Up All Night: An Approach to Fatigue

One day in GIM clinic, I saw a patient who was referred due to severe fatigue, influencing her daily life. She was unable to work, felt fatigued throughout the day, and these symptoms were negatively impacting his quality of life. Her family physician had completed a robust initial work-up, but I thought fatigue was an interesting chief concern, one with a broad differential and worth exploring further.

Fatigue is a common concern in primary care and can have major impacts on the quality of life of our patients. First, it is critical to distinguish fatigue from sleepiness. Fatigue is more likely when a patient describes non-restorative sleep, mental exhaustion, poor muscle endurance and intensified fatigue with activity. An important cause of fatigue to consider is medications, especially sedative-hypnotics, antidepressants, muscle relaxants, opioids, and antihistamines. It is also critical to take a thorough sleep history, identifying sleep hygiene, disrupted sleep (pain, urination, anxiety), daytime sleeping, exercise, and substance use. Depression may manifest as fatigue, so it is crucial to screen for low mood. As well, screening for constitutional symptoms, such as fevers and weight loss, should be included in the initial history.

Initial laboratory investigations are targeted to investigate secondary causes of fatigue (anemia, hypothyroidism, inflammatory state, liver disease, pregnancy, etc.) and should include CBC, lytes, creatinine, and thyroid function tests. In sexually-active women, it would be important to include a b-HCG test. Further investigations which could be considered are ferritin, iron studies, vitamin B12, and folate levels.

Initial bloodwork for this patient did not yield any indication to her profound fatigue. She is an active smoker with a 50-pack year history, so met criteria for CT thorax to investigate for a lung malignancy. Imaging did not reveal any occult malignancy which would explain her fatigue.

In this instance, the patient also reported a history of feeling fatigued upon waking and requiring naps during the day. Her partner also reported that she snored loudly at night. These symptoms prompted a further history, screening for Obstructive Sleep Apnea (OSA) with the STOP-BANG questionnaire:

• Do you Snore loudly (loud enough to be heard through closed doors or your bed-partner elbows you for snoring at night)?
• Do you often feel Tired, Fatigued or Sleepy during the daytime (such as falling asleep during driving)?
• Has anyone Observed you Stop Breathing or Choking/Gasping during your sleep?
• Do you have or are being treated for High Blood Pressure?
• Body Mass Index more than 35kg/m²?
• Age older than 50 years old?
• Neck size large? (Measured around Adams apple)
• Gender = Male?

A score of 0-2 is correlated with low risk of OSA, 3-4 with a moderate risk of OSA and 5-8 with a high risk of OSA. This patient had a score of 6 (snore, observed, tired, pressure, BMI, age), putting her at high risk for OSA. Her family physician had astutely ordered a sleep study, which demonstrated moderate obstructive sleep apnea.

Treatment for OSA involves behavioural modification and patient education. Patients should be encouraged to exercise, for its benefits in addressing fatigue, as well for the benefits of weight loss. As well, advising patients to avoid sleeping in a supine position and to avoid alcohol, as it can worsen OSA and fatigue. Continuous positive airway pressure therapy is the mainstay of treatment, which acts to prevent upper airway collapse and thereby prevent apnea and hypopnea events. Should patients be unable to use CPAP, they could be offered an oral appliance such as a mandibular advancement splint or tongue-retaining device, however these devices are not as effective as CPAP.

Fatigue is a common presenting concern and warrants thorough investigation to rule out serious secondary causes of fatigue, such as malignancy. It is critical to complete a thorough sleep history and consider a diagnosis of OSA in patients who screen positively on the STOP-BANG questionnaire.

 

-EB-

 

References:

Chung F, Abdullah HR, Liao P. STOP-Bang questionnaire: a practical approach to screen for obstructive sleep apnea. Chest. 2016 Mar 1;149(3):631-8.

Qaseem A, Holty JE, Owens DK, Dallas P, Starkey M, Shekelle P. Management of obstructive sleep apnea in adults: a clinical practice guideline from the American College of Physicians. Annals of internal medicine. 2013 Oct 1;159(7):471-83.

Rosenthal TC, Majeroni BA, Pretorious R, Malik K. Fatigue: an overview. American family physician. 2008 Nov 15;78(10):1173-9.