一只家猫的不明病因的所有爪的脓疱性甲病

王帆

Generalised pustular onychopathy of unknown aetiology in a domestic cat

一只家猫的不明病因的所有爪的脓疱性甲病

Luca Luciani | Sara Legnani | Chiara Brachelente

翻译：王帆

 

Abstract

Claw diseases are rare in cats and often associated with cutaneous lesions in other regions of the body. This case report describes an atypical manifestation of a generalised onychopathy of unknown origin in a domestic short hair cat.

摘要 

猫的爪部疾病很罕见，并且常与机体其他区域的皮肤病变有关。本病例报告描述了一只家养短毛猫中不明原因的所有爪甲病的非典型表现。

KEYWORDS

cat, claws, onychodystrophy, onychopathy, pustular

关键词

猫、爪、甲营养不良、甲病、脓疱

 

INTRODUCTION

介绍

Claw diseases in cats are rare and commonly associated with paronychia and lesions in other regions of the skin. In cats, paronychia is typically associated with bacterial infection or pemphigus foliaceus. Other claw disorders have rarely been reported, and in one of the few reviews which describe idiopathic onychodystrophy in cats, this term was applied to single claw growth abnormalities where the claws were thickened or curved. The aetiology was suspected to be prior traumatic injury. To the best of the authors' knowledge, conditions causing diffuse deformity of multiple claws have not been reported in cats.

猫爪部疾病很罕见，通常与甲沟炎和皮肤其他部位的病变有关。在猫中，甲沟炎通常与细菌感染或落叶型天疱疮有关。其他爪部疾病很少有报道，在少数猫特发性甲营养不良的综述中，这个术语被用于单个爪生长异常，表现为爪变厚或弯曲。病因怀疑为曾经的创伤损伤。据作者所知，引起多个爪弥散性畸形的病因在猫中尚未报道。

 

CASE REPORT

病例报告

A nine-year-old male, neutered, domestic short hair cat was presented for a generalised, progressive onychopathy of five months duration. The condition had not responded to 0.05% sodium hypochlorite foot baths performed daily for two weeks and two subcutaneous injections of cefovecin (Convenia; Zoetis, Belgium) at a dose of 8 mg/kg. The cat was kept indoors, fed a complete commercial diet and was otherwise in good general health. It was not receiving any treatment for external parasites and had not been vaccinated in the last eight years. On dermatological examination, the claws of all four feet showed varying degrees of onychodystrophy, onychorrexis, onycholysis and onychoclasis without apparent involvement of the nail bed (Figure 1).No pain or discomfort upon manipulation was noted. No other skin lesions were observed, and the cat was reported to be nonpruritic.

一只9岁的雄性已去势家养短毛猫，因持续五个月的所有爪渐进性甲病就诊。使用0.05%次氯酸钠，每日一次进行足浴，持续两周，皮下注射两次头孢维星（康卫宁），剂量为8毫克/公斤，治疗无效。患猫室内生活，饲喂商品化日粮，除皮肤异常外整体体况良好。没有针对外寄生虫进行过治疗，在过去8年里也没有接种疫苗。在皮肤学检查中，所有四肢的爪部均表现出不同程度的甲营养不良（onychodystrophy）、甲弯曲（onychorrexis）、甲脱落（onycholysis）和脆甲（onychoclasis），但没有明显甲床患病(图1)。触诊时未发现疼痛或不适。未观察到其他皮肤病变，据报道猫无瘙痒症状。

 

Cytological evaluation of the periungual skin did not reveal any micro-organisms. Wood's lamp examination and a fungal culture were negative for dermatophytes.

对甲周皮肤的细胞学检查未发现任何微生物。伍氏灯检查和真菌培养检查皮肤癣菌病均为阴性。

 

Complete blood count, biochemical results and thyroid profile were within normal limits, and the cat was negative for feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) (SNAP FIV/FeLV Combo Test; IDEXX Laboratories, Inc.). Thoracic radiography and abdominal ultrasonography were unremarkable.

全血细胞计数、生化结果和甲状腺评估结果均在正常范围内，猫白血病病毒(FeLV)和猫免疫缺陷病毒(FIV)均呈阴性。胸部x线片和腹部超声检查均无明显差异。

 

The third phalanx of the fourth digit of the left pelvic limb was surgically removed, and the sample was routinely processed for histological examination. Microscopically, multifocal pustular lesions affecting the nail matrix were observed (Figure 2). Pustules were of variable size and depth, from the more superficial layers (subcorneal) to full epidermal thickness, and contained neutrophils and rare acantholytic cells. The epidermis was spongiotic, with mild lymphocytic exocytosis. In the nail plate, multifocal and occasionally stratified pustules were observed, containing cellular debris and numerous round, hypereosinophilic cells interpreted as degenerated acantholytic cells. Hyperkeratosis of the nail fold and perivascular lymphoplasmacytic and neutrophilic inflammation also were observed in the superficial dermis, below the matrix and the nailbed. Periodic acid Schiff (PAS) and Gram stains were negative. Although the histopathological findings were not consistent with Leishmania infection, a PCR and immunohistochemical staining performed on the paraffin-embedded tissue were negative for L. infantum. A diagnosis of idiopathic neutrophilic pustular dermatitis of the nail matrix with acantholytic cells was made.

手术切除左后肢体第四趾的第三趾骨，并常规处理样本进行组织学检查。显微镜下，观察到甲基质患多灶性脓疱病变(图2)。脓疱大小和深度不等，厚度从表皮更浅层(角质层下)到表皮全层不等，含有中性粒细胞和罕见棘层松懈细胞。表皮呈海绵状水肿，伴轻度淋巴细胞外排。甲板（nail plate）内可见多灶且偶见分层的脓疱，包含细胞碎片和大量圆形高嗜酸性染色细胞，即为退行性棘层松懈细胞。甲襞（nail fold）角化过度、血管周围淋巴细胞浆细胞和中性粒细胞炎性反应，也见于真皮浅层、基质和甲床下方。周期性酸性希夫染色和革兰氏染色均为阴性。虽然组织病理学结果与利什曼原虫感染不一致，但对石蜡包包组织进行PCR和免疫组化染色均为阴性。诊断为伴有棘层松懈细胞的，特发性中性粒细胞性脓疱性甲基质皮肤病。

 

Based on the clinical presentation and the results of laboratory tests, an infectious cause was considered to be unlikely and the suspicion of an autoimmune or immune-mediated sterile pustular dermatitis was raised. Oral prednisolone (Prednicortone; Dechra Veterinary products Srl) at a dose of 2.5 mg/kg once daily was prescribed. At a three month recheck, lack of improvement was evident and treatment was tapered and then discontinued. The owner did not consent to further diagnostic investigations or therapeutic attempts, and 14months after the initial diagnosis, claw lesions remained unchanged.

根据临床表现和实验室检查结果，排除感染性病因，怀疑是自体免疫性或免疫介导性无菌性脓疱性皮肤病。口服泼尼松龙，剂量为2.5毫克/公斤，每天一次。在三个月后复查，没有明显的改善，治疗逐渐减少，然后停药。主人不同意进一步的诊断性检查或治疗尝试，距离初诊后14个月，爪部病变没有变化。

 

DISCUSSION

讨论

The histological lesions affecting the nail matrix in this case closely resemble those affecting the skin in cases of feline pemphigus foliaceus (fPF). However, fPF usually is characterised by more prominent acantholysis and, clinically, by pustules and crusting on other areas such as head, ears, feet and periareolar skin, which were not present in our case. Furthermore, the typical fPF changes are characterised by paronychia with no reported involvement of the nail itself. In the case reported here, lesions were restricted to the nail matrix and the acantholytic keratinocytes were scarce. Moreover, fPF tends to respond well to immunosuppressive therapy, with 90% of cases achieving disease control in less than a month and 97% in eight weeks, with prednisolone monotherapy being one of the most common therapeutic choices.

在本病例中，甲基质患病的组织学病变与猫落叶型天疱疮(fPF)皮肤的病变非常相似。然而，fPF通常以更明显额棘层松懈为特征，临床上，在其他部位如头部、耳部、足部和乳头周围皮肤上有脓疱和结痂，这些在本病例中没有发现。此外，典型的fPF改变特征是甲沟炎，没有报道涉及指甲患病。在本文报道的病例中，病变局限于甲基质，少见角质形成细胞的棘层松懈。此外，fPF往往对免疫抑制治疗反应良好，90%的病例一个月内疾病能得以控制，97%的病例在8周内得到控制，泼尼松龙单药治疗是最常见的治疗选择之一。

 

The clinical features of this case closely resemble those of canine symmetrical lupoid onychomadesis (SLO). However, the histopathological pattern of this canine disease is characterised by interface dermatitis with a lichenoid infiltrate and pigmentary incontinence that is clearly distinct from the pustular dermatitis reported here. Once again, response to immunosuppressive treatment in affected dogs usually is seen. A single case of canine pemphigus foliaceus with exclusive nail involvement has been reported. The affected dog, however, presented with paronychia, periungual yellowish exudation, and pain, with good response to corticosteroid treatment–features of pemphigus foliaceus that were absent in the present case.

本病例的临床特征与犬对称型狼疮样甲脱落(SLO)相似。然而，这种犬类疾病的组织病理学特征是界面性皮炎伴苔藓样浸润和色素失禁，这与本文报道的脓疱性皮炎明显不同。同样，患犬通常会对免疫抑制治疗有效。一例犬落叶型天疱疮单病例报道了仅甲部患病。然而，患犬表现为甲沟炎、甲周黄色渗出物和疼痛，对皮质类固醇治疗效果良好，这些属于落叶型天疱疮的特征，而本病例无此特征。

 

In human medicine, acrodermatitis continua of Hallopeau (ACH) can resemble this clinical appearance even though it is often associated with cutaneous lesions at other body sites. Lesions usually begin with the tip of one digit becoming erythematous and developing painful pustules that migrate under the nail bed and matrix, leading to onychodystrophy and, in severe cases, onychomadesis. In the acute phase, the pustules rupture and coalesce to form lakes of pus that dislodge the nail. Histologically, intraepidermal spongiform pustules filled with neutrophils are described.

在人医中，轻型持续性肢端皮炎(ACH)也有这种相似临床表现，但该病常有机体其他部位的皮肤病变。病变通常开始于指尖出现发红，随后发展为甲床和甲基质下形成疼痛的脓疱，导致甲营养不良，严重患者可发生甲脱落。在急性期，脓疱破裂，脓汁聚集，使指甲脱落。组织学上，表皮层内海绵状的脓疱内充满中性粒细胞。

 

A bacterial culture was not performed in our feline case, yet a bacterial aetiology was unlikely given the negative bacterial cytological results, a negative Gram stain of biopsy tissue, the absence of paronychia and pain, failure to respond to a four-week course on a systemic antibacterial drug and the generalised distribution of the lesions. The use of prednisolone as the sole therapy for an autoimmune or immune-mediated process could be deemed insufficient, yet in cats it represents the most widely used drug providing the best results, at least in the acute phase, for these types of disorders. Although complete healing of the feline claw may take up to six months, with a growth rate of about 1.9mm per week, the three month course of therapy in our case should have allowed at least a partial improvement of the clinical picture.

本文患猫没有进行细菌培养，但考虑到细胞学检查细菌结果阴性、活检组织革兰氏染色阴性、无甲沟炎和疼痛、对四周全身性抗生素治疗无效以及病变分布广泛，排除了细菌性病因。使用泼尼松龙作为自体免疫性或免疫介导性疾病的单一治疗可能不适合，但在猫中，泼尼松龙是对于这类疾病，至少是急性期，使用最广泛，效果最好的药物。虽然猫爪的完全愈合可能需要6个月以上的时间，每周的生长速度约为1.9毫米，但在本病例中，3个月的治疗疗程应该至少可以使临床表现达到部分改善。

 

An underlying neoplastic or endocrine trigger also was considered to be unlikely given the results of diagnostic imaging and blood tests, and a follow-up period of over 18months without a change in gross lesions. Likewise, an adverse drug reaction was deemed improbable as no history of drug or vaccine administration was reported. Finally, trauma has been speculated to cause asymmetrical onychodystrophy, yet the generalised presentation with involvement of all claws and the lack of any history of trauma, especially in an indoor cat, make this differential highly unlikely in our case.

根据诊断性影像学和血液检查的结果，以及超过18个月的随访没有全身性病变的结果，不太可能是潜在的肿瘤或内分泌疾病。同样，由于没有药物用药史或疫苗注射史，认为不太可能是药物副反应。最后，推测外伤会导致非对称性甲营养不良，但所有爪部都患病的广泛性表现以及没有外伤史，特别是患猫室内生活，排除该鉴别诊断。

 

To the best of the authors' knowledge, this is the first report of a chronic idiopathic generalised onychopathy of suspected autoimmune or immune-mediated origin unresponsive to first-line immunosuppressive treatment in a cat.

据作者所知，这是首例关于猫慢性特发性所有爪甲病的报告，怀疑是自体免疫性或免疫介导性疾病，对一线免疫抑制剂治疗无效。

 

 

 

 

 

 

 

 

 

 

FIGURE 1 Hind left foot: Abnormal claws with onychorrhexis and onychodystrophy

图1左后肢:爪部畸形，伴有脆甲症和甲营养不良。

 

 

FIGURE 2 Histological features of the biopsy of the affected cat. (a) In the epidermis of the nailbed, multifocal pustules are noted (asterisks), together with severe hyperkeratosis and multilayered crusts (arrows). Haematoxylin & eosin, ×1.25. (b) Pustules are of variable size and depth, from subcorneal to intraepidermal. H&E, ×10. (c) Severe hyperkeratosis and multilayered crusts are present on the surface with alternating layers of hyperkeratosis (asterisks) and degenerated neutrophils and cellular debris (arrows). H&E, ×10. (d) Pustules contained neutrophils and rare acantholytic cells (arrows). H&E, ×40.

图2患猫的活检组织学特征。(a)甲床表皮层可见多灶性脓疱(星号)，并伴有严重角化过度和多层结痂(箭)。HE染色，×1.25。(b)脓疱大小和深度不等，从角质层下到表皮层内。HE染色,×10。(c)表面出现严重角化过度和多层结痂，伴多层角化过度(星号)和退行性中性粒细胞和细胞碎片(箭)交替出现。HE染色,×10。(d)脓疱内含有中性粒细胞和罕见的棘层松懈细胞(箭)。HE染色,×40。

 

 

南海

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Urumqi冬

还需要更多地病例来研究