ClinDx

Bedside diagnosis of COVID-19

badgett — Sat, 06 Mar 2021 16:53:51 +0000

As with most other diseases, bedside diagnosis does not offer a single finding that is both sensitive and specific. However, while in other diseases there are findings that have either sensitivity or specificity over 90%, in COVID-19 there are no sensitive findings.

Per the abstract:

Sensitivity: “Only cough (25 studies) and fever (7 studies) had a pooled sensitivity of at least 50% but specificities were moderate to low. Cough had a sensitivity of 67.4% (95% confidence interval (CI) 59.8% to 74.1%) and specificity of 35.0% (95% CI 28.7% to 41.9%). Fever had a sensitivity of 53.8% (95% CI 35.0% to 71.7%) and a specificity of 67.4% (95% CI 53.3% to 78.9%).”
Specificity: ” Anosmia had a pooled sensitivity of 28.0% (95% CI 17.7% to 41.3%) and a specificity of 93.4% (95% CI 88.3% to 96.4%). Ageusia had a pooled sensitivity of 24.8% (95% CI 12.4% to 43.5%) and a specificity of 91.4% (95% CI 81.3% to 96.3%). Anosmia or ageusia had a pooled sensitivity of 41.0% (95% CI 27.0% to 56.6%) and a specificity of 90.5% (95% CI 81.2% to 95.4%). “

Regarding combining findings, per the abstract:

“Only two studies assessed combinations of different signs and symptoms, mostly combining fever and cough with other symptoms. These combinations had a specificity above 80%, but at the cost of very low sensitivity (< 30%)”

Reference:

Struyf T, Deeks JJ, Dinnes J, Takwoingi Y, Davenport C, Leeflang MM, Spijker R, Hooft L, Emperador D, Domen J, Horn SRA, Van den Bruel A; Cochrane COVID-19 Diagnostic Test Accuracy Group. Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19. Cochrane Database Syst Rev. 2021 Feb 23;2:CD013665. doi: 10.1002/14651858.CD013665.pub2. PMID: 33620086.

Diagnosing lumbar nerve root compression at the bedside

badgett — Fri, 25 Jan 2019 08:29:19 +0000

Summary: This article finds that the accuracy of the clinical exam (by a very expert clinician) depends on the location of the nerve deficit. For nerve root compression by a disc, the SLUMP and SLR dynamic tests were most sensitive. However, for foraminal compression, which was the most common site, the dynamic tests have less than 50% sensitivity. The presence of any one neurologic deficit (motor, sensory, or reflex) had sensitivities of 90% and 80% for disc and foraminal high-grade compression, respectively. In no analysis was the positive predictive value over 50% – in spite of the high prevalence of compression in this referred population. All patients had at least low-grade nerve compression.

A practical finding is that in the absence of nerve deficits (motor, sensory, or reflect), high-grade nerve compression is unlikely although some high-grade foraminal compression is possible.

Patients: 99 adults who were referred for transforaminal epidural steroid injection from the orthopedic clinic at a single hospital in the south of Sweden. The patients were classified into 3 groups of nerve compression:

Low-grade nerve compression (m=61): “neither high-grade subarticular nor high-grade foraminal nerve compression”
High-grade subarticular nerve compression (n=14)
High-grade foraminal nerve compression (n=25)

One subject was included in both of the latter groups

Examiners: An “experienced physiotherapist … who was blinded to all MRI information.”

Examination method:

Radiculopathy I “was considered when one of the neurologic signs above* was present and corresponded to the nerve root” of the planned injection.

* “patellar reflex, Achilles’ reflex, strength of the large toe in dorsiflexion, or sensibility (sensory deficit) in a specific dermatome area was asymmetrically deranged”

Radiculopathy II “was considered when 2 neurologic signs (sensory deficit + reflex impairment or muscle weakness) were present and corresponded” to the site of the planned injection.

The straight-leg raise test “performed with the patient supine according to the published instructions. The straight leg was slowly raised and the test was classified as positive or negative, using sensitizing maneuvers, beginning with the ankle and continuing with the neck.”

The slump test “was performed with the patient sitting and was assessed through a combination of sitting thoracolumbar flexion, cervical flexion, ankle dorsiflexion, and knee extension. With the use of sensitizing maneuvers, beginning with the ankle and continuing with the neck, the test was considered positive if one of the maneuvers reproduced the symptoms and the symptoms were different from the contralateral side.”

The femoral stretch test was “performed with the patient side-lying on the nonaffected side, assesses the presence/absence of neural mechanosensitivity (L2-4) using a combination of thoracolumbar flexion, cervical flexion, knee flexion, and hip extension. The test was classified as positive or negative, using sensitizing maneuvers, beginning with the knee and continuing with the neck. The test was considered positive if one of the maneuvers reproduced the symptoms and the symptoms were different from the contralateral side”.

Reference standard:

MRI for

Disk protrusion or extrusion
Subarticular nerve compression by a disc was assessed on axial T2-weighted images (PMID 21539702). High-grade compression required “periradicular cerebrospinal fluid or fat is obliterated”
Foraminal nerve compression assess on sagittal T1-weighted images (PMID 20308517). High-grade compression required “distortion or other morphologic change in the nerve root.”

Findings:

All patients had nerve compression:

Disc: low-grade (n=85) and high-grade (n=14)
Foraminal : low-grade (n=74) and high-grade (n=25)

High-grade subarticular nerve root compression

L2-S1 (N=99)	Sens	Spec	PPV	NPV
Pos slump test	1.00	.38	.21	1.00
Pos SLR test	0.93	.57	.26	0.98
Radiculopathy I	0.93	.34	.19	0.97
Radiculopathy II	0.71	.73	.30	0.94
L2–4 (n=18)
Pos femoral stretch test	1.00	.65	.14	1.00

High-grade foraminal nerve root compression

L2-S1 (N=99)	Sens	Spec	AUC	PPV	NPV
Pos slump test	.48	.26	.37	.18	.59
Pos SLR test	.32	.43	.38	.16	.65
Radiculopathy I	.80	.34	.57	.29	.83
Radiculopathy II	.28	.65	.47	.21	.73
L2-4 (n=18)
Pos femoral stretch test	.17	.50	.33	.14	.55

An addition table not shown is the analysis of disk extrusion.

Citation

1. Ekedahl H, Jönsson B, Annertz M, Frobell RB. Accuracy of Clinical Tests in
Detecting Disk Herniation and Nerve Root Compression in Subjects With Lumbar
Radicular Symptoms. Arch Phys Med Rehabil. 2018 Apr;99(4):726-735. doi:
10.1016/j.apmr.2017.11.006. PMID: 29253501.

Distinguishing true strokes from stroke mimics

badgett — Wed, 21 Sep 2016 14:54:18 +0000

Summary: This article provides the basis for a quick assessment of the likelihood of a stoke mimic, and therefore infers the likelihood of stroke. The score is not perfect. The presence of isolated sensory deficit at predicting a stroke mimic is interesting. The article does not state whether this finding is due to the presence of Bell’s palsies.

Patients: 784 patients (41% stroke mimics) in the emergency department who received MRI

Examiners: each patient was examined by both a neurology house staff and a vascular neurologist

Examination method:

FABS (6 variables with 1 point for each variable present):

absence of Facial droop,
negative history of Atrial fibrillation,
Age <50 years, systolic
Blood pressure <150 mm Hg at presentation,
history of Seizures, and
isolated Sensory symptoms without weakness at presentation.

Reference standard: assessment by stroke team after MRI

Findings:

	Accuracy for identifying stroke mimics		Predictive value for stroke mimics (assuming 41% prevalence of stroke mimics)
Finding	Sensitivity	Specificity	Positive predictive value	Negative predictive value
Absence of a-fib	96	17	45	86
Presence of isolated sensory deficit	15	97	77	62
FABS≥3	90	91	87	93

Citation

Goyal N, Tsivgoulis G, Male S, Metter EJ, Iftikhar S, Kerro A, Chang JJ, Frey JL, Triantafyllou S, Papadimitropoulos G, Abedi V, Alexandrov AW, Alexandrov AV, & Zand R (2016). FABS: An Intuitive Tool for Screening of Stroke Mimics in the Emergency Department. Stroke; a journal of cerebral circulation, 47 (9), 2216-20 PMID: 27491733

Should listen for bowel sounds?

badgett — Thu, 14 May 2015 11:10:10 +0000

A study of clinicians ranging from medical students to attending physicians found that many report never listening to bowel sounds. Then when the authors played recorded bowel sounds from actual patients, the clinicians could not distinguish normal controls, mechanical small bowel obstructions, or postoperative ileus.

Reference

Felder S, Margel D, Murrell Z, & Fleshner P (2014). Usefulness of bowel sound auscultation: a prospective evaluation. Journal of surgical education, 71 (5), 768-73 PMID: 24776861

Distinguishing neuropathic pain from nocioceptive pain

badgett — Thu, 23 Jan 2014 16:30:53 +0000

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

badgett — Mon, 06 May 2013 13:47:52 +0000

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

badgett — Thu, 21 Mar 2013 13:40:01 +0000

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.

MCP scissor – examine MCP joint lines for swelling or tenderness while MCPs flex 90 degrees
MCP squeeze – to assess tenderness on sides of MCPs
PIP 4-finger – examine for swelling or tenderness while squeezing joint from sides
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

badgett — Sun, 23 Sep 2012 15:42:12 +0000

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

badgett — Thu, 29 Mar 2012 14:48:38 +0000

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%
	Sensitivity	Specificity	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?

badgett — Thu, 15 Sep 2011 11:58:01 +0000

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