The Spot and the Pet (Damn It Jim, I’m a Doctor Not a Veterinarian!!) Gary L. Weinstein M.D. FCCP Internal Medicine, Clinical Grand Rounds Wednesday, January

The Spot and the PetThe Spot and the Pet

(Damn It Jim, I’m a Doctor Not a (Damn It Jim, I’m a Doctor Not a Veterinarian!!)Veterinarian!!)

Gary L. Weinstein M.D. FCCPGary L. Weinstein M.D. FCCP

Internal Medicine, Clinical Grand RoundsInternal Medicine, Clinical Grand Rounds

Wednesday, January 18Wednesday, January 18thth, 2006, 2006


HPI :HPI : DB is a 62 yo WM referred for eval of abnl DB is a 62 yo WM referred for eval of abnl

CXRCXR Found on pre-op w/u for spinal stenosisFound on pre-op w/u for spinal stenosis No cough, chest pain, hemoptysis, wt lossNo cough, chest pain, hemoptysis, wt loss Mild intermittent wheezingMild intermittent wheezing

PMH :PMH : T & AT & A AppyAppy Sx for spinal stenosisSx for spinal stenosis


Allergies : noneAllergies : none Meds at home : noneMeds at home : none Social Hx :Social Hx :

DivorcedDivorced Lives aloneLives alone BankerBanker 1 – 2 packs/day Tob for 40 years1 – 2 packs/day Tob for 40 years 21 beers/week21 beers/week


Family Hx :Family Hx : Lung cancer in motherLung cancer in mother CAD in fatherCAD in father

ROS : negROS : neg Exam :Exam :

P 80 R 16 BP 140/78 Ht 5”6” Wt P 80 R 16 BP 140/78 Ht 5”6” Wt 78 kg 78 kg

WDWN WM in NAD, plethoricWDWN WM in NAD, plethoric Scattered rhonchiScattered rhonchi No LANNo LAN


CXR (4/05)CXR (4/05)

The Pet and the SpotThe Pet and the Spot

CXR (6/05)CXR (6/05)


CT chest (6/05)CT chest (6/05)


Pt taken to the OR 7/05 for RU Pt taken to the OR 7/05 for RU Lobectomy and wedge resection of Lobectomy and wedge resection of RML noduleRML nodule

RUL nodule RUL nodule necrosis on frozen necrosis on frozen sectionsection

RML nodule RML nodule neg for tumor on neg for tumor on frozen sectionfrozen section

RUL necrotic nodule

Dirofilaria immitis (dog Dirofilaria immitis (dog heart worm)heart worm)

DIROFILARIASISDIROFILARIASIS — Dirofilariasis is caused by a — Dirofilariasis is caused by a zoonotic filarial nematode. There are two separate zoonotic filarial nematode. There are two separate clinical syndromes that are associated with infection clinical syndromes that are associated with infection with different dirofilarial species. Dirofilariasis is with different dirofilarial species. Dirofilariasis is particularly common in the Mediterranean region but particularly common in the Mediterranean region but has been reported from many different countries, has been reported from many different countries, including the United States [including the United States [11].].

Most cases of dirofilariasis in humans are either Most cases of dirofilariasis in humans are either pulmonary or subcutaneous infections, but there have pulmonary or subcutaneous infections, but there have been a few reports of human dirofilariasis in unusual been a few reports of human dirofilariasis in unusual sites, such as large vessels, mesentery, peritoneal sites, such as large vessels, mesentery, peritoneal cavity, spermatic cord or the liver.cavity, spermatic cord or the liver.

1. Jelinek, T, Schulte-Hillen, J, Loscher, T. Human dirofilariasis. Int J 1. Jelinek, T, Schulte-Hillen, J, Loscher, T. Human dirofilariasis. Int J Dermatol 1996; 35:872. Dermatol 1996; 35:872.


Pulmonary dirofilariasisPulmonary dirofilariasis —is caused by —is caused by Dirofilaria immitis, also known as the dog heart Dirofilaria immitis, also known as the dog heart worm since it is a common cause of congestive worm since it is a common cause of congestive heart failure in dogs. Although canines are the heart failure in dogs. Although canines are the most important natural host, other mammals most important natural host, other mammals can also be infected.can also be infected.

Adult worms of D. immitis live in the heart of Adult worms of D. immitis live in the heart of the definitive host, and microfilariae are the definitive host, and microfilariae are produced which circulate in the peripheral produced which circulate in the peripheral blood. The adult worms have a thick cuticle blood. The adult worms have a thick cuticle and are 400 to 500 µm in diameter. When a and are 400 to 500 µm in diameter. When a mosquito bites an infected animal, it can mosquito bites an infected animal, it can acquire infection and can transmit the infection acquire infection and can transmit the infection to other animals or accidentally to humans.to other animals or accidentally to humans.



The filariae never mature into fully gravid worms in The filariae never mature into fully gravid worms in humans but lodge in pulmonary arteries; infection can lead humans but lodge in pulmonary arteries; infection can lead to granulomas or lung infarctions [to granulomas or lung infarctions [22]. These can result in ]. These can result in the appearance of nodules or cavities on chest radiographs.the appearance of nodules or cavities on chest radiographs.

Most human infections are asymptomatic, and the infection Most human infections are asymptomatic, and the infection is only discovered if chest imaging is performed for some is only discovered if chest imaging is performed for some other reason. However, some patients develop chest pain, other reason. However, some patients develop chest pain, cough, hemoptysis, fever and malaise [cough, hemoptysis, fever and malaise [33]. The radiologic ]. The radiologic appearance is often described as a "coin lesion" that is appearance is often described as a "coin lesion" that is usually 1 to 3 cm in diameter and may be confused with a usually 1 to 3 cm in diameter and may be confused with a lung tumor.lung tumor.

2. Hiroshima, K, Iyoda, A, Toyozaki, T, et al. Human pulmonary 2. Hiroshima, K, Iyoda, A, Toyozaki, T, et al. Human pulmonary dirofilariasis: report of six cases. Tohoku J Exp Med 1999; 189:307.dirofilariasis: report of six cases. Tohoku J Exp Med 1999; 189:307.

3. Ro, JY, Tsakalakis, PJ, White, VA, et al. Pulmonary dirofilariasis: the great 3. Ro, JY, Tsakalakis, PJ, White, VA, et al. Pulmonary dirofilariasis: the great imitator of primary or metastatic lung tumor. A clinicopathologic analysis imitator of primary or metastatic lung tumor. A clinicopathologic analysis of seven cases and a review of the literature. Hum Pathol 1989; 20:69.of seven cases and a review of the literature. Hum Pathol 1989; 20:69.

Figure 1: Chest x-ray showing a pulmonary "coin" lesion caused by Dirofilaria immitis infection in an adult man.

DirofilariaDirofilaria Subcutaneous dirofilariasisSubcutaneous dirofilariasis —is caused by a few different —is caused by a few different

dirofilarial species, including D. tenuis, D. repens, and others. dirofilarial species, including D. tenuis, D. repens, and others. These species are filariae of dogs and cats (D. repens), raccoons These species are filariae of dogs and cats (D. repens), raccoons (D. tenuis), or other mammals. These filariae are also transmitted (D. tenuis), or other mammals. These filariae are also transmitted via mosquitoes. Adult worms can develop in humans, but sexual via mosquitoes. Adult worms can develop in humans, but sexual maturity and production of microfilariae do not occur since maturity and production of microfilariae do not occur since humans are an incidental host.humans are an incidental host.

Lesions consist of a coiled, degenerating worm in subcutaneous Lesions consist of a coiled, degenerating worm in subcutaneous tissues, typically around the eye or on the genitalia or limbs [tissues, typically around the eye or on the genitalia or limbs [4,54,5]. ]. The nodule can be erythematous and tender and can be associated The nodule can be erythematous and tender and can be associated with an abscess. There may be concomitant allergic symptoms, with an abscess. There may be concomitant allergic symptoms, including urticaria and fever.including urticaria and fever.

4. Fuentes, I, Cascales, A, Ros, JM, et al. Human subcutaneous dirofilariasis 4. Fuentes, I, Cascales, A, Ros, JM, et al. Human subcutaneous dirofilariasis caused by Dirofilaria repens in Ibiza, Spain. Am J Trop Med Hyg 1994; caused by Dirofilaria repens in Ibiza, Spain. Am J Trop Med Hyg 1994; 51:401.51:401.

5. Arvanitis, PG, Vakalis, NC, Damanakis, AG, Theodossiadis, GP. Ophthalmic 5. Arvanitis, PG, Vakalis, NC, Damanakis, AG, Theodossiadis, GP. Ophthalmic dirofilariasis. Am J Ophthalmol 1997; 123:689.dirofilariasis. Am J Ophthalmol 1997; 123:689.

DirofilariaDirofilaria

inflammatory lesion at the inner canthus of the eye

An immature adult female Dirofilariaspecies that measured more than 12 cmin length, removed intact from human

subcutaneous tissues.


DB tolerated sx well and had no DB tolerated sx well and had no post-op compspost-op comps

He has recovered fully and received He has recovered fully and received no specific treatmentno specific treatment

He is a fisherman and a hunter and He is a fisherman and a hunter and to his knowledge, his dogs are well.to his knowledge, his dogs are well.


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THE ENDTHE END

FarleyFarley

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The Spot and the Pet (Damn It Jim, I’m a Doctor Not a Veterinarian!!) Gary L. Weinstein M.D. FCCP Internal Medicine, Clinical Grand Rounds Wednesday, January