Distinguishing neuropathic pain from nocioceptive pain

January 23, 2014
This study quantifies the value of the history among 269 patients with chronic pain in three pain clinics.

Summary:

  • Neither their survey nor any individual findings were strong enough to hang one’s hat on.
  • The most helpful finding when present was a sensation of brushing.
  • The most helpful finding when absent was numbness.

 Methods:

  • Patients: 196 patients in whom two physicians agreed on the basis of the pain. Excluded were 106 patients for whom the physicians agreed that the pain had a mixed basis or for whom the physicians did not agree whether the pain was neuropathic.
  • Gold standard: consensus assessment by two physicians of the basis of the pain.

Findings:

Accuracy

Predictive value
(assuming equal pretest probabilities of neuropathic and nocioceptive pain)

Finding Sensitivity Specificity Positive predictive value Negative predictive value
DN4 7-item survey(score 4 or more)

74

79

78

75

Numbness sensation

74

68

70

73

Painful cold sensation

64

80

76

69

Brushing sensation

51

91

85

65

Citation

van Seventer R, Vos C, Giezeman M, Meerding WJ, Arnould B, Regnault A, van Eerd M, Martin C, & Huygen F (2013). Validation of the Dutch version of the DN4 diagnostic questionnaire for neuropathic pain. Pain practice : the official journal of World Institute of Pain, 13 (5), 390-8 PMID: 23113981

Ectopic pregnancy

May 6, 2013

The Rational Clinical Examination Series reviewed 14 original studies about diagnosing ectopic pregnancy and yielded the results in the Table.

For interpreting likelihood ratios, consult McGee (PMID: 12213147; PMC1495095); only transvaginal ultrasonography yields helpful accuracy. As frequently happens, the physical examination was much more specific than sensitive.

Sensitivity
(%)
Specificity
(%)
LR+ LR-
cervical motion tenderness 45 91 4.9 0.62
peritoneal findings* 23 to 27 94 to 95 4.2 to 4.5 0.78 to 0.81
adnexal mass 9 96 2.4 0.94
adnexal tenderness 61 65 1.9 0.57
transvaginal ultrasonography 88 99 111 0.12
* Only two studies. Did not pool

Reference

Crochet JR, Bastian LA, & Chireau MV (2013). Does this woman have an ectopic pregnancy?: the rational clinical examination systematic review. JAMA : the journal of the American Medical Association, 309 (16), 1722-9 PMID: 23613077

Diagnosing synovitis of the hand and wrist

March 21, 2013

Summary: This article provides excellent pictures and descriptions for the physical examination of synovitis of the hands. The descriptions are detailed as well as possible to facilitate reproducibility. The study found that the examination of the wrist joint line at the capitate yielded the best combination of sensitivity and specificity. Resulting positive predictive values never exceeded 80%. Negative predictive values were stronger. Note that this study yielded higher sensitivity than a prior study reviewed here that did not use a structured examination.

Patients: Adults with “history of morning stiffness in the small joints of their hands and/or pain in the small joints of the hands and wrist, with or without swellings. Onset of symptoms was not less than 3 months.”

Examiners: Experienced rheumatologists who were blinded to the reference standard. Unclear is the examiners were blinded to the patients’ histories.

Examination method:

A Delphi method with 21 rheumatologists identified 4 examination methods thought to be the most important. Below are brief descriptions for some of the maneuvers, but the article provides much more detail with figures.

  1. MCP scissor – examine MCP joint lines for swelling or tenderness while MCPs flex 90 degrees
  2. MCP squeeze – to assess tenderness on sides of MCPs
  3. PIP 4-finger – examine for swelling or tenderness while squeezing joint from sides
  4. Wrist 2-thumb – follow third meta-carpal proximally till encountering capitate. Follow capitate proximally until dimple at the wrist joint line.

Reference standard: Ultrasonographer who was blinded to the study who assessed :components of synovitis (i.e. effusion, proliferation and hyperaemia)”

Results:

Finding Sensitivity Specificity
 Wrist 2-thumb  80% 54%
MCP scissor
(swelling at second MCPjoint)
74% 50%
MCP squeeze
PIP 4-finger

Reference:

Almoallim H, Attar S, Jannoudi N, Al-Nakshabandi N, Eldeek B, Fathaddien O, & Halabi H (2012). Sensitivity of standardised musculoskeletal examination of the hand and wrist joints in detecting arthritis in comparison to ultrasound findings in patients attending rheumatology clinics. Clinical rheumatology, 31 (9), 1309-17 PMID: 22673791

Physical examination for detection of anemia

September 23, 2012
Twelve primary health care providers in Bangladesh examined 452 pregnant women (198 had Hb < 10) for the presence or absence of pallor on nine different anatomical sites, viz. nail-beds, nail-bed blanching, palm, palmar creases, face, lips, tongue, oral mucosa and conjunctiva
Below is a table (larger version is here) of the standardized colors the researchers used and the distribution of results for the conjunctival color.

Two other studies on this topic, all with different results are PMID 2297289 and 20049324

Distribution of color of the everted lower eyelid.
1 2 3 4 5 6 7 8 9 10 11 12 13
Hb < 10 28% 42% 36%
Hb 10 – 12 19% 19% 40%
Hb > 12 10% 53% Not
stated
Not
stated
Not
stated

References

Chowdhury ME, Chongsuvivatwong V, Geater AF, Akhter HH, & Winn T (2002). Taking a medical history and using a colour scale during clinical examination of pallor improves detection of anaemia. Tropical medicine & international health : TM & IH, 7 (2), 133-9 PMID: 11841703

Hoover’s sign for the diagnosis of functional weakness

March 29, 2012

In a study of 124 patients with suspected stroke who presented with leg weakness, clinical evaluation ultimately determined that in eight patients (6%) the weakness was functional.

For functional weakness:

Sensitivity Specificity Predictive values at prevalence of 6%
Positive Negative
Hoover’s sign* 63%
(95% CI: 24 to 91)
100%
(95% CI: 97 to 100)
100% 3%
* “was considered positive when there was weakness of voluntary hip extension in the presence of normal involuntary hip extension during contralateral hip flexion against resistance”.
Of note, the abductor sign is an alternative test for functional weakness. (PMID: 14707320)

Citation

McWhirter L, Stone J, Sandercock P, & Whiteley W (2011). Hoover’s sign for the diagnosis of functional weakness: a prospective unblinded cohort study in patients with suspected stroke. Journal of psychosomatic research, 71 (6), 384-6 PMID: 22118379

How well can an expert examiner detect synovitis of the fingers?

September 15, 2011

Summary:

Even an expert has difficulty and only detected by palpation 25% of finger joints that had swelling by ultrasounds.

Patients:

  • The authors examined 165 finger tendons from “33 consecutive patients who has originally presented with polyarthritis and clinical suspicion of inflammatory arthritis of the hands and wrists (symptoms < 24 months)”

Examiner:

  • “senior rheumatologist trained in the detection of musculoskeletal disorders (AS), who disregarded ultrasonography findings”

Reference standard:

  • Ultrasound

Results:

52% (17 patients) had flexor tenosynovitis by ultrasound.

Performance of the expert clinical examiner.

Sensitivity (%)

Specificity (%)

Tenderness

87

47

Crepitus

56

76

Swelling

25

100

Citation:

Hmamouchi I, Bahiri R, Srifi N, Aktaou S, Abouqal R, & Hajjaj-Hassouni N (2011). A comparison of ultrasound and clinical examination in the detection of flexor tenosynovitis in early arthritis. BMC musculoskeletal disorders, 12 PMID: 21549008

Signs of cervical spinal cord compression

August 18, 2011

This is a retrospective, unblinded  study of 120 patients without comorbidities undergoing laminoplasty for cervical myelopathy, defined as increased signal intensity (ISI) in T2-weighted magnetic resonance imaging (MRI).

On physical examination, the most sensitive findings were:

  • Hyperreflexia of knee 94%
  • Hoffmann reflex (“flexion of the ipsilateral thumb and/or index finger was considered as positive”) 81%
  • Babinski sign 53%
  • Ankle clonus 35%

These results are likely inflated due to lack of control group which prevented blinding.  In addition, the authors noted that the signs were less sensitive in patients with mild disability. Regardless, I suspect the relative values of the signs are correct and I was surprised on the value of the Hoffmann reflex.

Citation:

Chikuda H, Seichi A, Takeshita K, Shoda N, Ono T, Matsudaira K, Kawaguchi H, & Nakamura K (2010). Correlation between pyramidal signs and the severity of cervical myelopathy. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 19 (10), 1684-9 PMID: 20229121

A “mini” Mini-Mental State Examination

July 15, 2011

The authors propose a six item screener (SIS) that contains six items from the Mini-Mental State Examination (MMSE):

The examiner first asks the patient to remember three items: GRASS PAPER SHOE. The examiner could repeat the words 3 times as needed to help the patient.

  • Orientation to time
    1. Year
    2. Month
    3. Day of the week
  • Recall of three items (one point each)

Patients: The authors studied 371 patients in the emergency room after excluding 587 patients, mostly due to having received sedating medications.

Results: As compared to the full MMSE, the accuracy of the SIS was:

  • Sensitivity 74%
  • Specificity 77%

Citation:

Carpenter CR, Despain B, Keeling TN, Shah M, & Rothenberger M (2011). The Six-Item Screener and AD8 for the Detection of Cognitive Impairment in Geriatric Emergency Department Patients. Annals of emergency medicine, 57 (6), 653-61 PMID: 20855129

Differentiating epileptic seizures and pseuodseizures

June 4, 2011

In a study of 120 events from 35 consecutive patients referred for video electroencephalography (VEEG) monitoring:

Video-documented predictors of psychogenic nonepileptic seizures were:

  • “preserved awareness,” “eye flutter,” and “bystanders can intensify or alleviate”)

Video-documented predictors of epileptic seizures were:

  • “abrupt onset,” “eye-opening/widening,” and postictal “confusion/sleep”

However, “eyewitness reports of these 6 signs were inaccurate and not statistically different from guessing.”

Clinical examination for peripheral arterial disease

June 2, 2011

Summary:

If both pulses on both feet are normal and there are no femoral bruits, there is a less than 10% chance of an ABI being abnormal in a study population with a prevalence of disease of 28%. I could not make any other conclusions from this article.

Methods:

Patients:

1619 patients who has undergone peripheral arterial testing between December 2005 and February 2010. Excluded:

  • 228 due to an abnormally high ABI (greater than 1.30) in either leg
  • 155 patients because the examination for femoral bruit was not recorded
  • 1 patient because the examination for distal pulses was not recorded

Reference standad:

  • ABI <= 0.9

Results:

  • 1236 patients (2472 legs)
  • API was abnormal in at least on leg of 348 patients (28%)
  • 575 patients had a normal clinical examination (no femoral bruits and both pulses on both feet normal) and 546 of these (95%) has normal ABIs. I calculate the confidence interval is 92.75 % to 96.54 %.
  • The authors state that a complete clinical examination has a sensitivity and specificity of 58.2% and 98.3%; however, I cannot reproduce these numbers. The problem may be due to the authors inconsistently reporting number of patients versus number of legs and also not clearly stating whether an abnormal examination is when any one finding is abnormal or when all findings are abnormal.

Citation

Armstrong DW, Tobin C, & Matangi MF (2010). The accuracy of the physical examination for the detection of lower extremity peripheral arterial disease. The Canadian journal of cardiology, 26 (10) PMID: 21165366


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