Experiencing lower back pain while feeling unwell is common. This discomfort, ranging from a dull ache to soreness, often accompanies various illnesses. Understanding the underlying biological mechanisms clarifies why the lower back might ache when the body fights infection or experiences other health disturbances.
Generalized Body Aches
When the body combats an infection, the immune system responds. White blood cells release chemical messengers called cytokines, which trigger inflammation throughout the body. This inflammatory process leads to widespread muscle and joint pain, including in the lower back. Cytokines activate sensory nerve fibers, sending pain signals to the brain and contributing to discomfort during illnesses like the flu.
Dehydration, often associated with illness due to fever, reduced fluid intake, or fluid loss, also contributes to muscle soreness. Muscles are largely water, and insufficient hydration impedes their function, potentially leading to cramps and aches.
Malaise or muscle fatigue, common with many illnesses, also affects muscle comfort. This fatigue can make muscles feel heavy and achy, especially back muscles due to their role in posture and movement. Fever itself contributes to discomfort and muscle pain as the body generates heat to fight pathogens.
Specific Illnesses and Conditions
Lower back pain can indicate a more specific underlying medical condition beyond generalized body aches. Urinary Tract Infections (UTIs), especially if they spread from the bladder to the kidneys, are a common cause of lower back or flank pain. When bacteria ascend to the kidneys, the resulting inflammation can cause pain that radiates to the lower back, often accompanied by symptoms such as painful or frequent urination and sometimes fever. This pain may feel like a dull, constant ache and can affect one or both sides of the back.
Kidney infections, medically known as pyelonephritis, are a more severe form of UTI that directly inflame the kidneys, which are located on either side of the spine in the mid-back. Symptoms include severe, localized pain in the lower back or side, often described as flank pain, along with high fever, chills, nausea, and sometimes cloudy or bloody urine. This pain is constant and can range from dull to severe.
Respiratory illnesses, such as severe colds, bronchitis, or pneumonia, can also lead to lower back pain, primarily through mechanical strain. Persistent, forceful coughing associated with these conditions repeatedly contracts and strains back muscles, particularly the intercostal muscles. This repetitive stress can result in soreness, stiffness, and pain in the lower back.
When to Seek Medical Attention
While many instances of back pain during illness are temporary, certain symptoms warrant immediate medical evaluation. Severe or worsening back pain, particularly if it does not improve with rest, should prompt a consultation with a healthcare provider. The presence of high fever, chills, or night sweats accompanying back pain also signals a need for professional medical attention. These symptoms, especially when combined with pain in the lower back, can indicate a kidney infection.
Urinary symptoms, such as burning during urination, increased frequency or urgency, or blood in the urine, alongside back pain, indicate a potential urinary tract or kidney infection. Neurological symptoms like numbness, tingling, or weakness in the legs, or any loss of bowel or bladder control, require urgent medical assessment. Unexplained weight loss combined with back pain should also be investigated.
Relieving Back Pain While Sick
For general back pain experienced during illness, several home-based strategies can help provide comfort. Adequate rest allows the body to conserve energy and focus on recovery, reducing strain on fatigued muscles. Maintaining good hydration by drinking plenty of fluids, such as water, broth, or electrolyte drinks, is beneficial for overall well-being and can help alleviate muscle aches.
Over-the-counter pain relievers, such as ibuprofen or acetaminophen, can help manage pain and reduce fever and inflammation, but dosage instructions should always be followed carefully. Applying heat therapy, such as a warm bath or a heating pad, can help relax tense muscles and provide temporary relief from soreness. Gentle movement, if tolerable, can prevent stiffness, but strenuous activity should be avoided to support the body’s recovery process.