Dr. Howard Liss and Dr. Donald Liss are co founders of The Physical Medicine and Rehabilitation Center, a comprehensive spine, sports and occupational rehabilitation practice. This information is reproduced with kind permission from their educational website – www.Rehabmed.net. [Notes on medical terms in brackets are added by ProHealth for the benefit of lay readers.]
Nighttime pain may present as an important symptom several ways.
• There are conditions in which pain or discomfort is felt essentially only at night. These are fairly few but noteworthy.
• Then, there are those conditions which seem to be exacerbated at nighttime. The role of "nighttime" in these conditions’ exacerbation needs to be explored.
• Finally, there are those conditions which are not necessarily worse at night, although perhaps more apparent for their lack of disappearance. In other words, in most conditions one would expect relief at the end of the day when one finally climbs into bed. Lack of improvement of symptoms overnight may also be an important symptom.
Factors that May Cause Increased Nocturnal Pain
Factors which may result in emergence of or increase in pain at night can be grouped as hormonal and mechanical.
The effect of hormonal fluctuations on our physical biochemistry and pain perception is very poorly understood.
• We know, for example, that fluctuation in glucocorticoids results in early evening fevers in many infections or inflammatory conditions. [Glucocorticoids (including cortisol) are inflammation-inhibiting steroid hormones produced by the adrenal glands. Synthetic ‘replacement’ forms include for example hydrocortisone and prednisone.] It is possible that lower glucocorticoid levels in the evening allow emergence or exacerbation of pain at night, just as glucocorticoids can be used to reduce pain by reducing inflammation in rheumatic conditions. This stands to reason, but further investigation needs to be done.
• The role of the pineal gland in diurnal variations, the relationship of "jet lag" to changes seen in chronic fatigue, as well as the fatigue associated with fibromyalgia and other rheumatic conditions, needs further research. [The pineal gland, shaped like a pine cone and located deep in the brain, is known as the ‘third eye’ as it produces the sleep/wake cycle-regulating hormone melatonin.]
• What about the effect of variations in female hormones on a cyclical basis, and daily variations in estrogen and progesterone? These hormones almost definitely play a role in conditions involving pain. Estrogens are also known to play a role in promoting better sleep patterns.
Better understood are the roles of mechanical factors in causing or exacerbating pain.
• Being supine or prone (i.e., in extension) can compress posterior structures, and increases loading of posterior elements of the spine. Arterial flow to the lower extremities is impeded and venous return may be enhanced, resulting in central pooling and increased central edema [poor return of blood from legs & feet to the heart often resulting in collection of fluid in the tissues].
• Other mechanical factors include compression of structures in the neck and shoulders in certain positions, which may result in increased pain at night as well.
Pain Only Nocturnal
Several conditions may present with pain felt only at night.
• Cervical [neck] osteoarthritis and carpal tunnel syndrome, although normally felt during the day as well, may present with pain which is only nocturnal. This is especially true with mild carpal tunnel syndrome if there is a component of edema or fluid retention. Cervical osteoarthritis is often exacerbated by positioning at night, and additional support for the posterior neck may be necessary in addition to the regular pillow. Alternatively, many patients receive benefit from cervical pillows which distribute the weight bearing of the neck and head more evenly.
• There are patients who have low back pain or a "heavy" sensation in their legs only at night. This has been referred to as "Ondine’s curse", and is the result of borderline or mild lumbar spinal stenosis concomitant with incipient congestive heart failure. [Note: The lumbar spine is the 5 vertebrae in the lower back, whose nerves serve the lower extremities. Spinal stenosis, often age-related, is a narrowing of the space within the spinal canal that puts pressure on the spinal cord, or narrowing of the opening where the spinal nerves branch off from the spinal column. It can cause pain or numbness in different parts of the body depending on which nerves are affected. Congestive heart failure is a heart that keeps working but can’t pump blood to the body as efficiently as it should, often resulting in edema.]
These patients have venous pooling which results in increased venous engorgement in their epidural veins; this occurs primarily at night when lying down. This results in reduced effective lumbar canal diameter in an already compromised canal, precipitating the symptoms of spinal stenosis. Interestingly, in these patients, a diuretic may be the treatment of choice.
• Another condition which occurs solely at night is nocturnal paroxysmal myoclonus, or "restless leg syndrome." This condition is poorly understood, but is characterized by restlessness, as well as muscle cramping and involuntary contraction of muscles of the legs. This is a painful condition which may interfere with sleep and precipitate other painful conditions such as fibromyalgia. Once diagnosed, it responds fairly well to medications, splinting, and exercise. Its origin is poorly understood.
Pain Which Is Worse at Night
• As mentioned before, carpal tunnel syndrome usually is worse at night. This may be because of mechanical factors such as "sleeping on one’s hands" with wrists flexed, as well as fluid retention at night. At any rate, patients are often awakened or awaken in the morning with numbness and pain in their hands, often in a median nerve distribution.
Interestingly, many patients cannot localize the pain in their hands and they even report pain proximally in their forearms or arms and shoulders. Up to 7% of patients present with pain in the shoulder region, and only a thorough history and physical examination will detect the nocturnal pattern and association with numbness and tingling in the hands.
The trapezius symptoms are presently myofascial [related to connective tissues] and secondary. In terms of mechanical factors in the wrists themselves, prevention of excessive flexion or extension through splinting or better positioning may reduce symptoms.
• As mentioned, cervical and lumbar osteoarthritis can be worsened by positioning associated with lying in bed at night. Lumbar facet syndrome [degeneration of joints in back of the lumbar vertebrae that link the vertebra together] in particular is worsened by sustained extension. Unlike patients with discogenic pain, these people are often more comfortable on their side in some degree of lumbar flexion.
• As mentioned as well, patients with lumbar stenosis are often worsened at night by extension and by fluid retention. This is especially true in the elderly who may have some degree of congestive heart failure or venous insufficiency. Venous pooling at night results in decreased canal diameter with increased symptoms.
• Patients with rotator cuff disease or tendinitis often complain of worsening of symptoms at night when they attempt to lie on their sides, especially on the side of their complaints. This is probably due to compression of an already impinged tendon.
• Although less commonly described by patients with other shoulder problems, patients with instability or acromioclavicular disease [in the pivotal joint at the top of the shoulder that allows the ability to raise the arm above the head] may also complain of exacerbation of symptoms by lying on the side of the complaint, probably also due to compression.
• Patients with vascular insufficiency may have "night pain" in bed as compared to sitting or standing. Although classical "claudication" symptoms [pain caused by too little blood flow] are brought on by walking, arterial pressure to the legs is decreased by lying in bed as compared to sitting and may result in decreased blood flow and precipitation of symptoms as well.
• Myofascial pain syndrome and fibromyalgia are worsened by bed rest as well. Whether this is simply the result of relative immobility, whether it is related to hormonal variations at night, what role the non-restorative sleep disorder associated with fibromyalgia might play, or what other rheumatologic factors may be at play – are unclear at this time.
Pain Unrelieved by Rest
Sometimes, the lack of relief of symptoms at night should raise antennae.
Statistically, although patients between age 20 and 50 need rarely undergo lumbosacral X-rays for low-back pain, one of the symptoms which should trigger suspicion is unremitting pain.
• If the patient describes pain which is positional, this generally points to a mechanical cause.
• Pain worsened by sitting, arising, or associated with flexion and rotation is often discogenic.
• Pain worsened by extension is often related to the facet joint.
• Pain exacerbated by walking is often associated with lumbar spinal stenosis.
• But … pain which is unrelieved at night in any position may signify an underlying malignancy. This is especially true if there has been an associated loss of appetite, weight, or other constitutional symptoms such as change in bowel habits. At any rate, although most patients with this symptom do not have malignancy, this symptom should nevertheless trigger a more thorough diagnostic evaluation. One needs to have a high index of suspicion in these patients.
• The other broad category of patients with unremitting pain are those patients with non-malignant but non-mechanical pain. Patients with visceral pain [caused by an injury or disorder of an internal organ] may present with complaints that seem musculoskeletal. A patient with perforated duodenal ulcer, for example, may present with acute mid-back pain which is severe and may be mistaken for muscular or spine pain. Only a high index of suspicion after thorough examination will lead to appropriate diagnostic testing.
In summary, most patients do not arrive with an easy answer to their diagnostic dilemmas. Patients have not read the textbook before arriving in the practitioner’s office. It is therefore imperative that every component of the medical history and physical examination be viewed discriminately and thought about judiciously.
The effect of nighttime and bed rest on pain is an important example of this. The pattern of clinical presentation should affect our clinical impression and, therefore, our diagnostic workup; this in turn affects our treatment plan.
Note: This information has not been evaluated by the FDA. It is general and not intended to diagnose, prevent, treat or cure any condition, illness or disease. It is very important that you make no change in your healthcare plan or health support regimen without researching and discussing it thoroughly in collaboration with your professional healthcare team.