Orthopaedics — Bone Lesions and Chronic Joint Disease, NMC MBBS licence examination syllabus (Nepal Medical Council).
Bone pain that wakes a patient at night is a different complaint from bone pain that hurts when they walk, and the difference is the whole of the diagnosis.
The first two orthopaedics chapters covered the broken bone and the joint that has come out — injuries, where the history tells you what happened. This chapter covers the presentations where nothing happened: the bone that hurts without injury, and the joint that has been getting worse for years.
Most musculoskeletal pain is mechanical. It comes on with use, eases with rest, and has a story behind it — a job, a sport, a fall. That pattern is so common that the exceptions are easy to talk yourself out of.
The question that does most of the work: does the pain wake you at night, or hurt when you are lying still? Mechanical pain is relieved by rest. Pain that is present at rest, or that wakes someone from sleep, does not fit the mechanical pattern and needs explaining rather than treating.Two other features carry the same weight. A mass over the bone — particularly one that is deep, fixed and getting bigger — and a fracture from force that should not have broken a healthy bone. A bone that gives way under an ordinary load has been weakened by something, and finding out what matters more than fixing the fracture.
Tumour in bone is much more often a deposit from a primary somewhere else than a tumour arising in the bone itself. That single fact should redirect the examination.
The primaries that classically deposit in bone are the breast, prostate, lung, kidney and thyroid. In an older patient with an unexplained bone lesion, examining the breast and the chest, and asking about urinary symptoms, is a higher-yield use of five minutes than any rare investigation.
Myeloma belongs on the same list. It is a disease of the marrow rather than a deposit, but it presents the same way — bone pain in an older patient — and it brings anaemia and renal impairment with it. That combination is covered in NMCMD11, and it is worth thinking of whenever bone pain arrives alongside unexplained tiredness or a rising creatinine.
A primary bone tumour is uncommon, and it is largely a disease of the young — the growing skeleton. A secondary deposit or myeloma is a disease of later life. That single split does more to narrow a differential than most investigations.
What follows from all of this is a referral, not a diagnosis. A candidate is not expected to name the tumour from a plain film. What is expected is to recognise that the pain does not fit a mechanical pattern, image the bone, and refer — because the delay that harms these patients happens before anyone specialist has seen them.
The other half of this chapter is the joint that has been getting worse for years. Two patterns account for most of it, and they are separated by one question.
Osteoarthritis is mechanical. It hurts more as the day goes on and more with use, and the morning stiffness is brief. It affects the large weight-bearing joints and the small joints at the ends of the fingers.
An inflammatory arthritis behaves in the opposite direction. The stiffness is worst in the morning, lasts substantially longer, and eases with movement. The joints are warm and swollen rather than simply painful, and the distribution tends to be symmetrical and to favour the joints nearer the hand. The medical management of rheumatoid disease is in NMCMD20.
Ask how long the morning stiffness lasts. It separates the two patterns more reliably than the site or the severity of the pain, and it costs one question. Brief stiffness that loosens within minutes points to wear; prolonged stiffness that takes much of the morning to settle points to inflammation.The distinction matters because the treatments diverge completely. Osteoarthritis is managed with weight, activity, muscle strength and — in the end — surgery to replace the joint. Inflammatory arthritis is managed by suppressing the inflammation, and delay in starting that treatment costs joints permanently. Getting the pattern right early is the point.
One joint, hot, swollen and exquisitely painful, is a different problem from either of the above, and it is the orthopaedic emergency of this chapter.
Treat it as septic arthritis until proven otherwise. Infection destroys cartilage within days, and the joint does not recover. NMCOR01 covers the management; what matters here is that the presentation is recognised rather than absorbed into a story about arthritis.
The difficulty is that crystal arthritis looks the same. Gout and pseudogout both give a single hot, tender joint in a patient who feels unwell. A history of previous identical attacks that settled on their own makes crystals more likely — but it does not exclude infection, and a patient with gout can also have a septic joint.
A teenager with a painful thigh for six weeks, worse at night, with a firm swelling above the knee. The night pain and the mass together take this out of the mechanical category. It needs imaging of the bone and urgent referral. Infection is on the list alongside tumour, and neither is excluded at the bedside.
An older man with new back pain, worse at rest, who has lost weight. Back pain is common; this pattern is not. NMCOR02 covers the back-pain red flags — here, the age, the rest pain and the weight loss point towards a deposit or myeloma, and the prostate is worth examining.
A woman whose hands have been stiff every morning for two hours, easing by midday, with swollen knuckles. Prolonged morning stiffness that eases with use is the inflammatory pattern. This is not osteoarthritis, and the referral is not to a surgeon — it is for disease-suppressing treatment, and it is time-sensitive.
Rest pain and mechanical pain. Not a matter of severity. Mechanical pain can be severe and still ease when the limb is still; rest pain can be moderate and still be the significant symptom. The question is what the pain does when the patient stops moving.
Osteoarthritis affecting the fingers and rheumatoid arthritis. Both give painful, swollen finger joints in an older patient. The distribution differs — wear affects the joints at the ends of the fingers, inflammation those nearer the hand — and the morning stiffness differs in length.
Septic arthritis and a flare of an arthritis the patient already has. The most dangerous confusion in this chapter, because the patient has a ready explanation and so does the doctor. A known arthritis does not protect a joint from infection.
Pain at night or at rest, a mass over the bone, or a fracture from trivial force — image and refer, do not treat as a strain.
Older patient with a bone lesion — a secondary deposit or myeloma is far likelier than a primary. Breast, prostate, lung, kidney, thyroid.
Young patient with a bone lesion — primary tumour and infection both, and they look alike.
Brief morning stiffness, worse with use — osteoarthritis. Prolonged morning stiffness, easing with use — inflammatory, and refer early.
One hot joint — septic arthritis until the aspirate says otherwise.
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