Hand Infections You Don’t Want to Miss

Here are some questions that you should ask (or at least think about!) when evaluating patients with hand infections to help make sure that you don’t miss anything big.

Other than this pain, redness, swelling here (etc.), did you hurt your hand in any way?

This is perhaps better than asking “Did you punch anyone?” or “Did you get into a fight with a wall?” Either way, it’s important to think about trauma in general and of injuries from human teeth in particular.

Injuries from punching humans in the mouth (probably incorrectly called fight bites) are very infection-prone and have the potential for causing damage to joint capsules and tendons. Rarely, they can lead to the transmission of bloodborne viruses. Signs can be subtle and patients may be reluctant to volunteer information related to assaults. Ask specifically if in doubt!

Did you have any contact with animals?

Wild animals should, of course, make one think about rabies. (Incidentally, the one time in medicine when you need to assess the mental status of an animal is when it bites your patient!)

Cats should make you think about Pasteurella multocida and Bartonella henselae. Don’t confuse the two. Pasteurella multocida causes cellulitis, sometimes within hours of a cat bites. Treatment with antibiotic is required. Bartonella henselae causes a local papule several days after a cat scratch. This is followed by regional lymphadenitis (“cat scratch disease” or bartonellosis). Treatment is generally supportive.

Dogs bites in the setting of asplenia or other immunocompromised states should make one think of Capnocytophaga canimorsus.

Did you have any contact with plants or soil?

This question probably has better sensitivity than asking about “gardening,” which (I think) makes some people think about gardens specifically, and not household potted plants. In a child, you can ask about visits to floral nurseries or tree farms.

Either way, the important confusables here are regional lymphangitic sporotrichosis and nocardiosis. Both cause nodular lymphangitis, which consists of erythematous and necrotic nodules and ulcers that run parallel to the lymphatic channels. The two conditions can only be reliably distinguished with Gram stain and culture. (For test-taking purposes, you might be expected to know that Nocardia are gram-positive and weakly acid-fast filamentous and beaded organisms). However,  a history of immunosuppression probably favors nocardiosis.

Both conditions require antimicrobial therapy. Sporotrichosis is treated with antifungals, while nocardiosis is treated with trimethoprim and sulfamethoxazole. “Sporotrichosis” that’s not getting better with antifungal medication should make one think of nocardiosis.

As a bonus, asking about plants and soil can also help you assess the “dirtiness” of the infection from a tetanus standpoint.

Did you have any contact with the inside of a fish tank or have you been to the sea?

Mycobacterium marinum also causes nodular lymphangitis. You need to think about this bug because Mycobacterium marinum won’t respond to “regular” antibiotics and requires therapy with antimycobacterials. Think about this most especially in patient with indolent infections with draining sinuses.

Were there painful clusters of blisters?

Herpetic whitlow can be mistaken for cellulitis, paronychia or felon. You need to think about this specifically because, unlike its mimics, herpetic whitlow will not respond to antibacterials and attempt at incision and drainage will cause more harm than good..

If herpetic whitlow is suspected, make sure to ask about outbreaks in other parts of the patient’s body, including lips and genitals. Again, some patients may not volunteer this information, absent a specific question.

Did you have any contact with seawater or shellfish (particularly oysters)?

Think about an infection with Vibrio vulnificus, especially in a patient from the Atlantic seacoast with liver cirrhosis who is sporting a nice tan (hemochromatosis). It’s rare, but failure to think about this might result in loss of the hand, often along with the body attached to it. These patients often present with rapidly progressing cellulitis, hemorrhagic bullae, ulcers and septic shock.

Is your hand numb?

Compartment syndrome and infectious flexor tenosynovitis can present with hand numbness. Both require surgical attention.

Were you bitten, scratched or stung by anything?

This question could point to something relatively simple, like an allergic reaction, or to a myriad of nasty infections and envenomations.

What kind of work do you do, and what  hobbies do you have?

Again, a catchall compound question that will help you pick up an almost endless list of diagnostic possibilities, including many of the diseases mentioned above.

References