presents with night sweats, heat intolerance, weight loss, and palpitations; often associated with a goitre and ophthalmopathy.
Pheochromocytoma: Rare adrenal tumour causing paroxysms of sweating, palpitations, headache, and hypertension; episodic nature of symptoms is characteristic.
Menopause: Common cause of night sweats in women; associated with hot flashes, mood changes, and irregular menstruation.
Hypoglycaemia: Can cause night sweats, particularly in patients with diabetes on insulin or oral hypoglycaemic agents.
Acromegaly: Excessive growth hormone leads to sweating, enlargement of hands and feet, and characteristic facial features.

Rheumatologic Causes

Giant Cell Arteritis: Presents with night sweats, temporal headaches, jaw claudication, and visual disturbances; often elevated ESR and CRP.
Systemic Lupus Erythematosus (SLE): Autoimmune condition causing night sweats, fever, malar rash, and joint pain; often associated with positive ANA and other autoantibodies.
Rheumatoid Arthritis: Inflammatory arthritis with night sweats, morning stiffness, and joint swelling; extra-articular manifestations can include pleuritis, pericarditis, and vasculitis.
Adult-Onset Still’s Disease: Rare cause of night sweats associated with high spiking fevers, arthritis, and salmon-coloured rash; often elevated ferritin levels.

Symptomatology

Onset and Duration: Sudden onset may suggest an acute infection or malignancy, whereas chronic night sweats could indicate an endocrine or rheumatologic condition.
Associated Symptoms: Consider fever, weight loss, lymphadenopathy, cough, or haemoptysis, which can help narrow down the differential diagnosis.
Pattern and Severity: Determine if the sweats occur at the same time each night or if they vary; profuse sweating that soaks bedding may be more concerning for systemic illness.
Triggers and Relievers: Identify any factors that seem to trigger or relieve the night sweats, such as environmental changes, medications, or stress.
Impact on Daily Life: Assess how the night sweats affect the patient’s sleep quality, energy levels, and overall well-being.

Background

Past Medical History: Review for any history of infections, malignancies, autoimmune disorders, or endocrine conditions.
Drug History: Consider any medications that could contribute to night sweats, such as antidepressants, antipyretics, or hormone replacement therapy.
Family History: Ask about any family history of malignancies, autoimmune diseases, or endocrine disorders that may predispose the patient to similar conditions.
Social History: Assess lifestyle factors such as smoking, alcohol use, and occupational exposures that could contribute to underlying conditions.
Travel History: Recent travel to areas endemic with malaria, tuberculosis, or other infections may provide important diagnostic clues.

Laboratory Tests

Full Blood Count: To assess for anaemia, leukocytosis, or pancytopenia, which may suggest infection or malignancy.
Inflammatory Markers: Elevated ESR and CRP may indicate an underlying inflammatory or infectious process.
Blood Cultures: Indicated if there is suspicion of bacteraemia, endocarditis, or other systemic infections.
Thyroid Function Tests: Useful in diagnosing hyperthyroidism, which can cause night sweats.
HIV Test: Consider in patients with risk factors or symptoms suggestive of HIV infection.
Autoantibody Screen: ANA, RF, and other relevant autoantibodies may be indicated if an autoimmune condition is suspected.
Malaria Screen: Blood film or rapid diagnostic test if malaria is suspected based on travel history.

Imaging and Specialist Tests

Chest X-ray: First-line imaging to assess for tuberculosis, lymphoma, or other thoracic pathology.
CT Scan: Consider if malignancy is suspected, particularly if there is lymphadenopathy or organomegaly.
Echocardiogram: Indicated if infective endocarditis is suspected based on clinical findings and blood cultures.
Ultrasound: Abdominal ultrasound may be useful in assessing for abscesses, hepatosplenomegaly, or renal pathology contributing to night sweats.
Bone Marrow Biopsy: Consider if there is suspicion of haematologic malignancy or unexplained cytopenias.

Endocrine & metabolic