Clinical Impression II: Systemic, Visceral and Special Population Presentations

The patients who are harmed in practice are rarely the ones with an unusual mechanical problem; they are the ones whose cancer, infection, inflammatory disease or visceral disorder was treated as back pain for too long. This chapter teaches the systemic, visceral and special population presentations that Part III uses to test whether you can see past the musculoskeletal surface, and then shows how to pull history, examination, imaging and laboratory findings together into a defensible primary and secondary diagnosis.

Section 1Inflammatory, metabolic and systemic disease presenting as musculoskeletal pain

Inflammatory versus mechanical

The first discrimination in any joint or spine case is whether the pain is inflammatory or mechanical. Inflammatory pain is worst after rest, with morning stiffness longer than 30 to 60 minutes, eases with activity, may wake the patient in the second half of the night, and comes with soft tissue swelling, warmth and sometimes systemic features (fatigue, low grade fever, weight loss) and raised ESR or CRP. Mechanical pain worsens with use, stiffness after rest lasts minutes (gelling), and swelling, when present, is bony. The second discrimination is the pattern: how many joints (mono, oligo or polyarticular), which joints, symmetric or not, and whether the spine and entheses are involved.

The inflammatory arthritides

Rheumatoid arthritis is a symmetric, small joint polyarthritis (MCP, PIP, wrist, MTP) that spares the DIP joints and the thoracolumbar spine, with morning stiffness over an hour, fatigue, and in established disease ulnar deviation, swan neck and boutonniere deformities and rheumatoid nodules. It is three times more common in women, peaking at 30 to 50. Rheumatoid factor is positive in about 70 to 80 percent, but anti CCP antibody is more specific (about 95 percent). The chiropractic must know is atlantoaxial instability: synovitis erodes the transverse ligament and dens, so an anterior atlantodental interval over 3 mm in an adult on a flexion film is abnormal, and patients may report occipital pain, Lhermitte sign or myelopathic signs. Rotational and high velocity upper cervical manipulation is contraindicated in active RA until instability is excluded.

The seronegative spondyloarthropathies share HLA B27 association, sacroiliitis, enthesitis, asymmetric large joint oligoarthritis, anterior uveitis, and negative rheumatoid factor.

Gout is urate crystal arthritis: a sudden, exquisitely painful, red, hot, swollen joint, classically the first MTP (podagra), often overnight after alcohol, a large meat or seafood meal, dehydration, or starting a thiazide or loop diuretic. Risk factors are male sex, obesity, metabolic syndrome, chronic kidney disease and low dose aspirin. Serum urate may be normal during an attack. The definitive test is joint aspiration showing negatively birefringent needle shaped crystals. Chronic tophaceous gout causes punched out periarticular erosions with overhanging edges. Pseudogout (calcium pyrophosphate deposition) affects the knee and wrist of older adults, with chondrocalcinosis on films and positively birefringent rhomboid crystals. The must not miss alternative for a hot single joint is septic arthritis: fever, inability to bear weight or move the joint, and immunosuppression or a recent joint injection. A hot joint is septic until aspirated.

Polymyalgia rheumatica and fibromyalgia

Polymyalgia rheumatica occurs almost exclusively after 50 (mean around 70), more often in women. It causes bilateral aching and marked morning stiffness of the shoulder and hip girdles and neck, with difficulty rising from a chair, getting out of bed or combing the hair. Strength is normal when tested (pain limits it), CK is normal, and the ESR is high (often over 40, frequently over 50 mm per hour) with a raised CRP. The response to low dose prednisone is dramatic within days. About 15 to 20 percent also have giant cell arteritis, so ask every patient about new headache, jaw claudication, scalp tenderness and visual change.

Fibromyalgia is a central pain sensitization disorder: widespread pain for three months or more (both sides, above and below the waist, and axial), with fatigue, unrefreshing sleep and cognitive symptoms ("fibro fog"), often with irritable bowel, headache and mood disorder. Current criteria use a widespread pain index and symptom severity score rather than tender points. Laboratory tests are normal, which is the point: the impression of fibromyalgia requires that hypothyroidism, polymyalgia, inflammatory arthritis, vitamin D deficiency and statin myopathy have been considered. Management emphasizes graded aerobic exercise, sleep hygiene and education.

Metabolic and endocrine causes

Osteoporosis risk factors that appear in vignettes are female sex, age over 65, low body weight, smoking, excess alcohol, early menopause, family history of hip fracture, long term glucocorticoids (5 mg prednisone daily for three months or more), aromatase inhibitors, anticonvulsants, hyperthyroidism and rheumatoid arthritis. A T score between minus 1.0 and minus 2.5 is osteopenia. In osteoporosis, use low force techniques and avoid high velocity thrust to the thoracic spine and ribs.

Section 2Neoplastic and infectious presentations

The pattern of serious spinal pathology

Tumor and infection share a recognizable history, and the board builds cases around it. Pain is constant and progressive, not relieved (or even worsened) by lying down, worse at night, and unresponsive to rest, positioning and a few weeks of conservative care. Systemic clues include unexplained weight loss, fatigue, fever, night sweats and malaise. The patient's history supplies the risk: a prior cancer, age over 50, immunosuppression, intravenous drug use, diabetes, a recent infection or procedure. The strongest single predictor of spinal malignancy is a previous history of cancer, which raises the probability many times over. Bone tenderness to percussion over a spinous process and failure to improve within about four to six weeks complete the picture.

Metastatic disease and myeloma

Metastases are by far the most common malignant lesion of bone in adults. The primaries that metastasize to bone are remembered as "PB KTL" (lead kettle): Prostate, Breast, Kidney, Thyroid and Lung. Breast and prostate account for most; lung metastases appear early and in smokers; renal and thyroid lesions are typically lytic and expansile. Prostate metastases are usually blastic (sclerotic, "ivory vertebra" possible), breast may be lytic, blastic or mixed. Metastases reach the spine through the arterial supply and the valveless Batson venous plexus, which explains the predilection for the vertebral bodies and pedicles of the thoracic and lumbar spine and the pelvis. The classic radiographic sign is the absent pedicle ("winking owl") on the AP view, because the pedicle is destroyed; vertebral body collapse with preserved disc height distinguishes tumor from infection, which destroys the disc first. Radiographs miss lesions until 30 to 50 percent of the trabecular bone is gone, so a normal film does not exclude metastasis; MRI or bone scan is the next step when suspicion is high.

Metastatic spinal cord compression is an oncologic emergency. It occurs in about 5 to 10 percent of patients with cancer; it may be the first presentation of an unknown primary. Back pain (often band like, worse lying flat or at night) precedes neurologic deficits by weeks. New weakness, sensory level, gait change or sphincter disturbance in a patient with cancer and back pain requires same day MRI of the whole spine and urgent oncology referral; ambulatory status at diagnosis is the main predictor of outcome.

Multiple myeloma is a malignant plasma cell proliferation, typically after 60, more common in Black patients. Remember CRAB: hyperCalcemia (thirst, constipation, confusion), Renal insufficiency, Anemia (fatigue, normocytic) and Bone lesions (back pain, punched out lytic lesions, pathologic compression fractures, diffuse osteopenia). Recurrent infections are common. The ESR is markedly raised, with rouleaux on the smear; serum protein electrophoresis shows an M spike, and urine may contain Bence Jones protein. Bone scan is often falsely negative because the lesions are purely lytic with little osteoblastic response, so a skeletal survey or whole body low dose CT or MRI is used.

Primary bone tumors

Primary bone tumors are rare, so the board tests them through age, location and a single classic clue.

Spinal infection

Vertebral osteomyelitis and discitis in adults usually arise by hematogenous spread from a urinary, skin, dental or endocarditis source, or after spinal procedures. Staphylococcus aureus is the most common organism; gram negative rods follow urinary infection, Pseudomonas is associated with intravenous drug use, Salmonella with sickle cell disease, and Mycobacterium tuberculosis (Pott disease) with immigrants from endemic regions, causing a gibbus deformity, paraspinal cold abscess and relative disc sparing. The adult disc is avascular, so infection seeds the endplate and spreads to the disc and adjacent vertebra. The presentation is progressive, severe, constant back pain, often with exquisite percussion tenderness and muscle spasm; fever is present in only about half. ESR and CRP are almost always raised (CRP is the most sensitive marker and the one used to follow treatment). Radiographs lag by two to four weeks; MRI is the test of choice. In children, discitis presents as refusal to walk, sit or bend, with a lordosis loss.

Spinal epidural abscess is the emergency form. The classic triad of back pain, fever and neurologic deficit is present in only a minority at first, so suspicion must come from risk factors: diabetes, intravenous drug use, alcoholism, recent spinal injection or surgery, an indwelling catheter or a distant infection. The usual sequence is back pain, then radicular pain, then weakness and sphincter loss, then paralysis, sometimes within hours. Any patient with back pain, a raised CRP or fever and a risk factor needs same day emergency evaluation and MRI with gadolinium.

Section 3Visceral referral patterns in cases

Why viscera hurt in the back and shoulder

Visceral afferents travel with sympathetic nerves into the dorsal horn at the spinal segments that supplied the organ in the embryo, and they converge on the same dorsal horn neurons as somatic afferents from skin and muscle. The brain, more used to signals from the body wall, projects the pain to the corresponding dermatomes and myotomes. That is viscerosomatic convergence, and it explains why the heart (T1 to T5) refers to the chest, left arm and interscapular area, and why the gallbladder (T7 to T9 and the right phrenic nerve) refers to the right scapula. The diaphragm is a special case: its central part is innervated by the phrenic nerve (C3 to C5), so irritation of its undersurface by blood, pus or an inflamed organ refers pain to the shoulder tip (the C4 dermatome). Visceral disease can also cause reflex paraspinal muscle guarding and segmental tenderness (viscerosomatic reflex), which is why tenderness alone cannot tell you the source.

Organ by organ

Screening questions that unmask visceral pain

Musculoskeletal pain has a mechanical signature; visceral pain has a systemic signature. When the examination fails to reproduce the complaint, or the pain does not behave mechanically, run a focused review of systems for the organ systems that share the segment. Useful questions include: Does eating, bowel movement or urination change the pain? Is there fever, sweats or weight loss? Any change in urine color or stream, blood in the stool or urine, or black stools? Shortness of breath or pain with exertion? Any vaginal bleeding, discharge or missed period? Any relationship to the menstrual cycle? Examination maneuvers that help include palpation of the abdominal aorta (a width over 3 cm is abnormal), Murphy sign, costovertebral angle percussion (Murphy punch), and testing for peritoneal irritation (rebound tenderness, McBurney point tenderness, psoas sign and obturator sign). A positive psoas sign (pain with resisted hip flexion or passive hip extension) can come from appendicitis, psoas abscess or a retroperitoneal process and mimics hip or lumbar pain.

Section 4Pediatric, geriatric and pregnant patient presentations

Children: growing pains or pathology?

Musculoskeletal complaints in children are common, and most are benign. Growing pains affect children aged about 3 to 12: bilateral, intermittent, deep aching in the thighs, calves or behind the knees, in the evening or night, relieved by massage, with a completely normal child by morning, a normal examination, no limp and no joint swelling. Anything that breaks this pattern is not growing pains. Red flags in a child are unilateral pain, pain in a joint (rather than between joints), a limp or refusal to bear weight, morning stiffness, swelling, fever, weight loss, night pain that wakes the child, pain that persists in the day, bruising or pallor, and back pain in a child under about 10 (a structural or serious cause is more likely than in adults).

Slipped capital femoral epiphysis (SCFE) is displacement of the femoral head off the neck through the physis, posteriorly and medially, during the adolescent growth spurt. It is most common in overweight boys aged 10 to 16, and is bilateral in about 20 to 40 percent; endocrine disorders (hypothyroidism, growth hormone deficiency) should be considered when it occurs outside the usual age range. The trap is that pain is often referred to the knee or thigh through the obturator nerve. On examination the hip falls into external rotation as it is flexed (Drehmann sign), with limited internal rotation. On the AP film, Klein line along the superior femoral neck fails to intersect the femoral head; the frog leg lateral is more sensitive for early slips. An unstable slip (cannot bear weight) has a high risk of avascular necrosis. Management is urgent orthopedic referral and non weight bearing on crutches; never manipulate the hip.

Legg Calve Perthes disease is idiopathic avascular necrosis of the femoral head in children aged about 4 to 8, four to five times more common in boys, often small for age. It presents with an insidious, mostly painless limp or activity related groin, thigh or knee pain, and loss of hip internal rotation and abduction. Early radiographs may be normal or show a small dense epiphysis and a subchondral fracture line (crescent sign); later, fragmentation and flattening appear. Prognosis is better in younger children (under 6) with less head involvement. Refer to pediatric orthopedics.

Adolescent idiopathic scoliosis is a lateral curvature of 10 degrees or more (Cobb angle) with vertebral rotation, without a known cause, appearing at 10 years or older; it is usually a right thoracic curve and progresses most during the growth spurt, more often in girls. Screening uses the Adams forward bend test with a scoliometer (7 degrees or more of trunk rotation suggests a curve of about 20 degrees and warrants a radiograph). Risk of progression is highest with a large curve in a skeletally immature patient (Risser 0 to 1, premenarchal). Typical management thresholds are observation under 25 degrees, bracing for 25 to 40 (or 45) degrees in a growing child, and surgical referral beyond about 45 to 50 degrees. Red flags that suggest a secondary cause (tumor, syrinx, tethered cord) are pain, a left thoracic curve, rapid progression, abnormal neurologic findings or abdominal reflexes, and onset before 10.

Older adults: falls and fractures

In older adults, the important impressions are fragility fracture, the cause of the fall, and atypical presentations of serious disease. A fall is a symptom: ask whether it was a trip (mechanical), a faint or near faint (syncope from arrhythmia, orthostatic hypotension, medications), dizziness, or leg weakness, and look for polypharmacy (sedatives, antihypertensives, more than four medications), visual impairment, cognitive impairment, neuropathy, Parkinson disease and fear of falling. Screening tools include the Timed Up and Go (more than about 12 seconds suggests increased fall risk) and the 30 second chair stand.

A hip fracture after a fall presents with groin or thigh pain, inability to bear weight, and a shortened, externally rotated leg in displaced fractures; an impacted femoral neck fracture may allow walking and present only as groin pain, so pain on axial loading or log roll after a fall needs films (and MRI if films are normal). Distal radius (Colles) fractures and vertebral compression fractures are the other sentinel fragility fractures; any of them should prompt osteoporosis evaluation. Older adults also present atypically: myocardial infarction with dyspnea or confusion alone, infection without fever, and appendicitis or cholecystitis with little tenderness. New back pain after 50, new headache after 50 and unexplained weight loss carry more weight in this group.

Pregnancy

Low back and pelvic girdle pain affect about half of pregnant patients. Pregnancy related lumbar pain is above the sacrum and behaves mechanically. Pelvic girdle pain is felt between the posterior iliac crest and the gluteal fold, near the sacroiliac joints, or at the pubic symphysis, and is aggravated by walking, stairs, turning in bed and standing on one leg; the active straight leg raise and the posterior pelvic pain provocation (thigh thrust) tests help confirm it. Relaxin and estrogen increase ligament laxity, the center of mass moves forward, and lumbar lordosis increases. Symphysis pubis dysfunction causes anterior pelvic pain with a waddling gait. Carpal tunnel syndrome and meralgia paresthetica are also common from fluid retention and weight gain.

Technique is adapted (pregnancy pillows or drop sections, side lying positions, avoiding prolonged supine positioning after about 20 weeks because of aortocaval compression, and avoiding abdominal pressure), but the impression step is about red flags.

Section 5Synthesizing the clinical impression

From data to a working diagnosis

A clinical impression is not a single label; it is a ranked judgment built from probabilities. Experienced clinicians generate two to four hypotheses within the first minutes of the history, then use the rest of the encounter to test them. Part III mirrors that process: the stem gives demographics and a chief complaint (which set the pretest probability), the history and examination add or subtract weight, and imaging and laboratory findings confirm or redirect. The skill being tested is how to weigh each piece.

1. Frame the problem. Age, sex, chief complaint, duration (acute under 6 weeks, subacute 6 to 12, chronic over 12) and mechanism.
2. Screen for danger first. Red flags for fracture, cancer, infection, cauda equina or myelopathy, vascular emergency and visceral disease. If one is strongly present, the impression is that condition and the next step is referral at the right urgency.
3. Generate the differential. The most likely diagnosis, the must not miss alternative, and one or two others.
4. Test it with the examination. Use tests whose results change probability: a highly sensitive test that is negative rules out (SnNout), a highly specific test that is positive rules in (SpPin). Clusters outperform single tests.
5. Add imaging and labs only when they would change management. Interpret them against the clinical picture; incidental degenerative findings are common in asymptomatic people.
6. State the impression. Primary diagnosis, secondary diagnoses, complicating factors, and the plan or referral that follows.

Weighing evidence

Diagnostic accuracy can be expressed as likelihood ratios. A positive likelihood ratio (sensitivity divided by 1 minus specificity) above 10 produces a large increase in probability, 5 to 10 a moderate increase, and 2 to 5 a small one; a negative likelihood ratio below 0.1 produces a large decrease. A test with an LR near 1 changes nothing and should not drive a decision. Because a test's predictive value depends on prevalence, the same positive Spurling test means much more in a patient whose history already suggests radiculopathy than in a patient with nonspecific neck pain.

Cognitive errors are as dangerous as gaps in knowledge. Anchoring fixes on the first impression; premature closure stops thinking once a plausible diagnosis is found; availability bias favors what was seen recently; confirmation bias collects only supporting evidence. Two habits protect against them: always name the must not miss alternative, and treat failure to improve as new data.

Primary and secondary diagnoses

The primary diagnosis is the condition that best explains the chief complaint and that care is directed at. Secondary diagnoses are additional conditions that are present and relevant: a coexisting problem (myofascial pain with a radiculopathy), a complicating factor that changes prognosis or technique (osteoporosis, diabetes, anticoagulation, obesity, depression or fear avoidance), or a related finding (a transitional segment). Order matters for documentation and coding: the condition being treated is listed first, followed by those that affect care. When a red flag condition is suspected, the impression states it as suspected and the plan is referral; you do not need to prove it before acting.

Extended matching items

In extended matching style, a single long option list (often 10 to 20 diagnoses) is followed by several short vignettes; each vignette is matched to the best option, and options can be used once, more than once or not at all. Because every option is plausible for something, these items reward discriminating clues over general recognition. A good approach: read the vignette and name the answer before scanning the list; identify the one feature that rules out the near neighbors (age, laterality, timing, a specific sign or lab); and do not eliminate an option because you used it already.

Words worth knowing