Case 1: Nephrolithiasis
By Steven Fox, MD, ACP Member
A 57-year-old woman with a history of kidney stones and chronic kidney disease presented to a community clinic in the U.S. with flank pain. Three days prior to presentation, she had developed left flank pain radiating to the left groin and associated with intermittent dysuria. She did not report reduced urine output, fevers, or chills.
On initial assessment she was afebrile. Physical examination revealed costovertebral angle (CVA) tenderness. Urine dipstick revealed 2+ blood. Point-of-care ultrasound (POCUS) examination of the kidney revealed dilation of the calyces and renal pelvis, consistent with moderate hydronephrosis of the left kidney. A subsequent CT scan revealed bilateral renal calculi, including a 6-mm obstructing proximal left ureteral calculus and moderate left hydroureteronephrosis. She later underwent ureteroscopy with extraction of a calcium oxalate stone.
With POCUS assistance, this patient was diagnosed with an obstructing renal stone. Urolithiasis (defined as stones in the kidney, ureter, or bladder) is common, with a prevalence of approximately 9%. Small stones (less than 4 to 10 mm) often pass spontaneously, but large (greater than 10 mm) or obstructing stones require definitive management. Compared to CT scanning, ultrasound has a low sensitivity for detecting stones (44% sensitivity for detecting any stone in a patient), but it has good sensitivity (90%) for hydronephrosis compared to CT urography. Studies suggest a sensitivity and specificity of greater than 90% for diagnosis of hydronephrosis by POCUS compared to radiology-performed ultrasound. Additionally, POCUS identification of hydronephrosis has been shown to have a good negative predictive value for stones greater than 5 mm (89%). Stone-related serious adverse events have been shown to be rare (0.4%) in ED patients with suspected nephrolithiasis and negative POCUS exams.
A POCUS that does not show hydronephrosis suggests intervention is not warranted, thus aiding the decision to start with medical management, particularly in the absence of high-risk features such as fever or solitary kidney. Additionally, POCUS is specific for identifying hydronephrosis, which yields an indication for formal retroperitoneal ultrasonography, non-contrast CT scan (to identify stones), and/or urology referral.
- POCUS can effectively identify hydronephrosis, with a sensitivity of 94% and a specificity of 93%.
- Identification of hydronephrosis on POCUS in a patient with suspected urolithiasis is an indication for further imaging and urology referral; absence of hydronephrosis reduces the likelihood of stones requiring intervention.
Case 2: Extrapulmonary tuberculosis
By Michelle Fleshner, MD, ACP Resident/Fellow Member
A 35-year-old man with no known medical history presented to the hospital with convulsions, fever, and confusion, all preceded by one to two weeks of headache. On presentation, he was febrile, tachycardic, and oriented only to person. He had no nuchal rigidity, meningismus, or focal neurologic deficits. His cardiopulmonary, abdominal, and integumentary exams were unremarkable.
Laboratory testing for HIV was positive, and CD4 count was 173 cells/mm3 (reference range, 4 to 500 cells/mm3). His serum cryptococcal antigen (CrAg) test was negative, as was testing for malaria. Urine lateral flow lipoarabinomannan assay (LAM), a test for extrapulmonary tuberculosis (EPTB) in HIV patients, was negative. Empiric antibiotics were started for presumed meningitis. Serum Venereal Disease Research Laboratory (VDRL) testing was positive, and penicillin was added for empiric neurosyphilis coverage. Lumbar puncture revealed negative cerebrospinal fluid CrAg, a total protein level of 212 mg/dL (reference range, 15 to 60 mg/dL), a low glucose level, and a white blood cell count of 432 cells/mm3 (reference range, 0 to 5 cells/mm3) with 60% neutrophils and 40% lymphocytes. Chest X-ray was normal.
A bedside focused assessment with sonography for HIV-associated TB (FASH) exam was performed, which revealed splenic microabscesses and a small pericardial effusion, increasing the likelihood of EPTB. Treatment for tuberculous meningitis with antitubercular agents and corticosteroids was initiated, and his confusion and fevers slowly improved.
This patient's diagnosis is EPTB, manifesting as tuberculous meningitis. The incidence and severity of EPTB are increased in patients with HIV, who are 20 to 30 times more likely to develop active TB. TB meningitis is an uncommon manifestation of EPTB, the presentation of which may range from an acute meningitis to insidious confusion. TB meningitis is difficult to diagnose due to the limited availability and low sensitivity of diagnostic tests, including urine LAM, cerebrospinal fluid acid-fast staining, and nucleic acid amplification testing.
POCUS has emerged as a useful tool in resource-limited settings for establishing the diagnosis of EPTB. The FASH protocol identifies the following features of EPTB in HIV: pericardial effusion, pleural effusion, ascites, periportal or para-aortic lymph nodes, focal liver lesions, and/or focal splenic lesions. This rapid bedside assessment can be reliably taught and performed by clinicians seeing high-risk patients, especially in resource-poor settings. Findings of abdominal lymph nodes, ascites, hepatomegaly, and pericardial effusion are significantly associated with a diagnosis of EPTB in HIV patients. Moreover, up to 25% of patients with FASH findings suggestive of EPTB have no signs of TB on chest X-ray. The FASH exam should be considered to aid in diagnosis of EPTB in low-resource venues of care.
- The incidence and severity of EPTB are increased in patients with HIV, who are 20 to 30 times more likely to develop active TB.
- POCUS can be a useful tool for the diagnosis of EPTB when used with the FASH protocol, which assesses for pericardial effusion, pleural effusion, ascites, periportal or para-aortic lymph nodes, focal liver lesions, and/or focal splenic lesions.
Case 3: Complex pleural effusion
By Ayako Wendy Fujita, MD, ACP Resident/Fellow Member
A 30-year-old man recently diagnosed with heart failure and mitral regurgitation, presumably due to rheumatic heart disease, presented with one week of fever and dyspnea. His temperature was 38.1 °C. He had a heart rate of 130 beats/min, blood pressure of 90/60 mm Hg, respiratory rate of 20 breaths/min, and room air oxygen saturation of 95%. He had an elevated jugular venous pulsation, dullness to percussion over the right lung base, III/VI holosystolic murmur heard at the apex, and 2+ pitting lower-extremity edema.
Empiric antibiotics for sepsis and infective endocarditis were started. At this tertiary hospital in Malawi, routine laboratory tests and blood cultures are often unavailable or inconsistently performed. Without blood culture data or the ability to monitor renal function, the risk of inadequately treating endocarditis was weighed against the risk of unnecessary treatment with potentially toxic antibiotics. POCUS examination of the heart showed no vegetations, a finding subsequently confirmed by formal echocardiography. While the pleural effusion initially detected on physical examination was presumed secondary to volume overload, POCUS examination of the lung revealed a large right-sided pleural effusion with multiple septations, indicative of a complex effusion. A thoracentesis was safely performed using POCUS, yielding cloudy, serosanguineous fluid. Pleural fluid analysis was unavailable. Although endocarditis could not be ruled out, POCUS revealed an alternate source of infection in need of source control.
In this case, a complex pleural effusion requiring drainage was revealed by POCUS. Hospitalists encounter pleural effusions on a regular basis; approximately 44% to 57% of hospitalized patients with bacterial pneumonia are reported to have pleural effusions. Physical exam and posteroanterior chest X-ray have limited sensitivities for detecting effusions of less than 300 mL and 200 mL, respectively. In contrast, POCUS performed by an experienced practitioner can reliably detect an effusion with at least 20 mL of fluid, and sensitivity increases to 100% when there is at least 100 mL. Furthermore, POCUS can also characterize a pleural effusion as simple or complex based on its sonographic appearance. Simple effusions are anechoic and usually transudative, while complex effusions are homogeneously or heterogeneously echogenic and may demonstrate septations, a finding suggestive of exudative effusions.
POCUS of the lung also improves the safety of thoracenteses: In one study, using POCUS for thoracentesis reduced the rate of pneumothorax from 18% to 3% and increased the success rate for small effusions from 66% to 90%. POCUS is a useful tool for evaluating pleural effusions in hospital medicine and is particularly valuable in resource-poor settings when advanced imaging is often unavailable.
- POCUS lung examination reliably detects pleural effusions better than physical exam or chest X-ray and can demonstrate septations or loculations, which differentiate complex from simple effusions and may change management.
- Using POCUS to perform thoracentesis increases success rates and decreases rates of complications, including pneumothorax.
Case 4: Heart failure
By Thomas Robertson, MD
A 54-year-old man with no known medical history presented to an urban outpatient primary care clinic in Mozambique with three months of worsening dyspnea on exertion and lower-extremity edema. He reported no chest pain. On evaluation, he was afebrile, blood pressure was 184/106 mm Hg, heart rate was 102 beats/min, and room air oxygen saturation was 98%. On examination, jugular distention to 10 cm and bibasilar rales were noted, as were normal heart tones and absence of an S3 gallop.
A bedside cardiac POCUS of the heart was performed, revealing significant global hypokinesis of the left ventricle (LV), LV hypertrophy, grossly preserved right ventricle function, a mild pleural effusion, dilated hepatic veins, and no pericardial effusion (Figure 1). Diuretics and an angiotensin-converting enzyme inhibitor were initiated, and he was sent for electrocardiogram. He returned to follow-up care with significant improvement in symptoms and blood pressure, and an electrocardiogram revealed LV hypertrophy. A formal transthoracic echocardiogram could not be obtained.
This patient's diagnosis, as aided by cardiac POCUS testing, is acute heart failure with reduced ejection fraction and LV hypertrophy. Heart failure is a major public health problem worldwide, with an increasing incidence in sub-Saharan Africa. Dyspnea is a cardinal symptom of decompensated heart failure, and cardiac POCUS has been shown to decrease time to diagnosis in patients presenting with dyspnea.
When performed by an experienced clinician, cardiac POCUS has a published specificity and sensitivity approaching 100% for the diagnosis of acute decompensated heart failure in patients presenting with dyspnea. In addition to assessing LV systolic function, it can be used to accurately assess central venous pressure, LV dilatation, LV wall thickness, and left atrial dimensions. The detection of these findings has both therapeutic and prognostic implications for patients. Additionally, sonographic findings such as regional wall-motion abnormalities, LV wall thickness, and presence or absence of pericardial or pleural effusions can assist in the evaluation of the etiology and subsequent management of heart failure.
- Cardiac POCUS adds important diagnostic, therapeutic, and prognostic information in patients presenting with heart failure.
- In the hands of an experienced clinician, cardiac POCUS has a published specificity and sensitivity approaching 100% for the diagnosis of acute decompensated heart failure in patients presenting with dyspnea.
Case 5: Deep venous thrombosis
By Steven Fox, MD, ACP Member
A 55-year-old woman with no medical history presented to an ED in Guyana with dyspnea. On initial assessment, she was tachycardic to 120 beats/min, but afebrile and with normal blood pressure and room air oxygen saturation. On examination, she had right-sided neck swelling with erythema and tenderness, as well as right arm swelling. POCUS revealed a thrombosis in the right internal jugular vein (Figure 2) and right axillary vein.
Unfractionated heparin was initiated, and she experienced improvement in neck and right arm swelling. Formal ultrasonography performed three days later confirmed thromboses. Her subsequent clinical course was marked by deterioration, with new heart failure and cardiogenic shock, and she died seven days later.
In this case, POCUS confirmed the diagnosis of upper-extremity deep venous thrombosis (DVT) and facilitated early treatment with anticoagulation. Because POCUS showed no evidence of any underlying abscess, unnecessary treatments such as antibiotics or incision and drainage were avoided. Upper-extremity DVT refers to thrombosis of the internal jugular, brachiocephalic, brachial, subclavian, and/or axillary veins. For ultrasonography in the diagnosis of internal jugular thrombosis, published sensitivities range from 56% to 100% and specificities range from 94% to 100%. There are limited data on sensitivity and specificity of POCUS for internal jugular thrombosis, but case reports exist.
More investigation is warranted on the use of POCUS for the diagnosis of upper-extremity thrombosis. There is more substantial evidence for the use of POCUS for the diagnosis of lower-extremity DVT (via two-point compression ultrasonography), with sensitivity and specificity estimated to be higher than 95%. POCUS has a role in diagnosis of lower-extremity DVT when performed by experienced users and combined with appropriate assessment of pre-test probability.
- POCUS testing in experienced hands can aid in diagnosis of DVT and enable earlier initiation of anticoagulation when standard ultrasound is not immediately available, potentially reducing unnecessary treatment.
- POCUS has demonstrated good accuracy for lower-extremity DVT diagnosis, but evidence is limited for the use of ultrasonography in diagnosis of upper-extremity DVT.